The Use of Bamboo in Architecture Case Study Old Caldas Colombia

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THE USE OF BAMBOO IN ARCmTECTURE Case Stndy: Old Caldas, Colombia

A Thesis Sllbmitted to the Facllity ofGraduate Studies and Research in Partial Fulfillment orthe Reqllirements for the Degree of Master of Architecture.

CESAR O. GONZALEZ

School of Architecture McGiII University

Montreal November 15th , [999.

<0 C. O. Gonzalez, 1999.

1+1

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The Use ofBamboo in Architecture

Abstract. Bamboo has been one ofthe most important housing materials for familles of ail income-Ievels for generations in Many parts of the world. Through an analysis of methods of construction used for housing in the coffee region of Colombia, this thesis investigates the

MOst

important features of

the use of bamboo in the traditional and modem techniques used to build walls, noors and structures. In conducting this research 1 collected extensive graphie materia! such as pictures, sketches,

drawings and plans, from old and new town houses, rural houses, haciendas, and siums, in the three main regians of Colombia, where bamboo is the

MOst

important natural resource for

construction. The first part of the study gives a general overview of construction systems for walls, noors and structures in housing using bamboo throughout the world, especially in Asia and America. The second part is a study of one of the three regions in Colombia where environment, its preservation, and its sustainability are the main issues, and it cantains an analysis of the data coUected from the three regions. The main part of the thesis classifies and analyses new techniques and systems that are applied in the construction of walls, floors and structures in the region of Old Caldas, Colombia.

AbstractIRésumé

u

The Use ofBomboo in Architecture

Résumé Le bambou a été un des plus importants matériaux utilisés dans la construction de maisons pour des familles de tous les niveaux socia-économiques depuis des générations, dans beaucoup de parties du monde. Par l'analyse des méthodes de construction de maisons utilisées dans la région de la culture du

café en Colombie, cette thèse examine les caractéristiques les plus importantes des techniques d'utilisation du bambou pour construire des murs, des planchers et des structures. En effectuant cette recherche, j'ai rassemblé de nombreux documents visuels tels que photos, esquisses, dessins et plans d'anciennes et de nouvelles habitations urbaines, rurales, d'haciendas et de taudis, situés dans les trois principales régions de Colombie, où le bambou constitue la plus importante ressource naturelle pour la construction. La première partie de cette étude donne une vue d'ensemble des systèmes de construction en bambou des murs, des planchers et des structures de maisons à travers le monde, spécialement en Asie et en Amérique. La deuxième partie est une étude sur l'une des trois régions de Colombie où les principaux enjeux sont: l'environnement, sa préservation et sa capacité à se renouveler. La partie principale de la thèse classifie et analyse de nouvelles techniques et de nouveaux systèmes qui sont appliqués dans la construction des murs, des planchers et des structures dans la région du Old Caldas en Colombie.

AbstroctIRésumé

ID


Acknowledgments. Severa! years were spent on this research.. and many people helped by giving me the support and encouragement 1 needed. First 1 want to thank my professor and advisor V1kram Bhatt, for bis guidance, support and

understanding during the process of this study. 1 thank very much my family in

Colombi~

who

helped me get the information 1 needed in the early stages of the research. 1 want to thank my family here in Canada for their unconditional support and encouragement, especially to Michael Thomas for his patience and invaluable work on this paper, especially in dealing with corrections and editing; to Virginia Thomas for her criticism and precise cornments; ta Mrs. Belva Thomas for the wonderful energy she transmitted to me during the latest stages of my work.

1 would like ta give special posthumous thanks ta Prof Carlos Vergara (May He Rest in Peace)

for giving me good advice and he sharing the results of his research with me, especially about the Rice Husk wall

system~

ta Professors Alvaro Thomas for his enthusiastic encouragement and for

providing me with extensive material, even when we were sa far away; to Ms. Marcia King for her help in administrative matters and (or her wise advise and support when 1 really needed them.

1 also want to thank Prof. Oscar Hidalgo and Simon Velez, the most important architects in

Colombia working with bamboo construction. They have inspired me since the beginning of my career with their fascinating work and its development aver the years. Now the new generations of architeets and engineers have the great advantage of this knowledge in the development of bamboo architecture.

Finally, 1 want to thank my wife and best friend

Ruth~

for her unconditional love and support

during this time. T0 her 1 dedicate this work.

Acknowledgments

IV


Table of Contents. 1. Chapter 1 : Introduction. 1.1. Preface. 1.2. Rationale. 1.3. Research Questions. 1.4. Scope ofthe Study. 1.5. Thesis Outline. 1.6. Terminology.

2. Cbapter II : Organic Materials for Housing 2.1. Introduction. 2.2. Current Use of Organic Materials. 2.3. Scarcity.

2.4. Response and Adaptation to Scarcity. 2.5. The Bamboo in Colombia. 2.6. Physical Properties ofBamboo.

2.6.1. Tensile and Flexion Resistance. 2.6.1. Compression Resistance. 2.7. Cure ofBamboo. 2.7.1. Natural cure. 2.7.2. Immersion cure. 2.7.3. Heating cure.

2.8. Advantages ofthe Use of Bamboo in Construction. 2.9. Disadvantages of the Use ofBamboo in Construction.

Table ofContents

v


3. Chapter III : The Use of Bamboo in Asia and America, a General Overview. 3.1. Introduction. 3.2. The East Asian Region. 3.2.1. Japan. 3.2.1.1. Waiis. 3.2.1.2. Structure. 3.2.1.3. F1oors.

3.3 .1.1. WalIs. 3.3.1.1.1. Mat Walls. 3.3. L.l.2. Board Walls. 3.3.1.2. Strueture.

3.3.1.3. Floors. 3.3. The Middle Asian Region:

3.3.1. India. 3.3.1. I. Walls. 3.3.1.1.1. Mat Walls.

3.3.1.1.2. Board Walls. 3.3.1.2. Structure. 3.3. 1.3. Floors. 3.4. The Pacifie Island Region: Hawaii. 3.4.1. Walls.

3.4.2. Strueture.

3.5. Advantages. 3.6. Disadvantages. Table a/Contents

VI

The Use 0/Bamboo in Architecture

4. Chapter IV : The Use of Bamboo in Colombia. 4.1. Introduction. 4.2. Walls. 4.2.1. Bahareque

Walls.

4.2.2. Earth-Filled Walls.

4.2.3. The Quincha Wall. 4.2.3.1. System A. 4.2.3.2. System B. 4.2.4. Weaving tlattened bamboo walls. 4.3. Structure. 4.4. Floors. 4.5. Advantages.

3.5.1. Walls.

4.5.1.1. Bahareqlle Walls. 4.5.1.2. Earlh-Filled Walls. 4.5.1.3. The Quiflcha WalIs.

4.5.1.4. Weaving Flattened Bamboo Walls. 4.5.2. Structure.

4.5.3. FIoors. 4.6. Disadvantages. 4.6.1. WaIIs. 4.6.1.2. Bahareque WaIls. 4.6.1.3. Earth-FilledWaIls.

4.6.1.4. The Quincha Wans. Table afContents

vii


4.6.1.5. Weaving Flattened Bamboo Walls. 4.6.2. Structure. 4.6.3. Floors.

S. Chapter V : The New Techniques of Construction with Bamboo in Colombia. 5.1. Introduction.

5.2. Watts. S.2.1. Rice Husk Waiis. 5.2.1.1. Production. 5.2.1.2. The mixing. 5.2.1.3. Physical characteristics. 5.2.1.4. Process of production. 5.2.1.5. Process ofassembly. 5.2.1.6. Comparative analysis. 5.2.2. The Tendit/oso Walls. 5.3. Structure. S.3 .1. Prefabricated Three-dimensional Bamboo Structures.

5.3.2.1. Norms ofConstruetion. 5.3.2.2. Wooden triangular frames. 5.3.2.3. Assembly of the structure. 5.3.2.4. Application ofplaster as a roof. 5.3.2. Super-Structures with Concrete-Reinforced Bamboo. - Simon Velez 5.3.2.1. Km. 41 House, Manizales, Caldas - Colombia.

Table a/Contents

viii


5.3.2.1.1. The Main Pavilion. 5.3.2.1.2. The Children's Pavilion. 5.3.2.1.3. The Stan Nol. 5.3.2.1.2. The Stail No 2. 5.2.2.1.3. The Social Area 5.3.2.2. The ZERI Pavilio~ Manizales. 5.3.2.2.1. Foundations. 5.3.2.2.2. The A/izo posts. 5.3.2.2.3. Bamboo beams and concrete reinforcedjoints. 5.3.2.2.4. The Overhang. 5.4.1. Walls.

5.4.1.1. Rice Husk Walls. 5.4.1.2. The Tendinoso Walls. 5.4.2. Structure

5.4.2.1. Prefabricated Three-dimensional Bamboo Structures. 5.4.2.2. Super-Structures with Concrete-Reinforced Bamboo. 5.4. Advantages. 5.4.1. Walls. 5.4.1.1. Rice Husk Walls.

5.4.1.2. The Telldinoso Walls. 5.4.2. Structure.

5.4.2.1. Prefabricated Three-dimensionaI Bamboo Structures. 5.4.2.2. Super.. structures with Concrete.. reinforced Bamboo. 5.5. Disadvantages.

Table ofContents

IX


5.5.1. Walls. 5.6.1.1. Rice Husk Walls. 5.6.1.2. The Telldi1loso Walls. 5.5.2. Structure. 5.6.2.1. Prefabricated Three-dimensional Bamboo Structures. 5.6.2.2. Super-Structures with Concrete-Reinforced Bamboo.

6. Chapter VI : Conclusions. 7. Bibliography.

Table afContents

x


1. Chapter 1: Introduction. 1.1. Preface. Since the dawn of civilizatio~ bamboa has been widely utilized in various and ingenious ways. lapan, China, India, Philippines, Indonesia, and many other Asian countries, have used this marvelous grass in the construction of bridges, town and rural bouses, sewers, water canals, in the production of paper, musical instruments, and many other items. It is an aImast infinitely usefuI materia! with new applications being discovered every day in the fields ofMedicine, pharmaceuticaIs, and chemistry.

In Colombia there is a particular class of bamboo, with the scientific Dame Guadua Angustifolia, commanIy called glladua. This special type of grass is round in the

Mountains where coffee grows in fenile sail, along rivers and creeks where the temperature is between 12 and 25 degrees Celsius. During La Violencia (the civil war) in the 1940's in

Ca(ombi~

thousands of families trom

an extensive territory called Antiaquia fled, seeking refuge from the violence. They migrated to the least colonized and remate valleys of the Andes Mountains. The colonization of these fertile lands is called the Antioquian Colonization and the tf

Il

architecture derived trom this period has a special characteristic forming part of the historie legacy ofthe country. The colonizers took advantage of the rich land and staned ta utilize guadua as the main material in building their towns, rural houses, and haciendas. Sïnce then, the popularity of this type of bamboo has been growing, especially among the poor, who use it as a very economic and versatile construction material. After the arrivai of cement and concrete in the country, people began ta replace the guadua with what they thought were more "durable and resistant" materials for their homes, and bamboo lost its importance in construction; yet in siums and squatter settlements guacfua was still the material par Chapte,. 1

l


excellence for the poorest farnilies. As a result, the idea of building with bamboa became associated with low socio..economic status.

ln the beginnings of the 80's a young architect named Simon Velez, a man fascinated by y

local architecture, realized the beauty of bamboo and started ta experiment with new systems, uses and designs. A graduate from the Universidad Nacional (the National University), and a recognized structural designer, he gained popularity, especially among wealthy families for his creations of designs for country homes. ln bis study Bambao Building, D. Darrel shows how Velez introduces extremely

innovative structural features, 5uch as "Roof cantilevers of 28 feet! He arranges the bamboo in truss-lîke configurations, with every member in tension where possible, then for the few shear and compression bolted joints.. fills the bamboo with concrete. Not only does the roof cantilever that far, but it's covered with a mesh made of palm tree sUces holding I" of mortar and very heavy Spanish tiles. The drawings are incredibly sparse, freehand plan and section, then he stays on the job site where only ms same workers build these works of real beauty. (do 1 sound tao bubbly?) 1 was extremely impressed that these structures exis~ and even more when 1 found that they expressly forbid construction with bamboo in Colombia .. even though they don't enfarce the nlles on him.

l ft

While building these luxury projects, new ideas and techniques emerged for the incorporation and application of bamboo in lower-income and middle..incorne family houses. New professionals, architects and engineers, learning from Velez's experience, designed and built housing complexes for families of all socio..economic levels, using

guadua as the basic materiaL Realizing the inherent popuJarity ofbamboo, the government began to provide housing (oans to low..incerne famifies for construction with this material, something that had been prohibited in the past because of the Jack of laboratory testing information about the properties ofbamboo1

DarreI D.• 1996.

ChapterI

2


1.2. Rationale. In the cultures of the past human beings created shelter out of the local materials that

surraunded them, and the result of this creative pracess was an interactive relationship between people and their natura! environment. Vemacular architecture was integrated with the environment, and people were able to work with their own hands and few tools, for example, ta transform a tree into a post or a beam to build their houses.

Organic materials have been used for shelter since the earliest fonns of civilization emerged around the warld.

Today~

sorne ofthese groups still survive with all the customs,

building traditions and indigenous local knowledge of former times. In Africa, eotire tnlles depend on local organic materials for their survival, as these materials have Many domestic and constructive uses. [n Many parts of the developing world, organic materials are intensively used far shelter. Unfortunately, statistics have shown an alarming decrease in the availability of these materials due ta their overuse and uncontrolled harvesting, especially in arid regions. Because of the population explosion and since these sources are not ooly used for construction, but also for industrial and other domestic purposes, scarcity and the danger of extinction are the principal factors that national institutions, international organizations and non-governmentai foundations are attempting to address.

Development has otrered Many the possibility of raising their standard of living with new technologies for construction that facilitate the building ofa home more quicldy and easily. But what are the consequences ofthese new technologies for the environmen~ and for the relationship between man and nature? Are these technologies appropriate for crearing housing for the paor? Unfonunately, in my opinio~ feware, because ofthe high costs, the

.

disappearance of the customs of traditional and vemacular architecture, as weil as the potential environmental damage. These factors will be addressed in greater detail in the

Chapterl

3


second chapter ofthe thesis. On the other

hand~

traditional construction materials provide an alternative path toward

development and present the following three main advantages: • They involve the protection of environmental resources (for example, forest and soil conservation) over the long-term, for the sustainability of natural resources. • They proteet the link to the traditional techniques developed in the past, while alIowing scope for innovation and change. • They can be implemented at lower cost under Many circumstanees, or at comparable costs to other technologies.

Bamboo is the construction material used in Many developing countries. Its light weight, high resistance, law-cast and wide availab ility, make it desirable and atrordable - especially ta law-incarne familles. Commonly used in Asian countries, like lapan. The Philippines, India, Thailand, and Indonesia, and in Latin America, in Ecuador and Colombia, bamboo is one of the natural resourees that allows people to improve their living conditions while preserving their naturai environment. hs roots hold water and preserve the soil, giving it an important function near rivers and creeks on fann lands. Its fast growth is also one of the most important advantages ofthis material. In Colombia bamboo is used in housing with great success by poor communities. The

Guadua AlIgustifolia, a local species of bamboo, is widely used in the construction of siums, because of its great resistance, its ease of handling, Iightness, abundance, and low priee. That is the reason why it was syoonymous with poverty, and people had rejeeted its use for other purposes. Ho\vever recent generations of architects in tbis country have developed new techniques of construction with bamboo that represent the fusion of the old systems with the new ideas. This has attracted the interest ofthe upper classes. The intention of this researcn is to investigate and analyze new building techniques using bamboo, especially in structures, walls and floars (the mast cammon uses ofbamboo), in

Chapte,/

4


Old

CaIdas~

a bamboo-growing region ofColomhia. From

1991-1994~

1 was involved in

building law-cast housing with hamboo: a total of eight houses for poor warehouses~

families~

two kiosles and one auditorium for a school were built. l used bamboo

four

as the

main materia! for the construction of walls~ structures and floors, as weil as for scafFolding in the construction of the auditorium. My experience raised many doubts and questions about the best way to buiId with

bamboo; for example, how ta create spaces more dynamically using cantilevers ta span large distances, how ta incorporate new materials and systems ta make bamboo more resistant and durable, how ta proteet it from bugs and insects commonly affecting bamboo, etc. In the literature, l have found answers ta sorne of these questions, but unfortunately almast no information about new technologies based on the old techniques which l had round sa fascinating during my visit to new homes made of bamboo, which l had seen in Old Caldas. These experiences raised sorne important questions which helped to develop this research.

ChapterI

5


1.3. Research Questions. 1. What new methods ofbamboo construction are currently being used in the domestic architecture (ID particular ta build walls, f100rs and structures) ofOlrl Caldas? Keywords: Building construction, structural joint cutting, structural joint classification, joint assembly, structural and physicaI properties, durability, and maintenance for walls, tloors and structures, environmental factors.

2. What are the advantages ofbuilding with bamboo and how can they be best exploited? Key words: StructuraI resistance, joint reinforcement, cost effectiveness, sustainability, maintenance.

3. What are the disadvantages ofbuilding with bamboo and how can they be overcome? Keywords: Tension and compression properties and weaknesses, immunization and treatment, cutting ofbamboo, time and edge, maintenance, durability

ChapterI

6


1.4. Scope of the Study. This research is limited ta the analysis of the physical and technological aspects of construction with bamboo.. and although casts and statistics are touched on, it does not intend ta go deeply in the economic aspect. Issues such as environmental factors and sustainability are also described but not analyzed in detail. The thesis looks at Old Caldas~ a region of Colombia,. where bamboo has been the mast important material for construction throughout several generations.

1.5. Thesis Outline. The thesis is organized in six chapters: The first chapter introduces and states the problem under investigation; it gives a short historie description orthe use ofbamboo in housing in Colombia and introduces the recent work ofsorne architects involved in developing new technologies. The second chapter deals with the use of organic materials in

housing~

their scarcity~ and

their adaptation. Chapter three descnoes construction techniques to build walls.. floors and structures from lapan, India and Hawaii. Chapter four deals with Colombia, analyzing the traditional systems of bamboo construction used since the Antioquian Colonization

period~

a time when bamboo was

considered material par excellence for construction. The tifth chapter deals with the new technologies and systems for construction of walls~ floors and

struetures~

properties~

joint classification.. joint assembly and joint reinforcement. This principal

the analysis of the building

process~

structural and physical

chapter a1so includes a comparison of the Colombian techniques with those in the Asian countries. Finally~

chapter six concludes the research by summarizing the findings.

ChapterI

7


1.6. Terminology. 1. Alizo: A very resistant wood used for large structures.

2. Bahareque: Olrl construction technique for making walls. 3. Esterilla: Flattened bamboo. hs interior and soft bark is removed ta obtain a light and

multi.. use material for construction. 4. F1ute Supports: Type ofjoint assembly~ which consists of a concrete corbel and capital

with bamboo Bute supports embedded in concrete at the moment of the concrete pouring.

The bamboo is beautifully placed like a

f1ute~

without the help of any column or vertical

support. 5. Guai/ua: Common name ofthe Colombian barnboo ... Bambusa.. Guadua Angustifolia. 6. Bone-Tail: Japanese styled bamboo ceiling. 7. Karakasatei or Umbrella Harbour: Represents the structure ofa kiosk roofin Japan.

8. Ply-bamboo: Woven bamboo matting glued tagether like traditianal plywood. 9. Quincha Wall: One of the most important and traditional methods ofwaU-making in

Latin America, which consists ofwoven bamboo and plastered walls. 10. Rice Husk Walls: Porous walls made with riec

hus~

a waste product fram rice

factories. Il. Sekkatei Arbour: Rattan-thatch garret ceiling.

11. Tendinoso: Low-cost, ecologically-sound building material for walls. 13. Three-dimensional Structures: One of the systems for roof construction with a

prefabricated framework ofbamboo.

Chapeerl

8


2. Chapter fi: Organic Materials for Housing. 2.1 Introduction. In Many parts of the

world~

organic materials are the principal resource for housing

construction. These materials are inexpensive, easy to obtain and to transport. They are Iightweight and relatively durable, depending on the type of material. Because people associate them with poverty, shelters built with such materials are expected ta be upgraded with 'modem and better' ones. Because of the overuse of these natural resources, they are getting scarce in Many parts of the world. Timber and bamboo seem ta be disappearing rapidly, especially in Asia. Efforts are being made to alleviate the problem by promoting the use of alternate building materials and encouraging tree planting. 2

2.2. Current Use of Organic Materials.

• Timber: Timber is the best known and MOst used material for construction not only in

developed countries but also in the third world. Universally it is recognized as a resistan~ durable and beautiful material, which is also easy to work with. It is appreciated by the wealthy, and this gives it a high value in the market and it is in great demand world-wide. It is utilized in MOst countries as a structurai material for walis and roof. In low-cost buiIdin& timber is used in its naturaI state, known as round timber, country timber, or pales. A comman form of law-cast construction is a framework of pales covered with

mud. • Bamboos and canes: These are commonly used in American and Asian counties like

Hawaii, Colombia Jap~ and India,. Their (ow cast and availability make them excellent 2

Wells J.• 1995.

Chapteril

9


material par excellence for construction. • Grasses and leaves: Globally. this organic matenal is used for roofs and walls

particularly in Senegal, Venezuela,

Peru~

Iraq, North Central Sumatra., Zaïre and Brazil.

ln western countries, grass and reeds are used for roofs, together with timber. Palm leaves

are used in Brazil, Philippines, Thailand and Colombia. Another type of grass is the straw which is used in North America and Mexico for animal feed. Today it is used in construction with excellent results: it is very cheap, light weight, and a good thermic and acoustical insulator. Straw baie construction has been used in Canada and the USA with timber.

3

Jute is another kind of grass used for law-cast construction. In Colombia it is used to make cotfee sacks, one of the components of the Tendinoso wall descnbed in chapter V. • Agricultural residues: Like the riee husk. they are used as building materials for walls,

as descnoed in chapter V.

2.3. Scarcity.

An alanning scarcity of natural building materials has been observed in Mrica, Asia and the Americas. Deforestation and environmental degradation have several causes, the tirst ofwhich is the expanding population in settlements where the domestic demand for timber for fuel and construction is concentrated. The supply of bamboo is diminishing in several Asian countries like Iodia, Iapan and Colombia. In Many parts ofthe world, grasses like reeds, straw and palm Ieaves are widely used for thatching, creating an increasing scarcity. In sorne countries of Africa it is becoming more expensive to roof a house with thatch than with eorrugated iron. 4

3 4

Steen A... Steen B~ David B.• 1994: Wells 1. .. 1995:81

Chapteril

10


2.4. Response and Adaptation to Scarcity.

• The breakdown of sustainable praetices, like the restriction on cutting materials during certain seasons or times of the year, is being countered far example by the use of fines, taxes and fees levied in India, Zimbabwe and Bangladesh to prevent the irresponsible and non-sustainable use oftimber or bamboo. S • The seasaning and preservation of timber and bamboo have been intraduced in arder ta prevent excessive cutting. Although many experiments have been made ta preserve bambaa chemically, for example, in Bangladesh, they were ineffective because of the toxicity ofthese chemicals, and the resultant increase in the cost orthe material.6 • Changing building techniques is another response by people who can afford to switch from organic ta manufactured materials 5uch as bricks. But brick-making increases the use oftimber not ooly for pales but also for fuel to bake the bricks. 7 Another response is to switch from organic ta other indigenous materials. For instance in Niger a system was introduced from Iran and Egypt using unbaked earth for walls with very little use oftimber. This method was very weil received and easily assimilated into the local tradition. 8 • The movement to plant trees. Although it requires time ta grow trees, tree planting is a very good solution to the problem of scarcity. It has been applied in severa! countries like Calombia, and especially with bamboo, because ofits rapid growth. 9

s Wells 1. .1995:82

Wells 1. .1995:83 Wells J. ,1995:84 a Wells J. ,1995:85 9 WeUs 1. ,1995:85 6

7

ChapterlI

11


2.S. Bamboo in Colombia. In the middle of this

century~

bamboo was extensively used in the coffee region of

Colombia ta build towns such as ManizaIes, Dos Quebradas, Cartago and many others. Over the years the supply of bamboo was seriously depleted. National agencies and the private sector realized the danger of glladua disappearing and started infonnation carnpaigns and programs encouraging severa! types of cultivation. Sorne of these were rapidly assimilated because of their simplicity (bamboo grown using culms), but athers which were equally

important but more complex scientifically (bamboo grown in

laboratory), were implemented as weil. The bamboo in Colombia has been recognized by new generations of architeets and engineers, as a building material for the poor and for the rich, from squatter settlements to big town and country houses. Seminars, lectures, courses and advertisements for many years promoted the plantation of bamboo. Preservation and sustainabiIity have been encouraged by the government which imposes ta.xes and issues special pennits for cutting and transporting bamboo.

1.6. Physical Properties of Bamboo. 2.6.1. Tensile and Flexion Resistance. Bamboo can be used without concrete reinforcement. when spans and post distances do not exceed the 3 ~ described further in chapter

rv.

Together with concrete and steel,

bamboo is a material that can be used for tension purposes in overhangs,

beams~

and

trusses exceeding that distance, and can be applied as ilIustrated in chapter V. The naturaI tension strength of bamboo is due to the fine fibers that caver its skin between each knot. The knots are the elements that give the continuity and the strength to the fibers. The distances between knots vary between 0.05 M and 0.30 M. The flexibility of bamboo provides anti-seismic properties when it is used together with fibers, cement and barbed

wire (Tendinoso Wall).

Chapterii

12


Tensile Resistance

Between knots Maximum

3.515,5 kg/cm2 (50.000 PSI)

Minimum

1.828 kg/cm2 (26.000 PSI)

In theKnot Maximum

3.480)4 kg/cm2 (49.500 PSI)

Minimum

2.265~58

kglcm2 (18.000 PSI)

Flexion Resistance

Maximum

2.760 kg/cm2 (39.255 PSI)

Minimum

763 kg/cm2 (10.852 PSI)

2.6.2. Compression Resistance.

The knots and the fibers, as in tensio~ provide great advantages when building multi-story structures for housing on steep terrain. Maximum

863 kglcm2 (12.274,29 PSI)

Minimum

562,48 kglcm2 (8.000 PSn 10

2.7. Cure of Bamboo.

2.7.1. Natural cure.

Bamboos not younger than 3 years must not be cut for construction purposes. White spots on their surfaces determine their age. The more white spots the bamboo culm has the aider

it is. 10

Hidalgo. 1974:84

Chapterll

13


Bamboo must he cut before sunrise when the moon is waning. This anaent custom has been proven effective due to the natural process of plants during this period oftime. Once bamboo is eut it must be placed at the most vertical angle possible against the uncut ones~

without removing the branches. The bamboo must be raised from the soil by stone

supports to avoid moisture. According to weather conditions, bamboo culms must be kept in this position for a 4 to 8 week-period.

This is the MOst recommended system because with i~ the bamboo keeps its natural color~ it does not crack, and is not attacked by insects or bugs. Tests have shown that this natural process of immunization yields a 91 % greater probability of freedom from attach by inseets or bugs. II

2.7.2. Immersion cure.

This system consists in immersing the barnboo in a tank with water during a 4 week period then dried out for use. Even though it is very widely used, this method makes bamboo lighter than required and very often resu[ts in cracking. Il

2.7.3. Beating cure.

In tbis system eut bamboo must be rotated over a tire without burning it. In tbis way, bugs and insects are killed and the exterior layer ofbamboo is strengthened. Il

2.8. Advantages of the Use of Bamboo in Construction.

• Due to its hollow sections and circular

configuratio~

bamboo is very light, easy to

transport and store, allowing rapid construction oftemporary and permanent structures. • Due to its great lightness~ bamboo can he handled very easily~ (one man can carry severaI 11 12 13

Hidalgo~ 1974:92 HidaJgo~ 197-&.:93 Hidalgo~ 1974:93

ChapterIl

14


barnboo pieces). The ease ofcutting is also an advantage, especially when it done just after its natura! period ofcure. • Bamboo has knots in each sectio~ which makes it rigid without cracking when it bends; because of this~ bamboo is an ideal material for anti-seismic construction. • The natural surface of bamboo is smooth and clea~ bas a beautiful color and it does not require to be painted or polished. Varnish can be used to enhance its appearance and beauty. • Bamboo is a very law-cast material which can he used by lo\v-income families ta build their homes.

2.9. Disadvantages of the Use of Dam boo in Construction.

• The permanent contact with the soil rots the bamboo and it is attacked by termites and other insects; therefore~ it is not recommended for use in foundations unless it is treated. t

• Once bamboo is

cut~

it is attacked by insects 5uch as the Dinoenls Mimi/lis which builds

large galleries in its walls~ weakening il. • When it is

dry~

bamboo is a high combustible material,

50

it must be tire proofed or

protected from tire. • Bamboo does not have a regular diameter aIong its body and its variable width causes difficulties in the construction process. • When it is dried, bamboo contracts and its diameter is reduced~ causing difficulties in the construction proceS5. • Bamboo cannot he fastened with nails, the way it is used with timber, due to its tendency to crack, but it can be tied with ropes or screwed steel bars.

Chapter Il

15


3. Chapter ID : The Use of Bamboo in Asia and

America, a General Overview. 3.1 Introduction. Tlùs chapter deals with the main bamboo construction techniques used in Iapan and India, the Americas, and the Hawaiian Islands. These are the places where a considerable amount of work has been done on the use of bamboo. The emphasis in tms study is on the construction of walls, floors and structures. On analyzing these three elements and indicating where bamboo gives its best performance with respect to resistanee to tension and compression, versatility, ease ofhandling and eeonomy.

The first country ta be studied is lapan. In the analysis of Japanese bamboo architecture, the building techniques of walls, floors and structures for housing, such as those used in the traditional ways of building with bamboo, and in the implementation of new techniques, are addressed. These new techniques are evaluated to show the relative advantages, as weIl as the possible disadvantages of using bamboo. The traditional and the new techniques are eompared with those used in Colombia in ehapters l i and IV.

In general, the literature from Iodia emphasize the use ofbamhoo in housing for the poor.

rn Hawaii the popular use of bamboo links it ta the Asian cantext and provides another interesting ease study. In lapan by way of contrast, bamboo has been and still is, the material used for the housing of the wealthy, and the traditional methods afbuilding with bamboo have survived the advance of modem technology and have became a symbol of status, refinement and beauty. The information has been drawn from an extensive review of the available literature on the use of bambao in these countries. Graphie material such as drawings, sketches, and pietures are used ta clearly illustrate and concretize the practiees described. Basically this

ChapterIll

16

The Use ofBanlboo in A,.chitecture

chapter demonstrates in detail, how bamboo has been used for Many purposes in the construction field: low incarne families have utilized it as a principal, inexpensive and versatile mate rial for the construction of their dwellings and, as in the case of Jap~ it is valued for its aesthetic qualities above the economic ones. this chapter summarizes the main trends and techniques of domestic architecture built with bamboo pointing out significant differences, but also revealing the important common elements of housing construction.

3.2. The East Asian Region. 3.2.1. Japan.

For centuries, Japanese architecture has refleeted a deep appreciation of local materials, especially bamboo. Bamboo has had the most impressive development in arts and crafts such as weaving, e.g. basket making and in [he creation of fans, musical instruments, and many other applications. In homes, bamboo is found in water canals, wall frames, structures, floors, and ceilings. (Fig.3.01). For many generations, bamboo in Japan has been the material preferred by emperors and weU-to-do families, for its beauty, color, and texture. This section gives a general context for sorne of the mast important bamboo construction techniques, especially in the domestic architecture of lapan. The focus is on the building systems of walls, structures (including roof and ceiling structures), and Boors; these are the most representative uses ofbamboo in the lapanese house. With the help of drawings and pictures, the most important forms of joint assembly and cutting and carving techniques are descnoed. (Fig. 3.02)

Chapte,. III

17


Flutes

Fans

Kiosks

Baskets Figs.3.01

Source (http://www.omnics.co.jp/myhmtwnlshiroishilprocesslpaintwalIlpaintwaIl-E.html)

ChapterllI

18


Japanese gate

Garden ofthe bouse

Figs. 3.02 (Source: Austin R.& Ueda K., 1970:59 and 68)

Chapterm

19


3.2.1.1. Walls.

According to Hidalgo 14 and Yoshida15 in developed countries~ modern materiaIs for y

construetio~

such as cement and other synthetic

produets~

have been replacing clay as a

plastering material for walls; taday, clay is only used in isolated rural areas or in low incorne family homes. However in Japan, the most developed country in

Asi~

where the

most modem techniques of construction have been applied, the traditional clay wall is still being used, not only for housing but for new steel and concrete buildings. In sorne of these buildings, walls, f100rs and ceilings are constructed using the same materials and techniques utilized in the Middle Ages ta build luxurious homes. This tradition is maintained because of the coloring and beauty of the texture of clay, as weil as its resistance to weather changes, aJthough it lacks resistance to impact and wear. The clay wall is built within a wooden frame, which is part of the structure, of beams, props, and columns. Into tms wooden frame, a net made of very thin bamboa strips is inserted, reinforced by waaden sticks, as shown in the Fig. 3.03. Once this frame is made, 3-5 layers of specially prepared clay are applied to each side of the wall. The bamboo net is made by stems varying from 8-13 mm. in diameter or by sticks eut from wider bamboos. The principal ones are plaeed every 30 cm. horizontally and vertically, and their edges are tied ta the main frame, The secondary sticks are placed between the main ones every 2.5 to 4.0 cm, and tied with a 5mm-diameter straw rope called "Kaki-Nawa". Fig. 3.03

14

IS

Hidalgo, 1974:222-225 Yoshida, 1954:135

Chapte,. III

20


Figs. 3.03 Details ofthe clay wall constructiol\ and its bamboo frame

The wall is built with 3-5 layers of clay, each one of them having a different composition and process of preparation. These layers are placed on each side of the

wall~

and the

bamboo aets as reinforcement. The final layer is made of different kinds of clay and the type of finishing depends on the weather and local tradition. The initial layer is made of clay of different colars and consistency, rnixed with other produets such as fibers,

glues~

and sand, which give the wall resistance and durability. The second layer of clay is applied with more fine components in its mixture and the last one is a layer made of rnortars There is a variety in their appearance, color and texture, and sorne examples of these mortars are: • ltTsuchi-Kabe". A colored clay, sand and glue mixture lf

• "Ootsu-Kabe Colored clay, fine sand and lime •

• "Shikkui-Kabe". Lime and water • ItSuna-Kabe". A mixture of colored clay and glue l6 An example of these traditional Japanese clay walls is shawn with great splendor in the

Kojuro Katakuras castle tawn of Shiroishi; the wall called Takekomai is an old style of wall construction in Japan in which the frame, made of bamboo pales bound together, is

coated with layers ofclay and finished with white plaster. 17 Figs. 3.04

Il 17

http-.J/www.omnics.co.jplmyluntwnlshiroishilprocesslpaintwalVpe1intwall..E.htmI http-.J/ww\V.omnics.co.jplmyluntwnlshiroishilprocesslpaintwalllpaintwalI..E.html

ChapterIII

21


Kojuro Katakura's Castfe Town

Kojuro Katakura's Castle Town

Chapter III

22

The Use ofBambou in Architecture

This kind of wall is composed of a frame of green bamboo that has a thickness of 3 cm with bamboo stems within the frame separated every 10 cm. Poles are lied together with helm-palm rope forming a large frame. Large knots of this rope are alIowed to hang down tram the frame while it receives its first coating of plaster. The clay is extracted trom a rice field near the Family Cemetery of Lord Katakura. Ta prevent cracking shredded straw is y

mixed with the clay. In arder to strengthen the matenaI, the mixture is set aside to age and settle for one year before using il. Finally, layers of white plaster are applied to the wall until it reaches a thickness of approximately 24 cm. Fig.3.0S

Construction process of the traditional Japanese clay wall Figs. 3.05 (Source: (http://www.omnics.co.jp/myhmtwnlshiroishilprocesslpaintwaIVpaintwall-E.htmI)

ChapterIIl

23


Figs. 3.05 (Source: (http://www.omnics.co.jp/myhmtwnlshiroishilprocesslpaintwalVpaintwall-E.html) Continuation

ChapterIII

24


3.2.1.2. Structure.

3.2.1.2.1. Trusses and beams

According to Hidalgo 11 and Yoshida19~ the trusses~ beams and ceilings construeted with bamboo are the only traditional structural elements represented in Japanese architecture. These elements appear on the roofofthe traditional Japanese Tea House. As is the custom and legacy ofcenturies, trusses are tied with the traditional helm-palm rope, representing a deep knowledge of the capacity ofbamboo: when bamboo is tied with steel wire or nails,

it tends to show longitudinal cracks that eventually become dangerous to the structural frame. These cracks could even lead to a coUapse depending on their extent, on the load that this piece ofbamboo has to bear and on the position that the piece occupies within the truss. These cracks not only pose the potential danger of collapse but they allow insects and bugs ta penetrate the body of the bamboo, adding to the likehood of a short life ta the structure, as weil as a decrease in structural resÎstance. The traditional Japanese roof structure avoids these problems by tying joints with helm-palm ropes, which give the bamboo a longer life-span by protecting it against cracking, and provides the structure with a more natural and authentic finish and beauty. 3.2.1.2.2. Ceilings Harmonizing with the wooden structure, bamboo is used in the entire ceiling in severa! styles, as in Colombia and Hawaii. According ta Kitao and Janssen, the traditional ceiling of the Tai-an Hermitage and the ceiling of the Vuin use "tlattened bamboos or green bamboo culm opened on one side with a knife and then unfolded till flat. The diaphragms are removed. A 100 mm diameter bamboo results in a flattened bamboo surface about 320 mm wide. This is laid on top of the joists, and lashed to them or nailed.,, 20 AlI the ceiling

11

19 20

HidaIgo~ 1974:222-225 Yoshi~ 1954:135

Janssen, 1988:29

ChapterIII

25


area uses flattened

bamboo~

placed a10ng the joists of thin

bamboo~

5 and 7 cm in

diameter, polished with sand paper, and placed facing the outermost surface, along the truss and tied with tmn helm-palm rope. 21 (Fig.3.06). As shown in the images, the thickness of several kinds of wood used in the &anle is a perfeet fit with the long and thin pieees of bamboo. The other type of bamboo ceiling uses long and very thin bamboo branches 2 cm in diameter, which are tied with galvanized wire and placed together: a thatch type ceiling is laid a10ng the bamboo structure of the tmss and tied with rope. Two examples are the ceiling of the Karakasatei or Umbrella Arbour in the precincts of Takadaiji Temple Higashiyama in Kyoto, which represents the structure of a kiosk root: and the ceiling of Sekkatei

Arbour~

an example of rattan-thatch garret ceiling, thatched on

the lattice ofthe Hokedake bamboo beam and lateral bamboo poles crossed together. (Fig. 3.07). Another very simple but beautiful example of ceiling used in the tea house is called

"Horse-tail Styled Bamboo Ceiling", where the intermediary bamboo rafters are tied with wisteria vîne. This farro is popular for the ceiling over the dirt-tloor of the private house22 which uses thick pieces ofbamboo (10 ta 12 cm) tied together aiong the wooden structure with rope. AIthough it is a heavier root: it is supported by large wooden beams which are embedded into the walls, and supported by the posts and columns of the structured frame. (Fig. 3.08) The last two systems of ceiling construction are

first~

that used in the Tea-Ceremony

House representing ail the above-mentioned techniques. Combined with other wood structures, these bamboo ceilings integrate all thickness and lengths of severa! types of bamboo, including the thin branches, as weil as in manually woven ceilings. Second is the hurdled ceiling, made completely with

bamboo~

with trusses not exceeding 8 cm in

diameter, and ceilings of4 cm in diameter as shown in the illustrations. (Fig.3.09)

21 IGtao, 1958:58-69 22

IGtao~ 1958:127

ChapterIlI

26

The Use ofBamhoo in Architecture

Figs. 3.06 The ceiling oCthe Yuin (Source: Kitao, 1958).

The ceiling aCTai-an Hermitage 3.2.1.2.3. Joints.

There are several types of joints depending on the function and load of the beam, truss or joist that they carry. The first type is the MOst commonly used, specially on trusses and structural members orthe roof. Two barnboo stems are pfaccd perpendicularly and tied with a rope giving the bamboo its total capacity and resistance; in this case bamboo is not cut or

transformed to gain structural resistance. (Figs. 3.07) Severa! types of carving and cutting to level and secure the joints, are used in the traditional Japanese bamboo structure. The stems are cut or carved depending on the position and function that they have within the truss. As shawn in the drawings, cuttings can be made between two knots of the bamboo stell\ or else on the edges to adjust the ChapterIlI

27


joint completely to the joist.. the cut following the bamboo's circular contour. (Fig. 3.10) Figs.3.07

The celling oflCarakasatei or UmbreUa Harbour

Figs. 3.09.

Hurdled Ceiling Figs.3.10. Bamboojoint assemblage. (Source: Kitao~ 1958:(7)

ChapterIII

28

The Use ofBamboo in A,chitecture

3.2.1.3 Floors.

Bamboo floors in the Japanese house are works of art and beauty. Prestigious homes like the Imperial Katsura Palace, use bamboo in the terraces facing the garden as Tesuro Yoshida describes in bis book The Japanese House and Garden. 23 Bamboo tloars are used mainly in the contemplation places of the house, verandahs, and railings, commonly facing the garden or a pond. Long bamboo stems of approx. 3 cm diameter are placed across the wooden frame of the platform. Bamboo is held to this platform with nails as in the case of the Katsura Palace, or sometimes with a wire or a rope. The bamboo verandahs could vary in thickness and color depending on the interior design, and their location and function. For example, in the bamboo verandah of Sekkatei Arbour in the precinets of Kinkakuji Temple of Kyoto, the Susudake strips are arranged in a

horse-tail style. The colors and texture of the surrounding space are integrated and combined to produce an effect ofintimacy, local expression, and tradition. The bamboo hurdled verandah, installed in front of a tea-ceremony house, rises from the ground to meet the threshold. Beautifully cut, these pieces of bamboo of approx. 8 cm diameter, are attached to the walls, and give

acce~s

to the entrances of the house. The

irregularly arranged Madake bamboo verandah is constructed in a horse-tail style. (Fig. 3.11)

23

Yoshida, 1954:47,. 51,57. 135.

Chapter III

29


Fil'.. 3..11. (Source: Kitao,

Bamboo veranda of

1958)

Bamboo hurled veranda

Washroo~

Sekkatei Arbour

Imperial Katsura

Palace

Figs. 3.11 Continuation

Bamboo terrace, Imperial Katsura Palace

Bamboo terrace and raiIin~ Imperial Katsura Palace

(Source: Kitao.. (958)

Chapter III

30


3.3 The Middle Asian Region. 3.3.1. India.

In Indi~ bamboo is a material of daily use, especially as a construction matenal.

Manual bamboo weaving is a traditional way of creating walls, partitions, floors and structures. Extracted from the tropical

fores~

the Indian bamboos are sorne of the

strongest in Asia.; the impressive diameter the Dendrocalamus giganteus" make it suitable Il

for creating large structures, as in the case of, (Fig. 3.(2), an Indian specie of large bamboo. Transportation of bamboo is accomplished by horse or bullock carts, or by river, which provides an easy and economical way to bring them to sites where housing production by manual and/or mechanical means is carried out. Fig. (3.13a-b). One characteristic of bamboo construction in India is the value that people place upon traditional architecture, especially in the rural areas. where tradition is still an important element of the social and culturallife. Fig. (3.13.a) Fig. 3.12a. (Source: United Nations, 1972:8)

ChapterllI

31


Fig. 3.12. Dendrocalamus Giganteus. A large diameter bamboo (Source: United Nations, 1972:3)

Fig. 3.12b. Bamboo transportatio~ Kerala, India. (Source: United Nations, 1972:7)

ChaplerIIl

32

The Use ofBamboo in A,.chitecture

3.3.1.1. Walls.

3.3.1.1.1. Mat waUs.

As in Indonesia, bamboo mat walls in India are made by plaiting splits. These mats are

made in a variety of shapes and patterns. The strips are usually woven by hand, but lately small machines have been used to do the same job. Mats are used to enclose houses, (Figs. 3.14.) one very common method used is called ply-bamboo, and consists of woven bamboo matting glued together like traditional plywood. This is glued with phenol... fonnaIdehyde, malamine.. formaldehyde hot-press resins, casein and urea-formaldehyde. One-ply bamboo is made by applying pressure at 30 kglcm2 and 140°C: the results ofthis process are mats containing 15 per cent phenol-formaldehyde resins which have great

resistance to termites and weather.24

Bamboo matting 24

United Natio~ 1972:32

Chapterlll

33


Another technique used in India is called the plastered bamboo mat waIl; it is a wall made

using a thin bamboo mat which is nailed on bath sides ofa braced tÎmber frame, then attached to the timber ofthe bamboo frame and the strips are plaited horizontally between vertically stretched wires. Plaster is then applied to one or both sides. For plastering, cow dung, mud, sand, lime and portland cement are used alone or in combination. These bamboo mats are used for Iight partitions and walls, which are suspended from rafters on verandahs as protection against the sun. wind and rain. 25 (Fi s. 3.15 & 3.16)

Fig. 3.15. Mat wans. (Source: U. N., 1972:63-64

~~

~

t4

Fr

TM

M~ er-n

Figs. 3.16. Structural details for floors and post &beams. (Source: U. N., 1972:63-64) 2.3.1.1.2. Board Walls. Board walls or unrolled bamboo wa[)s, are made from a culm that is eut and unfolded until it is aImost tlat. This type of technique is used in Indonesia as weil, and consists of "panels placed vertically and lashed or pinned to horizontal round members which in tum are fitted to mortises made in the vertical bamboo framing pales ofthe structure. To make it weather-tight it is covered with c10sely plaited matting. Outer walls are finished with plaster on one or bath sides."26 2S 26

United Nations. 1972:53 United Nations.. 1972:53

ChapterIlI

34

The Use ofBamboo in Architeclure

3.3.1.2. Structure.

In India, bamboo and reeds are usually used for both roof traming and ro06ng. "The

simplest faon ofbamboo roof covering is made ofhalved bamboo tiles running full length from the overhangs to the ridge (Fig. 3.17). Large diameter culms are split into two halves, the diaphragm scooped out and the tiles seasoned in a sheltered place.....27 in this way bamboo is used as a tHe as "vell as in the structure. Another example is bamboo shingle rooting. Bamboo shingles are made from mature but still green culms of maximum diameter. "The shingles being formed of split segments 34 cm wide are dried in the shade. The maximum length is equal to the distance between nodes. A 'hanging-split' is formed on the outside ofthe shingle at the oode end and the tiles are fixed to split bamboa battens by hooking this haoging-split over them. ,,21 (Fig. 3.18)

In general, bamboo framing and structure are used in [ndia with the same designs and charaeteristics as traditionaI waaden or timber structures. " The individual structural elements that compose the frame of a conventional ali-bamboo house correspond closely to those found in an all-timber frame: Corner posts., girders or plates, joists, studs, strots or braces, tie beams, king posts~ purlins, ridge pales., rafters, sheathing and so forth..... 29

3.17. Bamboo tile roof

Fig.3.l8. Bamboo shingle roof

(Source: United Nations~ 1972:4647) n United Nations~ 1972:45 21 United Nations. 1972:45 29 United Nations. 1972:42

Chapterlll

35


Fig. 3.19. Structural details for trusses (Surce: United Nations, 19). (Source: United Nations.. 1972:66)

Chapterlll

36


Bamboo trusses are tied together with ropes and joints are made with simple unions of well-cut and carved bamboo poles to frame the structure.

Figs. 3.20. Structural details (Source: United Nations, 1972:65, 67)

In these examples, two systems of joint assembly for trusses are ilIustrated: one is the simple rape joint explained previously and shown above; the other shawn below, creates the joint by making small holes, which together with bamboo sticks, form the joint_ As is shawn in the Hawaiian examples (Figs. 3.27, 3.28, 3.29), this type of union provides the

Chapter III

37


joint with greater stability and strength and also provides a level support for the beams. The tight fit ofthe joint protects the bamboo from both cracking and insects.

·•• ".,1 ,

• J

I.J •

•••..L,,;

.. r:'\ _~

Il '1 Il

\~

Figs. 3.20, continuation. (Source: United Nations, 1972:68) These examples show the ditferent types ofjoint assembly for structures of trusses, posts and beams, as made in India and in sorne other Asian countries, such as Indonesia and the Philippines.

Chapterll1

38


3.3.1.3 F1oon.

In India many bamboo houses have no floor. The surface of the soil is used and it is raised by tilling with compacted earth to prevent flooding. The surface of the soil is usually paved with bamboo boards, generally fastened down by the use of thin strips of bamboo secured ta the supporting members by thongs, wiee lashings, or small nails. Another example is ofthe house raised above the ground. This raised flocr is mast suitable not only for hygienic but for functional purpases: it pravides a sheltered space below the Boar which has many patential uses. These raised floars are made entirely ofbamboo, including the supporting beams and tloor covering.

ChapterllI

39

The Use a/Bamboo in Architecture

3.4. The Pacifie Island Region: Hawaii. Hawaii is a group of islands where bamboo has been used as a traditional architectural element, especially for walls and structures. In wall-making, it is important ta emphasize the relation of the Hawaiian and Colombian traditional bamboo architecture. Perhaps they are related due ta the influence ofa European tradition in architecture for rural areas. Many houses are built entirely of bamboo, with woven bamboo walls, board bamboo walls, and pole walls. The following are sorne examples extracted from a web site where mainly Hawaiian architecture is shown. 30 These examples of houses show the most important elements in the bamboo wall and structure construction, especially those involving traditional architecture - the board bamboo walls, woven bamboo walls, bamboo pole walls, structures, detaiIs ofjoints, and ways of assembling and tying.

Bain C. and Coll E.•:1995. bttp://wwwlkatmi.netlbambooweblbambooslideslbambooslideslbambooslides.htnù

3Q

Chapter III

40

The Use ofBalllboo in Architecture

3.4.1. WaUs.

A great similarity between the wall techniques ofHawaii and those employed in Colombia is round especially in the fabrication of walls that resemble the Bahareqzle wall of the traditional Colombian technique. This tS a technique that is also based on flattened board bamboo which ts placed horizontally onto a bamboo frame. To apply the bamboo board a very thin wire is

used~

because of its flexibility and ease of handling. This wire is placed

along the vertical bamboo post with nails. (Figs. 3.24) The next step is ta apply chicken wire to the horizontal tlattened bamboo ta facilitate the adhesion of the plaster. The plaster could be clay or other materials such as

sail-cement~

cement plaster or mud. (Figs.

3.25) The final process is the painting that cauld he the clay, or commercial paiot or natural colorants. Sorne walls in Hawaii are made entirely of barnboo~ held together and vertically tied by a bamboo beam and a bamboo base. These walls are supported by timber foundation beams, and these beams are supported by stone foundatians. Figs. 3.26. Almost all the structures are raised above the ground to avoid contact with humid

soil~

enhancing the ventilation

and creating an additional space with multiple functions below the floor. Another technique used by the Hawaiians is woven bamboo walls, which strongly resemble those in Asian bamboo

architecture~

and the same principles of construction are

applied in these ancient techniques; bamboa is flattened and then eut in long strips to weave the waiL [n contrast ta the Asian example, waven bamboo walls in Hawaii have simple design patterns, and a characteristic feature is the bamboo or waoden stair to the entrance of the house.

Chapterlll

41


Figs. 3.24 Flattened or board bamboo walls (Source: http://www/kauai.netlbambooweblbambooslideslbambooslideslbambooslides.html)

Chapter III

42


ChapterlII

43


Figs.3.26 Bamboo pole wall

Model

Bamboo hut

Figs. 3.25 Madels orthe process for the construction ofthe board bamboo wall (Source: http://wwwlkauai.netlbambooweblbambooslidesJbambooslideslbambooslides.hbnl)

Chapter III

44

The Use ofBanrboo in Architecture

3.4.2. Structure. In Hawaii thece are sorne particular structural details where rope is used as a tie

elemen~

and pieces of bamboo sticks are crassed through the bamboo members to adjust and caMect bamboa posts, beams. jaists and trusses. (Fig. 3.27) This is sunilar to the Indian examples shawn previously. Nails are used on the inside of the bamboo board wall, but for the outer structure which is visible, bamboo nails and bamboo sticks are designed to adjust joints as shawn in the drawings and photographs. (Fig. 3.28) Two holes are made crossing the cafter or the cross bea~ and inside, the bamboo sticks are introduced to support the double beam. This beam is tceated the same way as the post, but now these sticks do not have a load-bearing function Iike the post" cather they help to adjust and affirm the stability of the cross beam. (Fig. 3.29)

The other example of structural assembly is the structure tied with natura! copes, which enhances the bamboo members' resistance ta attack by termites or inseets. This is not the case with the previously-mentianed stick holders. (Fig. 3.30) In this example the beam is supported by posts and

braces~

in South America it is called "pie de amigo" . Trusses are

simple bambao joists placed separated every 50 cm. Complex bamboo structures, as in the example in Figs. 3.31, can he implemented comhining other timber structures, and reach double and triple heights. To ereate 50ch structures it is necessary ta eover the house with a light root: sueh as thatch or leaves in t

arder ta avoid overloading the structure. The pasts of the structure in the Hawaiian example are very weil grounded and weil 5Opported. It is of the utmost importance to prevent the direct contact of the bamboo post with the soiL It is advisable to support posts with a concrete or a stone base in arder ta proteet them from humidity and rotting. (Figs. 3.32)

ChapterIll

45


Fig. 3.27

Fig. 3.29

(Source: httpJ/www/kauai.netJbamboowebibambooslidcslbambooslidesibambooslides.htmI)

Chapter III

46


(Source: http://www!'&1lk1Î.nelibambooweb/bambooslidesibambooslideslbambooslides.btml)

ChaplerIII

47

The Use ofBnnlboo in Architecture

Concrete foundation

(Source: http://w\Vwlkauai.neribambooweblbambooslidesibambooslidesibambooslides.htmI)

ChapterIII

48


3.S. Advantages.

The advantages of using these ancient and traditional bamboo construction techniques is evident in their continuai and wide spread use throughout many countnes.

3.5.1. Walls.

• The bamboo walls have the enormous advantage of being very light. This alIows very easy handling for manual work. • Bamboo is proteeted by the clay from weather and temperature changes, especially during the winter season. • The helm.. palm rope gives bamboo the flexibility to resist seismic movements, and aIso avoids cracking when tying and assembling the wall frames. • The clay wall't because of its natural charaeteristics, is a good insulator and maintains a comfortahle and even temperature in the interior spaces. • Because young bamboo poles can be 50 thin and light, they are used as frames for the traditional Japanese paper sliding doors and walls. • The tire risk of building with bamboo is diminished by the clay and plaster applications to its surfaces. • The extraordinary capacity of the Japanese bamboo to grow and resist ail kinds of weather through the seasons makes it an unusuaI natural building material. • When partitions are made with woven bamboo't they are highly mobile, which helps in case ofseismic movements. • The richness in the mat walls design is one of the most important charaeteristics of the architecture ofbamboo in Indi~ giving rise to hundreds ofdifferent varieties. • The use of bamboo in wall making allows the application of a great variety oftraditionai techniques: for example the use of mud~ cow dun& lime and/or other organic elements, on

ChapterIII

49


the bamboo frame. • These wall techniques are suitable for rural areas where the avaiJability of barnboo is greater than in urban areas. • The application ofvarious chemical substances ta the bamboo wall, structure) and floor, tan successfully prevent termites and insects from attacking the bamboo.

• New and simple machinery is now used in the fabrication of mats for walls and floors) wmch allows the possibility of standardization and industrialization of the traditional construction techniques. • Bamboo matting is fixed to wall frames with bamboo battens and given a coat of coaI tar that gives the walls greater durability. • The application of chicken wire ta the board bamboo wall provides better adherence ta plaster, cement, clay or mud.

3.5.2. Structure.

• The lightness, resistance, and ease of handling of bamboo makes it a perfeet materia! ta caver larger spans, taller ceilings, and more spacious interior rooms. • The Hem-Palm and the Kaki-Nawa ropes give protection to bamboo from bugs, cracks, and fissures in the tying of the joints and overlapping structural members of the truss. • In arder to level and adjust the joints together, carving and cutting of the bamboo is necessary. It enriches the possibilities of multiple styles ofassemblage and tlexibiIity. • The combination ofseveral degrees ofbamboo thickness give the structures and ceilings enormous possibilities ofinterior and exterior design. • The use of ropes and reeds ta tie the joints of the structural members of the bamboo house in India gives bamboo better possibilities ofa longer structurallife. • There is almost no use of nails and metal elements ta tie joints together: this provides better performance and less likelihood ofbamboo eaters and insects attacking the culms.

ChaplerlII

50


• The separation of bamboo from humid soil in the case of stone foundations, gives protection and a longer life ta the culm. • Steep roof structures for rainy seasons are covered with thatch or leaves, making them light and easy to replace. • 3 to 5 layers of plaster and clay make the Japanese wall very strong and resistant to compression, as weil as weather conditions and humidity, so that it can last for many years.

3.S.3. Floon.

• In lapan, barnboo floors have the advantage ofbeing made on top of wooden platforms, avoiding contact with the soil~ and preventing premature decomposition. • Bamboo tloors have a great number of possibilities of design, because of the variety of lengths, diameters, colors, and textures. • When the floor is raised above the ground, it provides excellent cross-ventilation, and separates the fioor from the eart~ which helps in cases of flood. It also provides an extra space to the house for storage.

Chapterm

SI

The Use olBomboo in Architecture

3.6. Disadvantages.

3.6.1. Walls.

• The time-consuming process of manual wall making roeans that tabor costs are high and it takes longer to produce 5uch waIls than it does with modem techniques. • Eventually, problems ofhumidity can create defective wall performance, especially when the clay wall is placed facing the exterior or kitchen and bathroom areas. • The exposure to rain and sun could reduce the life of bamboo walls and structure last a shorter time than expected when bamboo is not proteeted or is used outdoors. • My experience has shown me that chicken wire used to help in the adherence of plaster, can be omitted to reduce the costs, because when the rough part of the bamboo board is placed facing the exterior it provides a suitable texture for the plaster to adhere to.

3.6.2. Structure.

• In arder to tie the bamboo sticks to the exterior platforms, it is necessary to apply nails and metal wires, which increase the risk of cracks and insect attacks and

reduces

durability and resistance. • When cutting and carving is necessary, there is a high p05sibility of cracking and fissuring, which could diminish the performance of the structure and eventually could lead ta collapse if the bamboo piece is not replaced in time. • Because of the physical charaeteristics of bamboo, structures are highly tlammable, especially when they are not covered or embedded in walls of plaster or clay. • The use of certain bamboos is made difficu(t by the crookedness of the

cu~

the

prominence of the nodes, the unevenness of the intemodes and the rate of taper. This unevenness and the

Chapterlll

taper~

which is more marked toward the tip of the culm, may make it

52


difficult ta achieve tigh~ weatherproof, vermin proofconstruction. 31 • The costs of the house depend principally on the manual labor; the longer the house takes ta be completed. the more expensive it becomes. • Using nails and wires in the junctions and joints especially when making bamboo board t

walls is a potential danger to the whole structure, because it could create cracks and t

fissures, and even result in collapse if the piece or pieces are not replaced in time. • The hales made in the cross beam and rafters in the structure allow easy access to insects and bugs which eat the inside part ofthe barnboo culm. • Ali the load of the roof is given to the bamboo sticks. which do not always have the capacity ta support the weight.

3.6.3. Floors.

• Bamboo floors in Japan are principally used in the exterior terraces and verandahs. Due to its permanent outdoor location, the inclemency of weather conditions, wood-eating inseets, such as termites and post beetles, there are high possibilities of a very short durability and resistance. • Bamboo can not be placed in contact ,vith the sail,

50

the foundations must be on top of

solid stone or concrete for the exterior walls. • It is good to use bamboo on raised floors. however, it raises the costs of construction.

II

Colonial Building Notes, 1957:13

ChapterlIl

53


4. Chapter IV : The Use of Bamboo in Colombia 4.1. Introduction In this chapter, important bamboo construction techniques used in Colombia for Many

generations are analyzed. These methods are still in use in Many parts of the country. Many improvements in the construction assembly of joints and unions made completely with bamboo. The main objectives of this chapter is ta introduce the

MOst

advanced

current techniques to build walls, tloors and structures out ofbamboo. This chapter of the thesis is also devoted ta understand of the Colombian context as it relates ta bamboo architecture. The following is a selection of traditional systems used in the construction of walls, flaors and structures with bamboo in

Colombi~

which have existed since the pre-Columbian

period. Sorne of them have been improved ta address the specifie necessities of modern lire, using new materials such as concrete, steel, and sorne chemical substances ta make bamboo more durable and iosect resistant.

Guadua, as this family of bamboo is called, grows along the shores of the rivers and creeks in the lush green environment oftropical Colombia, with its hot and humid cümate. The soil is so fertile that beside the bamboo forests, cotfee is planted, and this coifee is commonly considered ta be the best in the world. This sail yields Many fruits and bamboo is one of them: abundant and tall, this strong plant grows with an the advantages of a climate with an average year-round-temperature of 12°C ta 25°C. This environment is ideal for the growing of bamboo. The versatility of bamboa permits a tremendously wide variety ofuses, especially in the field ofconstruction.

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S4


4.2. Walls.

Bamboo walls are common in

Colombi~

specially using esterilla or flattened bamboo

construction. Two construction systems use esterilla as a main material: the first one is called Bahareqlle. and the second is known as "earth-filled waUs". The Quincha wall is made using waven laths ofbamboo.

4.2.1. Bahareque Walls. The structure of the bahareqlle walls is formed by bamboo pasts of an average of 10 cm

in diameter, placed every 30 to 40 cm and framed by the superior and inferior beams. Once these posts are fixed and tied together they are covered with esterilla panels in the interior and on the exterior, placing them with the roughest part facing the exterior, in arder to provide the best adherence for the plaster. There are two systems used to tie the

esteri/la panels: the first one is to place a thin 2 cm bamboo stick which is taken from the external and strongest part of the bamboo culm, onto the eslerilla panel in the center of each bamboo post with nails separated every 8 cm. The second system is ta use galvanized wire, which is tied together with the nails before they are completely inserted into the postS. 32 (Figs 4.01)

12

Hidalgo, 1981:28

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5S


Figs. 4.01 (Source: Hidalgo, 1981:28)

PI~

Plast~r ~erillalt

boards-_ _-I-_~~

Lower be:un

Chapter/V

56

The Use o[Bamboo in Architecturf!

When building a hahareque wall, it is important ta take into consideration the foUowing recommendations : • The trapezoidal esterilla panels have one side wider than the other, and it is recommended that these panels should be placed with the narrowest part on the wider one and vice-versa. • The thickest panels must he placed onto the thinnest bamboo posts, and the thinnest panels onto the thickest bamboo posts, ta create a flat and regular surface thickness. • If the average esterilla panels are thi", it is necessary ta place the bamboo posts at a

smaller distance at about 30 cm of separatio", otherwise the application of any strong t

pressure would crack the plaster putting at risk the stability of the wall. t

• The plastering of the hahareque walls is made by two layers of sail and cow dung in a proportion of 1:2 or two layers ofcement and sand in a proportion of 1:5.33

4.2.2. Earth-filled walls.

The frame of the earth-filled wall as it is called in Colomhia, is built in the same way as t

the bahareque wall. The ditlèrence is that instead of panels of esterilla bamboo laths 4 t

cms wide are used: they are placed horizontally onto the bamboo posts, putting the rough part towards the exterior ta provide sufficient adherence for the plastering. The laths are separated every 8 c~ to facilitate the filling with sail, straw and clay. The wall is tilled up t

until the filling material reaches the Ievel of the laths and then it is left on site to dry for t

about a

month~

at which time it is ready to be covered with twa layers of sail and cow

dung, as with the baharequf! \valls. [f the laths are very thin, the separation of the posts must not he larger than 30 cm. The bamboo laths could be placed with the interior and the exterior ones at the same heigh~

lJ

or else the interior laths couId be placed in the center of the separation of the

Hidalgo~ 1981:29

ChapterIV

57


exterior ones~ ta provide a better barrier when tiUing with sail,

straw~

the bamboo laths on two corner wa1Is~ they must he put at different

etc. When placing heights~

in arder to

make the joint connect praperly, as shawn in the dra\vÏng. 3-' (Figs 4.02)

Figs. 4.02. (Source: Hidalgo, 1981 JO) Plan

IJamboo· 1

Mu'" \\ ilh Siraw . ~~

. P'~h:r

Perspective C~mi.w

wilh 5U':Iw P~wilh

sail :usd a1W dwg

30l

HicL'lIgo, 1981 :30

ChaplerlV

58


4.2.3. The Qllincha wall.

For many centuries this system of bamboo wall construction has been used in Latin America, especially in Peru, Ecuador and the southem regions of Colambia. This type of wall is used in the rural areas and for law-incorne family homes. This system of construction can produce very thin and resistant waJls, using the bamboo posts, beams, and structures which can be seen from the outside, just as in the traditional Japanese wall and structures. (Figs 4.03). In the construction of the qllincha wall, two systems are used according to the weaving direction ofthe laths to the posts. 4.2.3. [. System A.

The weaving of the lath is placed vertically, between the horizontal support bamboo sticks previously fixed to the column (or post) and separated uniformly every 50 ta 70 cm. 4.2.3.2. System B. The bamboo weaving laths are placed horizontally between the vertical support bamboo sticks previously fixed to the superior and inferior beam, separated uniformly at the same distance as in system A.

In the construction of the qllillcha wall, bamboo culms from 2 to 3 years old are used because these are flexible enough to weave properly. Older bamboo culms are more susceptible ta breaking when bending. If the laths are extremely flexible and thin, the separation between the support bamboo sticks must be narrower. At the time of the wall plastering, 2 to 3 layers of sail or cement are used, the most advisable being the latter. The first layer of pIaster must be appIied very strongly, pressing hard towards the center in order to penetrate between the laths and obtain the union of the plaster from each side. 3S

35

Hidalgo, 1981:31

ChapterlV

59


Figs~.03

Bam.boo

posts

Laths of bamboo

omontal sUPp"0rts

of-bamboo

Plaster f-'l-

Lower beam

A Bamboo osts Vertical supports ofbamboo

Laths ofbamboo

Lo\verbeam

PIa..c;;ter

B

ChapterW

60


4.2.4. Weaving flattened bamboo walls.

This system of bamboo wall construction is composed of a bamboo frame) posts) upper and lower bearns) and in betwee~ bamboo supports separated every 80

c~

as it is shown

in the figure. (Figure 4.04) The bamboo weaving is made with tlattened bamboo or esterilla, between 5 and 20 cm in width. Once the weaving is adjusted and weil cut at the edges, it is placed onto the bamboo frame: these woven panels are tied together to the beams and supports of bamboo with bamboo laths. The wall is made is tinished with plaster, or else it is left as is, the latter especially in rural areas where peasants and native tribes have used this method of construction for many centuries. The plastering of this wall is done with cow dung, soil + cemen~ and thatcb, or else cement mixed with sand. In each of these cases, 3 layers of plastering are used. 36 Figs. 4.04. (Source: Hidalgo, 1981:32). Bamboo weaving

36

Hidalgo. 1981:32

ChapterlV

61


4.3. Structure. For many generations, the traditional bamboo structure has been the most important construction system used in Colombia, especially in rural areas, and in low-cost-housing on the peripheries of the cities. In foundations, footing is constructed with stones, and on the stones bamboo is placed to create raised floors. These structures are used especially in very steep terrain, and consist of triangulated bamboo frames. Fig ~.05 Bamboo must be protected with bumt ail, applied to the area of the bamboo hase to he covered with concrete. This preventive measure is taken because humidity and cement contractions can damage the base of the bamboo posts. This is made before being embedded into the concrete footing. As we have seen in the traditional system tbis preventative measure is not taken, putting al risk the stability of the structure of the foundation. Bamboo posts are fused with the structure of the wall, creating a very resistant and strong frame to receive the load of the trusses and roof. There are many ways ta combine bamboo ta create

joints~

Figs. 4.06 provide sorne examples of traditional methods of

bambao joint construction for structures. When building structures for roofs (trusses), 1. Janssen states that: "In many regions where bamboo is a familiar building material, such trusses are in traditional use but they are often built with more bamboo than is necessary and are at the same time not always structurally sound. 1I37 On the other hand, according ta Hidalgo, in the construction of bamboa trusses, the same principles and sorne of the same standard designs as for the trusses made out of wood are used. He adds that due to the physicai form of bamboo, sometimes it is not possible ta build certain types of trusses; however, the implementation of new technologies (such as additional accessories like joints made of steel) permits 37

Janssen.. 1988:

ChapterIV

62


bamboo trusses to have the same standard designs as those made out of different kinds of wood.JI

Woocbboard

. or "esteriUa"

Diagonals

StruclLWOf'

found4ltion support raised

from tb~ ground

Up~rraft.:r

Figs.4.0S. (Source: Hidalgo~ 1981:38)

38

Hidalgo. 1981:38

ChapterIV

63


Ridgr:.

Diagowùs Cross-rafters

Raftcr _.

.Upp~r r:U\er

Rafler King

Detail 6

caola----.'

Detail 7 Figs. 4.06. (Source: Hidalgo~ 1981:35)

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64


A

A

A

B

B

B

Figs. 4.06. -Continuation- (Source: Hidalgo, 1981 :26 and 3.6.)

ChapterW

6S


Upper rafter- - - - . Cross mfters

b

a

ChapterlV

66

The Use ofBaniboo in Architecture

4.4. Floors.

The most common material used for floors is timber:

however~

rural dwellings often use

esterilla in one of two ways. Either it is placed directly on the earth or onto raised floors over the sub-flooring. According to

Hidalgo~

the first is used in very low..cost housing to

avoid dust, and is built as follows: the area of the f100r is filled with soil in layers of 10 cm., each of which is tamped. On the last layer, clay is placed and leveled, and then the

esterilla is placed on top; after this, the eslerilla and the layer of clay is compaeted. When the platform of the floor is separated from the ground~ or on a second floor, the esterilla is placed over the sub-flooring ofbamboo~ where the sub-flooring beams are separated by 30 cm. maximum. 39 The floors made of laths of bamboo are used ooly when the platform is separated from the ground. Laths of 3..6 cm. are nailed onto the sub-flooring and separated by 0.5 cm. to get better ventilation. Complete bamboo floors are made of thin bamboo placed over subflo 0 rings, separated every 60 cm or more. These floors are built where heavy work is done, for example in workshops or storage areas:m (Figs. 4.07 and Figs. 4.08).

39

Hidalgo~ 1974:181

40

Hidalgo, 1974:182

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67


Figs. 4.07. (Source: Hidalgo. 1981:27)

··-Detail!

Sections

Cross beam

Detail 2

ChapterIV

Sections

68

The Use of8anlboo in Architecture

-Detail 1. .__--Posts ~am

Wood.m.--

fluor

Section Detail 2 P..~;..\----Support ~ams

Wooden 110er

"î:-'1/ "'J..

"Pie de amigo"

JO.-IO cm ofsepornlion

Cross-be:Ul1S

Section

.J.os. Figs. ~.os. (Source: Hidalgo. 1981: 28)

ChapterIV

69


4.5. Advantages. 4.5.1. Walls. 4.5.1.1. Bahareque walls.

• Insects and wood-eating pests can be avoided when plastering is applied to the flattened bamboo panels: this prevents oxygen from penetrating and provides the wall with a long lire. • The lightness of this wall provides great resistance te earthquakes, which are very common in the cotree region ofColombia. • Because its ease of handling, the time spent on construction is shorter, decreasing the cost of labor. • The cost of the construction materials increases the affordability of these homes so that low-incorne families can solve their housing problems in many regions and cities of Colombia where wood and bamboo are easily available. • The space created by the two sets of panels, interior and exterior, provides great thennal and acoustic insulation properties ta the wall. • Because ofthe bamboo structure, this particular wall provides resistance ta compressio~ which gives the house versatility and strength especially when building on steep terrain. • Because of their lightness, bamboo walls can be construeted on wooden or stone foundations: this can also decrease laber costs and the time ofconstruction.

Chapter/V

70


4.5.1.2. Earth-Filled Walls.

• Because ofthe complete integration ofthe plaster with clay or cow dung, the possibility ofbugs and inseets penetrating the wall is reduced. • The resistance of the wall to pressure increases when the soil-cement mixture with clay and straw is applied inside the bamboo wall. • This type of wall provides thermal insulation to maintain the indoor temperature, in cool and warm weather. • Even though the earth-filled wall is heavier than the bahareque wall, the load orthe wall on the foundation is minimal compared with modem brick or concrete walls. This lightness permits the use of waoden or stone foundations, which are easier to canstruet and less expensive in teons of materials and labor costs campared ta conventional ones. • This traditional method ofconstruction has been used for many generations in Colombia, 50

there is a widespread knowledge in the field, and many special adaptations. Many

baquianos, the bahareque wall makers, have also passed on their wisdom to new

generations of earth-filled wall builders with the capacity to propagate this technique. • There is a commonly held belief in Colombia in the curative properties ofthe soil and an acceptance of its use as healthy or natural: tbis is a cultural factor that contributes ta the belief that people who have lived almost ail their lives in these types of homes generally enjoy a longer life. • Because of the flexibility of bamboo posts, beams, and laths, the earth-filled wall is an ideal solution to the destructive problem of earthquakes and seismic movements.

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71


4.5.1.3. The Quincha Walls.

• The high resistance of even these quite thin walls is due to the perfection of the bamboo weaving systems within the walls ypart ofthe traditionai wisdom ofthe region. • The thinness of the wally in the bamboo structure shawn bears a great sinularity to its Japanese counterpartywith similar advantages ysuch as ease ofhandling and transport. • Due to the physical characteristics ofthe bamboo weave the Quincha wall a1so helps to y

prevent the col1apse ofthe house during seismic movements. • Any kind of plastering can be used to coyer the wally giving the user the option to choose highly economical plastering materials. • Only bamboo is used to create this wall in i15 entirety, except for the plastering, and it is a highly economical construction matena!. • The internaI weaving of these bamboo walls can be cured with concretey sail or cow dung to prevent penetration of destructive inseet pests. • The external and strongest part of the bamboo laths which forro the weavin& makes the wall extremely resistant ta high levels of load from the structureytrusses y roo( and makes possible the construction ofstaries above. • Native and local people have developed this technique for Many generations, giving it great value as a cultural contnbution to local architectureyand meriting promotion as part of their traditional legacy.

4.5.1.4. \Veaving Flattened Bamboo \Valls.

• This type of wall does not need plasterin~ which greatly lowers labor and material costs. • OnIy one layer of weaving panels is needed to create a wall; this provides tremendous lightness when assembling. • Because of this lightnessy foundations are not

ChapterIV

neede~

and if necessary, only wooden

72


supports have ta be assembled. • The exterior and strongest parts of the bamboo panels are used to provide high resistance ta impact and to prevent collapse during seismic movements. • Only bamboo is used in this kind of wall~ making it even more economical than the rest

ofthe construction methods for walls mentioned in this chapter. • The structural frame provides the strength for the wall~ and permits the use of separate mobile panels when divisions inside the house are needed. • This is another one of the traditional indigenous methods of wall-making that maintains the cultural legacy of the vemacular architecture of Colombia and other parts of Latin America.

4.5.2. Structure.

• The physical fonn of bamboo provides great versatility in the

desi~

which means a

potential creativity for the structure~ as weil as in the joint making. • The traditional design of trusses and post-and-beam construction with bamboo for the structural part ofthe bamboo house~ has been used for Many generations, and today forms the basis from which to develop new designs and solutions for building. • The strength ofbamboo allows for the creation of large spaèes of great versatility in the design. • The capacity of bamboo to resist high levels of seismic movement makes the traditional bamboo structure one of the mast useful in Colombia. a country with a high level seismic activity. • The relatively low-cost ofbamboo has given many people the opportunity ta build better and more spacious homes.

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73


4.5.3. Floors.

• When elevated above the

ground~

bamboo floors provide for greater ventilation and

hygiene than t100rs at ground level. • The ease of installation of the esleri//a panels for floors, provides an economy in the overall cast of the house~ especially when provisional materials are used. • The traditional esterU/a floors can be removed easily if necessary to replace or when more permanent materiais are available. • Many other kinds of wood can be combined with the bamboo structure of the flaor and this characteristic gives bamboo great versatility in combination with other materiais. Timber, for example, can replace bamboo when necessary,

4.6. Disadvantages. 4.6.1. Walls.

4.6.1.2. Ba/laretflle Walls.

• Cracking may appear wheo plastering has oot been weB done particularly in applying the tirst layer, and especially when applying cow dung and other alternative materials for finishing. • Ta avoid these problems it is advisable ta place chicken wire onto the esterilla or flattened bamboo panels; however. this would increase the cast of the wall and the overall construction. • The bahareque wall system has traditionally been the construction solution for the poor ofColombia, and this had brought a feeling of rejection of this "lower status" construction

system on the part ofthose able to pay more.

Chapter/V

74

The Use ofBomboo in Architeclure

4.6.1.3. Eart/,-Filled Walls.

• The time needed for assembly when building tbis kind of wall results in higher labor costs compared to conventional ones. • Because ofthe long drying period of20 to JO days, it is difficult ta proteet tbis soil wall against the harmful effects of humidity, sunlight and insects. • The irregularity of the bamboo laths and posts makes these walls less flat when plastering, making the finishing more difficult and time-consuming. • Eventually cracking may occur because of the lack ofadherence between the plaster and the surface ofthe wall. • It may be necessary ta place chicken wire onto the surface of the wall, in arder for the plaster ta have a better adherence, and this results in an increase in the overall cast of the house.

4.6.1.4. The Quincha Wall.

• Building this type of wall is time-consuming and can generate greater labor costs. • This type of wall must be built by highly skilled people which can also delay the process of production. • The quilicha wall requires very specifie diameters of bamboo sticks and laths; this again could increase costs of labor and materials. • If the wall is not treated, the hamboo posts and beams are easily attacked by insects and

wood-eating pests because of the direct contact with the exterior. • The thinness of the quillcha walls results in a lack of thennal and acoustic insulation.

Chapter/V

75


4..6.1.5. Weaving F1altened Bamboo Walls.

• The long process of the wall-making increases labor costs. • This type of wall seriously lacks acoustic and thermal

insulatio~

and is ooly useful in

tropical and humid climates~ where temperatures vary little. • The life of the wall is quite short.. because putrefaction may occur due to humidity, termites and other insects
4.6.2. Structure.

• If nails are used in joints on the bamboo structure, they can damage the structure by causing cracks along the bamboo culm, and this eventually can lead to collapse. • If the joints are not properly assembled, i.e., in the cutting of the bamboo in the joints, then the structure is seriously jeopardized hecause insects and other wood-eating pests can penetrate very easily. • Bamboo must he protected with humt oil before being embedded into the concrete footing. In the traditional system this preventative measure is not taken, thus putting at risk the stability of the structure ofthe foundation. • The structure of the foundation is sometimes placed on stones or prefabricated concrete footing, but not embedded in them
ChapterlV

76


4.6.3. Floors.

• The esteri/la floars are vulnerable ta the attack of insects, which can seriously damage the entire fiaar. • The esterilla tloars cannat be used in areas in or near kitchens, bathraoms or laundry rooms, because high humidity generally damages them permanently. • The bamboo structure of these floars can also be negatively affected by the outdoor humidity because they are in direct and permanent contact with the exterior ofthe house.

ChapterW

77

The Use o[Bamboo in Architecture

5. Chapter V : The New Techniques of Construction With Bamboo In Colombia S.l Introduction. Many years passed before a great architect from Manizales, one of the coffee regions of Colombia, started to implement new and advanced methods of construction with bamboo and other local timber materials. Simon Velez used bamboo in a way that nobody had before; he expanded bamboo eaves providing ma.ximum capacity and resistance using conternporary materials such as reinforced concrete, steel and fibers. In this chapter l classify and analyze sorne of his master works, which are considered in Colombia and around the world ta be a reva[utianary in the use

of traditional materials and for

introducing new technologies of construction.

In this study one imponant source of information has been the work of Prof. Oscar Hidalgo, anather of several architeets who has developed new techniques of bamboo construction. The new techniques he developed are for prefabricated and in-situ use, and sorne ofthese l will describe in detail in this chapter.

Another important contribution to this chapter is the recognized wark of Prof. Carlos Vergara who died five years ago. His work focused on the employment of rice husk waste, and much of his later research was given to me by his own hand to develop and use in my warle, which was enriched by his formulas and important new applications in the

techniques ofbuilding with barnboo. The following is a selection forro the work of the above-mentioned great arcmteets which represents the most important achievements in the area of alternative bamboo technologies.

hapte,. V


5.2. Walls. The most representative examples ofbamboo walls in the modern and improved methods ofconstruction, are mixes ofboth styles; the Bahareque walls are made out ofalmost the same materials as the traditional ones with a variation in the finishin& a mix oflow.. cost y

painting components: Iime "nlarmolind' and water. Even though the following examples y

oflow-cost \-vaU are not made with bamboo their structural support is. y

S.2.1. Rice Husk Walls

Large quantities of rice husk are produced as waste material when the grain is processed

y

leading ta serious pollution problems. In the 60's. Prof. Carlos Vergara from Valle University started ta test its utility with different materials making slabs with sawdust y

using the ashes of rice husk as a component of Zorel cement. Later, in the 70·s. it was used rawas a light tiller material in concrete slabs (Los Fundadores residential compound

y

Cali 28.000 M2), Subsequently a house in a middle incarne neighbarhood and a country

house were built with cement panels containing raw rice husk. Theo Prof. Vergara tested rice husk with other waste materials which led him to the concept ofRice Husk watls or Parous Walls (/v/liras Espolljosos). The basic recyclable elements are: • Treated rice husk from rice mills. • Treated sawdust. a by-product ofsaw mills. • Waste coal resulting from incomplete combustion ofcoal in avens and boilers. y

• Hydrated lime, cement and water. 41 If it is possible ta get fly ash from the combustion of coal from industrial plants, it could be used by mixing it in bail mills ta diminish the quantity of cement up ta 50%. (Figs. 41

Vergara~ 1992:1-2

Chapter V

79


5.01.- 5.02).

Fig. 5.01. Silva house, Amanecer F. Rice Husk panels. (Source: Deselincourt, E. 1993)

Fig. 5.02. Workshop. Amanecer, Quindio (Source: Deselincourt, E. 1993)

Chapter V

80


S.2.1.1. Production.

The rice husk and the sawdust are treated in a solution oflime in water (5%) for 24 hours, or else rice husk and sawdust are mixed with lime and water then dried out for use.

S.2.1.2. The mixing.

• 1 cement sack (50 Kg) • 1/2 hydrated lime sack • 2112 waste coal sacks

• 2l/2 saw dust sacks • 4 rice husk sacks • 40 L ofwater The approximate volume resultant from the mixing is 1/4 M3 Ifit is possible to get flyash'l 112 of the cement sack is replaced by [/2 offly ash and 21/2 bumed and powdered rice husk sacks. 42

S.2.1.3. Physical characteristics.

• Resistance ta compression and flex tension currently being tested. • weight: 600 and 900 KglNl3 • Excellent thermic and acoustic insu(ator • Seismic resistant due ta elastie and plastic characteristics ofthe material • Hygroscopie, therefore it is necessary to waterproofthe exteriors

Ve~

1992:2

Chapter V

81

The Use afBamboo in Architecture

5.2.1.4. Process of production.

The components of the material are mixed

dry~

as in any concrete~ water is added and the

mix stirred again. The mix is poured in a rnold~ which will have convenient measurements to make blacks ar panels. The panels are of0.90 rn*OAS rn-O. 10 m.

5.2.1.5. Process oC assembly.

First the bambao structure must be completely finished in order ta make the walls. When blacks or panels are

used~

these are glued on their edges to the barnboo posts and beams

with plaster getting the adherence by barbed wire~ which is nailed to the bamboo structure. The panels are straightened~ to avoid lateral movement. If the wall is made in situ it is necessary to place the mold on each side of the bamboo

posts and make the plaster cast without vibration to avoid its disintegration; it is necessary ta compact the materiaI until it adjusts itself without leaving empty spots. Malds could be disassembled after 24 hours.",3

5.2.1.6. Comparative analysis.

The physical characteristics of the material and its components offer a comparative advantage ta traditional construction systems. a. The light weight (600 to 900 KglM3) gives simplicity and atfordability to the structure

and foundation.

43

Vergara~ 1992:3

Chapter V

82


b. As in any concrete~ its load capacity varies according ta the mixing dosage, but by the proved

tests~

a mix with 200 Kg. of cement1M3 gives appropriate charaeteristics for its

use for walls with a slimness = 30 c. It is a good thermie insulator. d. Its absorption coefficient from 8% ta 10% forces the protection of the surfaces exposed ta rain with a waterproofcoat or at least with a first coat of cement; however, because its surface could be even enough it would not need to be applied with the traditional plaster. A flat finishing could he

accomplished~

if wanted, with a coat of cement of minimum

thickness and then plaster and paint. e. The ductility of the material makes it resistant to cracking; the same characteristic makes it resistant to seismic movements. f. Because it is porous, it has good qualities as an acoustic insulator.

g. To add plastic elements, like carboximetil cellulose at 0.5% or povinilic alcohol at 10% in the water, allaw the immediate dismolding after pouring the mix iota the mold of the prefabricated wall, without collapsin~ up to a height of 10 times the thickness orthe wall. h. Qualitied tabor is needed only in the leveling and plumbing of the bamboo structure and molding~

the rest of the activities are carried out with unskilled laborers. This is an ideal

system for self-help construction programs.

i. Electrical and hydraulic installations are made before pouring the walls, to avoid their opening and restoration j. The low-cost of the rice husk waIls is based on the bamboo structure and the recyc1ing ofwaste products. The major costs are in the small amount ofcernent and in transport. oU

44

Vergc1ra.. 1992:4-5

Chapter V

83

The Use ofBanJboo in Architecture

5.2.2. ne Tendinoso Wall.

The Valle University aIso developed a technique that used bamboo as the main frame for the tendil1oso wall~ which consists of the rope-like plant fibers of coiTee jute sacks, barbed wire and cement.

This~

a law-cast, ecologically sound building materiaI that is quick to

construct and highly resistant ta compression, is one of the most eiTective and secure systems now implemented in the Quindio

are~

the coffee growing region of Colombia,

especially after the recent devastating earthquake which destroyed 60% of the region. It is important to mention that the bamboo buildings and homes remained intact after the earthquake, especially the Tendilloso wall houses at Amanecer near La

Tebaid~

a little

town in Quindio, which was 80% destroyed. Amanecer is entirely built with bamboo, Tendilloso and Rice Husk watIs. Ta make a Tendinoso wall it is necessary ta open up the jute coffee sacks and extend them on a tight barbed wire which is tied up to the knats of the bamboo posts. These posts must be separated by a maximum distance of 3 M. Once the sacks are extended on the barbed wire, they are tied together \vith thin wire. The sacks must be lied to the cement floor as weil as to the top bamboo beams of the structure. When there are no bamboo posts between the wall. but only wooden window or door frames, the barbed wire is extended along them, following the same steps as with bamboo. The next step is to make a cement-sand mixture and load the wall for the first coat; when this is ready - dry enoughthe next two or tree coats of thicker and drier plaster are added, the thickness of the wall depending on the design of the space and its internai characteristics. Usually the thickness depends on the width of the frame in arder to make a wall continuous and better finished. After the wall is plastered on both sides~ it is next painted either with lime or with commoR

acrylic or water base paint. (Figs. 5.03 - 5.04 - 5.05).

Chapter V

84


Fig. 5.03. Tendinoso wall with its tirst cement coat. (Source: Amanecer Bustillo R. 1993) t

t

Fig. 5.04. Ismail Hause, Arnanecer. Quindio tinished tendi"oso wall house (Source: Amanecer, Bustillo, R. 1993)

Chapter V

85


.=

.~~~~ ~ Ô\t~_.

••

Fig. 5.05. The 'Big Halr. Amanecer, Quindio. Tendinoso wall building. (Source: Arnanecer, Bustillo H. 1993)

S.3. Structure. In this decade the use ofbamboo has changed. Specially with the introduction ofbamboo in the construction of haciendas, country houses, and urban

houses~

new materiaIs, new

alternatives and ideas for bamboo structures are being developed by architects The following is a classification of the most important techniques and forms of bamboo structures, combining it with steel and concrete reinforcements ta get greater spans and more innovative ways of creating large spaces, and enriching and beautifying them with color and texture.

Chapter V

86


S.3.1. Prefabricated Three-dimensional Bamboo Structures.

A prefabricated framework of bamboo was designed and tested by Oscar Hidalgo in the Science Department of Palmira University. This was a model for rural school rooms measuring: 5.00 M * 8.00 ~ with a corridor for circulation and entrance of 2.00 ~ with a total of a 64 M of covered area. To caver the interior space it was necessary ta build 4 triangular rooftrusses, which are 8.00 M long * 2.00 M wide * 1.27 M high. Trusses were placed on a load-bearing bamboo structure and built with 3 parallei waoden beams of 6.00 cm * 20.00 cm, separated every 2.00 M and 5.00 M respectively. The roof could he built with channels from one side ta the other but a1so, between each threedimensional truss, with an extra gable roof sa that its two channels can take the water to the edge of the overhangs. olS

5.3.2.1. Norms of Construction.

• The three..dimensional bamboo structures are composed of three main pieces 8.00M long, placed parallel, farming in section an isosceles triangle of 2.14 M at its base and 1.27M high, with two equal sides 1.66M long. These pieces are joined at their sicles by other secondary ones which are composed of rafters and diagonal bamboo supports forming a triangular frame, and also by hamboo beams that join the two pieces perpendicularly. • In these structures only 3-year-old (or more) straight bamboos must he used, which have been previously cured in the bamhoo plantation, dried in the shade, and treated against insects. Their average diameter must be 10 cm. or greater and their average thickness one cm. Bamboo with the ones that have 4S

flowered~

fissures~

cracking or insects must not be used, nor should

because these have low resistance to traction and

HidaJgo~ 1978:69

Chapter V

87

The Use o[Banrboo in Architecture

compression. • The main pieces must be cut 9.00M or longer, to facilitate the transport of the finished truss. The remaining pieces will be eut once the structure is placed on the bamboo posts and beams. • It is not possible to establish an exact length for the rafters and diagonal supports due to the variation in size of the main pieees; however. if these pieces are going to he eut insidc the bamboo plantation and then taken to the place where they will be used, they must be eut l.SOM long ta be later re-cut to the exact measurement. • The three-dimensional bamboo structures must not be buUt on the earth but on four horizontal parallel bamboo bases., raised from the earth at least 30 cm, facilitating the nailing and tying ofthe joints of the secondary pieces to the two main pieces. These bases can also be made oftimher, leveled on its top side at the same height (30 cm). The bases must be 5. DOM or longer in arder ta allow at least the construction of two structures at the same time. 46

46

Hidalgo, 1978:69:70

Chapter V

88


5.3.2.2. Wooden triangular frames.

Ta make the bamboo structures the same in width and height, four frames or wooden triangles, are built with three pieces 10 cm wide and Sem thick. These are assembled by little wooden pieces that help to forro an isosceles triangle. Two equal sides which measure in the interior 1.66M

lon~

a longer side or base of 2.14M, and a height of

1.27M. These triangles must be made tight with wire in the joints for further dismantling once the structure is finished. To avoid movement of the structure, they are secured with braces that are placed at each side as is shown in the Figure 5.06.0$7

...

i _ _ _ _ _ _.=LH

-------t ~--.___r.

Fig. 5.06 (Source: Hidalgo, 1978:71)

47

Hidalgo., 1978:71

Chapter V

89


The rafters are placed every lM; they must he nailed loase ta maye them as necessary

when the diagonal pieces are placed. (Fig. 5.07).48

: tlanguler wOO
....

~/""'U.'=l~---Horizontal

Horizontal supports

supports

Fig. 5.07. (Source: Hidalgo. 1978:73). 48

Hidalgo. 1978:73

Chapter V

90


According to the kind of roof to be used, the structure is covered with &teri/la - unroUed bamboo- or the bamboo supports are placed with the dimensions and separations required. (Fig. 5.08). Fig. 5.08

Fig. 5.08. (Source: Hidalgo, 1978:73).

5.3.2.3. Assembly of the structure.

Due ta its lightness and rigidity, assembly is fast and easy. Trusses could be lifted manually or with a crane, which was used for the assembly of a four-bay experimental structure, which was assembled injust 40 minutes. (Figs. 5.09 to 5.12).49 Fig. 5.09. (Source: Hidalgo, 1978:77).

49

Hidalgo, 1978:77

Chapter V

91


Fig. 5.10.

~:';:~~:i~~'!.;~~

• ';

z~-

..

Fig. 5.1 1.

Fig. 5.12 L::.

...

Chapter V

'-

,j-~~'

...

:.~

'"r..

92

The Use ofBanlboo in Architecture

5.3.2.4. Application of plaster as a roof. The roof could be made on a bamboo structure using a coat of plaster of cement and sand in a proportion of 1:2, or ofsail-cement.

The esteril/a must be covered with a very liquid cement coat and then [et ta dry. Fig.S.14.

Fig. 5.14.

Chapter V

Fig. S.15

93


In this case it is necessary ta make tests with different proportions ta obtain the most

appropriate mix. Ta this mixing could be added straw cut 1 cm long. The quantity of water is detennined by the soil-cement when it is handled easily without leaking or defonning. (Fig. 5.14).50 Before the application ofthe soil-cement coat the roof must be humidified. (Fig. 5.15).

Application ofthe sail-cement to the roof. (Fig. 5.16). Leveling ofthe roof. (Fig. 5.17). Smoothing of the roof: (Fig. 5.18). Fig. 5.16.

,

Fig. 5.17.

Fig. 5.18.

~~ -

..

...

..

..

,~ ~.:~~ -

:...

..... .

•

~ ~

~_r-

Vamishing ofthe roof: (Fig. 5.19). Cutting of edges is done with a wooden board. (Fig. 5.20). Fig. 5.19. Fig. 5.20.

Chapter V

94


The application of the coat must he made vertically. (Fig. 5.21). The gutter ofthe roof. (Fig. 5.22). Exterior view ofthe finished room. (Fig. 5.23).

Fig. 04.21.

Fig. 04.22. (Source: Hidalgo, 1978:85).

Fig. 5.23. (Source: Hidalgo, 1978:84-86) 50

Hidalgo, 1978:83

Chapter V

9S


5.3.2. The Concrete-ReinCorced Bamboo, a New Technology The Concrete reinforced bamboo is a technology that uses the traditional bamboo construction methods combined with modem construction materials like concrete and steel bars, ta improve the tensile, compression and flexion properties ofbamboo. As in ail cases, bamboo needs ta be cured and protected previously in crder to be

reinforced with concrete. In each joint of the barnboo structure, a screwed 0.50 M steel bar of 0 112" is inserted along or across the bamboo, then the joint is filled with concrete of3.000 PSI. See Fig. 5.24.

The steel bars must cross the multiple bamboo posts, beams or trusses in order to work as one load-bearing element. Fig. 5.25. ln sorne cases, the bamboo knots must be removed to aIlow the steel bars and concrete to penetrate imide il.

gated

Steel ~....I. L;.•........,

1/2"

Fig. 5.24. Concrete-Reinforced Bamboo. (Source: Gonzal~ 1999)

Chapter V

Fig 5.25. Multiple bamboo truss crossed by the steel bars. (Source: Villegas, 1989:45)

96

The Use ofBamboo in A,chitectlUe

Fig. 5.26. The Coffee Par~ Quimbaya, Quindio. Funicular station. Simon Velez. (Source: Orozco. R. 1998) This process of reinforcement allows greater spans and interior free column spaces. Overhangs can be easily built with the help of the concrete-reinforced bamboo system. challenging gravity. these daring structures can support heavy roofs and f100r loads. (Fig. 5.26).

In the averhangs, joints must he carefully carved , in arder to allow the best adherence and accommodation in beams, trusses and posts. (Figs. 5.27).

Fig. 5.27. The Coffee Park Quimbaya, Quindio, lookout overhang. Simon Velez. (Source: Orozco, R. 1998)

Chapter V

97


Figs. 5.28. (Source: Villegas, 1989: 155) These carved joints are called in Colombia boca de pescado (Fish Mouth) joints, because its shape resembIes the open mouth ofa fish. Figs. 5.28

Chapter V

98

The Use ofBanlboo in Architecture

5.3.2. Super-Structures with Concrete-Reinforced Bamboo.

Simon Velez Arch.Twenty five years of experience in construction with timber, which was becoining every day

scarcer~

more expensive, and always badly cut and proportioned, led Simon Velez to

give his attention to mallg/e • very strang and resistant wood tram the Pacifie coasts of Colombia and to guadl,a~ whose commerciallength varies between 9 and 10 M. As mentioned before, guadua is the wood for the poor of the Old Caldas region. Mallg/e

is the wood of the poor on Pacifie coast. A few tests led Simon Velez ta leam to use it and to appreciate il. But with guadua he had the most difficult problems especially because of its wholeness. The difficulties arase when he had to resolve problems of structure assembly in joints to work in traction. At the beginning he used glladua in structures under compression loads; Le. arches. In this case he developed a technique that allowed him ta build structures with up to 20 M spans for roofs with cement plaster and clay tiles, a very heavy type of roof. For large overhang structures he filled the knots ofthe joints with cement in arder ta resist the strong tension forces present. These joints were the ones he used for placing the balts and steel reinforcements. The bamboo fibers are amazingly resistant ta tension; they are called vegetable steel'r. In these structures is necessary ta calculate the resistance of the Il

balts, not orthe bamboo. (Fig. S.29). Ir

With a construction system for structures of Bamboo-Guadua, where the joints for the

tension and compression forces are resolved, it is possible ta compete in equal conditions with materials such as timber~ steel and concrete

St

lr -

Simon Velez- .SI

Villegas. 1989:43

Chapter V

99


Fig. 5.29. The Catree Park

Quimba~ Quindio~ lookout.

(Source:

Chapter V

Orozco~

Simon Velez.

R. 1998)

100


S.3.2.1. Km. 41 House, Manizales, Caldas - Colombia. This house is composed of five main pavilions, each one of them with different structural characteristics. Only the 3 most important pavilions which contain the principal concept of Simon Velez's tirst approach to concrete reinforced bamboo super-structures are described.

5.3.2.1.1. The Main Pavilion.

In the main

pavilio~

shawn in the pictures, the overhangs are symmetrical spanning 6 M

overhangs. Concrete reinforced bamboo supports the heavy cement and clay roof in a way previously never exploited. This simple but very ingenious design allowed Simon Velez to start increasing spans in his constructions. The joint assembly is caUed: "Flute Supports", which consists of a concrete corbel and capital with bamboo flute supports embedded in concrete at the moment of the concrete pouring. The bamboo is beautifully placed lilee a flute, without the help of any column or vertical support. The ceiling is made with plastered chicken wire, and painted, letting bamboo show its beauty. Wooden planks were used as an additional support for the one..coat cement and clay roof. (Fig. 5.30a. to 5.32).

Chapter V

101


Fig. S.30a. Main Pavilion section. Km 41, Manizales. (Source: Gonzalez: 1999).

Fig. S.30b.

Fig.S.JOc.

Fig. S.29b Detail of concrete column and capital, with bamboo "fluted" support. Km. 41, Manizales (Source: Villegas, 1989:40)

Fig. 5.30. Central detaiI of the truss (Source: Villegas, 1989:45)

Chapter V

102


Fig. 5.31. Main Pavilio~ lateraI view. Km 41, Manizales (Source: Villegas, 1989:42)

Fig. 5.32. Main Pavilion. Rearview~ Km. 41, Manizales (Source: Villegas, 1989:43)

Chapter V

103


5.3.2.1.2. The Children's Pavilion.

This building uses mallg/e poles as columns and bamboo for the roof structure. Wooden planks are used as an additional support for the roof. Three pairs of mallg/e columns are raised from the t1oor~ but only two of them get to the top of the roof joining the three bamboo "flute" gable rafters. The third one has the function of supporting the 2 diagonal glladlla

braces~

which are aIso tied to the three

bamboo "flute" gable rafters. Also these braces are joined to the purlins by the so-called Boca de Pescado ("6sh mouth joint ta the bamboo collar beams. A O.SOM king post ties lt

)

the bamboo rafters and the cailar beams. The rafter is composed of groups of three reinforced-concrete bamboos; these have the funetion of supporting almast the whole load ofthe clay and cement roof The 6M long overhangs are~ as in the main

pavilio~

working

as one structure with the same elements: the concrete corbel and capital, and three horizontal arms which end at the overhangs in flute-like shapes. (Fig. 5.33a-b.).

Fig. 5.33a. Children's Pavilion section. Km. 41, Manizales. (Source: Gonzalez:1999).

Chapter V

104


Fig. S.33b. Interior of the Children's Pavilion. Km. 41, Manizales

(Source: Villegas, 1989:44)

Chapter V

105


5.3.2.1.3. The Stail No1.

As in the Children's Pavilian, the stail has treated mang/e posts and a concrete-reinforced bamboo roof structure. The rafters are composed of three fluted bamboos tied with balts at each union. Also the bamboo collar beams embrace these rafters and the purlins in a "Fish Mouth" joint assembly. The twa interior bamboo braces tied to the mang/e pasts give cantinuity to the 4M averhangs at each side. As shawn in the pieture, two mang/e posts raised from the ground and the other two meet their companions at the braces joint to form a perfect and balanced structure. The 8M span gives an open and column-free interior space, which is required for the circulation of the animais around the stail. The roof is covered with traditional Spanish clay tîle supported by 20 cm timber planks, separated every 35-40 cm. (Fig. 5.34a-b).

Fig. S.34a. Stail No 1 section. Km 41, Manizales (Source: Gonzalez:1999).

Chapte,. V

106


Fig. S.34b. Stail No 1. Km 41~ Manizales (Source: Villegas, 1989:170)

Chapler V

107


S.3.2.1.2. The Stail No 2.

This example of the combination of concrete and bamboo gives an idea of how wide a variety ofspaces could be conceived when using this type oftechnique. In tbis case the three bamboo tluted rafters are supported by six concrete-reinforced bamboo beams, also flute-like. These beams are at the same time supported by two 0.80 M diameter reinforced concrete columns. Single queen posts help to embrace the barnboo

fluted rafters and beams along the whole roof structure. Single king posts help to embrace the braced ridges to the beams. Ali this joinery is assembled with 0.30 M to 0.50 M long bolts, which combined with steeltensile, give the resistance ta this 6.00 M long overhang gabled roof. (Fig. 5.35a-b.).

Fig. 5.35a. StaIl No 2 section. Km 41, Manizales. (Source: : Go nzalez: 1999).

Chapter V

108


Fig. 5.35b. Stail No 2. Km 41, Manizales. (Source: Villegas, 1989:86-87).

Chapter V

109


5.3.2.1.3. The Social Area.

This arched structure is the central and main space ofthe house. Its 10 M interior span and 3.50 M long overhangs make every structural element work in compression. Concretereinforced bamboo in its joints tie the whole structure which has a footing foundation of l.00 M - 0.50 M. Every footing supports nvo main bamboo posts and two braces which are tied by the "tish mouth" joint ta the double bamboo collar beams. A third brace helps support the double bamboo ridge beams; a star shape is formed and embraced by a single double bamboo king post and four double diagonal bamboo king posts. Fig. 5.36.a- 5.37. Four secondary double beams are placed at the points of the star-like to form the arched structure. As in the above-mentioned examples, the overhangs are held by double bamboo braces and three bamboo fluted rafters. Wooden bamboo planks support the heavy clay tile root: together with the bamboo purlins. These elements support the esterilla ceiling which is covered with cement, a water-proof matenal.. and white painted chicken wire plastered for intenor finishing. (Fig. 5.38).

cloublc, "'", C,,"C~&Y&i~f(,e.d ID~DP joiMs

J

) Fig. 5.36a. Social area orthe house. Km 41, Manizales. (Source: : Gonzalez:1999).

Chapee,. V

110


Fig.S.36b.

Fig. 5.37

(Source: Villegas, 1989:170)

Fig. 5.38. (Source: Villegas, 1989:170)

Chapter V

111


5.3.2.2.The ZERI Pavilion, Manizales The ZERI Pavilion is a circular buildin~ which was built with

bamboo~

and also another

exceIlent resistant-to-tension-and-compression Colombian wood called Alizo. This 40 M diameter building was designed and built as a test model for the ZERI (Zero Emissions Research Initiative) Congress in Hanover~ Germany. (Figs. 5.38. - 5.40.).52 Fig 5.38. Longitudinal section orthe Pavilion. (Source: http://www.zericongress.org.co/pabellonlpabelIon5.htm)

"It is a prototype of a pavilion to be built at EXPO 2000 in Hanover. The technique is 50

revolutionary that German building regulations could not permit it to be built in Hanover until the Govemment was convinced a replica huilt elsewhere would stand up. Now they are sending a team out to Colombia to 5ee Simon Velez's MA5TERPIECE. ,,53 This mushroom-like construction was developed for ZERI by Simon Velez and can he considered as one ofthe most inspiring examples of "sustainability" and the re-usability (and not only ofthis) ofbuildings and their construction. Sol http://www.zeri.orglpa\illionlimg/ext ori.gif Brown. P. The Guardian~ Julv I·t 1999 S4 Deutsehes ArchitektenbIau No·t 1999 - 472

52

n

Chapter V

Il2


-

Extl.-m al Flut' 1 ColulTms 1~~~~3ii!sa

Intemal Flute· Columns

·{Vr

DI

1/

Fig. 5.39.

~

..

-- .

&tt.-rnal Cro\\'n

Internal

E~tcrnal

Column

CO[umn Fig. 5.40.

Figs.5.39. and 5.40. Pavilion sections. (Source: http://www.zericongress.org.co/pabellon/pabellon5.htm)

Chapter V

113


5.3.2.2.1. Foundatiolls.

To avoid any contact with the humid soil, raised concrete bases were made and which will also hold the alizo posts. (Fig. 5.41.). The bark from this long and highly resistant wood has to be removed before its use. Sockets are placed in their bases, to avoid contact of the wood with concrete, helping ta keep the structure free from humidity.

Fig. 5.41. Alizo posts base socket. (Source: http://www.zeri.orglpavillion/)

Chapter V

114


5.3.2.2.2. The Alizo Poso.

This wood has been used by Simon Velez for a number ofyears in his structures. Used in combination with bamboo, its resistance allows for great spans and overhangs. The a/izds rounded end aIlows easier accommodation for the sockets and better adherence to the steal bars. A hale is made in the base of the post to insert the el 3/4" steel bars of 0.8 M long, placed

and then inserted into the aUzo posts as shown in Figs. 5.42. ta 5.44.. Their diagonal position plays an important role in the holding and perfect balance of the immense load of the clay tHe roof.

Fig. 5.42. Concrete foundation. (Source: http://www.zeri.orgfpavillionl).

Chapeer V

Ils


Figs. 5.43 - 5.44. Connection between posts and foundation (Source: http://www.zerLarglpavillionl).

Fig. 5.43.

Chapter V

116


5.3.2.2.3. Bamboo beams and concrete reinrorced joints.

The 9 M bamboo beams are assembled on the ground.. and water cement is introduced into 11

the joints. 0 1/2 Steel bars are used. Steel braces are placed at the surfaces of the triple bamboo beams which surround the whoIe structure. (Figs. 5.45 and 5.47.). IIThe architect.. Simon Velez.. invented the technology for uniting severa! pieces to maximize the tension strength. He injects fine cement into the inside of the bamboo and tightens it with copper balts. It is ooly thanks to this invention that large structures like the pavilion with overhangs of up to 9 meters can be constructed at such a low priee, competing with steel and cement structures, while creating an immense visual effect both inside and outside. "ss

Fig. 5.45. Inserting the steel to the bamboo bearn. (Source: http://\vww.zeri.orglpavillionl). SS

hup:l/www.zeri.orgipavilIionl

Chapter V

1I7


Fig. 5.46. Assembling the bamboo beam. (Source: http://www.zeri.orglpavillionl).

Figs 5.47. Detail ofjoint ofreinforced bamboo and alizo. (Source: http://www.zeri.orglpavillionl).

Chapter V

1I8


After the on-ground wark is fini shed, scaffalding is assembled to raise the beams and rafters. (Figs. 5.48 ta S.5l.).

Fig. 5.48. (Source: http://www.zeri.orglpavillion/).

Fig. 5.49. (Source: http://www.zeri.orglpavillion/).

Chapter V

119


~~.. ~ . Fig. 5.50. Overview 1. (Source: http://www.zeri.orglpavillionl).

Fig. 5.51. Overvie\v 2. (Source: http://www.zeri.org/pavillion/).

Chapter V

120


At a height of 13.5 ~ This 2 M diameter steel ring receives aU the compression from the roofstructure. (Fig. 5.52 and 5.53.). (Source: http://www.zeri.orglpavillionl).

Fig. 5.53. Detail of metallic ring and steel reinforcement. (Source: http://www.zeri.orglpavilIionl).

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5.3.2.2.4. The Overhang. The most gravity·daring element of the whole structure is this 9 M long overhang. The joint in its base is a knot of four Ali:o posts, novo fluted bamboo capitals, and six fluted reinforced concrete bamboo overhang beams. (Figs. 5.54 to 5.61.)s6 The quadruple diagonal A/izo posts trom the interior hold the quadruple braces that are assembled to the steel ring. Cement is poured into each bamboo joint and then embraced with steel and copper bolts. Steel tensiJe are assembled ta strengthen the joints. AIso diagonal braces unify the whole structure, making it very stable and perfectly balanced. Because of the strong concrete reinforcement in every part of the buildin& this structure is earthquake resistant, one of the elements that have proved to be extremely effective when these natural disasters occur.

Fig. 5.54. Support joinery of overhang 1. (Source: http~lI\vww.zeri.org/pavillionlpaviIlion.htm#)

56

http://www.zeri.orglpavillionlimgfprocJp-I/ovcrhang.jpg

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122


Fig. 5.55. Supportjoinery ofOverhang 2. (Source: http://www.zen.orglpavillion/pavillion.htm#)

Fig. 5.56. Overhang structure. (Source: http://www.zeri.orglpavillion/pavillion.htm#)

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The Use ofBanlhoo in Architecture

Fig. 5.57. Upper floor corridor. (Source: http://www.zeri.orglpavillion/pavillion.htm#)

Fig. 5.58. Ceiling of overhang area. (Source: http://www.zeri.orglpaviliionlpavillion.htm#)

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Fig. 5.59. Applying mortar ta the ceiling. (Source: http://www.zeri.arglpavillionlpavillion.htm#) Fig. 5.53 .. (Source: http://www.zeri.orglpavillionlpavillion.htm#)

Figs. 5.60. Overview of the finished pavilion. (Source: http://www.zeri.orgfpavillion/).

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Figs. 5.6 L The Zen Pavilio~ Manizales, Colombia. (Source: http://www.zeri.orglpavillionl).

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126


5.4. Advantages. S.4.1. Walls. S.4.1.1. Rice Husk Walls. • Its Iightness makes walls very easy to handle, creating laber savings since one man can J

carry twe panels at the same time. • The lightness also saves money in

foundations~

because the quantity of steel is not the

same as in the traditional brick or concrete wall. • Because of its porosity, this kind of \vall has great thermal and acoustical insulation properties. • High compression resistance. • The rice husk panels can be cut easily with a saw~ aIlowing Many possibilities for shapes and forros when bamboo braces and beams are embedded inta the wall.

S.4.1.2. TelJdinoso Walls

• This wall is highly resistant to earthquake and seismic movements. • Very inexpensive materials are needed for its construction. Sorne of them are recyclable organie produets. • Like riee husk walls, tendinoso walls permit a variety of farms and shapes when braces and beams are ernbedded inta the waiL • Highly resistant ta compression. • The thiekness of the walls can he easily increased by adding more coats of plaster on each side ofthe wall, according ta the functian of the space.

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5.4.2. Structure. 5.4.2.1. Prefabricated Three-Dimensional Bamboo Structures.

The prefabricated three-dimensional bamboo structures have the following advantages compared with timber structures, used commonly in the construction ofgabled roofs. • The prefabrication system allows the structure of the roof to be made on the floor, before or during the construction of the structural bamboo frame. This way the danger of accidents is reduced and also the assembly time could be minimized, depending on the number ofworkers available. • Due to the rigidity and lightness of the bamboo structure, this could he prefabricated in places other than the site, where there could be better space, and avaiIability of materials and workers, and then transported ta the construction site. • The construction of the bamboo structures is

50

simple that it could be done by the

peasant or the community without the need of specialized carpenters. • Their cost is very low, especially where material is abundant and the distances are relatively short. Also the structures do not need the ceiling commonly used in the gabled roofs. • Due to their shape, they allow better illumination and ventilation in the interior spaces, important requirements in the construction of rural schoels. • These three-dimensional structures are appropriate for anti-seismic construction, due to the resistance and flexibility of bamboo and also to the rigidity given by their triangular shape. •

Besides their use for

schools~

housin& and rural buildings, these structures are

appropriate for the construction of shelters and emergency hospital installations in times of disasters by earthquakes or floods.

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128


5.4.2.2. Super-Structures with Concrete-Reinforced Bamboo.

• Great spans can be covered \vithout much Interference by posts in between. Ideal for wide corridors in rural houses. • Highly inexpensive bamboa structures~ • Because of its natural and chemical treatment, bamboo can last many decades with constant maintenance and care. • Structures are capable afbearing loads ofup ta tive floors. • Dynamic and beautiful structures can be used for multiple functions due ta the large and open interior spaces they permit. • A great variety ofspaces can be designed using a repetitive partico.

5.5. Disadvantages. S.S.l. \Valls.

S.S.l.l. Rice Husk Walls.

• Careless handling can cause wear. • If experienced labor is not

available~

the long process in the production can lead ta

delays. • When working on site, experienced labor is needed which is hard ta tind in an innovative system. • Panels can be difficult ta make ifthe right molding is not available. This could lead ta an increase the cost ofthe walls. • Transportation of panels can be costly due to their volume.

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129


5.5.1.2. Tendinoso Walls.

• Due to their physical characteristics.. lendilloso walls are not thermally and acoustically insulated;

therefore~

noise can invade interior spaces and temperatures can not be

regulated. • Unlike rice Husk walls.. tel1dillOSO walls need a frame ta extend the barbed

wire~

increasing costs for wood and bamboo. • Once the wall is made.. it cannot be changed or corrected unless it is completely demolished. • Cement can be wasted ifthere is no control over the thickness of the wall. AIso one side might have a different thickness from the other one.

S.S.2. Structure.

5.5.2.1. Prefabricated Tbree-DimensionaI Bamboo Structures.

• Fabrication ofthis kind of structure requires large areas ofland~ making it difficult when building in the city. • If gutters are not properly sealed.. Ieaking could become a problem and eventually the

rotting bamboo could cause serious structural problems. • Steep increases ofcosts when cranes are used to lift the structures. • Extra costs in labor could occur when using manpower for lifting structures.

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5.5.2.1. Super Structures with Concrete-ReinCorced Bamboo.

• Large amounts of bamboo are needed for this kind of structure. When there is no control in the municipality. eventual deforestation and damage in the ecosystem could oceur. • Highly experienced labor is needed, and this leads ta increased building costs. • The time required ta make the structure makes for high labor costs.

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6. Conclusions. During the study of techniques of bamboo construction for waIls, structure and Boors, 1 predictably the best representative examples occurred in countries with a strong tradition in building with bamboo. In Asia. the walls and the structures were, more than the floors,

the focal point of Many generations of architects engineers and builders. For instance in lapan, the detail in the interior design of the spaces with bamboo was very important, especially when building ceilings. The structures, in these examples, were bullt to give spatial and decarative sensations for each area. The care and measured treatment they gave to bambao is fascinating to see; bamboo was rarely nailed but was tied with ropes to avaid its cracking and future damage. The same care is seen in the wall-making, where walls were constructed with the bambao framed and then tied with ropes, Many centuries praye the resistance and structural strength ofthese walls. ln India we see a ditrerent

scenario~

first of ail these structures where built for little

villages and law-incarne families - not in cities as in lapan techniques were developed for walls that are still used

today~

the \voven bamboo walls have their roots in India. The

structure is also worked with ropes in the joinery in the Japanese style., but not as detailed or well-assembled. What is interesting in India is the extensive use of bamboo for thousands of families who live in villages, the way of transporting bamboo and ilS traditional in the culture of vemacular architecture. In America, the view is different from that in Asia. Hawaüan wall-making is very similar to Colombia; the unrolled bamboo walls and the esterilla walls are practically the same. In the structure~ which resembles the Asian systems in its joinery, rope is tied to the joints ta avoid, cracking, but aIsa prevents the development of the larger spatial structures which we saw in Colombia. Hawaiian architecture is vemacular as in Iodia, and could be c1assified as a mixture aftwo continental cultures. In Colombia the traditional architecture of bamboo has been develaped ta a point where

Chapte, VI


almost anything could be made raster, cheaper, stronger and more

beautifu~

and only

bamboo seems to be able to combine ail ofthese fundamental charaeteristics. In the last decade, the combination of new materials such as steel, cement, and copper

with bamboo has produced remarkable results. This had lead iota a new direction to consider traditionaI materiaIs in the new Iight. More scientific and technical work needs ta be done in promoting its use. Even though beauty and technical performance bas been demonstrated in this

researc~

critical analysis

ofenergy and sustainability should he undertaken. With the new constructio~

to-do

bambao has proved ta an excellent material for housing

not only for lo\v-ineome

families~

mavements~

technology~

families~

who have used for centuries but for well-

who find bamboa to be the best solution for resistance to seismic

the best element ta ereate greater spans far living spaces~ and one of the most

beautiful oatural product available.

The new generation ofarchitects and engineers have round bamboo ta he the ooly material ta combine ail the characteristics needed for the creation of a new kind of architecture, more alive~ more beautiful~ more human.

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133


7. Bibliography. 1. Austin, R. & Ueda, K. (1970). Bamboo. New York: Weatherhill.

2. Austin, R. & Ueda, K. (1983). The world ofBamboo. San Francisco. 236 3. Bain C. and Coll E. (1995). Bamboo Slide Show. http://www.kauai.netlbambooweblbambooslideslbambeoslides.html 4. Caceres, R. H. (1969). Ensayos de Preservacion de la Guadua Contra Hongos e Insectos. 59, 8-19, 60, 26-34. 5. Castane, N. F. (1982). Memerias dei II Simposio Latinoamericane de Guadua. Algunes Aspectos Sobre el Cultiva y Aprovechamiento de la Bambusa Guadua en Colombia. 52. Guayaquil. 6. Castane, N. F. (1985). Introduccion al Estudio Fitoecologico de los Guaduales dei Valle Geografico dei Rio Cauca en el Suroccidente de Colombia. 18. Cali: C.V.C. 7. Castano, N. F. (1989). Seminario La Guadua Como Material de Construccion. Reforestacion Con Guadua. Medellin: Universidad National. 8. Colonial Liaison Officer, Building Research Station. (1957). Colonial Building Notes, 46. Watford, Herts: Department of Scientific and Industrial Research. 9. Darrel, D. (1996). http://csf.colorado.edulpermaJbalancel0058.html

la. Del Castillo, M. T. Aja La Casa. {1993}. La Guadua Prodigio Natural de Mil Usas. 1. (3), 32-40.

Il. Dicken C. (1981). Forma Viva- El Oficio dei Diseno-. Bagota: Escala LTDA..

12. Duly C. (1979). The Hauses ofMankind. Thames and Hudson. 13. Englerth't G. H. & Maldonado, E. Tropical Forest Notes. Bamboo For Fence Post. 6. Rio Piedras, P. R.: Tropical Forest Research Center. 14. Farrelly, O. (1984). The Book ofBamboo. 340. San Francisco: Sierra Club Books. 15. Flores, O. & Noreiia, C. (1981). Nueve Metodos de Propagacion Vegetativa de la Guadua. 2.1, 32-47.

ChapterVII


16. Gom~ H. M. (1994). La Guadua Programa de Desarrollo alternativo en Colombia,

Serie Cartillas. Bogota: Editorial Antares.

4

17. Hajada J. (1985). The Lesson ofJapanese Architecture. New York: Dover Publications, !NC. 18. Hidalgo, O. (1974). Bamboo, Sil Cultivo y Ap/icaciones en: Fabricacion de Papel,

Constnlcciol1. Arquitectllra. /ngenieria. Artesauia, Bogota: Estudios Tecnicos

Colombianos LIDA. 19. Hidalgo O. (1978). Nuevas Técnicas de Construccion Con Bamboo. Bogota:

Universidad Nacional de Colombia. 20. Hidalgo, O. (1981). Manual de Construccién con Bambu. Construction Rural 1. N

Bogota: Estudios Tecnicos Colombianos LIDA. 21. Janssen 1. A. (1988). Bllilding Wilh Bamhoo. London: Intermediate Technology

Publications. 22. Kitao H. (1958). Formation ofBamboo. Tokyo: Shokokusha 23. Liese, W. (1980). Anatomia y Preservacion dei Bambu. Singapore: International

Development Research Center. 24.

Londono~

F. & Montes. M. A. (1970). La Guadua y su Aplicacion en La

Construccion. Cali: Bedout. 25. Londono~ X. (1988). Bambues dei Nuevo Mundo~ con Enfasis en el Genero Guadua.

Cali: Inciva. 26. McClure, F. A. (1966). The Bamboos a Fresh Perspective. Cambridge: Harvard University Press. 27. McClure, F. A. (1973). Genera ofBamboos Native to the New World (Gramineae: Bambusoideae). Washington: Smithsonian Institution Press. 28. McClure, F. A. (1986). Chinese Handmade Paper. Newton: Bird & Bull Press. 29. National Council of Applied Economie Research. (1995). Demand Forecast for

Bambao Sulphate Husk. New Delhi.

Chapter VII

13S


30. Revista El Buen Vivir. (1996). La Guadua: Una Alternativa Viable. 23. 36-41. 31.

Sharm~

Y. M. L. (1980). Bamboo Research in Asia. 28-30. Singapore: Gilles Lessard

and Amy Chovinard. 32.

Stee~

A. S.,

Stee~

B., David B. (1994). The Straw Baie House. Vermont: Chelsea

Green Publishing Company. 33. Susuky, T. (1984). Ecology, Physiology and Cultivation Practices: Bamboo. Forestry

and Forest Researeh Institute. 34. Takama S. (1985). Bamboo oflapan. Tokyo: Gurafikkusha. 35. United Nations. (1972). The Use ofBamboo and Reeds in Building Construction.

New York: Department ofEconomie and Social Affairs. 36. Vargas, L. R. (1990). La Guadua: Un Regalo de La Naturaleza. Bogota: Federacion Naeio~al

de Cafeteros. 72.

37. Villegas M. (1989). Bambusa Guadua. Bogota: Villegas Editores. 38. Wells 1. (1995) . Population, Settlements and the Environment: The Provision of Organic Materials for Shelter. Habitat International, 19 (1). 73..90. 39. Williams, G. (1991). Wovell Archïtecture Thailalld t

http://stafInavisoft.comlgwwrrhaiIand1techniques.html(1994). 40. Yoshida T. (1954). The Japanese House and Garden. London: The Architectural Press London.

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The Use of Bamboo in Architecture Case Study Old Caldas Colombia

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