A TECHNICAL REPORT ON POST GRADUATE WORK EXPERIENCE AND RESPONSIBILITY IN CIVIL ENGINEERING
PRESENTED BY
ALLI-OLUWAFUYI, MAKNUN OLORUNTOFARATI (B.ENG. CIVIL ENGINEERING)
SUBMITTED TO THE COUNCIL FOR THE REGULATION OF ENGINEERING IN NIGERIA
(COREN)
IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR REGISTRATION AS A MEMBER OF THE COUNCIL FOR THE REGULATION OF ENGINEERING IN NIGERIA (COREN)
FEBRUARY 2016
CERTIFICATION This is to certify that I, ALLI-OLUWAFUYI, MAKNUN OLORUNTOFARATI OLORUNTOFARATI have written this report myself and it is a true account of my training and work experience in partial fulfillment of the requirements for admission into the corporate membership of the Council of Regulation of Engineering in Nigeria.
--------------------------------------Signature of candidate and date date ALLI-OLUWAFUYI, ALLI-OLUWAFUYI, MAKNUN O. AWOSANYA Name of Candidate
--------------------------------------Signature of Senior Engineer and
ENGR. ABAYOMI Name of Senior Engineer
CERTIFICATION This is to certify that I, ALLI-OLUWAFUYI, MAKNUN OLORUNTOFARATI OLORUNTOFARATI have written this report myself and it is a true account of my training and work experience in partial fulfillment of the requirements for admission into the corporate membership of the Council of Regulation of Engineering in Nigeria.
--------------------------------------Signature of candidate and date date ALLI-OLUWAFUYI, ALLI-OLUWAFUYI, MAKNUN O. AWOSANYA Name of Candidate
--------------------------------------Signature of Senior Engineer and
ENGR. ABAYOMI Name of Senior Engineer
ACKNOWLEDGEMENT I wish to show gratitude to my current employers – LuxxorGas, LuxxorGas, for giving me the privilege to undertake the project that has been a focus of this report and to all my former employers who gave me the opportunity to acquire these various civil engineering experiences. Particular mention is Engr. Gabriel Ojo and Engr. Sanni of Sanni, Ojo & Partners who helped me appreciate civil engineering during my six months internship at their firm. And lastly, to my teacher, Professor A.A. Adedeji of Department of Civil Engineering, University of Ilorin who taught me Structures in the most beautiful way.
TABLE OF CONTENTS Acknowledgment List of pictures List of tables List of figures Summary CHAPTER ONE 1.0 Introduction 1.1 Brief history on personal experience 1.2 About LuxxorGas 1.3 Organisational culture CHAPTER TWO 2.0 Project Discussion 2.1 Introduction of the project design 2.2 Site construction 2.3 Gas Station site selection 2.4 Location of Gas Plant CHAPTER THREE 1.0 Design discussion 2.0
PAGES
1 – 3 3
LIST OF SYMBOLS BS 8110 – British Standards 8110 As – Area of Steel c – concrete cover b – width of the section f cu – characteristic strength of concrete f y – characteristic strength of steel h – height of section d – effective depth of section gk – characteristics dead load IL – imposed load LC = load combinations LL – live load M – moment due to ultimate load qk – characteristics live load V – shear force v – shear stress WL – wind load Vc – ultimate shear stress in concrete Y – high yield steel N – design load
ABSTRACT It is a standard for prospective corporate members seeking admission into the Council of Regulation of Engineering in Nigeria (COREN) to have undergone four years of postgraduate engineering experience, write and submit a report of experience of work after graduation. This report is hereby presented by me. The report is comprised of a summary of my post-graduate experience till date composed of five chapters each detailing the various experiences I acquired over the period after graduation. The experience covered in the various aspect of civil engineering includes: 1. Building Construction 2. Road construction 3. Piling 4. Gas Plant Development and Construction 5. Structural drawing and detailing 6. Project Management 7. Preparation of Bill of Engineering Measurement and Evaluation.
CHAPTER 1 1.0 1.1
INTRODUCTION BRIEF HISTORY OF PERSONAL EXPERIENCE
I graduated from the University of Ilorin after studying Civil Engineering and awarded a Bachelor of Engineering (B.Eng) degree. I started my career as an Engineering Supervisor with Hydraform during my NYSC. I worked on a 200 unit residential estate with infrastructure. The project was a mass housing residential estate in Kuje. The housing units were three bedroom semi-detached built from lateritic blocks which required no mortar. This was an innovative technology from south Africa. The blocks were producing my mixing 1 part of cement to 8 parts of lateritic soil. For soils with high clay content, one part of sharp sand is added. Water/Cement ratio is about 0.2. The mix is fed into a machine with top and bottom molds. This compresses the mix to produce a block. Average weight of blocks is 10kg. There were 200 housing units to be built along with road networks. While working on the project, I was involved in the construction of 48 units out of which 12 were completed ready to be habited. I directly supervised using direct labour the construction of six unit bungalows, a 200m road, a reinforced concrete reservoir, 2 overhead steel water tanks. I was also solely responsible for our production facilities - which produced hydraform blocks, sandcrete blocks, concrete pavers and concrete kerbs. In my stay ay at hydraform , I produced a total of about 200,000 hydraform blocks, 50,000 kerbs and over 500,000 paving stones. I also headed a quality audit team which was responsible for quality control of all concrete works on site. I attended a road construction management course organized by the Nigerian Institute of Civil Engineers in Abuja. In conjunction with my project manager, I designed the drainage and pavement structure of the road and was solely responsible for the construction of a 200m road. Interlocking paving stones were used as wearing course for the road. I carried out remedial works on a failed underground water structure. In addition, I successfully supervised the construction, installation and commissioning of a water plant for the estate. Before leaving Hydraform, I completed trenching for electrical cabling, and piping from the river (water source for the plant) to the water plant site of about 10km stretch across the site. This work involved taking spot levels, transfer pump installations and erection of safety signs. I proceeded to Kharrl Tech Engineering Nigeria Limited as a Projects Engineer, where I successfully completed three bored pile installation projects and a shoreline protection project. I was involved in pile design and construction. I was also involved in sheet pile production. A manufacturing like process was adopted in the sheet pile production.
I presently work as a Project Manager with LuxxorGas, a subsidiary of The Luxxor Group. I have oversight responsibility for all construction projects across the group’s subsidiaries. I have three projects on-going.
1.2 ABOUT LUXXORGAS LuxxorGas L.L.C, is a privately owned company specialising in the distribution and commercialisation of Natural Gas in West Africa. It is a wholly owned subsidiary of The Luxxor Group. We serve the market a cheaper, cleaner, more sustainable alternative fuel. Our Services are aligned to the Nigerian Federal Government's efforts to increase domestic Natural Gas utilisation as an alternative energy source to the more costly, overwhelmingly imported fuel oils, which negatively impact the local economy. We are committed to continually introducing innovations that have, and will change the face of the Industry. LuxxorGas views every Natural Gas distribution challenge as one more opportunity for an exciting and comprehensive solution. Our proprietary delivery mechanisms are only part of the answer to the sustainability related problems that continue to challenge the Energy industry at large. Our corporate philosophy and business model is centered on the core belief that investment in innovation, progressive development and consistent implementation is the key to success. While our company takes pride in its past successes, our unwavering corporate focus continues to look towards the new and dynamic natural gas opportunities of the future. 1.3 ORGANIZATIONAL STRUCTURE The Group CEO has the overall responsibility for the company. The project management team is headed by the Project Manager who assigns project developers, engineers and superintendents to the various projects. Find the organogram attached in Appendix 1.
CHAPTER 2 2.0 PROJECT INTRODUCTION This section explains in details one of my designs and built project I undertook after graduating from the Department of Civil Engineering, Faculty of Engineering and Technology, University of Ilorin, Kwara, Nigeria.
This design involves the design of a reinforced concrete isolated pad foundation manually with use of the text book “Reinforced Concrete, Analysis and Design” by S.S. Ray, BE (Cal), CEng, FICE, MBGS. The design calculation was carried out manually and structural details presentation was drawn with the use of AUTOCAD. This project is based on a Compressed Natural Gas (CNG) Plant development and construction for LuxxorGas Nigeria. 2.1 Project Purpose This project has been created to supply gas to meet internal demand for use in power generation, and also to enter the untapped segment of CNG processing and distribution in the gas market in Nigeria. The business objectives for this project are in direct support of The Luxxor G roup’s corporate strategic plan to streamline process across its subsidiary groups. Distribution of Compressed Natural Gas (Methane/Pipeline Gas) to stranded assets which are off pipeline networks Enabling wider access to cleaner, cheaper more sustainable natural gas Strategically place CNG in the automotive market place as a verifiable alternative to conventional fuel sources including Petrol and Diesel.
2.2 Project Description The project is to develop a CNG Mother Station in Ota, Ogun State, Nigeria with a capacity of producing 866.44 MMSCF/year of gas in the first year and increased to 8,385.00 MMSCF/year by the 5th year. The project will be used to supply internal demands for gas which will account for 35% of production in the first year. The excess production will be commercialised by serving areas that have no access to pipeline gas using our proprietary distribution network which is also part of this project. The distribution network will make use of trailers, trucks and barges to distribute CNG to areas with no pipeline accessibility.
2.3 Project Duties and Responsibilities I am the Project Manager and Technical Lead for this project and have ultimate responsibility for the project. The project involves the design, construction, commissioning and transfer of operation of a Compressed Natural Gas (CNG) Mother Station. My main duty and responsibility as a project manager was to manage all phases of the project up to handing over for operations. Other duties I effectively carried out include the following: - Site assessment and selection
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Commercial negotiations with land owners Site recommendation for onward purchase Selection of design professionals Co-ordination of all design activities Selection of equipment vendors and material suppliers Assembly of project team Assignment of roles and responsibilities to team members Co-ordination of activities with external agencies – Ministry of Works, Town Planning, Fire Agency, Police etc. Direct supervision of construction works Engineering Design of pavement structure Implementing QA/QC program Chief Safety Officer Direction of project management activities
The project deliverables are as follows: - Trailer park - Compressor building - Piping system - Fencing - Drainage - Compressors Installation - PRMS (Pressure Reducing Metering Station) Installation 2.4
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PROJECT SCOPE OF WORK Designs Soil Tests Equipment/Materials Procurements Project/Construction Management Contracts Management Gas Piping System Testing and Commissioning of the Gas Station
2.5 GAS STATION SITE SELECTION Different sites were visited prior to final selection. Sites were assessed based on the following criteria: - Proximity to gas pipeline route - Site accessibility - Absence of encumbrance - Site Topography
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Property Title Documents Final Acceptance by Gas-Line Franchisor
The site was selected based on certain criteria which include proximity to a natural gas pipeline, easy trailer access to site, traffic considerations etc. An Environmental Impact Assessment (EIA) was carried out and approved by the planning authority.
2.6 GAS PLANT DESCRIPTION A CNG Mother Station, is a gas processing facility which off takes gas from the pipeline, compresses it using mechanical compressors and then transfers it in skids or tubes that are loaded and transported using trailers. Natural gas is transmitted through pipelines at low pressures from the gas fields in Escravos. The natural gas is thereafter processed at the Mother Station by compressing at high pressures. The term “Mother Station” refers to a compressing station, where gas is processed. A “Daughter Station’ on the other hand - mostly located at client sites - is a downloading station where compressed natural gas is decanted from the gas trucks. A valve is connected at the take-off point located in a valve pit. The valve-pit is a manhole for the pipe connection.
2.7 PROJECT DESIGN CONSIDERATION The overall design consideration was to design a gas compression station that gives most value and least cost. Value Engineering was done on all designs. This was done by seeking second opinions from equally qualified design professionals and subsequently getting the designer to meet with the constructor/contractor prior to starting works. The main structure is a compressor building which houses the compressors. The compressors are heavy mechanical equipment used in natural gas compression. Other structures include the office building, generator and gate houses, trucking bay, car park area and a piping system. Other design considerations include, storm water drainage, slip proof easily maintained pavement structure, long span high clearance building, transparent fencing etc. Site layout designed was carried out by me in conjunction with the gas project development team. This formed the basis of the design brief subsequently transmitted to the Architect. Structural design of steel frame, M&E Services, ICT were outsourced to external consultants.. The project design can be sub-divided as follows, - General Site Layout - Architectural
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Civil/Structural Electrical Mechanical/HVAC ICT Gas Piping
2.8 SITE DESCRIPTION The site covers 4,200 sq.m area of land located along Idiroko Road in Igboloye Village, Ota, Ogun State. It is of a steep topography with maximum and minimum spot heights of xxx and xxx respectively. Top soil is black organic soil with underlying firm lateritic soil of close to 2m depth.
CHAPTER 3 3.0 DESIGN OBJECTIVE The design objective was to design a structurally fit and economic isolated pad footing to transfer the stanchion loads to the ground. 3.1 PROJECT DESIGN RESPONSIBILITY Site layout was done by me taking into consideration international standards, guidelines and regulations of CNG station development. The particular project to be discussed in this report is the design of an isolated pad footing. I was solely responsible for this design and creation of its BEME.
Structural design of steel frame for the compressor building was outsourced while I carried out other designs which included pavement design, drainage design and the design of a r etaining wall submitted to the consultant engineer for review and approval.
3.2 BILL OF ENGINEERING MEASUREMENTS AND EVALUATION I was solely responsible for carrying out BEME for the entire project. Civil engineering related items of the project were estimated and billed by me. This include the following - Earthworks - Fencing - Compressor Building - Fencing - Paving - Trenching Other non-civil related items were outsourced to their respective professionals. These include; - M&E Services - HVAC -
3.3 LEARNING OUTCOME FROM THE DESIGN PROJECT I learnt the various stages of the design process, gained a knowledge of the overall project lifecycle and appreciated the practice of value engineering. I made use of BS8110 in the design of the pad footing.
3.4 OVERALL DESIGN REPORTS As this is an in-house project, I was appointed as the Project Manager with the sole mandate to deliver the project.
3.5
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SCOPE OF WORK Designs Soil Tests Topographical Survey Project/Construction Management Contract Management
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Installation of Piping System Testing and Commissioning of the Gas Station
3.6 DESIGN STANDARDS AND PARAMETERS The design processes and parameters employed in this report are based on the applicable British Standards Code of Practices as recommended by the Nigerian Society of Nigeria. Particular BSI codes employed are BS 8002 and BS 8110. 3.7
DESIGN INFORMATION
Project Name and Location: CNG Mother Station, Ota, Ogun State 3.8 DESIGN OF REINFORCED CONCRETE PAD WITH SINGLE COLUMN 3.8.1 Pad footing details Length of pad footing; L = 1500mm Width of pad footing; B = 1500mm Area of pad footing; A = L × B = 2.250m2 Depth of pad footing; h = 300mm Depth of soil over pad footing; hsoil = 900mm Density of concrete; ρconc = 24kN/m3 Column spacing = 5m x 6m on plan
3.8.2 Column details Column base length; lA = 600mm Column base width; bA = 600mm 3.8.3 Soil details Suitable bearing stratum at 1200mm below ground level. Firm lateritic soil. Density of soil; ρsoil = 20.0kN/m3 Angle of internal friction; φ’ = 10.0deg Design base friction; δ = 19.3deg Allowable bearing pressure; Pbearing = 200kN/m2 3.8.4 Axial loading on column Dead axial load on column; DL = 200.0kN Imposed axial load on column; IL = 169.0kN Total axial load on column; V = 369.0kN 3.8.5 Moment on column base
M x = 31.571kNm My = 31.571kNm
Total moment on column in x direction; Total moment on column in y direction;
3.8.6 Foundation Type and Depth Type: Reinforced concrete pad with single RC column Depth: 1200mm below finished ground level
The depth was selected from considerations of: Swelling of soil Suitable bearing stratum 3.8.7 Size Approximation Allowable bearing capacity = 200kN/m2 Maximum vertical load V = 369kN M x and M y = 31.571kNm
Maximum eccentricity = ex =
. =
= 0.08m
Assuming foundation pad dimension of 1.5m by 1.5m; A= 1.5m, B=1.5m
200 = 7.3
6ex = 0.48m ≤ A
3.8.8 Determine minimum thickness of pad Assume concrete grade C25
= 0.8 = 0.8√ 25 = 2( + ) = 2600+600 = 2400 5 50. 4 ×10 ≥ = 4×2400 = 57.33 ≥ [ + 4 ] = = 400 = . ×.× = 101925.93 , or 3N/mm2 (whichever is lesser) =
Total factored load from column Nu = 1.4 x 200 + 1.6 x 169 = 550.4kN
= 129.14mm
where C 1 =
C 2 =
= 4N/mm2
Assumed v c = 0.45N/mm2 Assume overall depth of pad of 300mm allowing for cover
3.8.9 Load combinations Bearing pressure calculations
== 1.1.00 +1.+1.00 +1.0
where DL = dead load IL = imposed load WL = wind load LC 1: Combined vertical column load, N = 200 + 169 = 369kN H x = 0, H y = 0, M x = 0, M y = 0 LC 3: N = vertical load =369kN H x = 0kN My = 31.571kNm, Hy = 0, Mx = 0
== 1.1.24 +1.+1.62 +1.2 = 1.4 +1.4 : = 1.4 × 200 +1.6 ×169 = 550.4 : = 1.2 × 200 +1.2×169 = 442.80 : = 1.4 × 200 +1.6 ×169 = 550.4 Bending moment and shear calculations
H xu = 0, H yu = 0, M xu = 0, M y = 0
H xu = 0 H yu = 0 M xu = 0M y = 0
H xu = 0 H yu = 0 M xu = 0M y = 0
3.8.10 Bearing pressure analysis
2.25 × 0.30 ×24/ 2.25 × 0.90 ×20/ + 2.25 × 0.2 × 1.125 × 5 = 5.625
Weight of foundation = = 16.2kN Weight of backfill +ground slab = = 51.3kN Surcharge on ground slab = 5kN/m2
24/
Weight of surcharge on half foundation = Eccentricity of surcharge = 0.50m Weight of surcharge on full foundation = 11.25kN LC 1: p = total vertical load = 369 + 16.2 + 51.8 + 11.25 = 448.25kN Bearing pressure under foundation LC 1:
p =
..
= 199.22 < 200kN/m 2
3.8.11 Sliding resistance of foundation P = 200 + 16.2 + 51.3 = 267.5kN (dead load only) P s = P tan∂ = 267.5 x tan19.3 = 93.68kN P H = qA tanø + cA = 267.5 x tan22 + 10 x 2.25 = 130.57kN > Ps = 93.68kN
3.8.12 Check combined sliding and bearing P = 448.25kN P v = 200kN/m2 x 2.25m2 = 450kN H x = 0kN P Hx = 0kN
+ = 448.45025 + 00 = 0.9961 > 1 OK
3.8.13 Analysis of bearing pressure for bending moment and shear LC 5: N U = 550.4kN P U = N U + 1.4(foundation + backfill) + 1.6 (surcharge on backfill) = 550.4 + 1.4 x (16.2 + 51.3) + 1.6 x 11.25 = 662.9kN
H xu = 0 LC 6:
H yu = 0
M xxu = 0
M yyu = 0
P U = N U + 1.2(foundation + backfill + surcharge) = 550.4 + 1.2 x (16.2 + 51.3 + 5.625) = 638.15kN M yyu = M y + H xu h + M * yu = 1.2 x 31.571 + 0 + 1.2 x 5.625 x 0.75 = 42.95kNm
LC 7:
PU = NU + 1.4(foundation + backfill) + 1.6 (surcharge o backfill) = 550.4 + 1.4 x (16.2 + 51.3) + 1.6 x 11.25 = 662.9kN M yyu = M y + H xu h = 1.4 x 31.571 + 0 = 44.20kNm 3.8.14 Calculate bearing pressure for bending moment and shear LC 5: LC 6:
= = .. = 294.62/ = + = .. + ×.. = = .. ×.. = 283.622 + 76.36 = 359.98kN/m2
= 283.622 – 76.36 = 207.26kN/m2
3.8.15 Calculate bending moments and shears in pad
LC 5: Downward load on pad = pd p d = self-weight of pad + backfill + surcharge Upward load on pad = p u p u = pressure of ground on pad p d = (0.30 x 24 + 0.90 x 20 + 0.15 x 24) x 1.4 + (5kN/m2) x 1.6 = 48.32kN/m2 p u = 294.62kN/m2 constant
Cantilever overhang at section 1-1 = 750 – 300 = 450mm = l
. =−.−×.×. = =
Bending moment at section 1 =
Shear at section 1 =
= 37.41kNm
= 246.3 x 1.5 x 0.45 = 166.25kN
Assume d = 150mm Shear at section 2 = Shear at section 3 = LC 6:
== 2×0. 0.1501 50= 110. 8 4 = 55.42 283.62+ ..×. = 314.16/ 314.1691.44 ×1.5 × . + 359.98314.16 ×0.5×0.45×
Pressure at section 1-1 =
p d = 1.2(0.30 x 24 + 0.9 x 20 + 0.15 x 24 + 5) = 91.44kN/m 2 Bending moment = M1 =
1.5× ×0.45
=33.83 + 4.64 = 38.47kNm
3.8.16 Cover to reinforcement Class of exposure = 3 Minimum cover = 50mm Assume Y16 Effective depth d = 300 – 50 – 16 – 8 = 226mm 3.8.17 Area of tensile steel Maximum bending on section 1-1
37. 4 1×10 = = 30×1500 ×226 = 0.016 = [0.5 + 0.25 0.9] ≤ 0.95 = 0.5 + 0.25 0.0.0169 = 0.98 > 0.95
Adopt 0.95d = 0.95 x 226 = 214.7mm
37. 4 1×10 = 0.87 = 0.87×460×214.7
= 435.39mm2 Provide 8 nos. 12mm dia. @ 250c/c (452mm2) 3.8.18 Distribution of tension reinforcement Cx = Cy = 600mm dx = 300 – 50 – 8 = 242mm dy = 300 – 50 – 16 – 8 = 226mm
1.5(Cy + 3dy) = 1917mm 1.5(Cx + 3dx) = 1989mm
23 = 23 ×435.39 = 290.26 = 21.90.27826 = 227.12/
Reinforcement over central Cy + 3dy = 1278mm and C x + 3dx = 1326mm
Provide 7 nos. 10mm @ 250c/c (314mm2) over the central zone in each direction 3.8.19 Check shear stress
= . ≤0.×8 5/ = × = 0.49N/ < 0.87 = . ≤0.×8 5/ = × = 0.33N/ =100 100×791. 7 = 1500×242 = 0.22% Check
Check
Ast = 7nos. 12mm dia. bars = 791.7mm2 Using larger d for calculation of p
For f cu = 25N/mm2 vc = 0.42N/mm2 shear stress O.K.
3.8.20 Check punching shear dx = 242mm dy = 226mm d = 0.5 (242 + 226) = 234mm U0 = 2(Cx + Cy) = 2(600 + 600) = 2400mm U1 = (U0 + 12d) = 2400 + 12 x 234 = 5208mm
= ≤ 0.8 5/ 5 50. 4 ×10 = 2400 ×234 = 0.98/ < 0.8 = = 294.6248.32 = 246.3/ LC5: Nu = 550.4kN
A1 = (Cx + 3.0dx)(Cy + 3.0dy) = (600 + 3.0 x 242)(600 + 3.0 x 226) x 10 -6 = (1326 x 1278) x 10-6 = 1.69m2
= = 550.45208246.×2343 ×1.69 = 0.11N/mm2 O.K. vc = 0.42N/mm2
structural detailing of the pad footing can be found in Appendix3.
3.9 CONSTRUCTION OF PAD FOOTING 3.9.1 Site Preparation and Excavation Foundation soils at the bottom of the base trench must be firm and solid. If the soils are made up of heavy clay or wet soils, or the areas have been previously excavated, the entire material must be removed and replaced with granular base compacting in 8 in. (200 mm) lifts or less. In this case, the existing soil was firm lateritic soil and thus there was no need for soil replacement. All surface vegetation and organic soils were removed and carted away from site. 26 nos. base trenches of 1.5m by 1,5m were excavated, leveled and compacted using a 5tons hand operated roller.
Fig. 3.1 Profile board for compressor building. This is to serve as a guide in excavation works.
3.9.2
Concrete Blinding
A thin layer of concrete with mix ratio 1:3:6 was laid as blinding to achieve perfect level of the excavated surface.
Fig. 3.2 Compaction of excavated trench
Fig. 3.3 Concrete blinding of base pit
3.9.3 Placing of rebar Concrete biscuits of 50mm thickness were tied to the rebar cage. The base cage was tied outside the excavated pit and thereafter placed in the pit. Formwork was placed at the sides of the pit and concrete was placed for the base. A construction key was provisioned at the construction joint to ensure continuity between the base and the stub column.
Fig. 3.4 Typical column base reinforcement cage
Fig. 3.5 Stub column reinforcement cages to be lowered into excavated pit
Fig. 3.6Placing of the reinforcement cages in the trenches. The cages were aligned using lines tied on the profile board.
Fig. 3.8 Typical excavated column base
Fig. 3.7 excavation of column base
Fig. 3.9 Levels were taken to determine column heights. for rebar and formwork.
3.9.4
Formwork
Fig. 3.10 Column boxes of 600 by 600 with depth corresponding to site levels at each column point.
3.9.5
Placing of concrete
Fig. 3.11 Fresh concrete mix
Fig. 3.12 Arrangement of column rebar cages prior to casting of column base
Fig. 3.13 Freshly placed base concrete
Fig. 3.14 Typical finished concrete base
Fig. 3.15 Formwork lined with membrane to prevent seepage along formwork
3.9.6
Curing
Fig. 3.16 Alignment of formwork using string lines tied to the profile board
Formwork was left for a minimum of 7 days before removal. Columns were wetted daily for 21 days after formwork removal.
Fig. 3.17 Front view of completed stub columns Fig. 3.18 Side view of completed stub columns
Fig. 3.19 Completed concrete columns.
3.10
BILL OF ENGINEERING MEASUREMENTS AND EVALUATION (BEME)
This section details the creation of the BEME for the pad footing. It involves cost estimation for each item of work – concrete, rebar, formwork etc. 3.10.1 MATERIALS EXTRACTION 3.10.2 Reinforcement Extraction: From bending schedule, Numbers of Bars * cut length of Bar = Total length of Bars on any (Bar Mark) (I). 12mm bar – Bar mark 01 = 208 x 1800mm = 374400mm Total length of 12mm bar is 374400mm, convert to meter length is 374400/1000 = 374.4m 1 length of standard reinforcement = 12m Therefore: 374.4m/12m = 31.2 lengths: use 33 length (II). 10mm bar – Bar mark 02 = 208 x 1800mm = 374400mm 374400/1000 = 374.4m 1 length of standard reinforcement = 12m Therefore: 374.4m/12m = 31.2 lengths: use 33 length However, factors of constant used in converting round bar in kg is as specified here below; Y10 = 0.617kg/m Y12 = 0.888kg/m Converting all bars into kg: 12mm bar = 374.4m x 0.888kg/m = 332.45kg = 333kg 10mm bar = 374.4m x 0.617kg/m = 231.00kg 3.10.3 Concrete Volume (1:2:4) Column stub volume = length x width x depth Average width due to site topography = 2.1m Col. Dimensions L = 0.6m W = 0.6m D = 2.1m For one column, concrete volume = 0.6 x 0.6 x 2.1 = 0.756cu.m
Column stub volume = length x width x depth Average width due to site topography = 2.1m
Col. Dimensions L = 0.6m W = 0.6m D = 2.1m For one column, concrete volume = 0.6 x 0.6 x 2.1 = 0.756cu.m For 26 columns = 0.756 x 26 = 19.66cu.m Column base volume = length x width x depth Base dimensions L = 1.5m W = 1.5m D = 0.3m For one base, concrete volume = 1.5 x 1.5 x 0.3 = 0.675cu.m For 26nos = 0.675 x 26 = 17.55cu.m Total foundation concrete volume = 19.66 + 17.55 = 37.21cu.m
For a 1:2:4 concrete mix, therefore, Multiply by 1.4 to compensate for shrinkage, = 1.4 x 37.21 = 52.09m 3 Add 10% wastage = 1.1 x 52.09 Adjusted vol. = 57.30m 3
×57.30 ×57.30 ×57.30
Cement = Sand =
Aggregate =
= 8.12m3 of cements required
= 16.37m3 = 32.74m3
To convert all materials to kg, ρ = m/v Density of concrete 2400kg/m3 Density of sand, dry 1602kg/m3 Density of Portland cement 1506kg/m3 Density of crushed stone (granite broken) 1650kg/m3 Cement ρ = density of portland cement = 1506kg/m3 V = Volume = 8.12m3 M = Mass =? ρ= M/V
M= ρ x V = 1506kg/m3 x 8.12m3 =
.
= 244.57 = approx. 245 bags of Cement
Sharp sand ρ= density of sharp sand = 1602kg/m3 V = 16.37m3 M =? M = 1602kg/m3 x 16.37m3 = 26224.74kg
For a 20tons truck therefore,
6224.7 = 1.311 = 220000
Granite (½ Inch) ρ= density of granite = 1650kg/m3 V= 32.74m3 M= 1650kg/m3 x 32.74m3 = 54021kg
For a 30tons truck therefore,
54021 = 1.80 = 30000
Water Water/cement ratio of 0.5 Water required therefore is, W/C = 0.5 Where W = quantity of water, C = quantity of cement W = C* 0.5 = 12228.72 kg *0.5 = 6114.36kg or litres Adopt 6200 litres
3.10.4 Concrete Volume (1:3:6) - Blinding volume = length x width x depth Base dimensions L = 1.5m W = 1.5m D = 0.075m For one base, concrete volume = 1.5 x 1.5 x 0.075 = 0.16875cu.m For 26nos = 0.16875 x 26 = 4.39cu.m For a 1:3:6 concrete mix, therefore, Multiply by 1.4 to compensate for shrinkage, = 1.4 x 4.39 = 6.15m 3 Add 10% wastage = 1.1 x 6.15
Adjusted vol. = 6.77m 3
×6.77 ×6.77 ×6.77
Cement = Sand =
Aggregate =
= 0.677m3 of cements required
= 2.03m3 = 4.06m3
To convert all materials to kg, ρ = m/v Density of concrete 2400kg/m3 Density of sand, dry 1602kg/m3 Density of Portland cement 1506kg/m3 Density of crushed stone (granite broken) 1650kg/m3 Cement ρ = density of portland cement = 1506kg/m3 V = Volume = 0.677m3 M = Mass =? ρ= M/V
M= ρ x V = 1506kg/m3 x 0.677m3 =
.
= 20.39 = approx. 21 bags of Cement
Sharp sand ρ= density of sharp sand = 1602kg/m3 V = 2.03m3 M =? M = 1602kg/m3 x 2.03m3 = 3252.06kg
For a 20tons truck therefore,
252.06 = 0.16 = 320000
Granite (½ Inch) ρ= density of granite = 1650kg/m3 V= 4.06m3 M= 1650kg/m3 x 4.06m3 = 6699kg
For a 30tons truck therefore,
Water Water/cement ratio of 0.5 Water required therefore is,
= 6699 30000 = 0,22
W/C = 0.5 Where W = quantity of water, C = quantity of cement W = C* 0.5 = 1019.56 kg *0.5 = 509.78kg or litres Adopt 510 litres 3.10.5 Concrete Summary Cement = 245 + 21 = 266bags Sharp sand = 1.31 + 0.16 = 1.47 = 2trucks Granite (1/2 inch) = 1.80 + 0.22 = 2.02 = 2trucks Water = 6200 + 510 = 6710litres
3.10.6 Formwork For one column, Side area of stub column = (0.6 x 4 sides) x 2.1 = 5.04m2 For 26 columns, = 5.04m2 x 26 = 131.04m 2
Using 8ft by 4ft 1Inch marine board Converting to metres = 2.44m by 1.22m
= 2. 4131.4 ×1.0422
= 44 pieces Provide for 50 pieces
BEME – BILL OF ENGINEERING MEASUREMENT AND EVALUATION FOR ISOLATED PAD FOOTING CONSTRUCTION S/N 1 2 3
DESCRIPTION Mobilization Site Clearing Setting-out/excavation for 26 nos. column bases to a minimum depth of 1200mm (1.5m by 1.5m)
UNIT SUM SUM SUM
QUANTITY
RATE
AMOUNT 300,000.00 120,000.00 160,000.00
4
5
6 7 8
Reinforcement cast in plain in-situ concrete 12mm bar 10mm bar Plain in-situ concrete 61.69m3 Cement Granite (1/2inch) Sharp sand Water Formwork for all sides of stub column (marine boards) Post construction cleaning Sub Total
Length Length
208 208
1,250 1,150
260,000.00 239,200.00
Bags 30tons 20tons litres Nos.
266 2 2 6710 50
1,950 155,000 70,000 10 9,000
518,700.00 310,000.00 140,000.00 67,100.00 450,000.00
SUM
60,000.00 2,625,000.00
CHAPTER FOUR 4.0 DISCUSSION OF CNG PLANT CONSTRUCTION 4.1 DEVELOPMENT OF A PROJECT SCHEDULE Prior to commencing the project, I developed a project management plan which included the Project Schedule. This can be found in Appendix 2. 4.2 SITE CLEARING The construction phase began with site clearing using a D8 Caterpillar Bull dozer. After site clearing, the surveyor was called to re-establish the boundary beacons and carry out a topographical survey of the site. This can be found in Appendix yyuy. In addition, temporary benchmarks/reference points were established on the site. This served as a datum for all levels to be taken on site.
Fig. 4.1 First site clearing operation
Fig. 4.2 D7 Caterpillar Bulldozer in operation
Fig. 4.3 Site clearing using a D7 Caterpillar Bulldozer
Fig. 4.4 Cleared site
4.3 EARTHWORKS Final ground levels were determined and referenced to the established TBMs (temporary benchmarks0. Suitable fill material was located from a nearby burrowed pit. 421 trips of 30 tons of lateritic soil were deposited on the site to achieve the required fill. This was done in four batches of a 100 trips each. After each batch, a grader was used to level the fill and compacted immediately with an 18ton steel drum roller. The level of fill was limited to 20mm to ensure proper compaction of the layers.
Fig. 4.5 Site clearing
Fig. 4.6 Dumping of laterite fill
Fig. 4.7 Grading and compaction
4.5 DRAINAGE CONSTRUCTION 4.5.1 Excavation Excavation for the drainage was done manually. The drainage was of two types – trapezoidal section and rectangular sections. The rectangular section was blinded with weak concrete 1:3:6. The trapezoidal section due to absence of base reinforcement had a concrete overlay of 1:2:4 with 100mm thickness. The side slopes of the trapezoidal section were reinforced wit BRC mesh. 50mm biscuits were attached to both sides of the mesh to provide cover at both surfaces. For the rectangular section, reinforcement cages of U shape were placed in the excavated pits. The concrete base for the rectangular section was placed immediately after rebar placement.
Fig. 4.8 Concrete blinding for drainage
4.5.2 Formwork
Fig. 4.9 Concrete blinding for drainage
Fig. 4.10 Marine board cut to size for formwork
Fig. 4.11 Formwork for trapezoidal drainage
4.5.2 Concreting The drainage was concreted in panels. This was to optimize the use of the formwork. The wall thickness was 100mm and concrete mix ratio of 1:2:4.
Fig. 4.12 Formwork for rectangular drainage
Fig. 4.13 Formwork for rectangular drainage
Fig. 4.14 Completed drainage wall
Fig. 4.15 Completed drainage with trench covers
4.6 COMPRESSOR BUILDING CONSTRUCTION 4.6.1 Foundation Construction
The compressor building sits on a pad foundation with 26 column points. Each footing is a stub column of 600 x 600 with a minimum depth of 1.2m depending on site levels. Pad dimension is 1.5m by 1.5m and 300mm thick. A profile board was set out around the building to guide excavation works. The site was excavated manually for both strip and pad foundations. Thereafter lean concrete of 1:3:6 was placed at the base of the pits as blinding to form a perfect level. Biscuits of 50mm were tied to the base cage to allow for cover. Thereafter the column rebar cage was tied to the base cage. The bases were cast to 300mm thickness of 1:2:4 concrete. 25mm anchor bolts were tied to the top of the column cages to receive the stanchions. Thereafter, formwork for the stub columns were placed and aligned and the concrete placed. Concrete samples were taken at each batch, cured for 7 days and sent to the consultant for testing. Blockwalls were erected at the sides of the wall. At the north end of the building, where there is steep topography, an inverted tee beam was introduced at the base of the wall. The blockwalls wre filled with concrete. Laterite fill was dumped in the building and compacted at 200mm layers using an 18ton steel drum roller.
Fig. 4.16 Tying of column rebar cages
Fig. 4.17 Construction of column formwork
Fig. 4.18 column rebar cages in place
Fig. 4.19 fresh concrete during column casting
Fig. 4.20 completed and cured stub columns
Fig. 4.21 Filling of building foundation
Fig. 4.22 20 tons truck dumping laterite in building Foundation
Fig. 4.23 Payloader spreading laterite in foundation
Fig. 4.24 Compaction using an 18ton steel drum roller
Fig. 4.25 Laterite fill in foundation compacted in 200mm layers
CHAPTER FIVE 5.1 CONCLUSION This report gives a fairly detailed representation of my professional and practical experience in civil engineering though there are other projects not mentioned here for convenience sake. In summary, my exposure in the engineering profession includes the area of structural design both manually and the use of structural software, road construction, piling, building construction, contract management and project management. With my experience I can proffer viable, economic and sustainable solutions to emerging problems in the society.
