Timber Chapter 1

CHAPTER 1: DETERMINATION OF DEAD LOAD, LIVE LOAD, MAXIMUM ALLOWABLE STRESSES, UNIT WEIGHT AND NOMINAL SIZES OF TIMBER

PROJECT CONTENTS LABORATORY EXERCISE

TITLE

1

DETERMINATION OF DEAD LOAD, LIVE LOAD, MAXIMUM ALLOWABLE STRESSES, UNIT WEIGHT AND NOMINAL SIZES OF TIMBER

2

DESIGN OF FLOOR JOIST

3

DESIGN OF GIRDERS

4

DESIGN OF COLUMNS

5

WORKING DRAWING 1

6

DESIGN OF STRESSES

7

DESIGN OF PURLINS

8

DESIGN OF TOP CHORD

9

DESIGN OF BOTTOM CHORD

10

DESIGN OF INTERMEDIATE MEMBERS

11

DESIGN OF NOTCH, NUTS AND WASHERS

12

DESIGN OF SPLICING

13

WORKING DRAWING 2

RATING

1


MINIMUM DESIGN DEAD LOADS (kPa) (Use actual loads once available) CEILINGS Acoustical Fiber Board Gypsum Board (per mm thickness) Mechanical duct Allowance Plaster on tile or concrete Plaster on wood lath Suspended steel channel system Suspended metal lath and cement plaster Suspended metal lath and gypsum plaster Wood furring suspension system

0.05 0.008 0.20 0.24 0.38 0.10 0.70 0.48 0.12

COVERINGS, ROOFS AND WALL Asphalt Shingles Cement tile Caly tile Book tile, 50mm Book tile, 75mm Ludowici Roman Spanish

0.10 0.77 (for mortar add 0.48 kPa) 0.57 0.96 0.48 0.57 0.91

COMPOSITION Three-ply ready roofing Four-ply felt and gravel Five-ply felt and gravel Copper or tin Corrugated asbestos-cement roofing Deck metal, 20 gage Deck metal, 18 gage Fiberboard, Fiberboard , 13mm Gypsum sheathing, 134 mm

0.05 0.26 0.29 0.05 0.19 0.12 0.14 0.04 0.10

INSULATION, ROOF BOARDS (per mm thickness) Cellular glass 0.0013 Fibrous glass 0.0021 Fiberboard 0.0028 Perlite 0.0015 Polystyrene foam 0.004 Urethane foam with skin 0.009 Plywood (per mm thickness 0.006 Rigid insulation, 13mm 0.04 Skylight, metal frame, 10mm wire glass 0.38 Slate, 5mm 0.34 Slate, 6mm 0.48

2


WATERPROOFING MEMBRANES Bituminous, gravel-covered Bituminous smooth surface Liquid, applied Single-ply, sheet Wood sheathing (per mm thickness) Wood shingles

0.26 0.07 0.05 0.05 0.0057 0.14

FOR FILL Stone concrete, per mm Sand, per mm Lightweight concrete, per mm Cinder concrete, per mm

0.017 0.015 0.015 0.023

FLOOR AND FLOOR FINISHES Asphalt Block (50mm) 13mm mortar Cement finish (25mm) on stone – concrete fill

1.44 1.53

Ceramic or Quarry tile (20 mm) on 13mm mortar bed

0.77

Ceramic or Quarry tile (20 mm) on 25mm mortar bed

0.10

Concrete fill finish (per mm thickness) Hardwood Flooring, 22m Linoleum or Asphalt Tile, 6mm Marble and Mortar on stone – Concrete Fill Slate (per mm thickness) Solid Flat Tile on 25mm Mortar Base Sub Flooring, 19mm Terrazzo (38mm) directly on slab Terrazzo (25mm) on stone-concrete fill Wood block (76mm) on mastic, no fill Wood Block (76mm) on 13mm mortar base

0.023 0.19 0.05 1.58 0.028 1.10 0.14 0.91 1.53 0.48 0.77

FLOORS, WOOD JOIST (no plaster) JOIST SPACING JOIST 300 400 600 SIZES (mm) (mm) (mm) (mm) 50x150 0.3 0.25 0.25

50x200

0.3

0.3

0.25

50x250

0.35

0.3

0.3

50x300

0.4

0.35

0.3

3


FRAME PARTITIONS

Movable steel partitions Wood or steel studs, 13mm gypsum board each side

0.19 0.38

Wood studs, 50 x 100, unplastered Wood studs, 50 x 100, plastered one side Wood studs 50 x 100, plastered two sides

0.19 0.57 0.96

FRAME WALLS

Exterior stud walls 50 x 100mm @ 400mm, 15 mm gypsum Insulated, 10mm siding 50 x 150 mm @ 400mm, 15 mm gypsum Insulated, 10mm siding Exterior stud wall with brick veneer Windows, glass, frame and Sash Clay brick withes 100mm 200mm 300mm 400mm MASONRY, ASHLAR STONE Granite Limestone, crystalline Limestone, oolitic Marble Sandstone

0.53

0.57 2.30 0.38 1.87 3.80 5.50 7.42

25.9 25.9 21.2 27.2 22.6

MASONRY BRICK

Hard (low absorption) Medium (medium absorption) Soft (high absorption)

20.4 18.1 15.7

MASONRY, CONCRETE

(Solid portion) Lightweight units Medium Weight units Normal Weight units Masonry Grout

16.5 19.6 21.2 22.0

4


MASONRY, RUBBLE STONE

Granite Limestone, crystalline Limestone, oolitic Marble Sandstone Mortar, cement or lime Particleboard Plywood

24.0 23.1 21.7 24.5 1.5 20.4 7.1 5.7

RIPRAP (not submerged)

Limestone Sandstone

13.0 14.1

SAND Bank Bank screening Machine Sand Slate Steel, cold-down

11.0 17.0 15.1 8.2 27.0 16.8

STONE, QUARRIED, PILED Basalt, Granite, Gneiss Limestone, Marble, Quartz Sandstone Shale Greenstone, Hornblende

15.1 14.9 12.9 14.5 16.8

TERRA COTTA, ARCHITECHTURAL

Voids filled Voids unfilled Tin

18.9 11.3 72.1

WATER Fresh 9.8 Sea 10.1 Wood (see Table 6.2 for Relative Densities for the Philippine wood)

Zinc, rolled sheet

70.5

5


HOLLOW CONCRETE MASONRY UNITS (unplastered, add 0.24 kPa for each face plastered) Grout Spacing

No Grout 800 600 400 Full No Grout 800 600 400 Full No Grout 800 600 400 Full

Wythe Thickness (mm) 100 150 16.5 kN·m³ Density of Unit 1.05 0.15 1.53 1.63 1.92 2.63 3 19.6 kN·m Density of Unit 1.24 1.34 1.72 1.87 2.11 2.82 3 21.2 kN·m Density of Unit 1.39 1.44 1.82 1.96 2.20 2.97

200 1.48 2.01 2.20 2.54 3.59 1.72 2.25 2.44 2.82 3.88 1.87 2.39 2.59 2.92 3.97

6


MINIMUM UNIFORM AND CONCENTRATED LOADS

USE OF OCCUPANCY

CATEGORY Access Floor System Armories Assembly Areas and Auditorium and Balconies therewith

Cornices and Marquees Dining Rooms and Restaurants Exit Facilities Garages

Hospitals

Libraries Manufacturing Office Printing Plants

Residential

Restrooms Reviewing Stands, Grandstands, Bleachers and Folding and Telescoping Seating Roof Decks

Schools Sidewalks and Driveways Storage

DESCRIPTION Office Use Computer Use --Fixed Seating Movable Seating Lobbies and Platforms Stages Areas ------General Storage and/or Repair Private or Pleasuretype Motor Vehicle Storage Wards and Rooms Laboratories and Operating Rooms Reading Rooms Stack Rooms Light Heavy --Press Rooms Composing and Linotype Rooms Basic Floor Area Exterior Balconies Decks Storage -----

Same as Area Served or Occupancy Classrooms Public Access Light

UNIFORM LOAD

CONCENTRATED LOAD

kPa 2.4 4.8 7.2 2.9 4.8 4.8

kN 9.0 2 9.0 2 0 0 0 0

7.2 3.6 4 4.8 4.8 4.8

0 0 0 0 ---

2.4

---

1.9 2.9

4.5 2 4.52

2.9 7.2 6.0 12.0 2.4 7.2 4.8

4.5 2 6.7 2 9.02 13.42 9.02 11.0 2 9.02

1.9 4 2.4 4 1.9 1.9 --4.8

06 0 0 0 --0

---

---

1.9 12.0 6.0

4.52 (- - -) 7 ---

7


Stores Pedestrian Bridges and Walkways

Heavy Retail Wholesale ---

12.0 4.8 6.0 4.8

--4.5 2 13.4 2 ---

NOTES: 1. See Section 205.5 for live load reductions. 2. See Section 205.3.3, first paragraph, for area of load application. 3. Assembly areas include such occupancies as dance halls, drills rooms, gymnasiums, playgrounds, plazas, terraces, and similar occupancies that are generally accessible to the public. 4. For special-purpose roofs, see Section 205.4.4. 5. Exit facilities shall include such uses as corridors serving an occupant load of 10 or more persons, exterior exit balconies, stairways, fire escapes and similar uses. 6. Individual stair treads shall be designed to support a 1.3 kN concentrated load placed in a position that would cause maximum stress. Stair stringers may be designed for the uniform load set forth in the table 7. See Section 205.3.3, second paragraph, for concentrated loads. See table 205-2 for vehicle barriers. 8. Residential occupancies include private dwellings, apartments and hotel guest rooms. 9. Restrooms loads shall not be less than the load for the occupancy with which they are associated, but need to exceed 2.4 kPa.

8


SPECIAL LOADS

USE OF OCCUPANCY

CATEGORY Construction, Public Access at Site (Live Load) Grandstands, Reviewing Stands, Bleachers, and Folding and Telescoping Seating (Live Load) Stage Accessories (Live Load)

Ceiling Farm (Live Load) Partitions and Interior Walls Elevators and Dumb Waiters (Dead and Live Loads) Cranes (Dead and Live Loads) Balcony Railings and

Guardrails

Vehicle Barriers Handrails Storage Racks

UNIFORM LOAD

CONCENTRATED LOAD

DESCRIPTION Walkway Canopy Seats and Footboards

kPa 7.2 7.2 1.75 kN/m2

Kn ------See Note 3

Catwalks Follow spot, Projection and Control Rooms Over Stages All uses except Over Stages -----

1.9 2.4

-----

1.0 0.52

-----

--2x Total Loads 1.25x (Total Loads) 5

0.25 ---

Total Loads Including Impact Increase Exit facilities serving an Occupant load greater than 50 Other than Exit facilities Components ----Over 2.4 meter high ---

Fire Sprinkler Structural Support

0 to x (Total Loads) 6

---

0.75 kN/m7

---

0.30 kN/m7

----See Note 10 (Total Loads)11 1.1kN plus (weight of water-filled pipe)12

1.28 27 kN9 See Note 10 See Table 208-12 See Table 208-12

NOTES: 1. The tabulated loads are minimum loads. Where other vertical by this code or required by the design would cause greater stresses, they shall be used. Loads are in kPa unless otherwise indicated in the table. 2. Unit is kN/m 3. Lateral sway bracing loads of 350N/m parallel and 145N/m perpendicular to seat and footboards

9


4. Does not apply to ceilings that have sufficient total access from below, such that access is not required within that space above the ceiling. Does not apply to ceilings if the attic areas above the ceiling are not provided by with access. This live load need not to be considered as acting simultaneous with other live loads imposed upon the ceiling framing or its supporting structure. 5. The impact factors included are for cranes with steel wheels riding on steel rails. They may be modified if substantiating technical data is acceptable to the building official is submitted. Live loads on crane support girders and their connections shall be taken as the maximum crane wheel loads. For pendant-operated traveling crane support girders and their connections, the impact factors shall be 1.10. 6. This applies in the direction parallel to the runway rails (longitudinal). The factor for forces perpendicular to the rail is 0.20 times traverse load (trolley, cab, hooks, and lifted loads). Forces shall be applied on the top of rail and may be disturbed among rails of multiple rain cranes and shall be distributed with due regard for lateral stiffness of the structure supporting with these rails. 7. A load per linear meter(kN/m) to be applied horizontally at right angles to the top rail. 8. Intermediate rails, panel fillers and their connection shall be capable of withstanding a load of 1.2kPa applied horizontally at right angles over the tributary area, including openings and spaces between rails. Reactions due to this loading need not to be combined with those of footnote 7. 9. A horizontal load in kN applied at right angles to the vehicle barrier at a height of 450mm above the parking surfaces. The force may be distributed over 300 millimeter square area. 10. The mounting of handrails shall be such that the complete handrail and supporting structure are capable of withstanding a load of at least 890 Newtons applied in any direction at any point on the rail. These loads shall not be assumed to act cumulatively with item 9. 11. Vertical members of storage racks shall be protected from impact forces operating equipment, or racks shall be designed so that failure of one vertical member will not cause collapse of more than the bay or bays directly supported by that member. 12. The 1.1kN load is to be applied to any single fire sprinkler support point but not simultaneously to all support joints.

10


National Structural Code of the Philippines (NSCP), Volume 1 WOOD Table 6.1 – WORKING STRESSES FOR VISUALLY STRESS-GRADED UNSEASONED STRUCTURAL TIMBER OF PHILIPPINE WOODS. 80% Stress Grade Bending & Tension Parallel to Grain

Modulus of Elasticity in Bending

MPa

GPa

MPa

MPa

MPa

12

13

14

15

16

mPa

mPa

mPa

mPa

mPa

Agoho (Casuarina equisetfolia Forst)

26.3

8.22

14.5

5.91

2.95

Liusin [Parinari Crymbosa (Blume miq]

25

9.36

15.6

4.31

2.64

Malabayabas (Tristania spp.)

28.7

8.3

15.8

8.7

3.02

Manggachapui (Hopea spp.)

25.8

9.63

16

6.03

2.78

24

6.64

15.4

6.34

2.88

Narig (Vatica spp.)

21.8

8.33

13.7

4.97

2.61

Sasalit [teijmanniodendron ahernianum (Merr Bkh.)]

31.3

9.72

21.6

10.2

3.38

Yakal (Shorea spp)

24.5

9.78

15.8

6.27

2.49

5.35

10.8

3.9

2.06

Species (Common and Botanical Names)

1

Compression Compression Shear Parallel to Perpendicular parallel to grain to Grain Grain

I. High Strength Group

Molave (Vitex parvifglora Juss.)

II. Moderately High Strength Group

Antipolo (Arthocarpus spp.)

18.6

11


Binggas (Terminalia spp.)

18.9

6.57

11.4

3.27

2.24

Bok-bok [xanthophyllum excelsum (Blume)]

18.1

6.36

11.3

3.41

2.18

Dao (Dracontomelon spp.)

16.2

5.3

9.44

2.27

1.92

Gatasan [Garnicia venulosa (blanco) Choisy]

20.8

6.84

13.5

3.52

2.36

Guijo (Shorea spp.)

21.8

8.47

13.2

4.26

2.4

Kamagong (Diospyros spp.)

20.9

7.2

11.7

4.39

2.47

19

7.56

11.2

3.95

2.35

Katmon (Dillenia spp.)

18.8

6.82

11.9

4.84

2.29

Kato (Amoora spp.)

18.4

8.04

10.6

3.46

1.96

Lomarau (Swintonia foxworthyi Elm.)

19.8

7.92

11.8

2.98

2.18

Mahogany, Bigleafed (swintonia macrophylla King)

16.5

4.66

10.5

3.83

2.71

Makaasim (Sisigium nitidum Benth)

20.5

6.72

11.4

3.7

2.4

Malkakauayan [decusocapus philippinensis (foxw.) de Laub.]

18.9

6.66

11.12

2.32

2.14

18

5.94

11.4

3.07

1.91

16.5

6.53

10

2.5

2.05

Kamatog [(Erythrophloeum densiflorum(elm) Merr.]

Narra (Pterocarpus indicus wild) Puhutan (Mangilera spp.)

12


III. Medium Strength Group

Apitong (Dipterocarpus spp.)

13

5.67

7.53

1.73

1.36

Bagtikan [Parashorea malaanonan (blanco) Merr.]

13.1

5.1

7.79

1.84

1.43

Dangkalan (Calophyllum spp.)

16.3

6.38

9.2

2.48

1.98

Gisau (Canarium spp.)

14.3

5.33

8.16

1.99

1.9

15

6.06

8.96

2.02

1.84

Lauan (Shorea spp.)

13.9

5.83

8.18

1.72

1.48

Malaanonang (Shorea spp.)

13.8

5.41

8.54

1.96

1.59

Malasaging (Aglaia spp.)

16.8

5.94

9.51

2.92

1.85

Malugai (Pometia spp.)

15.4

6.3

9.33

3.07

2.07

Miau (Dysoxylum spp.)

15.7

6.5

8.83

2.78

2.06

Nato (Palaquium spp.)

16.2

5.56

9.17

2.33

1.98

Palosapis (Anisoptera spp.)

13.8

5.98

8.38

2.73

1.68

Pine (Pinus spp.)

14.7

6.66

8.29

1.88

1.56

Salakin (Aphanamixis spp.)

15.7

5.67

8.83

2.94

1.88

Vidal lanutan [hibiscus campylosiphon Turez. Var. glabrecens (har.Ex.Perk)]

19.5

5.83

8.54

2.65

2.39

5.47

6.27

1.44

1.47

Lanutan-bagyo [Gonystylus macrophyllum (miq.) Airy Shaw]

IV. Moderately Low Strength Group

Almaciga [Agathis Dammara

11.8

13


(lamb.) Rilh.] Bayok (Pterosermum spp.)

12.6

4.75

7.33

1.3

1.2

Lingo-lingo (vitex turezaninowii Merr)

13.2

4.13

6.85

2

1.66

Mangasinoro (Shorea spp.)

12.8

5.36

7.46

1.97

1.44

Raintree [Samanca saman (jacq.) Merr.]

11.9

2.75

7.23

3.32

2.07

Yemane (Gmelina arborea R. Br.)

12.6

4.09

7.87

3.4

1.96

14


Association of Structural Engineers of the Philippines WOOD Table 6.1 (continued) 63% Stress Grade Bending & Tension Parallel to Grain


MPa

GPa

MPa

MPa

MPa

12

13

14

15

16

mPa

mPa

mPa

mPa

mPa


20.7

6.47

11.4

4.65

2.32


19.7

7.37

12.3

3.39

2.08


22.6

6.53

12.5

6.85

2.38


20.3

7.58

12.6

4.75

2.19


18.9

5.15

12.1

5

2.27

Narig (Vatica spp.)

17.2

6.56

10.8

3.92

2.06


24.7

7.65

17

8.07

2.67

Yakal (Shorea spp)

19.3

7.7

12

4.94

1.96

4.21

8.53

3.07

1.62


1





14.7

15



14.9

5.17

8.98

2.57

1.77


14.3

5.01

8.9

2.68

1.72


12.8

4.28

7.43

1.79

1.51


16.4

5.39

10.6

2.77

1.86

Guijo (Shorea spp.)

17.1

6.67

10.4

3.35

1.89


16.6

5.67

9.21

3.46

1.95

15

5.95

8.79

3.11

1.85


14.8

5.37

9.38

3.87

1.8

Kato (Amoora spp.)

14.5

6.33

8.34

2.73

1.54


15.6

6.24

9.3

2.34

1.71

13

3.67

8.24

3.014

2.13


16.1

5.29

8.95

2.92

1.89


14.9

5.24

8.79

1.83

1.69

Narra (Pterocarpus indicus wild)

14.2

4.68

8.97

2.42

1.51

Puhutan (Mangilera spp.)

13.1

5.15

7.88

1.97

1.61



16




13

5.67

7.53

1.73

1.36


13.1

5.1

7.79

1.84

1.43


12.8

5.03

7.24

1.96

1.56


11.2

4.2

6.43

1.56

1.49


11.8

4.77

7.06

1.59

1.45

Lauan (Shorea spp.)

10.9

4.59

6.44

1.35

1.17


10.9

4.26

6.72

1.54

1.25


13.3

4.68

7.49

2.3

1.46


12.1

4.96

7.35

2.42

1.63


12.3

5.12

6.96

2.19

1.62


12.7

4.38

7.22

1.84

1.56


10.9

4.71

6.6

2.15

1.33

Pine (Pinus spp.)

11.6

5.24

6.53

1.48

1.23


12.4

4.47

5.96

2.32

1.48


15.4

4.59

6.73

2.09

1.88

4.3

4.94

1.13

1.16



9.26

17



9.94

3.74

5.78

1.03

0.95


10.4

3.25

5.39

1.58

1.31

10

4.22

5.87

1.55

1.14


9.37

2.16

5.7

2.61

1.63


9.9

3.22

6.2

2.68

1.55


18


Natural Structural Code of the Philippines (NSCP), Volume 1 WOOD Table 6.1 (continued) 50% Stress Grade Bending & Tension Parallel to Grain


MPa

GPa

MPa

MPa

MPa

12

13

14

15

16

mPa

mPa

mPa

mPa

mPa


16.4

5.14

9.06

3.69

1.84


15.6

5.85

9.76

2.69

1.65


17.9

5.19

9.9

5.44

1.89


16.1

6.02

10

3.77

1.74

15

4.09

9.6

3.96

1.8

Narig (Vatica spp.)

13.6

5.2

8.59

3.11

1.63


19.6

6.08

13.5

6.4

2.12

Yakal (Shorea spp)

15.3

3.11

9.55

3.92

1.55


1






19



11.6

3.34

6.77

2.44

1.29


11.8

4.11

7.13

2.04

1.4


11.3

3.97

1.06

2.13

1.36


10.1

3.39

5.9

1.42

1.2

13

4.27

8.42

2.2

1.47


13.6

5.3

8.22

2.66

1.5


13.1

4.5

7.31

2.74

1.54


11.9

4.72

6.98

2.47

1.47

Kato (Amoora spp.)

11.7

4.26

7.44

3.03

1.43


11.5

5.02

6.62

2.17

1.23


12.4

4.95

7.38

2.86

1.36


10.3

2.91

6.64

2.39

1.69


12.8

4.2

7.1

2.31

1.5

Narra (Pterocarpus indicus wild)

11.8

4.16

6.98

1.45

1.34

Puhutan (Mangilera spp.)

1.2

3.71

7.12

1.92

1.2

Guijo (Shorea spp.)

20




10.4

4.08

6.25

1.56

1.28


10.3

4.57

5.97

1.37

1.08


10.2

3.99

5.75

1.55

1.24


8.93

3.33

5.1

1.24

1.18


9.39

3.79

5.6

1.26

1.15

Lauan (Shorea spp.)

8.68

3.64

5.11

1.07

0.93


8.63

3.38

5.34

1.23

0.99


10.5

3.71

5.95

1.83

1.16


9.62

3.94

5.83

1.92

1.3


9.8

4.06

5.52

1.74

1.29


10.1

3.48

5.73

1.46

1.24


8.65

3.73

5.24

1.7

1.05

Pine (Pinus spp.)

9.19

4.16

5.18

1.18

0.98


9.83

3.54

5.52

1.84

1.18


12.2

3.64

5.34

1.66

1.5

3.42

3.92

0.9

0.92



7.35

21



7.89

2.97

4.58

0.81

0.75


8.27

2.58

4.28

1.25

1.04


7.98

3.35

4.66

1.23

0.9


7.43

1.72

4.52

2.07

1.3


7.86

2.55

4.92

2.13

1.23

22


ASSOCIATION OF STRUCTURAL ENGINEERS OF THE PHILIPPINES SIZES OF TIMBER PRODUCT

NOMINAL (inches) 5 6 8 10 12 Over 12

NOMINAL (mm) 127 152 203 254 305 Over 305

THICKNESS AND WIDTH ROUGH ROUGH DRESSED (inches) (mm) (inches) 4¾ 121 4½ 5¾ 146 5½ 7¾ 197 7½ 9¾ 248 9½ 11 ¾ 298 11 ½ ¾ off 6 mm off ½ off

DRESSED (mm) 114 140 191 241 292 13 mm off

Note: Full sawn timbers have the same dimension as normal. GRADE CLASSIFICATIONS o

Depending upon size, Western Red Cedar is classified as Light Framing, Structural Joist and Planks, Beams and Stringers, or Posts and Timbers. In general, the grades referred to herein rough sawn.

o

Light Framing is lumber 2” to 4” (51 mm to 102 mm) thick and 2’ to 2” to 4” (51 mm to 102 mm) thick, 5” (127 mm) and wider, either rough sawn or surfaced four sides (S4S).

o

Beams and Stringers are rectangular members, either rough sawn or surfaced, 5” (127 mm) and thicker with width 2” (51 mm) greater than thickness.

o

Posts and Timbers are square members, either rough sawn or surfaced, 5” (127 mm) and larger with width not more than 2” (51mm) greater than thickness.

23


Table 6.2- GROUPING OF SPECIES DETERMINING ALLOWABLE LOADS FOR TIMBER JOINTS I

Species

II

III

IV

Relative Density

Species

Relative Density

Species

Relative Density

2

3

4

5

6

1 Malabayaba s Sasalit Agoho Liusin

0.9

Makaasim

0.74

Maligal

0.61

0.9 0.84 0.79

Kamagong Guijo Binggas

0.72 0.7 0.7

Dangkalan Apitong Salakin

0.58 0.57 0.56

Yakal

0.76

Katmon

0.68

Pine

0.55

Narig

0.72

Gatasan

0.67

Lanutan bagyo

0.53

0.71

Bok-bok

0.64

Miau

0.52

0.69

Kamatog Lomarau

0.64 0.64

0.52 0.51

Kato

0.59

Pahutan Mahogany, Big Leaf

0.55

Antipolo

0.52

Narra Malakauay an Dao

0.52

Palosapis Malasagin Vidal Lanutan Gisau Nato Bagtikan Malaanona ng Lauan

Manggachap i Molave

SOURCE:

0.54

Species

7 Lingolingo Raintree Bayok Almaciga Mangasin oro

Yermane

Relative Density 8

0.48 0.48 0.44 0.42 0.42 0.42

0.5 0.5 0.49 0.44 0.41

0.5 0.48

PHILIPPINE Timber Design Standards (JE Rocafort and JO Siopongco) November, 1991 (FPRDI Terminal Report)

24


NOMINAL SIZES OF TIMBER

SIZES

EFFECTIVE LENGTH 8 ft

10 ft

12 ft

14 ft

16 ft

1x1

available

available

available

available

available

1x2

available

available

available

available

available

2x2

available

available

available

available

available

2 x 3 76.2

available

available

available

available

available

2 x 4 101.6

available

available

available

available

available

2x6

available

available

available

available

available

2x8

available

available

available

available

available

2 x 10

available

available

available

available

available

2 x 12

available

available

available

available

available

4x4

available

available

available

available

available

4x6

available

available

available

available

available

4x8

available

available

available

available

available

6x6

available

available

available

available

available

25


The objective of this Chapter 2 is to design a wooden joist that will be able to withstand all the loads to which it is subjected and will not exceed the allowable stresses of a given material. In order for us to understand this concept, the following are defined: Types of loads commonly encountered in the design structures namely, a.) Dead load – are loads made up of the weights of the building components, they are typically non- moving loads. b.) Live load - are the weights of people, furniture, supplies, machines, stores, and so on, borne by the building during its use and occupancy. 

IMPORTANT NOTE: - Live and Dead loads are obtained by building code.

Allowable stress is the maximum unit force per unit area that may be safely applied to a material. We consider the following: a.) Allowable bearing stress b.) Allowable shearing stress c.) Allowable maximum deflection GOAL: To design a dimension of a cross section of floor joist that will not exceed the allowable shearing, bending and deflection stresses. Hence, considered safe for use.

Consider following data with its corresponding values, Type of Wood Used

Unit Weight (kN/m3)

MOLAVE

6.77

USES OF OCCUPANCY Classroom Faculty Room Principal’s Office Guidance’s Office Computer Room Clinic Laboratory Library Canteen Hallway Conference Hall Stack Room Stage Comfort Rooms

Modulus of Elasticity (GPa) 6.64

Allowable Bending Stress (MPa) 24

DESIGN OF LIVE LOADS UNIFORM LOAD(kPa) 1.9 2.4 2.4 2.4 4.8 2.9 2.9 2.9 4.8 4.8 2.9 7.2 7.2 1.9

Allowable Shear Stress (MPa) 2.88

SIZE OF ROOM 8m x 7.5m 10m x 6m 10m x 6m 8m x 7.5m 8m x 7.5m 7m x 5m 10m x 5m 13m x 5m 13m x 5m 2

m

20m x 6m 3m x 2m 10m x 5m 3m x 6m

26

Timber Chapter 1

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