Nscp Design Loads

rIt

1i1~.

SECTION 203COMBINATIONS OF LOADS

20J.1 GeneralBuilding», towers and other vert ical structures and allportions thereof shall he designed to resist the loadcombinauuns specified in Section 203.3 or 203.4 and.\\ here required by Section 2()X. or Chapter -t and the

'pL'cial ~ei"llic load combinations of Section 203.5.

The mos( nit icul effect can occur when one or more o l11lL'L'untributing loads arc not acting. All applicable loadsshall hr considered. including both earthquake and wind,in .ucordancc with the specified load combin.uions.

1

203.2 Symbols and Notations

f) = dead loadF = earthquake load set forth in Section 20X.5.1.1r". ::: l"tilllated maximum earthquake force that can he

developed in the structure as set forth in Section

20X.5.1. Il load due to fluids with well-defined pressures and

maximum heights/I Illad due to lateral pressure of soil and water in

,oi I

I. := II\L' load. except roof live load. including any

permitted live load reductionl., = root" live load. including any permitted live load

rcduct ion

l' = ponding loadI< ::: rain IO:ld on the uudcllcctcd roofl = 'l'lf-.'training torcc and efkcis arising from

cuntrnct ion or expansion resulting fromicmpcr.uurc changL'. shrinkage. moisture change.CI\'CP In component materials. movement due todi lfcrcntiul settlement. or combinations thereof

II' = Illad due to wind pressure

!I

1I

20J.J l.nad Combinations using Strength Design orLoad and Resistance Factor Design

211.'.3.1 Basic Load Cum hi nationsWhere lo.u] and resistance factor design is used. structures:11111 all portions thereof shall resist the most criticulL'lll·l·tS troru the following cornbinution-, of factored loads:

(203-1)

12(n + 1+ r)+ 16{t. + fll+ 0.5(/" or 1<) (2<n-2)

(203-3)

12f)+ 1.6W + /;1.+0.5([., or R)

121) + 1.0/: + III. (203-5)

CHAPTER 2·- fvll1l1l"ill.lI!l.) t:c.•• )

O.9D+I.6W+I.6H

O.9D+1.0E+1.6H

(203-6 )

where:

.Ii = 1.0 for floors in places of public asxcmbly. fpr liveloads in excess of 4.X kPa. and for garage live load

= 0.5 for other live loads

Exception:

Factored load combinations for structural concrete perSection 409.3.

203.J.2 Other LoadsWhere P is to be convidcrcd in design. the appllcahk IO:ldshall be added t() Section 20.\ ..\. I f:ll'lmet! as 1.:'/'.

21UA Load Cornhinations lsing AI"I\\ able Stn'ss

Design

203.4.1 Basil' Load Com hi nationsWhere allowable s(rL'SS deSign (\I'orking ,11\'" dL"lgn i I'

used, structures and all poruou-. thcrcol ,hall rcsl~1 thl'i110st critical efkch n:sulting lroru til~' followingcomhination-, of loads:

()+F

f) + H + F + I. + t

f) + H + F + (1'1011<)

[) + H + F +0.75['- + T + (i'Ior R)j

I :,03-X )

(203-lJ)

(203-10)

(203-1 I )

( f. \/) + 1/ + r + I IV or I

\ 1.-11

No increase in allowable stresses shall h.: usc'd \11th IhL"L'

load combinations except as specifically pcrmiucd hI

Section 2mA.2.

2-6 CHAPTER 2 - Minimum Design Loads

203.4.2 Alternate Basic Load CombinationsIn lieu of the basic load combinations specified in Section203.4.1, structures and portions thereof shall be permittedto be designed for the most critical effects resulting fromthe following load combinations. When using thesealternate basic load combinations, a one-third increaseshall be permitted in allowable stresses for allcombinations, including War E.

IJ+ H + F+(J.7Sl L+Lr +( W or I~ JJ (203-13 )

O.60LJ+W+H (203-14)

E0.60D + -+H

1.4(203-IS)

D+ L+ Lr(or R)

D+L+W

(203-16)

(203-17)

D +L+E1.4

(203-18)

Exception:

Crane hook loads need not be combined with roof liveload or with more than one-half of the wind load.

203.4.3 Other LoadsWhere P is to be considered in design, each applicableload shall be added to the combinations specified inSections 203.4.1 and 203.4.2.

203.5 Special Seismic Load CombinationsFor both allowable stress design and strength design, thefollowing special load combinations for seismic designshall be used as specifically required by Section 208, orby Chapters 3 through 7.

1.2D+fIL+I.OEm (203-19)

O.9D±I.OEm (203-20)

where:

Ii = I.n for floors in places of public assembly. for liveloads in excess of 4.8 kPa, and for garage live load.

= 0.5 for other live loadsEm = thc maximum effect of horizontal and vertical

forces as set forth In Section 208.5.1.1

Association of Structural Engineers of the Philippines

~--------------------------=

•jj

CHAPTER 2 - Minimum Design Loads 2-7

Material Density

Table 204-1 Minimum Densities for Design Loads from Materials (kN/m3)

Material DensityAluminum .......................................... 26.7 Lead . 111.5

LimeHydrated, loose .Hydrated, compacted .

Masonry, Ashlar StoneGranite .Limestone, crystalline .Limestone, oolitic ...Marble .Sandstone .

5.07.1

25.925.92l.227.222.6

Bituminous ProductsAsphaltum 12.7Graphite 21.2Paraffin 8.8Petroleum. crude 8.6Petroleum. refined 7.9Petroleum, benzine 7.2Petroleum. gasoline 6.6Pitch 10.8Tar 11.8

Brass 82.6Bronze 86.7

. Cast-stone masonry (cement, stone, sand) 22.6··Cement. portland, loose 14.1Ceramic tile 23.6Charcoal. .. I .9Cinder fill 9.0Cinders, dry. in bulk 7.1

CoalAnthracite, piled 8.2Bituminous, piled 7.4Lignite. piled 7.4Peat, dry. piled 3.6

Concrete. PlainCinder 17.0Expanded-slag aggregate 15.7Haydite (burned-clay aggregate) 14.1Slag 20.7Stone 22.6Vermiculite and perlite aggregate, nonload-bearing .3.9·7.9Other light aggregate. load bearing 11.0·16.5

Concrete. ReinforcedCinder 17.4Slag.. 21.7Stone. (including gravel) .. 23.6

Copper 87.3Cork. compressed 2.2

Earth (not submerged)Clay. dry .. 9.9Clay. damp 17.3Clay and gravel. dry............................................................ 15.7Silt. moist. loose 12.3Silt. moist. packed 15.1Silt. flowing 17.0Sand and gravel, dry. loose 15.7Sand and gravel. dry. packed 17.3Sand and gravel. we!.................. 18.9

Earth (submerged)Clay 12.6Soil 11.0River mud 14.1Sand or gravel.................................. 9.4Sand or gravel and clay..................... 10.2

Glass 25.1Gravel. dry.... 16.3Gypsum. loose 11.0Gypsum. wallboard .. 7.9Ice 9.0

IronCast .Wrought .

70.775.4

Masonry. BrickHard (low absorption)Medium (medium absorption)Soft (high absorption)

MASONRY. Concrete (solid portion)Lightweight units .Medium weight units .Normal weight units .

Masonry grout .

Masonry, Rubble StoneGranite .Limestone, crystalline .. .Limestone, oolitic .Marble . .Sandstone .Mortar, cement or lime ..

20.418.115.7

16.519.621.2

22.0

24.023.121.724.521.520.4

7.15.7

Particle board .Plywood .

Riprap (not nubmerged)Limestone .Sandstone .

13.014.1

SandClean and dryRiver. dry .

14.116.7

SlagBank II.nBank screenings 17.0Machine 15.1Sand 1>.2

Slate 27.0Steel, cold-drawn 77.3

Stone, Quarried, PiledBasalt, granite, gneiss 15.1Limestone, marble, quartz 14.9Sandstone 12.9Shale 14.5Greenstone, hornblende 16.8

Terra Cotta, ArchitecturalVoids filled 18.9Voids unfilled .. 11.3

Tin 72.1

WaterFresh 9.8Sea 10.1

Wood (see Table 6.2 for relative densities for Philippine wood)

Zinc, rolled sheet 70.5

National Structural Code of the Philippines s" Edition Volume 1


Component Load

Table 204-2 Minimum Design Dead Loads (kPa) (Use actual loads when available)

LoadComponent Load Component

CEILINGSAcoustical Fiber Board 0.05Gypsum Board (per mm

thickness) 0.008Mechanical duct allowance 0.20Plaster on tile or concrete 0.24Plaster on wood lath 0.38Suspended steel channel

system 0.10Suspended metal lath and cement

plaster 0.72Suspended metal lath and

gypsum plaster 0.48Wood furring suspension

system 0.12

COVERINGS, Roof and WallAsphalt shingles 0.10Cement tile 0.77Clay tile (for mortar add 0.48 kPa)

Book tile, 50 mm 0.57Book tile, 75 mm 0.96Ludowici 0.48Roman 0.57Spanish 0.91

Composi tion:Three-ply ready roofing 0.05Four-ply felt and gravel 0.26Five-ply felt and gravel 0.29

Copper or tin 0.05Corrugated asbestos-cement

roofing 0.19Deck, metal 20 gage 0.12Deck, metal, 18 gage 0.14Fiberboard, 13 mm 0.04Gypsum sheathing, 13 mm O.10Insulation, roof boards (per mm

thickness)Cellular glass 0.0013Fibrous glass 0.0021Fiberboard 0.0028Perlite 0.0015polystyrene foam 0.0004Urethane foam with skin .. 0.0009

Plywood (per mm thickness) 0.0060Rigid Insulation, 13 rnrn 0.04Skylight, metal frame,

10 mm wire glass 0.38Slate, 5 mm 0.34Slate, 6 mm 0.48Waterproofing membranes:

Bituminous, gravel-covered . 0.26Bituminous, smooth surface .. 0.07Liquid, applied 0.05Single-ply, sheet 0.03

Wood Sheathing (per mmthickness) 0.0057

Wood Shingles 0.14

FLOOR FILL

Cinder concrete, per mm 0.0 17Lightweight concrete, per mm ..0.015Sand, per mm 0.015Stone concrete, per mm 0.023

FLOOR AND FLOOR FINISHESAsphalt block (50 mm), 13 mm

mortar 1.44Cement finish (25 mm) on stone-

concrete fill 1.53Ceramic or quarry tile (20 mm)

on 13 mm mortar bed 0.77Ceramic or quarry tile (20 mm)

on 25 mm mortar bed 1.10Concrete fill finish (per mm

thickness) 0.023Hardwood flooring, 22 mm 0.19Linoleum or asphalt tile, 6mm 0.05Marble and mortar on stone-

concrete fill 1.58Slate (per mm thickness) 0.028Solid flat tile on 25 mm mortar

base 1.10Subflooring, 19 mm 0.14Terrazzo (38 mm) directly on

slab 0.91Terrazzos (25 mm) on stone-

concrete fill 1.53Terrazzo (25 mm), 50 mm stone

concrete 1.53Wood block (76 mm) on mastic,

no fill 0.48Wood block (76 mm) on 13 mm

mortar base 0.77

FLOORS, WOOD-JOIST (noplaster)

Joist .........!?\s!~p_a£i~gSizes 300 400 600(mm) mm mm mm

50xl50 0.30 0.25 0.2550x2oo 0.30 0.30 0.2550x250 0.35 0.30 0.30

50x3oo 0.40 0.35 0.30

FRAME PARTITIONSMovable steel partitions 0.19Wood or steel studs, 13 mm

gypsum board each side 0.38Wood studs, 50 x 100,

unplastered 0.19Wood studs 50 x 100, plastered

one side 0.57Wood studs 50 x 100, plastered

two side 0.96


FRAME WALLSExterior stud walls:

50xloo mm @ 400 mm, l S-rnmgypsum, insulated, IO-rnrnsiding 0.53

50xl50 rnrn @ 400 mm, 15-mmgypsum, insulated, IO-mmsiding 0.57

Exterior stud wall with brickveneer 2.30

Windows, glass, frame andsash 0.38

Clay brick wythes:100 mm 1.87200 mm 3.80300 mm 5.50400 mm 7.42

CONCRETE MASONRY UNITSHollow Concrete Masonry units

(Unplastered, add 0.24 kPa foreach face plastered)

Grout Wythe thickness (mm)Spacing : 100 150; 200


205.1 GeneralLive loads shall be the maximum loads expected by theintended use or occupancy but in no case shall be lessthan the loads required by this section.

204.1 GeneralDead loads consist of the weight of all materials ofconstruction incorporated into the building or otherstructure, including but not limited to walls, floors, roofs,ceilings, stairways, built-in partitions, finishes, claddingand other similarly incorporated architectural andstructural items, and fixed service equipment, includingthe weight of cranes.

205.2 Critical Distribution of Live LoadsWhere structural members are arranged to createcontinuity, members shall be designed using the loadingconditions, which would cause maximum shear andbending moments. This requirement may be satisfied inaccordance with the provisions of Section 205.3.2 or205.4.2, where applicable.

204.2 Weights of Materials and ConstructionsThe actual weights of materials and constructions shall beused in determining dead loads for purposes of design. Inthe absence of definite information, it shall be permittedto use the minimum values in Tables 204-\ and 204-2. 205.3 Floor Live Loads

204,3 Partition LoadsFloors in office buildings and other buildings wherepartition locations are subject to change shall be designedto support, in addition to all other loads, a uniformlydistributed dead load equal to 1.0 kPa of floor area.

205.3.1 GeneralFloors shall be designed for the unit live loads as set forthin Table 205-1. These loads shall be taken as theminimum live loads of horizontal projection to be used inthe design of buildings for the occupancies listed, andloads at least equal shall be assumed for uses not listed inthis section but that creates or accommodates similarloadings.

Where it can be determined in designing tloors that theactual live load will be greater than the value shown inTable 205-1, the actual live load shall be used in thedesign of such buildings or portions thereof. Specialprovisions shall be made for machine and apparatus loads.

205.3.2 Distribution of Uniform Floor LoadsWhere uniform floor loads are involved, considerationmay be limited to full dead load on all spans incombination with full live load on adjacent spans andalternate spans.

205.3.3 Concentrated LoadsFloors shall be designed to support safely the uniformlydistributed live loads prescribed in this section or theconcentrated load given in Table 205-1 whicheverproduces the greatest load effects. Unless otherwisespecified the indicated concentration shall be assumed tobe uniformly distributed over an area 750 mm square andshall be located so as to produce the maximum loadeffects in the structural member.

Provision shall be made in areas where vehicles are usedor stored for concentrated loads, L, consisting of two ormore loads spaced 1.5 m nominally on center withoutuniform live loads. Each load shall be 40 percent of the

National Structural Code of the Philippines e" Edition Volume 1

r2-10 CHAPTER 2 - Minimum Design Loads

accordance with Section 203.3 or 203.4 as appropriate,producing the greatest stresses shall govern.

gross weight of the maximum size vehicle to beaccommodated. Parking garages for the storage of privateor pleasure-type motor vehicles with no repair orrefueling shall have a floor system designed for aconcentrated load of not less than 9 kN acting on an areaof 0.015 m2 without uniform live loads. The condition ofconcentrated or uniform live load, combined in

205.3.4 Special LoadsProvision shall be made for the special vertical and lateralloads as set forth in Table 205-2.

Table 205-1 - Minimum Uniform and Concentrated Live Loads

Use or Occupancy Uniform Load IConcentrated

Load1-------- ---- -----------Category Description kPa kN

Office use 2.4 9.02

1. Access floor systems9.02Computer use 4.8

2. Armories -- 7.2 0

Fixed seats 2.9 0

3. Theaters, assembly areas 3 and Movable seats 4.8 0auditoriums.

Lobbies and platforms 4.8 0

Stages areas 7.2 0

4. Bowling alleys, poolrooms and similar3.6 0recreational areas --

5. Catwalk for maintenance access -- 1.9 1.3

6. Cornices and marquees -- 3.64 0

7. Dining rooms and restaurants -- 4.8 0

8. Exit facilities 5 -- 4.8 06

General storage and/or repair 4.8 7--9. Garages Private or pleasure-type motor 7

vehicle storage1.9 --

Wards and rooms 1.9 4.52

10. Hospitals Laboratories & operating 2.9 4.52rooms

Corridors above ground floor 3.8 4.5

Reading rooms 2.9 4.52

11. Libraries Stack rooms 7.2 4.52

Corridors above ground floor 3.8 4.5

Light 6.0 9.02

12. Manufacturing13.42Heavy 12.0


~-----------------------~~\---,


Use or Occupancy Uniform Load IConcentrated

Load--------_._-_._ .._._---_ ...._._ .._ ..._ ...._-_._ ...-_.-----------_ .._--------_._. __.__ ._.__ ._- -----_._-- ..._-_._-_. __ ...•._--------_ .._---_. __ .__.- ._----_ .._--------_._._---_._-_ ..._"---- ._------_._--_._--_ .._. __ ..._-,._._-

Category Description kPa kN

Call Centers & BPO 2.9 9.0Lobbies & ground floor 4.8 9.0

13. Officecorridors

Offices 2.4 9.02

Building corridors above 3.8 9.0ground floor

Press rooms 7.2 11.02

14. Printing plants Composing and linotype 4.8 9.02

roomsBasic floor area 1.9 06

Exterior balconies 2.94 015. Residential 8

Decks 1.94 0Storage 1.9 0

16. Restrooms 9 -- -- --

17. Reviewing stands, grandstands,Bleachers, and folding and telescoping -- 4.8 0seating

18. Roof decks Same as area served orOccupancy

-- --

Classrooms 1.9 4.52

19. Schools Corridors above ground floor 3.8 4.5Ground floor corridors 4.8 4.5

20. Sidewalks and driveways Public access 12.0 7--

Light 6.0 --21. Storage

Heavy 12.0 --

Retail 4.8 4.52

22. Stores 13.42Wholesale 6.023. Pedestrian bridges and walkways -- 4.8 --

NOTES FOR TABLE 205-1I See Section 205_5 for live load reductions.

See Section 205.3.3, first paragraph, for area of load application ..I Assembly areas include such occupancies as dance halls, drill rooms, gymnasiums, playgrounds, plazas, terraces and similar occupancies that

are generally accessible 10 the public.4 For special-purpose roofs, see Section 205.4.4.

Exit facilities shall include such uses as corridors serving an occupant load of 10 or more persons, exterior exit balconies, stairways, fire escapesand similar uses.

• Individual stair treads shall be designed to support a 1.3 kN concentrated load placed in a position that would cause maximum stress. Stairstringers 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 205-2for vehicle barriers.H Residential occupancies include private dwellings, apartments and hotel guest rooms.9 Restroom loads shall not be less than the load for the occupancy with which they are associated, but need not exceed 2.4 kPa.

National Structural Code of the Philippines e" Edition Volume 1


Table 205-2 Special Loads/

Use OccupancyVertical Lateral

or Load LoadCategory Description kPa kPa

1. Construction. Walkway 7.2 -public access atsite (live load) Canopy 7.2 -

2. Grandstands,reviewing,stands bleachers, Seats and 1.75 Seeand folding and footboards Note 3telescopingseating (liveload)

3. Stage Catwalks 1.9 -

accessories (live Follow spot,load) projection and 2.4 -

control rooms

Over stages 1.0 -4. Ceiling framing

(live load) All usesexcept over 0.54 -stages

5. Partitions and0.25interior walls, - -

6. Elevators anddumbwaiters 2 x total(dead and live loads -

loads)Total load 0.10 x7. Cranes (dead including 1.25 x total

totaland live loads) impact load"load6

increaseExit facilitiesserving an 0.75occupant load - kN/m7

greater than8. Balcony railings 50

and guardrails Other than 0.30exit facilities - kN/m7

Components - 1.28

9. Vehicle barriers -- - 27 kN9

10. Handrails See SeeNote 10 Note 10

Over 2.4 m Total See11. Storage racks high loads" Table

208-12

12. Fire sprinkler1.1 kN plus

Seestructural -

weight of Tablewater-filledsupport pipe12 208-12

Notesfor Table 205-21 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 indicatedin the table.

2 Units is kNlm.3 Lateral sway bracing loads of 350 Nlm parallel and 145 Nlm

perpendiculars 10 seat andfootboards.4 Does not apply to ceilings that have sufficient total access from

below, such that access is not required within the space abovethe ceiling. Does not apply to ceilings if/he attic areas above theceiling are not provided with access. This live load need not beconsidered as acting simultaneously with other live loadsimposed upon the ceiling framing or its supporting structure.

5 The impact factors included are for cranes with steel wheelsriding on steel rails. They may be modified if substantiatingtechnical data acceptable 10 the building official is submitted.Live loads on crane support girders and their connections shallbe 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 is0.20 x the transverse traveling loads (trolley, cab, hooks andlifted loads). Forces shall be applied at top of rail and may bedisturbed among rails of multiple rail cranes and shall bedistributed with due regard for lateral stiffness of the structuressupporting these rails.

7 A load per lineal meter (kNlm) to be applied horizontally at rightangles to the top rail.

8 Intermediate rails, panel fillers and their connections shall becapable of withstanding a load of 1.2 kPa applied horizontally atright angles over the entire tributary area, including openingsand spaces between rails. Reactions due to this loading need notbe combined with those of Footnote 7.

9 A horizontal load in kN applied at right angles to the vehiclebarrier at a height of 450 mm above the parking surface. Theforce may be distributed over a 300-mm-square area.

/0 The mounting of handrails shall be such that the completedhandrail and supporting structure are capable of withstanding aload of at least 890 N applied in any direction at any point onthe rail. These loads shall not be assumed 10 act cumulativelywith Item 9.

/I Vertical members of storage racks shall be protected fromimpact forces of operating equipment, or racks shall be designedso that failure of one vertical member will not cause collapse ofmore than the bay or bays directly supported by that member.

12 The 1.1 kN load is to be applied to any single fire sprinklersupport point but not simultaneously 10 all support joints.


r\ CHAPTER 2 - Minim, 2-15

Table 205-3 Minimum Roof Live Loads J

METHOD I METHOD 2Tributary Area (mz) Uniform Rate of IV.

ROOF SLOPE o to 20 I 20 to 60 I Over 60 Load 2 Reduction,Reo, .1

, itUniform Load (kPa) (kPa) r (percentage)

1. Flat 3 or rise less than 4 units vertical in !12 units horizontal (33.3% slope). Arch 1.00 0.75 0.60 1.00 0.08 40and dome with rise less than one-eighth ,of span. i

2. Rise 4 units vertical to less than 12 units II

vertical in 12 units horizontal (33.3% toless than 100% slope). Arch and dome 0.75 0.70 0.60 0.75 0.06 25with rise one-eighth of span to less thanthree-eighths of span.

3. Rise 12 units vertical in 12 unitshorizontal (100% slope) and greater.

0.60 0.60 0.60 0.60/'

Arch or dome with rise three-eighths of;

span or greater.No reduction permitted

4. Awnings except cloth covered. 4 0.25 0.25 0.25 0.25

5. Greenhouses, lath houses and 0.50 0.50 0.50 0.50agricultural buildings. 5

I For special-purpose roofs. see Section 205.4.4.2 See Sections 205.5 and 205.6 for live-load reductions. The rate of reduction r in Equation 205-1 shall be as indicated in the table. The maximum

reduction. R. shall not exceed the value indicated in the table ..I A flat roof is any roof with a slope less than 1/4 .mit vertical in 12 units horizontal (2% slope). The live load for flat roofs is in addition to the

ponding load required by Section 206.7.4 See definition in Section 202.5 See Section 205.4.4 for concentrated load requirements for greenhouse roofmembers.

205.4 Roof Live Loads

205.4.1 GeneralRoofs shall be designed for the unit live loads, Ln setforth in Table 205-3. The live loads shall be assumed toact vertically upon the area projected on a horizontalplane.

205.4.2 Distribution of LoadsWhere uniform roof loads are involved in the design ofstructural members arranged to create continuity,consideration may be limited to full dead loads on allspans in combination with full roof live loads on adjacentspans and on alternate spans.

For those conditions where light-gage metal preformedstructural sheets serve as the support and finish of roofs,roof structural members arranged to create continuityshall be considered adequate if designed for full deadloads on all spans in combination with the most criticalone of the follow ing superimposed loads:

1. The uniform roof live load, Ln set forth in Table 205-3 on all spans.

2. A concentrated gravity load, Ln of 9 kN placed onany span supporting a tributary area greater than 18m2 to create maximum stresses in the member,whenever this loading creates greater stresses thanthose caused by the uniform live load. Theconcentrated load shall be placed on the member overa length of ~150mm along the span. The concentratedload need not be applied to more than one spansimultaneously.

3. Water accumulation as prescribed in Section 206.7.

National Structural Code of the Philippines s" Edition Volume 1

/"

j

p d

rI 2-14 CHAPTER 2 - Minimum Design Loads

205.4.3 Unbalanced LoadingUnbalanced loads shall be used where such loading willresult in larger members or connections. Trusses andarches shall be designed to resist the stresses caused byunit live loads on one half of the span if such loadingresults in reverse stresses, or stresses greater in anyportion than the stresses produced by the required unitlive load on the entire span. For roofs whose structuresare composed of a stressed shell, framed or solid, whereinstresses caused by any point loading are distributedthroughout the area of the shell, the requirements forunbalanced unit live load design may be reduced 50percent.

205.4.4 Special Roof LoadsRoofs to be used for special purposes shall be designedfor appropriate loads as approved by the building official.Greenhouse roof bars, purlins and rafters shall bedesigned to carry a 0.45 kN concentrated load, L" inaddition to the uniform live load

205.5 Reduction of Live LoadsThe design live load determined using the unit live loadsas set forth in Table 205-1 for floors and Table 205-3,Method 2, for roofs may be reduced on any membersupporting more than 15 m2, including flat slabs, exceptfor floors in places of public assembly and for live loadsgreater than 4.8 kPa, in accordance with the followingequation:

R = r(A-IS) (205-1 )

The reduction shall not exceed 40 percent for membersreceiving load from one level only, 60 percent for othermembers or R, as determined by the following equation:

R = 23.1(1 + Df L) (205-2)

where:

A = area of floor or roof supported by the member,square meter, m2

D = dead load per square meter of area supported bythe member, kPa

L = unit live load per square meter of area supported bythe member, kPa

R = reduction in percentage, %.r = rate of reduction equal to 0.08 for floors. See Table

205-3 for roofs

For storage loads exceeding 4.8 kPa, no reduction shall bemade, except that design live loads on columns may bereduced 20 percent.

p,

The live load reduction shall not exceed 40 percent ingarages for the storage of private pleasure cars having acapacity of not more than nine passengers per vehicle.

205.6 Alternate Floor Live Load ReductionAs an alternate to Equation (205-1), the unit live loads setforth in Table 205-1 may be reduced in accordance withEquation 205-3 on any member, including flat slabs,having an influence area of 40 m2 or more.

(205-3)

where:Al = influence area, m2 ..L = reduced design live load per square meter of area

supported by the memberL; = unreduced design live load per square meter of area

supported by the member (Table 205-1 )

The influence area Al is four times the tributary area for acolumn, two times the tributary area for a beam, equal tothe panel area for a two-way slab, and equal to theproduct of the span and the full flange width for a precastT-beam

'.

The reduced live load shall not be less than 50 percent ofthe unit live load L; for members receiving load from onelevel only, nor less than 40 percent of the unit live load Lafor other members.

.<


Documents

Nscp Design Loads