Calculating Building Loads

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TextNotebookCalculator (optional)1/8 = 1 print of foundation (basement) planWith dimensionsCalculating Building Loads

pages 173-177

Types of structure loadsLive loadsloads that move or changefurniture, appliance, people, wind, snow, etc.

Dead loadsloads that are constantThe weight of the structureconstruction materials & plumbing fixtures, etc.

Beams and GirdersBeams or girders support floor joists over long spans.May be wood or metal.Wood beams may be built-up or solid. (p.291)Two types of steel beamsStandard or WideBeam size based upon weight of the structure and the span.Typical Steel Beams

Loads on the beam1/2 of the buildings weight rests on the beam

1/2 of the buildings weight rests on the foundation walls

Weight Supported by Beam

Values for residential buildings1st floorlive load + dead load = 50 lbs/ft22nd floorlive load + dead load = 50 lbs/ft2Ceilinglive load + dead load = 30 lbs/ft2Wallsdead load = 10 lbs/ft2Roof has no load on the beam

Heres what you needCalcualtorNOTEBOOK!Copy of floor plan or foundation planArchitects ScaleDetermine where your beam(s) will goLets Begin!A) AREA = L x W = xxxx sq. ft.B) Floor sq. ft. x 50 lbs./ft = ?C) Ceiling sq. ft. x 30 lbs./ft = ?D)Subtotal C + B = ?E) total D 2 = ?F) Wall weight length x 8 x 10 lbs./ft. = ?G) Weight on Beam F + E = ?

How much weight does your beam need to support? Time to do the math . . .Now what?Convert to KipsRefer to tablesS-Beam or W-BeamDetermine size & spacing of postsRefer to your textbook pp. 175-177Load AssumptionsFirst Floor and Second FloorLive + dead load = 50 pounds per square foot.CeilingLive + dead load = 30 pounds per square foot.WallsDead load = 10 pounds per square foot.RoofNo load on beam.Weight Calculations ExampleTwo Story Frame Structure28' x 40'.Area of the House1120 square feet per floor.Wall Area320 square foot per wall.Assumes a bearing wall on each floor.Weight Calculations ExampleFoundation of the house.

Weight Calculations ExampleWeight of first floor = 56,000 lbs.Weight of second floor = 56,000 lbs.Weight of ceiling = 33,600 lbs.Total weight = 145,600 lbs.Half bears on the beam = 72,800 lbs.First and second floor wall weight total = 6,400 lbs.Weight bearing on the beam = 79,200 lbs.Beam capacity tablesS-Beam (p.249)standard I-beamW-Beam (p.249)wide flange I beamWood beamsMicrollam

Weight Calculations ExampleW-beam span and load table.(American Institute of Steel Construction)

Typical Steel Beams

Weight Calculations ExampleLength of beam = 40 feet.Three columns reduce span to 10'-0" and 19.8 kips(1 kip = 1000 pounds).An 8" x 6 1/2" WF beam will support 23 kips, but an 8 x 4 SF beam will also work and is cheaper

Weight Calculations ExampleThree supporting posts are added.

Weight Calculations ExamplePost SelectionSize is determined by weight to be supported and length of post.Post must support 19.8 kips.Post length is 8 feet.Chart (Figure 11-32 in text) shows that a 3" post will support 34 kips.Weight Calculations ExampleWeight supported by each post.

Weight Calculations ExampleSteep pipe columns load table.(American Institute of Steel Construction)