Transcript Calculating Building Loads - Hatboro

What you need today
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Text
Notebook
Calculator (optional)
1/8” = 1’ print of foundation (basement)
plan
– With dimensions
Calculating Building Loads
pages 173-177
Types of structure loads
• Live loads
– loads that move or change
– furniture, appliance, people, wind, snow, etc.
• Dead loads
– loads that are constant
– The weight of the structure
– construction materials & plumbing fixtures, etc.
Beams and Girders
• Beams 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 beams
• Standard or Wide
• Beam size based upon weight of the
structure and the span.
Typical Steel Beams
Loads on the beam
• 1/2 of the building’s
weight rests on the beam
• 1/2 of the building’s
weight rests on the
foundation walls
Weight Supported by Beam
Values for residential buildings
• 1st floor
• live load + dead load = 50 lbs/ft2
• 2nd floor
• live load + dead load = 50 lbs/ft2
• Ceiling
• live load + dead load = 30 lbs/ft2
• Walls
• dead load = 10 lbs/ft2
• Roof has no load on the beam
Here’s what you need
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Calcualtor
NOTEBOOK!
Copy of floor plan or foundation plan
Architect’s Scale
Determine where your beam(s) will go
How much weight does your beam need
to support? Time to do the math . . .
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) ½ total
D2=
F) Wall weight length x 8’ x 10 lbs./ft. =
G) Weight on Beam F + E =
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Now what?
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Convert to Kips
Refer to tables
S-Beam or W-Beam
Determine size & spacing of posts
– Refer to your textbook pp. 175-177
Load Assumptions
• First Floor and Second Floor
– Live + dead load = 50 pounds per square foot.
• Ceiling
– Live + dead load = 30 pounds per square foot.
• Walls
– Dead load = 10 pounds per square foot.
• Roof
– No load on beam.
Weight Calculations Example
• Two Story Frame Structure
– 28' x 40'.
• Area of the House
– 1120 square feet per floor.
• Wall Area
– 320 square foot per wall.
• Assumes a bearing wall on each floor.
Weight Calculations Example
• Foundation of the house.
Weight Calculations Example
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Weight 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 tables
• S-Beam (p.249)
– standard I-beam
• W-Beam (p.249)
– wide flange I beam
• Wood beams
– Microllam®
Weight Calculations Example
• W-beam span and load table.
(American Institute of Steel Construction)
Typical Steel Beams
Weight Calculations Example
• Length 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 Example
• Three supporting posts are added.
Weight Calculations Example
• Post Selection
– Size 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 Example
• Weight supported by each post.
Weight Calculations Example
• Steep pipe columns load table.
(American Institute of Steel Construction)