architectural drawing structural calculations. beams and girders beams or girders support floor...
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Beams and Girders
Beams or girders support floor joists over long spans.
Beams or girders May be wood or metal.
Wood beams may be built-up or solid.
Steel beams may be S-beams or W-beams.
Size based on weight of the structure and the span.
Structure Loads
Dead load is the weight of the structure itself:
Roofing, siding, joist, etc.
Live load is the fixed or moving weights:
Furniture, appliances, occupants, snow on the roof, etc.
Structural Calculations
Building Loads Make a sketch of the load distribution. Make a listing of the building loads using the following format:
Area Construction Live Load (lbs/sq ft)
Dead Load (lbs/sq ft)
Total Load (lbs/sq ft)
ROOF BUILT-UP 30 8 38
ATTIC WITH STORAGE 20 10 30
FLOOR FIRST FLOOR 40 10 50
PARTITIONS PARTITIONS FIRST FLOOR 0 10 10
Total Building Load 128 LBS/SQ FT
Structural Calculations
Beam Support Area with no columns
60'-0" (SPAN)
30'-0
"
15'-0
"15
'-0"
7'-6
"7'
-6"
BEAM SUPPORT AREANO COLUMNS
15'-0
"
Structural Calculations
Beam Support Area with one column
30'-0" (SPAN)
BEAM SUPPORT AREAONE COLUMN
60'-0"
30'-0
"
15'-0
"15
'-0"
7'-6
"7'
-6"
15'-0
"
Structural Calculations
Beam Support Area with two columns
20'-0" (SPAN)
BEAM SUPPORT AREATWO COLUMNS
60'-0"
30
'-0"
15
'-0"
15
'-0"
7'-6
"7
'-6"
15
'-0"
Structural Calculations
Beam Calculations Make a listing of the loads acting on the beam using the following format:
Area Building Load (lbs/sq ft) ROOF 0
ATTIC 30
FIRST FLOOR 50
PARTITIONS 10
Total Load acting on the beam 90 LBS/SQ FT
Make a series of trials using various numbers of columns and record the date using the following format:
Trial Number of Columns
Span (ft) Support Width (ft)
Support Area (sq ft)
Load (lbs/sq ft)
Support Load (Kips)
Beam Size
1 0 60 15 900 90 81 NA
2 1 30 15 450 90 40.5 W12 x 53
3 2 20 15 300 90 27 W8 x 31
4 3 15 15 225 90 20.25 W8 x 18
Mark final selection of beam size and number of columns.
Structural Calculations
Column Support Area with one column
30'-0" (SPAN)
COLUMN SUPPORT AREAONE COLUMN
60'-0"
30
'-0"
15
'-0"
15
'-0"
7'-6
"7
'-6"
15
'-0"
Structural Calculations
Column Support Area with two columns
20'-0" (SPAN)
COLUMN SUPPORT AREATWO COLUMNS
60'-0"
30'-0
"
15'-0
"15
'-0"
7'-6
"7'
-6"
15'-0
"
Structural Calculations
Column Calculations Make a series of trials using various numbers of columns and record the date using the following format:
Number of Columns
Span (ft) Support Width (ft)
Support Area (sq ft)
Total Load (lbs/sq ft)
Support Load (Kips)
Column Height (ft)
Column Size
1 30 15 450 90 40.50 13 5
2 20 15 300 90 27.00 13 4
3 15 15 225 90 20.25 13 3.5
Structural Calculations
Procedure for Using Span Data Charts• Select species of wood to be used.• Select appropriate live load.• Determine lumber grade to be used.• Scan the lumber grade row and note the maximum spans.• Select the joist size and spacing that will support the desired
live load (16" OC spacing is typical).
Structural CalculationsJoist and Rafter selection Indicate the selection of joist and rafter sizes and spacing by listing the data using the following format (be sure to show all possible combinations):
Live Load 40 Dead Load 10 Area Species Grade Span (ft) Size Spacing
Floor Joist Southern Pine #2 15 2 x 10 16
Floor Joist Southern Pine #1 15 2 x 10 16
Floor Joist Southern Pine SS 15 2 x 10 16
Floor Joist Southern Pine #2 15 2 x 12 16
Floor Joist Southern Pine #1 15 2 x 12 16
Live Load 20 Dead Load 10
Area Species Grade Span (ft) Size Spacing Ceiling Joist Southern Pine #2 15 2 x 10 16
Ceiling Joist Southern Pine #2 15 2 x 10 16
Ceiling Joist Southern Pine #1 15 2 x 10 16
Ceiling Joist Southern Pine SS 15 2 x 10 16
Ceiling Joist Southern Pine #2 15 2 x 10 16
Live Load 30 Dead Load 8
Area Species Grade Span (ft) Size Spacing Roof Rafter Southern Pine #2 16 2 x 10 16
Roof Rafter Southern Pine #1 16 2 x 10 16
Roof Rafter Southern Pine SS 16 2 x 10 16
Roof Rafter Southern Pine #3 16 2 x 12 16
Roof Rafter Southern Pine #2 16 2 x 12 16
Mark the final selection of materials. Use the same species and grade for the selected structural components.
Structural CalculationsFooting Calculations Make a listing of the loads acting on the footings using the following format:
Type of Ground Safe Ground Loading (lbs/sq ft)
Area Length (ft) Building Load
(lbs/sq ft)
Total Load (lbs/ft)
Roof
Attic
Floor
Partitions
Area Wall Width (ft)
Length (ft) Building Load
(lbs/cu ft)
Total Load (lbs/ft)
First floor wall
Basement wall
Total load acting on the footing Safe ground loading for soil type Minimum footing width (ft)