Timber & Wood Design Examples

Tension Members

Example 1 - Analyzing a tension sawn lumber member subjected to dead and snow loads per NDS 2012

Calculate the actual and allowable tensile stress parallel to the grain of the tension member given the following parameters:

 

Wood Type - No. 3 Hem-Fir
Wood Size - 2 x 8, dressed
Tensile Force - Dead + Snow Load, 5000 lbs
Moisture Content - >19%
Temperature - Normal

 

The tension member has a row of 5/8" diameter bolts with 1/8" oversized holes

Example 2 - Analyzing a tension glulam member subjected to dead and snow loads per NDS 2012

Calculate the actual and allowable tensile stress parallel to the grain of the tension member given the following parameters:

 

Wood Type - Glulam Axial Combination 5DF
Wood Size - 2 1/2 x 6 (net finished dimensions)
Tensile Force - Dead + Snow Load, 10000 lbs
Moisture Content - >16%
Temperature - Normal

 

The tension member has a row of 5/8" diameter bolts with 1/8" oversized holes

Example 4 - Analyzing a glulam member subjected to tensile force plus bending moment per NDS 2012

Check the adequacy of the member given the following parameters:

 

Wood Type - Glulam Axial Combination 3DF

Wood Size - 5 1/8" x 10 1/2"
Tensile Force - 40000 lbs
Bending Moment - 80000 lbs-in
Moisture Content - Dry
Temperature - Normal
Load Duration Factor - 1.0
Span Length - 30 ft

 

Lateral supports provided at the member ends only, loading is due to uniformly distributed load

Flexural Beam Members

Example 1 - Analyzing a deck beam subjected to dead and snow loads per NDS 2012

Check the adequacy of the simply supported deck beam loaded on its narrow face given the following parameters:

 

Wood Type - No 1 Douglas fir-larch
Wood Size - 2 x 8, dressed
Bracing - Adequately braced to prevent lateral torsional buckling
Dead Load - 15 lbs/ft^2
Snow Load - 20 lbs/ft^2
Moisture Content - >19%
Temperature - Normal
Span Length - 15 ft
Deck Beam Spacing - 1.5 ft

Example 2 - Analyzing a tension glulam member subjected to dead and snow loads per NDS 2012

Calculate the allowable stress values per NDS of the beam given the following parameters:

 

Wood Type - Select Structural Red Oak
Wood Size - 6 x 10, full sawn
Load Type - dead, live, snow, wind (loading on narrow face)
Bracing - Adequately braced to prevent lateral torsional buckling
Moisture Content - Dry
Temperature - Normal