University of Washington



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NDS Supplement

Allowable [pic] Actual?

Analyze actual beam for max moment, shear and deflection

Lumber or gluelam?

Compute allowable bending [pic]and shear [pic]stresses using adjustment factors and Table 4A+ as appropriate : assume CF; if the unsupported length [pic], go thru CL analysis

Set allowable bending stress [pic] equal to actual [pic]and solve for the minimum section modulus required.

Select member size from Table 1B of NDS supplement.

Recalculate [pic] and [pic]

Assume adjustment factors such as CV; check for unsupported lengths for CL analysis: to obtain using Table 5A+ [pic]

Set allowable bending stresses equal to actual values for positive and negative bending to solve for the section modulus required: e.g., [pic]

Lumber

Gluelam

Select member size from Table 1C of NDS supplement.

Recalculate [pic] and check with appropriate fb values.

Calculate shear stresses for a rectangular section:

[pic]

Allowable [pic] Actual?

Allowable [pic] Actual?

Calculate maximum deflection for actual beam using the adjusted modulus of elasticity.

Calculate shear stresses for a rectangular section:

[pic]

Calculate maximum deflection for actual beam using the adjusted modulus of elasticity.

Calculate camber as [pic]

Calculate beam loading from structural loading description.

End

Solve for area required:

[pic]; resize beam

Solve for area required:

[pic]; resize beam

Solve for required moment of inertia; resize beam

Solve for required moment of inertia; resize beam

No

Yes

Yes

Yes

Yes

Yes

no

no

no

no

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