Load Combination

The load combination employed is D + 0.5L + Wa, from ASCE 7 CC.1.2.

This combination is used for serviceability calculations only, i.e., story drift limits, and is not used for the deflections used to distribute loads for shear wall design, which use the ASD load combination, 0.6W + 0.6D.

Wind Load W_a

The wind load Wa is derived from the serviceability wind speeds using the same provisions that are used to generate wind loads for shearwall design from ASCE 7 Chapters 26-28. The only difference is the wind velocity used to create pressures in 27.3.2 and 28.3.2.

In determining deflections, W_a is used for:

• the segment force v, including v used to calculate overturning hold-down force
• the wind uplift component of the hold-down force
• the overturning component of hold-down forces transferred from upper stories.

Dead Load D

The dead load factor is 1.0, as opposed to the 0.6 ASD factor for MWFRS deflections. his factor is for dead loads counteracting the wind overturning hold-down force, used for the hold-down displacement component of deflection.

Live Load L

The 0.5L component is not considered, as the program does not include live loads.