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The shear force v is the unit shear (force per unit length) in the sheathing of the shear resisting elements, however it may be factored differently for deflection calculations than for shear wall design.
Wind Analysis
When deflections are used to calculate stiffnesses for shear force distribution to shear lines and within shear lines, the ASD force is used, i.e. the design wind force factored by 0.6.
When deflections are used for allowable story drift calculations, a special serviceability combination is used in which both the dead and wind factors are 1.0. A different intensity of wind pressure is used to generate the forces.
Seismic Analysis
For seismic deflection calculations, the strength-level shear force from ASCE 2.3.6 is used as per ASCE 7 12.8-6. The force is thus factored by 1.0 rather then the 0.7 ASD load combination factor used for seismic design, The counteracting dead load factor for hold-down displacement calculations is 0.9 rather than 0.6 that is used for ASD design.
Redundancy Factor r
The unit shear used is the shear line force without the redundancy factor r applied. In some cases, r is 1.3 for shear wall line design, but it remains 1.0 for deflection analysis, according to ASCE 7 12.3.4.1.
Perforated Shear Walls
For perforated shear walls, the v used is vmax, that is the force on the wall per unit distance of full-height-sheathing segment divided by the perforation factor Co , as per SDPWS 4.3.2.1. Co is given in SDPWS 4.3.3.5; vmax by Eqn. 4.3-9 in 4.3.6.4.1.1.
Force-Transfer Walls
The shear force used for deflection analysis of force transfer walls is the force in the central piers adjacent to openings, extending vertically from the bottom of the lowest adjacent pier to the top of the highest.
Distribution of v to Sides of Wall
The second and third terms of the 4-term equation and the second term of the 3-term equation apply to the sheathing, which can be different for each side of a composite wall. Therefore, the two sides of the wall can have a different shear value v (the third term includes v indirectly through en.) such that the sheathing deflection is the same on both sides. Refer to Deflection of Two-sided Shear Wall for an explanation of how shear is apportioned to each side of a composite wall.
Distribution of v Within Shear Lines
The distribution of v within a shear line depends on the Design setting which allows you to choose between capacity-based and deflection-based force distribution. For deflection-based design, an iterative procedure is required as distribution to shear resisting element within the line depends on the deflection calculated with the previous distribution.