including seismic requirements. Requirements for shear walls in buildings located in seismic zones 1 through

4 are given in TM 5-809-10/NAVFAC P-355/AFM 88-3, Chapter 13, Seismic Design for Buildings. Except

as contained herein, design criteria, section properties, material properties, design equations, and allowable

stresses are contained in chapter 5.

in-plane horizontal forces. A shear wall is a vertical element in the building lateral load resisting system. It

transfers horizontal forces vertically downward from a diaphragm above to a diaphragm or a foundation

below. Thus, horizontal wind or seismic forces are collected at floor or roof diaphragm levels and transferred

to the building foundation by the strength and rigidity of the shear walls. A shear wall may be considered

analogous to a plate girder cantilevered off the foundation in a vertical plane. The wall performs the function

of a plate girder web and the integral vertical reinforcement at the ends of wall panels, between control joints,

function as the beam flanges. Pilasters or floor diaphragms, if present, function as web stiffeners. Axial,

flexural, and shear forces must be considered in the design of shear walls, including the tensile and

compressive axial stresses resulting from loads tending to overturn the wall.

of the ratio of M/(Vd), where M is the maximum moment applied to the wall due to the in-plane shear force,

V, and d is the effective length of the wall. Therefore, if the shear wall is assumed fixed at the top and bottom

(a multistory shear wall), M = hV, and M/(Vd) becomes h/2d, where h is the height of wall. However, if

the shear wall is assumed fixed at the bottom only, (a single-story cantilevered shear wall), M = hV, and

M/Vd becomes h/d. Figure 7-1 illustrates these conditions.

The allowable shear stress is also dependent upon whether or not shear reinforcement is provided. If the

calculated shear stress, fvm, exceeds the allowable shear stress, Fvm, then shear reinforcement will be provided.

The shear reinforcement will be designed to carry the entire shear force. The following equations illustrate

the limitations and requirements of determining the allowable shear stress in a shear wall.

stress, Fvm.

designed to carry the entire shear force. The calculated shear stress in the reinforcement, fvm, shall not

exceed the allowable shear stress, Fvs.

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