for lateral out-of-plane loads and axial loads. The design of reinforced masonry walls for in-plane lateral loads

(shear walls) and axial loads is covered in chapter 7. General design criteria, section properties, and allowable

stresses used but not contained herein are covered in chapter 5.

in TM 5-809-1/AFM 88-3, Chapter 1 or from seismic forces as given in TM 5-809-10/NAVFAC P-355/AFM

88-3, Chapter 13.

live, snow, and wind uplift forces as given in TM 5-809-1/AFM 88-3, Chapter 1.

roof, floor or foundation. Normally, the walls are designed as simple beams spanning between structural

supports. Simple beam action is assumed even though reinforcement, which is needed to control horizontal

flexural cracking at the floor levels or to provide connectivity, may be present and will provide at least partial

continuity. Under certain circumstances, such as when a system of pilasters is present, the masonry walls may

be designed to span horizontally between pilasters which in turn span vertically to transfer the lateral loads

to the horizontal structural support elements above and below.

foundation. When the resultant axial force is tension from wind uplift loadings, mortar tension will not be

used to resist these uplift forces. Instead, adequate reinforcement will be provided to anchor the top of wall

bond beam to the remainder of the wall and on down to the foundation. If the resultant of the vertical loads

which are applied to the wall at any level is not at the center of the wall; that is, it is not concentric; due

allowance will be made for the effects of eccentric loading. This includes any moments that are due to

eccentric loading as well as any additional moments caused by the rotation of floor or roof elements that

frame into the wall.

(1) Uniform loads. Uniform loads enter the wall as line loads, stressing the wall uniformly along its

length.

(2) Concentrated loads. When concentrated loads are not supported by structural elements, such as

pilasters, they may be distributed over a length of wall equal to the width of bearing plus four times the wall

thickness, but not to exceed the center to center distance between concentrated loads. Concentrated loads

will not be distributed across control joints.

the straight-line interaction equations given in this chapter or may be combined by other methods which are

based on accepted principles of mechanics.

to bending and axial loads. Lateral (wind or seismic) loading will be applied inward and outward on all

exterior walls. Both the condition where the moment due to wind loading and the moment due to axial load

eccentricity are additive and the condition where they are not additive are shown on figures 6-1 and 6-2,

respectively.

eccentric and lateral loads is "Ra" and is determined as follows:

Pe

wh

Ra '

(lb/ft of wall)

(eq 6-1)

2

12h

Where:

P = The axial load, pounds per foot of wall length.

e = the distance from the centerline of the wall to the load P, inches.

h = The height of the wall, feet.

w = The lateral load on the wall, psf.

The "" in equation 6-1 refers to the two conditions; (1) where the eccentric and lateral loads are additive, and (2) where the eccentric and lateral loads are

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