Note that when the reinforcing steel is being checked, the minimum axial stress, ~a, must be used. Note also

that it is conservative to *not *consider axial loading (fa = 0) when checking the reinforcing steel stress.

Ra

fv '

(psi)

(eq 6-17)

bwd

Where:

bw = The width of the masonry element effective in resisting out-of-plane shear as given in

chapter 5, inches.

d = The depth of the masonry element effective in resisting shear, given "d1" for one reinforcing bar

per cell and "d2" for two bars per cell in chapter 5.

the mid-height defection of a wall (due to lateral and eccentric loadings as discussed above) by the summation

of the axial load, P, at the top of the wall and the weight of the top half of the wall. When the height to

nominal thickness ratio of the wall is less than 24, the "P-delta effect" is minor and may be neglected. For

walls where the height to nominal thickness ratios is greater than 24, the mid-height deflection, )s, will be

computed as follows:

When Mmid < Mcr;

(5)(Mmid)(h 2)(144)

)s '

(in)

(eq 6-18)

(48)(Em)(Ig)

When Mcr < Mmid < Mr;

(5)(Mcr)(h 2)(144)

(5)(Mmid & Mcr)(h 2)(144)

)s '

%

(in)

(eq 6-19)

(48)(Em)(Ig)

(48)(Em)(Icr)

Where:

h = The wall height, feet

Mmid = The moment at the mid-height of the panel, including the "P-Delta effect", inch-pounds.

Ig = The gross moment of inertia of the wall cross section, in4.

Icr = The cracked moment of inertia of the wall cross section, in4

Mrm = The allowable resisting moment of the masonry wall, inch-pounds.

additional tributary axial and lateral loads. The additional tributary axial loads are due to the weight of

masonry above the opening and vertical loads applied to the tributary masonry above the opening. The

additional tributary lateral loads are the lateral loads on non-masonry wall components (doors, windows, etc.)

that are laterally supported by the adjacent masonry wall elements. The tributary load area width will be

measured from the centerline of the openings. Masonry wall elements between and alongside openings that

are subjected to combined loading will be designed in accordance with equations 6-13 through 6-16. Due

allowance will be made for eccentricity.

walls. Tables B-1 through B-14 provide the properties of wall stiffeners with varying reinforcement (size,

spacing and number of bars per cell), varying wall thickness (6, 8, 10, and 12 inch nominal thickness) and two

mortar types (S and N). Tables B-15 through B-50 provide reinforcing steel sizes and spacings for varying

wall heights, lateral loads, wall thicknesses, axial loads (with and without eccentricity), using type S mortar.

in Appendix B.

loading. When performing a complete wall design, all appropriate load combinations must be considered.

(1) *Given--*

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