Determine distribution or mezzanine shear force to vertical resisting elements

Mezzanine shear forces in the transverse direction are distributed to the interior CMU shear walls (B1-B2

& H1-H2) and the exterior walls (A1-A2 & I1-I2) based on their relative rigidities. For longitudinal forces,

it is assumed that each braced frame bay receives of the force due to symmetry.

Wall Rigidity Calculations

Mechanical Properties of Masonry

1500.psi

f' m

(10.34 MPa)

Assume masonry strength of 1500 psi with

Type S mortar.

6

1.6.10 .psi

Em

( 11032MPa )

Elastic Modulus of CMU (ACI

530-95 Table 5.5.2.3)

5

0.4.E m

E v = 6.4 10 psi

Ev

( 4413 Mpa )

Shearing Modulus of CMU (ACI

530-95 Sec. 5.5.2.3 b)

4.7.in (117 mm)

est

Equivalent solid thickness 8" CMU grouted

at every 40" o/c

1.kip

P

( 4.45 N)

Shear load to determine pier stiffness

Masonry Stiffness Functions:

est .d

A( d )

Area of wall segment

1. . 3

I( d )

est d

Use uncracked section (Assuming that wall

12

piers will not crack, per FEMA 273 Sec.

7.4.4.1)

3

( 1.2.P.h )

P.h

∆ c( h ,d )

Deflection of a cantilevered pier

A( d ) .E v

3.E m.I( d )

3

( 1.2.P.h )

P.h

∆ f( h ,d )

Deflection of a fixed-fixed pier

A( d ) .E v

12.E m.I( d )

1

R f( h ,d )

Rigidity of fixed pier

∆ f( h ,d )

H1-18

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