where:

A

= Horizontal cross sectional area of the column or

wall including piers, but excluding the non-

load-bearing wythe, if any, of an external wall for

cavity construction. (mm2)

ha

= Clear height of a column or wall between

restraining surfaces (m)

t

= Wall thickness or column dimension (m)

3.3 ft length of a load-bearing wall must provide a required tie strength equal to:

6.2x10-4 A (ha/t)2

or 22.5 whichever is larger

(kips)

where:

A

= Horizontal cross sectional area of the column or

wall including piers, but excluding the non-

load-bearing wythe, if any of an external wall for

cavity construction. (ft2)

ha

= Clear height of a column or wall between

restraining surfaces (ft)

t

= Wall thickness or column dimension (ft)

Minimum thickness of a solid wall or

150 mm (5.9 in)

one load-bearing wythe of a cavity wall

Minimum characteristic compressive

5 N/mm2 (725 psi)

strength of masonry

Maximum ratio ha/t

20

Allowable mortar designations

S, N

If it is not possible to provide the vertical required tie strength in any of the

load-bearing elements, then apply the Alternate Path method for each such deficient

element. Remove each deficient element from the structure, one at a time, and perform

an AP analysis to verify that the structure can bridge over the missing element. The

amount of element to be removed from the structure is given in Table 6-2 and additional

detail is provided in Appendix B.

6-5

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