Ord 1999-017 - Laserfiche WebLink

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(1) New Materials. All new materials introduced into the building to meet the requirements of this section which are subjected to combined vertical . and horizontal forces shall comply with Section ' 2303(f). (2) Existing Materials. When stresses in existing lateral force resisting elements are due to a combination of dead loads plus live loads plus seismic loads, the allowable working stress specified in the Uniform Building Code may be increased 100 percent. However, no increase will be permitted in the stresses allowed in Section 7 -5 -860, and the stresses in members due only to seismic and dead loads shall not exceed the values permitted by Section 2303(d) of the Uniform Building Code. (3) Allowable Reduction of Bending Stress by Vertical Load. In calculating tensile fiber stress due to seismic forces required by this Article, the maximum tensile fiber stress may be reduced by the full direct stress due to vertical dead loads. Section 7 -5 -860: MATERIALS OF CONSTRUCTION (a) General. All materials permitted by the Uniform Building Code including their appropriate allowable stresses and those existing configurations of materials specified herein may be utilized to meet the requirements of this Article. (b) Existing Materials. (1) Unreinforced Masonry Walls. Unreinforced masonry walls analyzed in accordance with this Article may provide vertical support for roof and floor construction and resistance to lateral loads. The facing and backing of such walls shall be bonded so that not less than 4 percent of the exposed face area is composed of solid headers extending not less than 4 inches into the backing. The distance between adjacent full - length headers shall not exceed 24 inches vertically or horizontally. Where the backing consists of two or more wythes the header shall extend not less than 4 inches into the most distant wythe, or the backing wythes shall be bonded together with 9