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(a) General. All materials permitted by the Uniform Building Code including their <br />appropriate allowable stresses and those existing configurations of materials <br />specified herein maybe utilized to meet the requirements of this Article. <br />(b) Existing Materials. <br />(1) Unreinforced Masonry Walls. Unreinforced masonry walls analyzed in <br />accordance with this Article may provide vertical support for roof and <br />floor construction and resistance to lateral loads. The facing and backing <br />of such walls shall be bonded so that not less than 4 percent of the exposed <br />face area is composed of solid headers extending not less than 4 inches <br />into the backing. The distance between adjacent full-length headers shall <br />not exceed 24 inches vertically or horizontally. Where the backing <br />consists of two or more wythes the header shall extend not less than 4 <br />inches into the most distant wythe, or the backing wythes shall be bonded <br />together with separate headers whose area and spacing conform to the <br />foregoing. <br />Tension stresses due to seismic forces normal to the wall maybe <br />neglected if the walls do not exceed the height to thickness ratio in Table 2 <br />of this Article and the in-plane shear stresses due to seismic loads as set <br />forth in Table 3 of this Article, and the in-plane shear stresses due to <br />seismic loads as set forth in Table 4 of this Article. If the wall height- <br />thickness ratio exceeds the specified limits, the wall maybe supported by <br />vertical bracing members designed in accordance with Section 7-5-855. <br />The deflection of such bracing member at design loads shall not exceed <br />one-tenth of the wall thickness. <br />All vertical bracing members shall be attached to the floor and roof <br />construction for their design loads independently of required wall anchors. <br />Horizontal spacing of vertical bracing members shall not exceed one-half <br />the unsupported height of the wall nor ten feet. The wall height maybe <br />measured vertically to bracing elements other than a floor or roof. Spacing <br />of the bracing elements and wall anchors shall not exceed six feet. <br />Bracing elements shall be detailed to minimize the horizontal <br />displacement of the wall by components of vertical displacements of the <br />floor or roof. <br />(2) Existing Roof, Floors, Walls, Footings, and Wood Framing. Existing <br />materials including wood shear walls utilized in the described <br />configuration maybe used as part of the lateral load resisting system, <br />provided that the stresses in these materials do not exceed the values <br />shown in Table 4 of this Article. <br />ORDINANCE NO. 2007-030 E) <br />