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ORDINANCE K£-2182 0~ <br />PAGE 15 <br /> <br /> (a) General. Ail materials permitted by this Code including <br />their appropriate allowable stresses and those existing <br />configurations of materials specified herein may be utilized to <br />meet the requirements of this article. <br /> <br />(b) Existing materials. <br /> <br />(1) <br /> <br />Unreinforced masonry walls. Unreinforced masonry walls <br />analyzed in accordance with this section may provide <br />vertical support for roof and floor construction and <br />resistance to lateral loads. <br /> <br />Tension stresses due to seismic forces normal to the wall may <br />be neglected if the wall does not exceed the height or length <br />to thickness ratio in Table D and the in-plane shear stresses <br />due to seismic loads as set forth in Table G. <br /> <br />If the wall height-thickness ratio exceeds the specified <br />limits, the wall may be supported by vertical members designed <br />in accordance with the requirements of Chapter 23 of the <br />Uniform Building Code. In addition, deflection of the <br />supporting members at design loads shall not exceed one-tenth <br />(1/10) of the wall thickness. The vertical supporting members <br />shall be attached to the floor and roof construction for their <br />design loads independently of the required wall anchors. <br />Horizontal spacing of the vertical members shall not exceed <br />one-half (1/2) the unsupported height of the wall or ten (10) <br />feet maximum. However, the maximum horizontal spacing of wall <br />anchors at any anchorage level shall not exceed that specified <br />in section 8-2007. <br /> <br />The wall height or length may be measured horizontally to <br />existing supporting elements providing the stiffness of the <br />supporting member is at least twice as stiff as the tributary <br />wall. Stiffness shall be based on the gross section. <br /> <br />(2) <br /> <br />Existing roof, floors, walls, footings and wood framing. <br />Existing materials utilized in the described <br />configuration may be used as part of the lateral load <br />resisting system, provided that the stresses in these <br />materials do not exceed the values shown in Table E. <br /> <br />TABLE D <br /> <br />ALLOWABLE VALUE OF HEIGHT-THICKNESS RATIO OF <br /> <br /> QUALITY MORTA~'-' <br /> <br />Buildings with crosswalks <br /> <br />15 <br /> <br /> <br />