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ORDINANCE NO. NS-1598 <br />Page Eight <br /> <br />FOOTNOTES: <br /> <br /> (1) Minimum quality mortar shall be determined by <br />laboratory testing in accordance with subsection (f) of <br />Section 8-2005. <br /> <br /> (2) Walls of buildings within rating classification <br />shall be analyzed in accordance with subsection (f) of <br />Section 8-2005. <br /> <br /> (3) Allowable shear stress may be increased by the <br />addition of ten (10) percent of the direct stress due to the <br />weight of the wall directly above. <br /> <br /> (4) The height to thickness ratios may be increased by <br />twenty percent (20%) for the first floor of a building of <br />two or more stories. The height or length may be measured <br />horizontally to supporting elements provided the stiffness <br />of the existing unreinforced masonry supporting member is at <br />least twice the stiffness of the tributary wall. Stiffnesses <br />are to be based on gross section. For new or existing <br />stiffening elements which are not of unreinforced masonry, <br />the element shall be capable of resisting three times the <br />tributary load determined by subsection (b) of Section <br />8-2005 without yielding or failing. The stiffening element <br />shall be connected to the structure in accordance with <br />subsection (c) of Section 8-2005 for the loads specified in <br />subsection (b) of Section 8-2005. <br /> <br />(2) EXISTING ROOF, FLOORS, WALLS, FOOTINGS, AND <br />WOOD FRAMING. Existing materials utilized in the described <br />configuration may be used as part of the lateral load resisting <br />system, provided that the stresses in these materials do not <br />exceed the values shown in Table E. <br /> <br /> TABLE E <br /> VALUES FOR EXISTING MATERIALS <br /> <br />MATERIALS(2) ALLOWABLE VALUES <br /> <br />(1) <br /> <br />HORIZONTAL DIAPHRAGMS <br /> <br />(a) Roofs with straight <br />sheathing and roofing <br />applied directly to the <br />sheathing. <br /> <br />150 lbs. per foot for <br />seismic shear. <br /> <br />(b) Roofs with diagonal <br />sheathing and roofing <br />applied directly to the <br />sheathing. <br /> <br />400 lbs. per foot for <br />seismic shear. <br /> <br />(c) Floors with straight <br />tongue and grove sheathing <br /> <br />150 lbs. per foot for <br />seismic shear. <br /> <br />(d) Floors with straight <br />sheathing and finished <br />wood flooring. <br /> <br />300 lbs. per foot for <br />seismic shear. <br /> <br />(e) Floors with diagonal <br />sheathing and finished <br />wood flooring. <br /> <br />400 lbs. per foot for <br />seismic shear. <br /> <br />(f) Floors or roofs with <br />straight sheathing and <br />plaster applied t~l~he <br />joist or rafters.- ' <br /> <br />Add 50 lbs. per foot <br />to materials (1) (a) and <br /> (1) (c). <br /> <br /> <br />