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550 South Hope St, Suite 1700 <br />Los Angeles, CA 90071 <br />915 N. Vicentia new garage <br />11/25/19 <br />CCN <br />Scope of work: <br />Provide like for like replacement of existing 4 car residential garage. <br />Page 11 <br />514-516 S Ross St CCN <br />12/2025 <br />North wall <br />Vb = 12.9k / 1.4 = 9.2k <br />V to each wall = Vb / 2 = 4.6k <br />W = 12.2k / 1.4 = 8.7k <br />W to each wall = W / 2 = 4.35k <br />Existing <br />lnorth wall = 35'-0" <br />vnorth wall = V / lnorth wall = 131plf <br />vn = 370plf (see following page for capacities) <br />dcrexisting seismic = vnorth wall / vn = 0.36 << 1.0 <br />wnorth wall = W / lnorth wall = 124.3plf <br />vn = 520plf (see following page for capacities) <br />dcrexisting wind = wnorth wall / vn = 0.24 << 1.0 <br />Proposed <br />lnorth wall = 35'-0" - 2'-6" = 32'-6" <br />vnorth wall = V / lnorth wall = 141plf <br />vn = 370plf <br />dcrproposed seismic = vnorth wall / vn = 0.38 << 1.0 <br />wnorth wall = W / lnorth wall = 133plf <br />vn = 520plf (see following page for capacities) <br />dcrexisting wind = wnorth wall / vn = 0.25 << 1.0 <br />Compare demand capacity ratios (dcr) <br />Seismic dcrproposed / dcrexisting = 1.05 <br />Wind dcrproposed / dcrexisting = 1.04 <br />The proposed demand-capacity ratio with the alteration is NOT more <br />than 10 percent greater than its demand-capacity ratio with the <br />alteration ignored. Per 503.4 it is permitted to remain unaltered. In <br />addition the actual demand capacity ratios are very low. <br />permitted. <br />[BS] 503.4 Existing structural elements carrying lateral <br />load. Except as permitted by Section 503.13, where the alter- <br />ation increases design lateral loads, results in a prohibited <br />structural irregularity as defined in ASCE 7, or decreases the <br />capacity of any existing lateral load-carrying structural <br />element, the structure of the altered building or structure shall <br />meet the requirements of Sections 1609 and 1613 of the Cali- <br />fornia Building Code. Reduced seismic forces shall be <br />permitted. <br />Exceptions: <br />1. Any existing lateral load-carrying structural element <br />whose demand-capacity ratio with the alteration <br />considered is not more than 10 percent greater than <br />its demand-capacity ratio with the alteration ignored <br />shall be permitted to remain unaltered. For purposes <br />of calculating demand-capacity ratios, the demand <br />shall consider applicable load combinations with <br />design lateral loads or forces in accordance with <br />Sections 1609 and 1613 of the California Building <br />Code. Reduced seismic forces shall be permitted. <br />For purposes of this exception, comparisons of <br />demand-capacity ratios and calculation of design <br />lateral loads, forces and capacities shall account for <br />the cumulative effects of additions and alterations <br />since original construction.