Tiêu đề PSAD 45 - Seismic Design.pdf ✅

PSAD 45: Seismic Design Video Transcript SITUATION. Given: Floor Live Load = 2.4 kPa S1 = 2.5 m S2 = S3 = 3.0 m L2 = 6.0 m L1 = L3 = 8.0 m 1. What is the design live load carried by floor beam IJ, in kN/m? 2. What is the design live load carried by floor beam FG, in kN/m? Solution: 205.5. Reduction of Live Loads. The design live load determined using unit live loads as set forth in Table 205-1 for floors and Table 205-3, Method 2, for roofs may be reduced on any member supporting more than 15 m2, including flat slabs, except for floors in places of public assembly and for live loads greater than 4.8 kPa, in accordance with the following equation: R = r(A − 15) The reduction shall not exceed 40 percent for members receiving load from one level only, 60 percent for other members or R, as determined by the following equation: R = 23.1 (1 + D L ) Where: A = area of floor or roof supported by the member, m2 D = dead load per square meter of area supported by the member, kPa L = live load per square meter of area supported by the member, kPa R = reduction in percentage r = rate of reduction equal to 0.08 for floors, flat roofs, roofs with rise less than 1 unit vertical in 3 units horizontal (33.3% slope), arches and domes with rise less than 1/8 of the span, and 0.06 for roofs between 33.3% slope and 100% slope or arches and domes with rise between 1/8 and 3/8 of the span. For storage loads exceeding 4.8 kPa, no reduction shall be made, except design live load on columns may be reduced 20 percent. The live load reduction shall not exceed 40% in garages for the storage of private pleasure cars having a capacity of not more than 9 passengers per vehicle.