为模板自重施加在底肋上的不均匀细数。Рc、方木自重:0.48×1.2×0.36 =0.209(KN)Рd、施工人员、料具运输堆放荷载:2.5×0.36 = 0.9(KN)Рe、倾倒砼时产生的冲击荷载:4.0×0.36 = 1.44(KN)Рf、振捣砼的荷载:2.0×0.36 = 0.72(KN)Рg、风、雪可能产生的荷载:1.0×0.36 = 0.36(KN)Р合计荷载:15.7248+0.18+0.209+0.9+1.44+0.72+0.36= 19.53(KN)Р则:每米均布荷载19.56 / 0.6 =32.6(KN/m)Р2)、底肋强度验算Р跨中弯矩:M = (qL2)/8=(32.6×0.6 2 ) / 8 =1.467(KNm)Р截面模量:W = (b×h2)/6 = (100×100 2 ) / 6 = 166667(mm2)Р则:σ= M/W =1.467×103×10 3 /166667 = 8.802(Mpa)< [σw] =14.5(Mpa),安全Р注:参照《路桥施工计算手册》P176表8-6,松锯材为东北落叶松[σw]=14.5 Mpa。Р3)、底肋刚度验算Р挠度公式:f =5qL4/(384EI)Р 其中:q =32.6(KN/m)РE=1.1×104(Mpa)=1.1×107(Kpa)Р I= bh3/12 = 0.1×0.13/12 = 8.333×10-6(m4)Р故:f = 5qL4/(384EI) = 5×32.6×0.64/ (384×1. 1×107×8.333×10-6)Р = 6×10-4(m)Р 则:f/L= 6×10-4/0.6 = 1/999< [ f /L] = 1/400,满足要求。Р(4)、纵梁(纵向方木)强度验算Р方木截面b=10 cm、h=15 cm,横梁处跨度60 cm、跨中处跨度90 cm,横向间距60 cm。
全文预览
