.9×(0.03+2.4+0.11)×0.4=0.91KN/mP=2.5×1.4=3.5KNq13001000300Aq23001000300Bq33001000300C图1-8当施工荷载均布作用时支座弯矩MA=0.5q1l12=0.5×2.35×0.3×0.3=0.10KN.mMB=q1l2/8×(1-4n2)=2.35×1×1/8×(1-4×0.3×0.3)=0.19KN.m当施工荷载集中作用于跨中时MA=-0.5q2l12=0.5×1.09×0.3×0.3=-0.05KN.mMB=q2l2/8×(1-4n2)+Pl/4=1.09×1×1/8×(1-4×0.3×0.3)+3.5×1/4=0.87KN.m比较以上荷载值,其中以施工荷载集中作用于跨中时弯矩最大。б=M/W=0.87×106/83×103=10.59N/mm2<215N/mm2故强度满足要求wc=q3l1l3/24EI×(-l3+6n2+3n3)=0.91×300×10003(-3003+6×0.3×0.3+3×0.3×0.3×0.3)/24×2.06×105×417×104=-0.005mm<1000/400=2.5mmwE=q3l4/384EI×(5-24n2)=0.91×10004×(5-24×0.3×0.3)/384×2.06×105×417×104=0.008mm<1000/400=2.5mm故刚度满足要求4)立柱验算立柱采用Ф48×3.5钢管,净截面积A=489mm2,钢管使用长度2800mm,在中间设置水平横杆取l0=0.5l=1400mm,i=15.78mm长细比λ=1400/15.78=88.71查表,稳定系数φ=0.723钢管承受的荷载N’=0.5×1.0×5.89=2.95KNб=N’/φA=2950/0.723×489=8.32N/mm2<215N/mm2故满足要求。第二章施工组织设计