江苏某高层框剪结构住宅楼落地双排双立杆外墙脚手架搭设施工方案

4×13+1.2×22.95×0.005)】×65%=4.19KN,式中4为外立杆两道栏杆、一道踢脚杆和一道竹笆板支承杆的钢管根数和。④密目式安全立网双管立杆双排钢管脚手架挡风系数φ36m以下敞开式双管立杆脚手架挡风系数φ2=1.2An2/(la·h)=1.2(la+2h+0.325la·h)·d/(la·h)=1.2(1.2+2×1.8+0.325×1.2×1.8)×0.048/(1.2×1.8)=0.1467密目式安全立网网目密度2300目/100cm2,每目孔隙面积约为Ao=1.3mm2,安全立网挡风系数φ1=1.2(10000-2300×1.3)/10000=0.841φ=φ1+φ2-φ1·φ2/1.2=0.841+0.1467-0.841×0.1467/1.2=0.8849⑤验算长细比k=1,μ=1.5,λ=lo/i=kμh/i=1×1.5×1800/15.8=171<[λ]=210,可k=1.55,μ=1.5,λ=lo/i=kμh/i=1.55×1.5×1800/15.8=197.4,φ=0.185⑥风荷载设计值产生的弯距Mw场区粗糙度B类,场面处风压高度变化系数μz=1,风荷载体型系数μs=1.3φ=1.3×0.8849=1.15Mw=0.85×1.4×(0.7×1×1.15×0.5)×1.2×1.82×0.1=0.186KN·m⑦主立杆稳定性组合风荷载时:立杆段轴向力设计值N=[1.2×(4.30+4.19)+0.85×1.4×0.5×1.05×1.2×4]×1000=13187NN/(φA)+Mw/W=13187/(0.185×489)+0.186×1000000/5080=182N/mm2<205N/mm2,满足要求不组合风荷载时:立杆段轴向力设计值N=[1.2×(4.30+4.19)+1.4×0.5×1.05×1.2×4]×1000=13716NN/(