Z形檩条

设计一两端简支直卷边Z形冷弯薄壁型檩条（1）设计资料封闭式建筑、屋面材料为压型钢板，屋面坡度1/8（7.13），檩条跨度6m，于1/2跨度处设一道拉条，水平檩距1.5m，钢材Q235钢（2）荷载标准值（水平投影）1)永久荷载：压型钢板（两层含保温层）0.30KN/m2檩条（包括拉条）0.05KN/m22）可变荷载标准值：屋面均布活荷载0.30KN/m2雪荷载0.35KN/m2试设计该檩条。解：（1）选择檩条形式选用直卷边Z形钢檩条16060202.5Z查附表1-1得知：16060202.5Z截面的毛截面几何特性为：244331124331219.98,7.13,7.48288.12,323.13,44.00,34.9523.14,9.00,8.71sin()sin(19.987.13)0.2224cos()cos(19.987.13)0.9750xxxxyyyAcmIcmIcmWcmWcmIcmWcmWcm（2）荷载效应组合荷载组合为：1.21.4max{}永久荷载屋面均布活荷载，雪荷载222221.20.300.051.40.350.91/cos()1.50.910.97501.51.33/sin()1.50.910.22241.50.304/1.3365.985880.30460.3423232xyxxyyqkNmqqkNmqqkNmqlMkNmqlMkNm（）(3)有效截面计算160602052.673.0,243131602.5205a2087.0,2.5hbbtt且故檩条全截面有效。(4)强度验算：yqqxqyyXX1X1X根据公式，验算檩条在荷载组合作用下①、②、③、④点的强度22211222224481.33.5(/2)441.96/2834.9581.33.5(/2)432.92/28xenxxenxWhAyWhWhAyWh662213331166222433225.985100.34210180.6/205/41.96109.00105.985100.34210221.1/205/32.92109.0010yxenxenyyxenxenyMMNmmfNmmWWMMNmmfNmmWW（5）整体稳定验算：受弯构件的整体稳定系数按GB50018规范计算由表1-5121.35,0.14,0.50b60160sincossin19.98cos19.982222300.342800.94085.58.55abhemmcm由式（1-70）22/20.148.55/160.15aeh由式（1-71）2240.156tbyyIIlhIIh2242634.30.1560.15590.56002.14831623.1423.1416300170.51.76yyyli由式（1-69）2124320bxyxAhW2243207.48161.350.152.14830.15170.534.951.1150.7'0.2740.2741.0911.0910.8451.115bxbx6622'335.985100.34210206.8/205/0.84541.96109.0010yxbxenxenyMMNmmNmmWW（6）挠度验算：由式（1-74）41cos5384kyxqlvEI45450.910.71.5cos7.1360003842.0610288.121026.9640150lmmmm