350,满足x5入y=整体稳定性验算IOyiy=2.54=177<入=350,满足4505、再分式腹杆(cd-Df、Fe-ef)N192X103177.3N215kN/.==<f=,满足再分式腹杆d、e节点处不断开,采用通长杆件。该杆最大压力为即NFe=16.37KN,Nef=13.78KNo最大压力Ncd=-40.48kN,NdF=29.03kN,NFe=16.98kN,Nef=26.84kNo可见,该杆截面由cd杆的最大压力确定,即N=-40.48kN。计算长度lox=2014mm,loy=1.86l=3745mm。截面选用短肢相并,肢背间距a=6mm,2Z75X50X5所提供的截面几何特性为:A=12.25cm2,ix=1.44cm,?iy=3.61cm。(1)刚度验算Ax=l0x201.4==140<X=150,满足xl0y375入y===104<X=150,满足yl0ybl75==15^0.56=15.041因此绕y轴弯扭屈曲的换算长细比...入yz=入y=104入yz<Xx上弦杆绕x轴弯扭屈曲,按b类截妞査得稳定性系数O=0.320N40.48xl03•••==95.8<215N/mm2,满足(2)整体稳定性验算6、竖腹杆Kf杆件轴力为N=49.5kN,计算长度lou=lov=0.9l=0.9X3063=2757mm。截面选用2Z45X4,十字形截面,肢背间距a=8mm,所提供的截面几何特性为:A=6.97cm2,iu=1.74cm,iv=2.51cm。(1)刚度验算IOu275.7Xy===l58<X=350,满足yl0v275.7入x===110<入=350,满足x(2)强度验算??14.49xl03==20.7<215N/mm2,满足其余杆件的截面设计过程不再一一列出,详见表2所示。6表2杆件截面验算表
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