?mxMxN?1Arx2W2x(1?1.25NNEx)9?105??124800.883?1.35?108

9?10551.2?6.75?10(1?1.25?)553.06?10?72.1?186.77?114.67Nmm2＜f?205Nmm2（4）弯矩作用平面外的整体稳定验算

loy?8m?y?8000?132.9 60.18查b类 ?y?0.374

9?107?tx?0.65?0.35??0.883

1.35?108?b?1?0.0022?yfy 235?1?0.0022?132.9?0.708?MN??txx?yA?bW1x9?1050.883?1.35?108 ??1?60.374?124800.708?1.68?10?192.82?100.23?293.05Nmm2＞f?205Nmm22f?295Nmm3.解：查附表1.1得：

查表3-9和3-10得：，P?125KN，??0.50 一个螺栓的抗剪承载力：故

Nvb?0.9nf?P?0.9?2?0.50?125?112.5KN

N?nNvb?10?112.5?112.5KN

净截面验算：

An?t?b?n1d0??2.0??21?2?2.2??33.2cm2

N??N?0.5N1125n1?1125?0.5??2?1012.5KNn10

N?1012.5?10322?n???305Nmm?f?295Nmm2A33.2?10n 不满足要求。

故应按钢板的抗拉强度设计。

N??fAn?295?10?3?33.2?102?979.4KN

N?则

N?n1?0.51n?979.421?0.5?10?1088.22KN

4.（1）平面内：

N?mxMx??f?xA?x2W2x(1?0.8N/NEX)?MN?txx?f?yA?bW2xql2Mx?8

平面外：

（2）平面内：

N?mxMx??f?xA?x1W1x(1?0.8N/NEX)N?mxMx??fA?x2W2x(1?1.25N/NEX)

平面外：5.等稳定条件为

?y?loyiy?MN?txx?f?yA?bW1x

?ox??y

10?102??101.99.81

?x??2y?27A69.82?101.92?27??100.6A12?3.49

lox10?102?x???9.94cm?x100.6bIx?2I1?A?()22

2b?2i2x?t1?19.4cm

6.

N?433P,V?P,M?P?120555

4p?103N5?N???0.33pAe2?0.7?6?290

3p?103N5?N???0.25pAe2?0.7?6?290

?M

3p?120?103M5???0.61p1Wf2??0.7?6?29026

?N??M20.33P?0.61P2()?(?V)2?()?(0.25P)2?ffw?160N/mm21.221.22

P?197.5kN

7.(1)整体稳定计算： 最大弯矩Mx?200?2?400kMm

?b?0.68?0.6,?b??0.64?b?0.68?0.6,?b??0.64??Mx/(?b?Wx)

?400?106/(0.64?2.05?106)?305N/mm2?f满足要求

验算局部稳定 翼缘腹板

b??122mm,tf?12mm,b?/tf?10.2?13235/fy?10.7h0/tw?576/6?96?80235/fy?66满足要求

h0/tw?96?170235/fy?140应布置横向加劲肋