y1 y2
解:(1)截面几何特征计算
2000490窗间墙截面尺寸
2截面面积A?2000?240?380?490?666200mm 截面重心位置
2000?240?120?490?380?(240?190)?207mm 666200y2?620?207?413mmy1?截面惯性矩计算
1?2000?2403?2000?240?(207?120)212 1??490?3803?490?380?(413?190)2?305.9?108mm412I?回转半径
i?I305.9?108??214mm A666200截面的折算厚度hT?3.5i?3.5?214?749mm (2)内力计算
荷载偏心矩
e?M41000??128mm?0.6?413?248mm N320(3)偏心受压承载力验算
He1286.48??0.171,????0?1.0??8.652hT749hT0.749
?0?11???2?1?0.8698
1?0.002?8.6522??1?e??1?1????1?12??1?h12??0??????2?1?1?1???1?12?0.171??1???12?0.8698????2?0.5105查表得到
f?1.30MP,aA?0.6662m2?0.3m2,?a?1.0
?fA?0.5105?1.30?0.6662?106?4421kN?N?320kN,满足要求。
4.某单层单跨无吊车的仓库,壁柱间距4m,中开宽度1.8m的窗口,车间长40m,屋架下弦标高5m,壁柱为370×490mm,墙厚240mm,M2.5混合砂浆砌筑,根据车间的构造去定为刚弹性方案,试验算带壁柱墙的高厚比。 1800 y1
y2240250
3704000
带壁柱墙截面
解:(1)求带壁柱墙截面的几何性质
A?250?370?240?2200?620500mm2 y1?250?370?(240?250/2)?240?2200?120?156.5mm
620500y2?240?250?156.5?333.5mm
1?2200?2403?2200?240?(156.5?120)212 1??370?2503?370?250?(333.5?125)2?7740000000mm412I?i?I?111.8mm,hT?3.5i?3.5?111.8?391mm A(2)确定计算高度
H?5?0.5?5.5m,H0?1.2H?6.6m
(3)整片墙高厚比验算
M2.5混合砂浆砌筑查表得到[?]?22,开门窗的墙,修正系数
bs1.8?1?0.4??0.82?0.7 s4H6600??0??16.9??1?2[?]?0.82?22?18满足要求。
h391?2?1?0.4(4)壁柱间墙的高厚比(略)
5.某仓库外墙240mm厚,由红砖、M5砂浆砌筑而成,墙高5.4m,每4m长设有1.2m宽的窗洞,同时墙长每4m设有钢筋混凝土构造柱(240mm×240mm),横墙间距24m,试验算该墙体的的高厚比。
1200 构造柱 4000240解:s?24m?2H?2?5.4?10.8m,H0?1.0H?5.4m
?2?1?0.4bs1.2?1?0.4??0.88?0.7 s4M5砂浆[?]?24
H05400??22.5??1?2[?]?0.88?24?21.1,不满足要求 h240b240?0.06 考虑每4m设置构造柱,bc?240mm,l?4m,c?l4000b?c?1??c?1?1.5?0.06?1.09
lH??0??1?2?c[?]?1.09?0.88?24?23?????22.5,满足要求。
h??构造柱间墙高厚比验算略。