q1k??s?z?0B?0.8?1.014?0.45?6?2.19kN/mq2k??s?z?0B?0.5?1.014?0.45?6?1.37kN/mq1?rQq1k?1.4?2.19?3.07kN/m(?)q2?rQq2k?1.4?1.37?1.92kN/m(?)风向
-0.6 W I1 q1 I2 +0.8
-0.5 I3 q2
I4 -0.5 10.5m 2.求W 高度取10.5+2.1=12.6m
?z?1?1.14?1.0(12.6?10)?1.07
15?10Wk?[(0.8?0.5)h1?(0.5?0.6)h2]?z?0B?[1.3?2.1?0.1?1.2]?1.07?0.45?6?7.54KN
W?rQWk?1.4?7.54?10.56kN 3.计算参数?,n
I3I12.13?1097.2?109n???0.37n???0.1599I214.38?10I419.5?10A柱: B柱:
HH33??u??0.29??u??0.29H10.5H10.54.在柱顶虚拟加不动铰支座
查表计算:
113[1??4(?1)]3?[1?0.294(?1)]n0.15A柱:C11???0.34 118[1??3(?1)]8?[1?0.293(?1)]n0.152.1m 1.2m 113[1??4(?1)]3?[1?0.294(?1)]n0.37B柱:C11???0.36 118[1??3(?1)]8?[1?0.293(?1)]n0.37
RA?q1HC11?3.07?10.5?0.34??11(?)RB?q2HC11?1.92?10.5?0.36??7.3(?)故:柱顶剪力
VA,1?RA??11(?)VB,1?RB??7.3(?)
5.撤消不动铰支座,反向施加支座反力。 A柱:C0?33??2.64 111??3(?1)1?0.293(?1)n0.1533??2.88 111??3(?1)1?0.293(?1)n0.37B柱:C0?于是:
H31.53?uA??EcIlC0Ec?1.3?10 9?24.6804H310.53 ?uB??EcIlC0Ec?19.5?109?2.882.64?14.38?0.42.64?14.38?2.88?19.5所以分配系数:
2.88?19.5?B??0.62.64?14.38?2.88?19.5?A?故,柱顶剪力:
VA,2??A(RA?RB?W)?0.4?(11?7.3?10.56)?11.54kN(?)VB,2??B(RA?RB?W)?0.6?(11?7.3?10.56)?17.32kN(?)6.叠加两个受力状态
VA?VA,1?VA,2?11.54?11?0.54(?)VB?VB,1?VB,2?17.32?7.3?10.02(?)
7.绘制弯矩图
0.54KN 10.02KN q1=3.07 KN/m 175 A柱
15.44 q1=1.92 KN/m 211.05 38.7 M图(KN·m) B柱 M图(KN·m)
49. 如图所示排架,在A,B牛腿顶面作用有力矩M1和M2。试求A,B柱的内
力,已知:M1=153.2KN.M,M2=131.0KN.M,柱截面惯性距同上习题13-2。
I1 M1 I2 I3 M2 I4 解:1.计算参数?,n
I3I12.13?1097.2?109n???0.37n???0.1599I214.38?10I419.5?10A柱: B柱:
HH33??u??0.29??u??0.29H10.5H10.52.在柱顶虚拟加不动铰支座
1??21?0.292?1.5??1.21 A柱:C3?1.5111??3(?1)1?0.293?(?1)n0.151??21?0.292?1.5??1.32 B柱:C3?1.513131??(?1)1?0.29?(?1)n0.37M1153.2C3??1.21??17.65kN(?)H10.5故:
M131.0RB?2C3??1.32?16.47kN(?)H10.5RA?3.撤消不动铰支座,反向施加支座反力
R?RA?RB?17.65?16.47?1.18kN(?)
?A?0.4,?B?0.6 所以:
VA?R?A?1.18?0.4?0.47kN(?)VB?R?B?1.18?0.6?0.71kN(?)
3.叠加内力
VA??17.65?0.47??17.18(?)VB?16.47?0.71?17.18(?)
4.弯矩图:
17.18KN 17.18KN 101.66 51.54 M=153.2KN.m M=131KN.m 51.54 79.46 27.19 A柱 M图(KN.M) B柱 49.39 M图(KN.M)
50. 如图所示柱牛腿,已知竖向力设计值Fv?324kN,水平拉力设计值
Fh?78kN,采用 C20(ftk?1.54N/mm2)混凝土和HRB335级钢筋,
试设计牛腿的纵向受力钢筋。
(截面宽度b=400mm(另加的条件))