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混凝土结构中册习题答案
第11章
11.1 解:1、求支座截面出现塑性铰时的均布荷载q1 首先计算支座截面极限抗弯承载力MuA:
2
C20混凝土查得fc=9.6N/mm2, 316 As=603mm
x?Asfy?1fcb?603?300?94mm??bh09.6?200MuAx94?Asfy(h0?)?603?300(465?)?75.6KNm22 A 1 B 按弹性分析:MA?MuA12MuA12?75.6ql2?, q???25.2kNm 2212l6?q1?25.2kN/m
2、计算跨中极限抗弯承载力Mu1:2
16 As=402mm
2
x?63?402?300??63mm, Mu1?402?300?465???52.3kNm
2?9.6?200?总弯矩M总?MuA?Mu1?75.6?52.3?127.9kNm 由M总
8M总8?127.9pul2???28.4kN/m 得 pu?228l63、若均布荷载同为pu,按弹性计算的支座弯矩
MAe?22M总??127.9?85.3kNm 33MAe?MAu85.3?75.6??0.114
MAe85.3则调幅系数??
11.2 解:As1=AsA=644mm2/m, fy=210N/mm2, h0=120-20=100mm
644?210?14.1mm??bh09.6?100014Mu?644?210(100?)?12.58kNm/m
2x?M总?2Mu?25.2kNm/m
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8/10@100
8?25.2pu?2?2?12.6kN/m2
ln?14?18M总A
8/10@100 B
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11.3 解:塑性铰线位置如图所示。
a
a
l
取出一块梯形板块为隔离体,对铰支座AB取力矩平衡:
B 1(l?a) ?32l?a 4l?a 2A ??l?a?21?l?a??l?a??l?a??m?(l?a)?pu????a?????
23224????????l?a?2a?l?a??l?a?l?a??l?a?m?pu???p??apu?l?2a?????u2488324???? 24m?pu??l?2a??l?a?
第12章
12.1 解:
y3?10.45?0.0756影响线 0.45?4.4y2??0.80861.6y4??0.2676y1?y1
y2 y3
y4 0.45 4.4 1.15 4.4
1.6
?yi?1?0.075?0.808?0.267?2.15Dmax?0.9Pmax?yi?0.9?2.15?115?0.9?247.25?222.5kN18?9.8?10?9.8?115?22.2kN2P22.2Dmin?min?Dmax??222.5?43kNPmax115水平荷载系数??0.12 Pmin?1?0.12?3.94?10??9.8?4.098kN4
4.098Tmax,k??222.5?7.93kN115Tk?
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12.2 解:
1计算柱顶水平集中力Wk:柱顶标高处?z○
?1.0, 檐口处?z?1.07
Wk?W1k?W2k???0.8?0.5??2.1??0.5?0.6??1.2??1.07?0.45?6??1.3?2.1?0.12??1.07?0.45?6?7.54kN2 q1k??s?zw0B?0.8?1.0?0.45?6?2.16kN/m ○
q2k??0.5?1.0?0.45?6??1.35kN/m
Wk 3 剪力分配系数计算: ○
2.13?0.14814.387.2nB??0.369
19.510.5?8.4???0.2;10.5nA?q1k q2k
A B
C0A?3C0B?1?1?0.23??1??0.148?
3??2.96因只需相对值,故略去109?1?1?0.23??1??0.369??3?2.8681?0.008?5.757???
H3H3H31?uA????;EcI2C0AEc?14.38?2.868Ec41.24?uB?H1H1???;Ec19.5?2.96Ec57.7233
EE11??c3?41.24?57.72??98.96c3 ?uA?uBHH
?A?41.2457.72?0.417, ?B??0.583 98.9698.964 计算约束反力RA、RB: ○
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C11A
??1??3?1?0.24??1???0.148??3.028????0.362??1??98.968?1?0.23??1???0.148?????1??3?1?0.24??1???0.369??3.008????0.3718.11??1??8?1?0.23??1???0.369???
C11B
RA?q1HC11A?2.16?10.5?0.362?8.21kN???RB?q2HC11B?1.35?10.5?0.371?5.26kN???
?R?8.21?5.26?13.47kN
5 剪力计算: ○
?A??R?Wk??0.417??13.47?7.54??0.417?21.01?8.76kNA柱顶剪力 VA=8.76-8.21=0.55Kn (?) B柱顶剪力 VB=12.25-5.26=7kN (?)
?B??R?Wk??0.583??13.47?7.54??0.583?21.01?12.25kN
6 弯矩图: ○
MA底?
MB底
11q1H2?VAH??2.16?10.52?0.55?10.5?124.85kNm22
1??1.35?10.5?7?10.5?147.8kNm2MA=124.85kN
MB=147.8kNm
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12.3 解:从前题知 nA=0.148, nB=0.369, 1 计算剪力分配系数: ○
??3.5?0.318 11C0A?
C0B3?2.531??1?0.3183??1?0.148??
3??2.841??1?0.3183??1??0.369?Ec11??H314.38?2.5336.38
Ec11?uB?3??19.5?2.8455.38H?uA?
EE11??(36.38?55.38)c3?91.76c3 (相对值) ?uA?uBHH
?A?36.3855.38?0.4, ?B??0.6 91.7691.762 计算约束反力RA、RB: ○
C3A
1?0.31820.899?1.5??1.5??1.13811.185??1?0.3183??1?0.148??1?0.3180.899?1.5??1.2781.055?1?1?0.3183??1??0.369?2M1 M2
A
B
C3B?1.5?
M1153.2?C3A??1.138?15.85kN???H11
M2?131RB??C3B??1.278??15.22kN???H11RA??R?15.85?15.22?0.63kN???
3 柱顶剪力: ○
VA?RA??A?R?15.85?0.4?0.63?15.6kN???VB?RB??B?R??15.22?0.6?0.63??15.6kN???98.6kNm
54.6kNm
4 弯矩图: ○
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76.4kNm
54.6kNm
18.4kNm 40.6kNm