混凝土结构中册混凝土结构与砌体结构设计知识题目解析

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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：

16 As=603mm2

C20混凝土查得fc=9.6N/mm2, 3

A

1 B x?Asfy?1fcb?603?300?94mm??bh09.6?200x94MuA?Asfy(h0?)?603?300(465?)?75.6KNm22按弹性分析：MA?MuA12MuA12?75.6ql2?, q???25.2kNm 12l262?q1?25.2kN/m

2、计算跨中极限抗弯承载力Mu1：2

16 As=402mm2

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

x?644?210?14.1mm??bh09.6?1000,

8/10@100

A

8/10@100 B

.

Mu?644?210(100?14)?12.58kNm/m 2M总?2Mu?25.2kNm/m

pu?8M总2ln?1?8?25.2?12.6kN/m2 24?1B 11．3 解：塑性铰线位置如图所示。

取出一块梯形板块为隔离体，对铰支座AB取力矩平衡：

a a 1(l?a) ?32l?a 4l?a 2l

A ??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?????u8?8?324??24

24m?pu??l?2a??l?a?

第12章

12．1 解：

y1

y2 y3

y4 1.6

.

y3?10.45?0.0756影响线 0.45?4.4y2??0.80861.6y4??0.2676y1??yi?1?0.075?0.808?0.267?2.1518?9.8?10?9.8?115?22.2kN2P22.2?min?Dmax??222.5?43kNPmax115Dmax?0.9Pmax?yi?0.9?2.15?115?0.9?247.25?222.5kNPmin?Dmin

水平荷载系数??0.12

1?0.12?3.94?10??9.8?4.098kN4

4.098Tmax,k??222.5?7.93kN115Tk?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

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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： ○

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?8.76kN?B??R?Wk??0.583??13.47?7.54??0.583?21.01?12.25kNA柱顶剪力 VA=8.76-8.21=0.55Kn (?) B柱顶剪力 VB=12.25-5.26=7kN (?)