P-△效应对高墩抗震性能的影响
P-△效应对高墩抗震性能的影响(任务书,开题报告,外文翻译,论文12200字)
摘要
随着交通事业的发展，一座座桥梁拔地而起。而我国处在地震多发的地区，桥梁的抗震性能就被格外的关注。其中高墩桥梁的抗震性能显得尤其重要，我们本文所研究的就是高墩抗震性能的重要部分P-△效应对高墩抗震性能的影响。P-△效应即为重力二阶效应，在地震时桥墩发生水平位移时，桥梁上部结构的竖直荷载就会发生偏移，会造成墩顶位移增大和墩底内力增加，从而导致高墩结构受到更严重的破坏。我们研究P-△效应对高墩抗震性能的影响就是为了在未来的桥梁建设中尽量避免P-△效应的危害使高墩的尺寸结构更加经济合理安全。我们采用软件是分析抗震的有限元软件OpenSees，该软件专长于动力问题的分析，我们利用它建立高墩模型和进行时程分析。建立高墩模型包括定义钢筋混凝土型号、建立节点和单元、定义截面尺寸参数、输入重力荷载等，时程分析则是输入地震荷载进行运算，输出墩顶位移、系梁出位移、墩底轴力、剪力、弯矩和曲率。最后，我们把考虑P-△效应的位移内力结果和不考虑P-△效应的结果进行对比，得出我们的结论。我们的实验步骤有：
1.参阅相关文献，了解P-△效应对高墩（或者高耸结构）的影响规律并作出预测结果。 [版权所有：http://DOC163.com]
2.学习OpenSees、originlab等软件，建立高墩模型，输入地震荷载，输出位移和反力的数据并绘出图形进行比较。
3.得出结论跟预期的结果进行对比，并解释结果不同的地方。
4.我们得出的结果是：P-△效应会增加墩底的反力、弯矩和曲率，高墩系梁处的顺桥位移增大但是墩顶的位移不一定增大。
关键词：高墩；P-△效应；桥梁抗震性能；OpenSees；时程分析
Abstract
With the development of transport, a bridge between the ground. And our country in the earthquake-prone areas, the seismic performance of the bridge was particularly concerned about. The seismic performance of the high-pier bridge is especially important. In this paper, we study the influence of the P-△ effect on the seismic performance of the high pier. The P-△ effect is the second-order effect of gravity. When the horizontal displacement of the bridge pier occurs during the earthquake, the vertical load of the bridge superstructure will be shifted, which will cause the pier top displacement to increase and the internal force of the pier bottom increase, leading to high pier structure Suffer more serious damage. We study the effect of P-△ effect on the seismic performance of high piers in order to avoid the harm of P-△ effect in the future bridge construction so that the size structure of high pier is more economical and reasonable. We use the software is the analysis of seismic finite element software OpenSees, the software specializes in the analysis of dynamic problems, we use it to establish a high pier model and time history analysis. The establishment of high pier model includes the definition of reinforced concrete model, the establishment of nodes and units, the definition of cross-sectional size parameters, input gravity load, time history analysis is the input seismic load to calculate the output top of the pile displacement, beam displacement, , Shear, bending moment and curvature. Finally, we compare the results of the displacement force considering the P-△ effect and the results without considering the P-△ effect, and draw our conclusion. Our experimental steps are: [来源：http://Doc163.com]
1. See the relevant literature to understand the P-△ effect on the high pier (or tall structure) of the law and make predictions.
2. Learn OpenSees, originlab and other software, the establishment of high pier model, the input seismic load, output displacement and reaction data and draw the graphics for comparison.
3. Compare the results with the expected results and explain where the results are different.
The result is that the P-△ effect increases the reaction force, bending moment and curvature of the pier bottom, and the displacement of the bridge at the pier of the high pier is increased but the displacement of the pier top is not necessarily increased.
Key words: high pier; P- △ effect; bridge seismic performance; OpenSees; time history analysis
[资料来源：www.doc163.com]
目录
第一章 绪论 8
1.1研究背景 8
1.2研究现状 8
1.3研究内容和研究方法 10
第二章 计算软件的介绍 11
2.1 OpenSEES的介绍 11
2.2originlab的介绍 12
第三章 P-△效应的介绍和建立桥墩模型 14
3.1 P-△效应的介绍 14
3.1.1P-△效应的定义 14
3.1.2P-△效应的应用 14
3.1.3预期结果 15 [版权所有：http://DOC163.com]
3.2模型的建立 15
3.2.1定义材料 16
3.2.2定义节点 17
3.2.3定义单元 19
3.2.4定义截面 21
3.2.5重力计算 22
3.2.6恒载作用下的结构响应 23
第四章 时程分析 24
4.1.时程分析的介绍 24
4.2地震波的选取 25
4.3 地震作用下的结构响应 26
4.3.1 加速度峰值为0.122g的左肢墩位移内力 27
4.3.2 加速度峰值为0.122g的右肢墩位移内力 32
4.3.3 加速度峰值为0.4g左肢墩位移内力 36
4.3.4 加速度峰值为0.4g右肢墩位移内力 41
4.3.5 加速度峰值为0.6g左肢墩位移内力 45
5.3.6 加速度峰值为0.8g的左肢位移内力 50
第六章 结论与展望 54
6.1结论 54 [来源：http://www.doc163.com]
6.2研究展望 55
参考文献 55
致谢 57 [资料来源：www.doc163.com]