地震作用下高墩大跨连续刚构桥动力响应分析

地震作用下高墩大跨连续刚构桥动力响应分析(任务书,开题报告,论文13000字)
摘 要
随着公路交通的发展，连续刚构桥的跨径及墩高记录不断被刷新。另一方面，近几年的大地震表明，桥梁震害带来的损失惨重，本文所研究的课题基于这一背景提出。论文首先简介了刚构桥的特点、桥梁震害以及高墩大跨连续刚构桥梁抗震的研究进展，然后详述了桥梁结构地震荷载计算方法的相关理论。最后以经简化后的庙子坪岷江大桥中的连续刚构部分用midas Civil建立模型，考虑其动力特性和在地震作用下的动力响应。
论文着重分析了该桥的前十阶模态，总结主要振型的规律。在此基础上，用midas Civil的动态时程分析功能计算三向El地震波共同作用时该桥各控制截面的响应，找出其最薄弱部位。然后分别对模型施加纵桥向、横桥向和竖向地震波，分析各向地震波对结构的影响。最后考虑是否可以忽略竖向地震荷载。
结果表明，地震作用下桥墩的内力响应值要大于主梁，尤其需要重视主梁中跨与桥墩交接部位的抗震性能。高墩大跨连续刚构桥受横桥向地震的影响最大，纵桥向的次之，竖桥向的最小。另外，竖向地震一般不能被忽略。
关键词：高墩；大跨；连续刚构桥；模态分析；动态时程分析；地震响应

Abstract
With the development of the highway transportation, the span of continuous rigid frame bridge and its pier height records are constantly refreshed. On the other hand, the great earthquakes in recent years show showed that the losses caused by bridge damages are heavy, the subject of this paper is based on this background. First of all, the paper introduces the characteristics of rigid frame bridge, the seismic damages of bridges and the research progress of seismic resistance of high-pier and long-span continuous rigid frame bridges, then the related theories of seismic load calculation methods of bridge structure are described in detail. At last we use midas Civil to build the simplified model of continuous rigid frame part in Miaoziping Min River Bridge, considering its dynamic characteristics and the dynamic responses under earthquakes.
The first ten order modes of the bridge are analyzed in the paper, and the main modes of vibration are summarized. On this basis, using the dynamic time-history analysis function of midas Civil to calculate the responses of the control sections in the three direction El seismic waves, and find out the weakest section. Then the longitudinal, transverse and vertical seismic waves are applied to analyze the influence of each seismic wave on the structure. Finally we consider whether the vertical seismic load can be neglected.
Results show that the internal force responses of the bridge piers are greater than the main beam, the seismic performance of the bridge and the bridge pier. In particular, great attention should be paid to the seismic performance of joints of the beam and the bridge pier. The high-pier long-span continuous rigid frame bridge is worst impacted by the transverse direction earthquake, the longitudinal to the second and the vertical to the minimum. In addition, generally, the vertical earthquake can not be ignored.
Key Words：high-pier; long-span; continuous rigid frame bridge; modal analysis; Dynamic time-history analysis; seismic response 
 

目录
第1章 绪论    1
1.1 研究目的和意义    1
1.2 国内外研究现状    1
1.2.1 连续刚构桥的特点及发展现状    1
1.2.2 地震及其危害概述    3
1.2.3 桥梁震害    4
1.2.4 桥梁地震响应分析方法简介    5
1.2.5 连续刚构桥抗震研究    5
1.3 本文的主要工作    6
第2章 高墩大跨连续刚构桥有限元模型的建立    7
2.1 工程概况    7
2.1.1 工程资料    7
2.1.2 构造定位图    8
2.2分析软件简介    9
2.3模型建立    10
2.3.1 模型简化    10
2.3.2 模型建立步骤    10
第3章 高墩大跨连续刚构桥的动力特性    12
3.1 桥梁结构动力学基本概念    12
3.1.1 运动方程    12
3.1.2 结构动力特性    12
3.1.2.1 自振频率和振型    12
3.1.2.2 结构阻尼    13
3.2 特征值分析基本概念    13
3.3 特征值分析    14
3.3.1 质量的输入    14
3.3.2 自振特性方程求解    14
3.2.3 特征值分析结果    15
第4章 地震作用下高墩大跨连续刚构桥动力响应分析    17
4.1时程分析法    17
4.1.1 动力理论概述    17
4.1.2 动态时程分析方法    17
4.1.2.1 时域分析方法计算结构地震响应    17
4.1.2.2 振型叠加法计算结构地震响应    18
4.2 模型的地震动时程分析    18
4.2.1 地震动输入    18
4.2.2 相关说明    19
4.2.3 结果分析    20
4.2.3.1 三向地震同时作用下全桥的最不利截面    20
4.2.3.2 各向地震影响的大小    21
4.2.3.3 能否忽略竖向地震的作用    24
第5章 结论与展望    26
致 谢    27
参考文献    28