【作者】 宋鑫；

【导师】 张哲；

【作者基本信息】 大连理工大学 ， 桥梁与隧道工程， 2005， 硕士

【摘要】 近年来在国内外桥梁中,斜拉桥特别是大跨度斜拉桥所占的比重越来越大,斜拉桥的抗震性能也得到越来越多的关注和研究。吉林兰旗松花江大桥是单索面双塔半漂浮体系斜拉桥,主跨240m,其体系独特,桥位处于地震烈度7度区,因此,分析其地震响应是非常重要和有意义的。本文在总结国内外研究结果的基础上,对吉林兰旗松花江大桥的动力特性和地震反应进行了全面系统的研究。主要内容如下: (1)对斜拉桥的斜拉索、主梁结构、支承、联接等结构细节模型进行了评述与分析后,建立了吉林兰旗松花江大桥的动力计算模型。利用结构分析程序ANSYS对吉林兰旗松花江大桥的自振特性进行了分析研究,得出了前15阶频率和相应振型。 (2)采用标准反应谱作为输入的谱曲线,分别考虑了纵向、横向、竖向输入下该桥的地震响应,并考虑了两种地震组合,即纵桥向+竖向输入和横桥向+竖向输入。为了保证计算精度,在计算中采用了CQC方法。 (3)由于吉林兰旗松花江大桥为半飘浮体系斜拉桥,基本周期较长。而长周期结构采用规范设计反应谱或由地震危险性分析给出的场地设计反应谱计算所得的地震反应结果偏大。所以本文对设计反应谱进行了修改,并对比了反应谱修改前后桥梁地震响应的结果。 (4)斜拉桥的整体抗震性能主要取决于所选用的结构体系,因此,本文对斜拉桥的各种结构体系进行了分析研究,从中选用了抗震性能较好的结构体系,即塔、梁弹性约束体系,并进一步研究了弹性约束刚度对兰旗松花江大桥动力特性和地震反应的影响。 (5)谱分析是一种线性分析,无法考虑非线性的影响,因此,本文对吉林兰旗松花江大桥又进行了动态时程分析,这种分析方法可以考虑一些非线性因素的影响,两种方法的计算结果相互校核,得到该桥最终的地震响应结果。 本文得到的研究结果可以作为该桥抗震设计的参考依据,对其它类似桥梁地震反应分析也有一定的指导意义。更多还原

【Abstract】 With the scale of cable-stayed bridge enlarging, more and more attention is paid for the aseismatic capability of cable-stayed bridge. Lanqi Songhua River Bridge in Jilin City is a concrete cable-stayed bridge with double towers and single cable plane, which is 240 meter. The earthquake intensity of the situation of this bridge is VII and the system of this bridge is peculiar. So analyzing the earthquake response of this bridge is significant. The dynamic behavior and seismic response of Lanqi Songhua River Bridge in Jilin City are investigated in this paper. The main research work covers the following aspects:(1) After investigating the properties of cable-stayed bridge component, i.e. the cables deck and joints in detail, the bridge model with reference to Lanqi Songhua cable-stayed bridge for seismic analysis is established. The advanced analysis program ANSYS is used to get the 15 frequencies and corresponding vibration modes.(2) The standard seismic response spectrum is inputted from longitudinal, transverse and vertical direction respectively. Two kinds of seismic combinational modes, which are longitudinal vibration plus vertical vibration and transverse plus vertical vibration are considered. In order to ensure the precision, the CQC (Complete Quadratic Combination) approach is applied.(3) Because of the half floating structural system, the basal period of Lanqi Songhua River Bridge is comparative long. The seismic response of the structure with long period will be over estimated, if the standard spectrum or the design spectrum given by seismic risk analysis is applied. So this paper amends the design spectrum and analyzes the influence of long period response spectrum on dynamic character and seismic response.(4) The aseismatic capability of cable-stayed bridge lies on the selected structural system. So several structural systems are analyzed and a sort of elastic restriction structural system composed of towers and beams is selected. This paper also analyzes the influence of longitudinal elastic restriction on dynamic character and seismic response.(5) The spectral analysis is linear so the nonlinear factors can not be taken into account. The dynamic properties of Lanqi Songhua River Bridge are calculated also with dynamic time-history analysis considering the nonlinear factors. The earthquake response is gained according to the calculation results of the two methods.These laws can be used as the basis of seismic design of the Lanqi Songhua River Bridge and is useful for directing seismic response analysis of such kind bridge.更多还原