深水库区高墩大跨连续刚构桥地震响应分析

发布时间：2018-07-05 15:21

本文选题：矩形空心墩 + 动水压力　；参考：《兰州交通大学》2010年硕士论文

【摘要】： 近年来,我国桥梁在朝着更大跨度发展的同时,出现了许多建成和拟建的深水桥梁。目前为止,已建或在建的深水桥梁其桥墩入水深度最深已达百米。深水桥梁在地震作用下,桥墩自身的运动会引起周围水体的辐射波浪运动,而波浪运动也反过来影响桥墩的运动,这样桥梁结构的水下部分便产生了动水压力,从而使桥梁的结构动力特性发生改变并影响结构的动力响应。若忽略动水压力,则在计算全桥的动力特性和地震内力时会出现较大的误差甚至错误的结果。从当前深水桥梁抗震研究的文献来看,国内外对深水桥梁的计算理论及地震响应特性的研究仍较少。本文在查阅大量国内外文献的基础上,评述了当前关于水与结构相互作用的计算理论、水中结构地震响应的分析方法及相关的研究成果,并针对深水桥梁在地震作用下的动力响应特性开展了以下几个方面的详细研究： (1)阐述了深水桥梁考虑动水压力的必要性,以及动水压力的研究现状。 (2)以深水库区主跨为220m,墩高为173m的红旗大桥为例,利用Morison方程所得的圆形墩附加质量公式的矩形修正公式模拟水对桥墩的作用,建立了全桥考虑附加质量影响的变截面三维有限元模型。 (3)运用有限元方法并结合JTG/T B02-01-2008《公路桥梁抗震设计细则》中的有关规定进行了该桥的模态分析,反应谱和时程反应分析。 (4)分析与讨论了不同地震动输入情况下,动水压力对该桥地震动响应的影响程度。研究结果表明由于动水压力的作用,不仅使桥梁结构的自振频率明显降低,而且随着频率阶数的增加,自振频率总体上的下降率有增大趋势,即考虑水的附加质量后对桥梁高阶频率的影响较大。多工况地震响应的结果表明,由于附加动水压力的影响,使得本桥在地震作用下的弯矩、剪力明显增大,深水桥梁的抗震问题较无水桥梁更为突出。对比反应谱法与时程分析法的计算结果,可以看出,按反应谱计算得到的内力结果小于按时程响应计算得到的结果。显然,就本桥而言,仅采用反应谱进行地震响应分析是不够的,遵循地震响应分析的多波原则进行时程响应分析是完全必要的。本文研究方法与所得结论可为同类桥梁的抗震设计提供参考。
[Abstract]:In recent years, there are many deep water bridges in our country. Up to now, the deep water depth of the bridge piers has reached 100 meters. Under the earthquake, the movement of the pier itself will cause the radiation wave motion of the surrounding water body, and the wave motion will affect the bridge pier movement in turn, so the underwater part of the bridge structure will produce dynamic water pressure. Thus, the dynamic characteristics of the bridge structure are changed and the dynamic response of the structure is affected. If the hydrodynamic pressure is ignored, there will be large errors or even wrong results in the calculation of the dynamic characteristics of the bridge and the seismic internal force. According to the literature of seismic research on deep water bridges, there are few researches on the calculation theory and seismic response characteristics of deep water bridges at home and abroad. Based on a large number of references at home and abroad, this paper reviews the current computational theory on the interaction between water and structure, the analysis method of seismic response of water structure and the related research results. The dynamic response characteristics of deep water bridges under earthquake are studied in detail in the following aspects: (1) the necessity of considering the dynamic pressure of deep water bridges is expounded. (2) taking the Hongqi Bridge with a main span of 220 m and a pier height of 173m in the deep water reservoir area as an example, the effect of water on the pier is simulated by using the rectangular modified formula of the additional mass formula of the circular pier obtained by Morison equation. A three-dimensional finite element model with variable cross-section considering the effect of additional mass is established. (3) the modal analysis of the bridge is carried out by using the finite element method and the relevant regulations of JTG / T B02-01-2008 "detailed rules for Seismic Design of Highway Bridges". Response spectrum and time-history response analysis. (4) the influence of hydrodynamic pressure on the seismic response of the bridge is analyzed and discussed under different ground motion input conditions. The results show that the natural vibration frequency of the bridge structure is obviously decreased due to the effect of hydrodynamic pressure, and with the increase of the frequency order, the decrease rate of the natural vibration frequency on the whole has a tendency to increase. That is to say, considering the additional mass of water, it has a great influence on the high frequency of the bridge. The results of multi-condition seismic response show that due to the influence of additional dynamic water pressure, the bending moment and shear force of the bridge under seismic action are obviously increased, and the seismic problem of deep water bridge is more prominent than that of non-water bridge. By comparing the results of response spectrum method and time history analysis, it can be seen that the results of internal force calculated by response spectrum are smaller than those obtained by time-history response calculation. Obviously, for this bridge, it is not enough to use response spectrum for seismic response analysis, and it is necessary to follow the multi-wave principle of seismic response analysis. The methods and conclusions of this paper can be used as reference for the seismic design of similar bridges.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：U441.3

【引证文献】