【作者】 聂肃非；

【导师】 李黎；

【作者基本信息】 华中科技大学 ， 结构工程， 2010， 博士

【摘要】 进入21世纪以来全球高烈度地震发生频率很高,在国内外的多次大地震中,作为生命线工程的桥梁遭受了严重破坏,由地震导致的桥梁破坏引起各国高度重视。传统的桥梁抗震设计,主要是从结构的强度和延性方面考虑,耗费大量材料,在高烈度区桥梁的抗震能力往往还难以满足要求。能有效减小地震作用效应的桥梁减隔震技术得到推广使用。桥梁隔震技术主要针对大量使用的连续梁桥型,通过在桥面底部与桥墩顶部的结合部位放置能起到水平柔性支承和能量耗散作用的隔震支座降低地震响应。橡胶铅芯支座是广泛使用的桥梁隔震支座。适合桥梁使用橡胶铅芯支座的力学性能有必要深入研究。能与目前规范接轨的简化计算方法的研究对隔震技术在桥梁上的应用有实际意义。本文以适合连续梁桥隔震的橡胶铅芯支座为对象,开展了以下几个方面的研究工作：1对橡胶铅芯支座的性能进行了理论分析。利用橡胶弹性理论推导的橡胶约束受压时纵向压缩刚度、橡胶弯曲变形时候纵向表观弹性模量,得到叠层橡胶支座竖向刚度计算表达式,叠层橡胶支座水平刚度表达式。推导了叠层橡胶支座在压剪时候底部橡胶的竖向应力分布表达式,利用分析结果,推导了底部钢板应力分布公式,并利用应力分布结果探讨了方形支座和多铅芯支座的设计中相关问题。2对橡胶铅芯支座进行了试验分析。试验分析了各种支座在不同使用环境下的力学性能。对方形橡胶铅芯支座进行了不同水平位移,不同频率下的动力力学性能试验、极限剪切变形试验、极限压应力试验、支座疲劳性能试验,验证方形支座是一种可靠的桥梁隔震支座；对多橡胶铅芯隔震支座进行了不同水平位移,不同频率下的动力力学性能试验、极限剪切变形试验、极限压应力试验、支座疲劳性能试验、不同水平加载方向试验,验证多铅芯支座是一种可靠的桥梁隔震支座。对不同直径的隔震支座进行了静力加载模拟试验,试验结果显示隔震支座的静力性能与动力性能存在差异。对隔震支座进行了温度试验,揭示橡胶铅芯支座在不同温度下不同水平位移时力学性能的变化,回归了隔震支座第一刚度、第二刚度、屈服剪力的变化曲线,得出支座温度性能的定量结论。3利用三维非线性动态有限元程序分析了橡胶铅芯支座的动力特性。并把分析结果与试验结果对比,发现分析结果与试验结果吻合较好,有限元分析方法可以作为支座研发的一个手段。利用三维非线性动态有限元分析研究了方形橡胶隔震支座的各向异性,研究了多橡胶铅芯隔震支座的铅芯放置位置对支座性能的影响,对支座橡胶应力、支座钢板应力作了分析,并与理论值作了对比。4对现阶段不同的支座等效线性化方法作了对比分析,对各个方法的主要区别作总结归纳：发现支座等效阻尼比的确定和结构阻尼影响系数的确定是等效线性化方法要解决的首要问题。对一座实体桥,通过用不同等效线性化方法的算例,与多条地震波时程反应结果对比,对不同等效线性化方法作出对比评价。通过不同温度下隔震支座的试验研究得到的隔震支座的力学参数与温度的曲线关系,利用非线性时程方法计算了隔震桥梁的地震响应,得到需要考虑温度效应对隔震支座性能影响的响应区间。更多还原

【Abstract】 High intensity earthquakes have happened more frequently since 21st century. As the most significant projections, many bridges have been destroyed in many serious earthquakes. As a result, more and more countries take into account for the damage of bridges caused by earthquakes. The traditional anti-seismic designs of bridge are mainly in accordance with the strength and ductility of the structure, which may consume a large number of materials and are often difficult to meet the anti-seismic requirements in high-intensity zone. However, seismic isolation technology which can can effectively reduce the effect of earthquake is widely used. Seismic isolation technology is mainly fit for the continuous beam bridges that are largely constructed, and to reduce the response through setting bearings which provides flexible support and causes energy dissipation at the junction of the top of pier and the bottom of beam. LRB is the most widely used bearing in bridge bearings. Further in-depth study of the mechanical properties of LRB which is suitable for bridge are quite necessary. Nevertheless, simplified calculation method which integrates with current norms has practical significance to the application of isolating technology in bridge. In this paper, based on LRB which is suitable for seismic isolation of continuous beam bridge, research is carried out in the following areas:1 Theoretical analysis of LRB properities. Firstly, getting the calculation expression of longitudinal and horizontal stiffness of LRB through longitudinal compressed stiffness of rubber and the longitudinal apparent elastic modulus which are derived by rubber elasticity theory. Then deriving expression of the lingitudinal stress distribution of the bottom of rubber. Finally, according to the data, deriving the expression of shear distribution at the bottom of steel plate. after that, discussing the questions in the design of the square bearing and multi-lead-bearing according to the distribution of stress.2 Experimental Analysis of LRB. The experiments reveal the mechanical properties of varieties of bearings in different circumstances. Using different horizontal displacement, different frequencies in the dynamic mechanical properties test, ultimate shear deformation test, ultimate stress test, bearing fatigue test, verifying square bearings is a reliable bearing in the isolatation of bridge; Using different horizontal displacement, different frequencies in the dynamic mechanical properties test, ultimate shear deformation test, ultimate stress test, bearing fatigue test, verifying multiple lead core rubber bearings is a reliable bearing in the isolatation of bridge; Doing simulated static load test on the bearings in different diameters, and the results shows that there are something different between the static properties and the dynamic properties of bearing. Doing temperature test on the bearings, and the results reveals the changes of mechanical properties at different temperatures and different horizental displacement. Getting the fisrt and the second stiffness, and yield force variation curve of bearing, then draw quantitative conclusions of temperature properity of bearing.3 Analysis of dynamic characteristics of LRB, based on three-dimensional nonlinear dynamic finite element program. Compared with the experimental results and find that the results agree well with the experimental results, so finite element analysis can be developed as a means of the research and invention of bearings. The anisotropy of square rubber bearings is researched by using three-dimensional nonlinear dynamic finite element analysis, and researched the bearing porperity, stress on the rubber bearings, stress on steel plate when lead is located in different parts, and make a comparation with the theoretical value.4 Compared analysis between the different current equivalent linear method. Summary the main difference between the various methods and find that the equivalent damping ratio and the structure damping coefficient are the primary problem of equivalent linear method. When it comes to a bridge, compared with some seismic response time history results, assess different equivalent linearization methods through examples of different equivalent linearization method. According to the mechanical parameters and the temperature curve obtained by test and using equivalent linearization methods and elastic response spectrum method of seismic response of compute the response of isolated bridge, get the response range that bearing may be effected by temperature.更多还原