低塔斜拉桥合理抗震体系及耗能减震措施研究

发布时间：2018-02-11 12:27

本文关键词： 低塔斜拉桥地震时域叠加法反应谱拟合耗能减震钢阻尼器振动台试验　出处：《湖南大学》2015年博士论文　论文类型：学位论文

【摘要】：大跨径桥梁作为交通枢纽和生命线工程,一旦在地震中遭到破坏,可能导致的生命财产以及间接经济损失将会非常巨大。因此,大跨径桥梁选择合理的抗震体系,并进行正确的抗震分析,对确保大桥抗震安全具有非常重要的意义。本文结合目前斜拉桥抗震性能研究的现状,以一低塔斜拉桥——榕江大桥为工程背景,进行了如下研究工作:1、介绍了地震动输入的基本理论,总结概括了人工地震波的比例幅值法、傅立叶幅值调整法、时域叠加法。时域叠加法保留了实际加速度记录的全部相位特性和时变频谱特性,对原始地震动修改最小,在大多数情况下,可保留输入记录的非平稳特性和保持原始地震动的自然积分关系,是一种比较精确的方法。2、提出了拟合反应谱的基于时域叠加的窄带时程反演构造法。该法在频域内通过单自由度体系的稳态反应推导出窄带时程与反演输入时程之间的关系式,拟合后的人工波反应谱与目标反应谱非常吻合,拟合精度较高。以榕江大桥为工程背景,利用这一新方法对5条天然地震波记录进行叠加拟合调整,使它们具有相同的目标反应谱,并进行了非线性时程分析。本方法可供同类桥梁抗震设计参考。3、在研究钢阻尼器耗能减震机理的基础上,设计了桥梁用钢阻尼滑板支座,探讨其在常规桥梁上耗能减震的可行性;提出并探讨了钢阻尼器与速度锁定器串联的方案应用于斜拉桥上耗能减震的可行性。研究结果表明,钢阻尼器在常规桥梁和斜拉桥上均具有良好的耗能减震作用,是可行的。4、针对榕江大桥主跨380m低塔混合梁斜拉桥方案,提出了提高斜拉索体系竖向刚度及减小主梁轴压力的准辐射形斜拉索布置方式,把斜拉索集中锚固在塔顶。整体钢锚室集中锚固方式具有独创性,而且该措施能延长结构纵飘振动周期,减小结构内力地震响应。5、以榕江大桥为工程背景,对比研究了塔梁墩固结体系(RS体系)和半飘浮体系(FS体系)的动力特性及地震反应,分析结果表明半飘浮体系的抗震性能比固结体系优越、合理。并在此基础上从斜拉桥减震的机理出发,提出了榕江大桥的纵横向减震方案,通过参数敏感性分析,确定了纵向粘滞阻尼器、钢阻尼器以及横向钢阻尼器的合理参数。6、对榕江大桥进行缩尺比1:20的全桥模型振动台模型试验。试验结果表明,本文提出的顺桥向采用粘滞阻尼器、横桥向采用钢阻尼器的耗能减震体系能有效地减小关键点的位移及关键截面的应变,且随着地震动的增加,减震效果越明显。
[Abstract]:As a transportation hub and lifeline project, long span bridges may result in huge loss of life and property and indirect economic losses once they are damaged in earthquake. Therefore, long span bridges choose a reasonable seismic system. The correct seismic analysis is of great significance to ensure the seismic safety of the bridge. This paper takes a low tower cable-stayed bridge-Rong River Bridge as the engineering background, combined with the current research situation of the seismic performance of the cable-stayed bridge. The following research work is carried out: 1. The basic theory of earthquake input is introduced, and the proportion amplitude method and Fourier amplitude adjustment method of artificial seismic wave are summarized. Time domain superposition method. The time domain superposition method preserves all the phase characteristics and time-varying spectrum characteristics of the actual acceleration records and minimizes the modification of the original ground motion. In most cases, The non-stationary nature of the input record and the natural integral relationship of the original ground motion can be preserved. It is a more accurate method .2.A narrow band time-history inversion method based on time-domain superposition is proposed to fit the response spectrum. The relationship between narrow-band time-history and inverse input time-history is derived by steady-state response of single-degree-of-freedom system in frequency domain. The fitted artificial wave response spectrum is in good agreement with the target response spectrum, and the fitting accuracy is high. Taking the Rong River Bridge as the engineering background, this new method is used to superposition and adjust the 5 natural seismic wave records. They have the same target response spectrum and nonlinear time-history analysis. This method can be used as a reference for the seismic design of similar bridges. On the basis of studying the energy dissipation mechanism of steel dampers, a steel damping slide bearing for bridges is designed. The feasibility of energy dissipation and shock absorption on conventional bridges is discussed, and the feasibility of applying steel dampers and velocity lockers in series to cable-stayed bridges is discussed. Steel dampers have good energy dissipation and seismic absorption on both conventional bridges and cable-stayed bridges. It is feasible. 4. Aiming at the main span 380m low tower hybrid girder cable-stayed bridge of Rong River Bridge, In this paper, a quasi-radiative cable arrangement is proposed to improve the vertical stiffness of the cable system and reduce the axial pressure of the main beam. The cable is concentrated anchored on the top of the tower, and the centralized anchoring mode of the integral steel anchor chamber is original. Moreover, this measure can prolong the longitudinal floating vibration period of the structure and reduce the seismic response of the internal force of the structure. Taking the Rongjiang Bridge as the engineering background, the dynamic characteristics and seismic response of the tower, girder and pier consolidation system (RS system) and the semi-floating system (FS system) are comparatively studied. The analysis results show that the seismic performance of the semi-floating system is superior to that of the consolidation system and is reasonable. Based on the mechanism of seismic absorption of cable-stayed bridge, the longitudinal and transverse seismic absorption scheme of Rongjiang Bridge is put forward, and the sensitivity analysis of parameters is carried out. The reasonable parameters of longitudinal viscous dampers, steel dampers and transverse steel dampers are determined. The full-bridge model shaking table model tests at 1:20 scale ratio of Rongjiang Bridge are carried out. The test results show that viscous dampers are used in the forward direction of the proposed bridge. The energy dissipation system with steel dampers can effectively reduce the displacement of key points and the strain of key sections, and the more obvious the effect is with the increase of ground motion.
【学位授予单位】：湖南大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U442.55;U448.27

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