柔性墩柱梁桥地震响应分析

发布时间：2018-06-26 06:03

本文选题：柔性墩 + 地震响应　；参考：《长安大学》2014年硕士论文

【摘要】：本文是陕西省科学技术研究发展计划项目的一个组成部分。通过大量的调查资料显示，汶川地震后大多数梁桥的震害表现在：沿纵桥向伸缩装置破坏、梁端混凝土开裂或者压碎、以及主梁运动位移过大导致落梁；沿横桥向挡块破坏、主梁位移过大导致横向落梁；支座滑移脱落导致主梁脱空、墩柱弯剪破坏等。由此可见，梁桥纵横向的连接装置及墩柱在地震作用下较易发生破坏，从而会引起更大的震害，因此，对不同组合下梁桥的地震响应进行分析，特别考虑了板式支座和盆式支座的摩擦滑移作用，总结梁桥沿桥纵横向的地震响应规律，对此类桥型设计提出一些理论依据。本文选择常用的简支梁桥和连续梁桥进行分析，通过大量的计算分析表明：简支梁桥沿纵桥向，桥台与梁、梁与梁间容易发生碰撞现象，碰撞力很大。沿桥横向，墩柱刚度越大，挡块与梁越容易发生碰撞，碰撞力越大，墩柱底弯矩和剪力越大。相比较之下墩底横向剪力和弯矩明显大于纵向。对于连续梁桥，纵桥向地震响应受跨数影响小，既跨数增多，固定墩承受的弯矩和剪力增加不多，而是墩柱刚度越大，固定墩受力越大；横桥向地震响应受跨数影响大，随着跨数的增多，，墩底弯矩和剪力快速加大，故对于跨数较多的连续梁桥，墩柱横向受力更不利，而且桥台处的横向固定支座承受的水平力很大。根据分析得出的梁桥的地震响应规律，对于该类型梁桥的抗震设计提出一些建议：对于简支梁桥，沿桥梁纵向，应采取缓冲措施，减轻桥台与梁间的巨大碰撞力，同时考虑撞击力对桥台的不利影响；沿桥横向，桥台挡块与桥墩挡块受力不同，对于抗震等级较高的桥梁应分别进行设计。对于连续梁桥，桥台处支座的锚固应该加强，以保证地震作用下锚栓不被破坏；对于跨数较多（5跨、6跨）、墩柱刚度较大的梁桥应在墩顶设置系梁，减轻横向固定支座处桥墩的受力，避免其过早破坏。对于墩柱刚度较大的简支梁桥和跨数较多的连续梁桥，建议采取矩形墩，纵横向受力会更合理，材料能得到充分利用。
[Abstract]:This paper is an integral part of Shaanxi province science and technology research and development project. According to a large number of investigation data, the earthquake damage of most beam bridges after Wenchuan earthquake is shown as follows: damage of stretching devices along the longitudinal bridge, cracking or crushing of concrete at the end of the beam, and excessive movement displacement of the main beam resulting in the fall of the beam, and the damage of the block along the transverse bridge. The large displacement of the main beam leads to the transverse fall of the beam, the slip of the support causes the void of the main beam, the bending and shear failure of the pier column, etc. It can be seen that the connection device and pier column of beam bridge in longitudinal and transverse direction are liable to damage under earthquake action, which will cause greater earthquake damage. Therefore, the seismic response of beam bridge under different combinations is analyzed. Especially considering the friction and slip action of plate and basin bearing, the seismic response law of beam bridge along longitudinal and transverse direction is summarized, and some theoretical basis for the design of this kind of bridge is put forward. In this paper, the commonly used simply supported beam bridge and continuous beam bridge are selected for analysis. Through a large number of calculation and analysis, it is shown that the simple supported beam bridge is prone to collide with each other along the longitudinal direction of the bridge, between abutment and beam, and between beam and beam, and the collision force is very large. Along the lateral side of the bridge, the greater the stiffness of the pier column, the easier the collision between the block and the beam, the greater the impact force, the greater the bending moment and shear force at the bottom of the pier column. The transverse shear force and bending moment at the bottom of the pier are obviously larger than that in the longitudinal. For continuous beam bridges, the seismic response of longitudinal bridge is less affected by span number, the moment and shear force of fixed pier is not much increased, but the greater the stiffness of pier column, the greater the force of fixed pier, and the greater the seismic response of transverse bridge is affected by span number. With the increase of span, the bending moment and shear force at pier bottom increase rapidly, so the lateral force of pier and column is more disadvantageous for continuous beam bridge with more span, and the horizontal force of lateral fixed support at abutment is very large. According to the seismic response law of beam bridge, some suggestions are put forward for the seismic design of beam bridge of this type: for simply supported beam bridge, along the bridge longitudinal, buffer measures should be taken to reduce the huge collision force between abutment and beam. At the same time, considering the adverse impact of impact force on abutment, along the bridge lateral, abutment block and pier block force is different, the bridge with higher seismic grade should be designed separately. For continuous beam bridges, anchoring at abutment supports should be strengthened to ensure that anchors are not damaged under earthquake; for bridges with more span (5 span, 6 span), beam bridges with larger pier stiffness should be provided with tie beams at the top of the pier. Reduce the force of the bridge pier at the transverse fixed support and avoid its premature damage. For simply supported beam bridge with larger pier stiffness and continuous beam bridge with more span, it is suggested that rectangular pier should be adopted, the longitudinal and transverse forces will be more reasonable, and the material can be fully utilized.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.55

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