摘要
针对中小跨径桥梁常用钢筋混凝土挡块在地震作用下破坏严重和修复困难等问题,提出了一种可更换自复位摇摆挡块,该挡块通过高强度无粘结预应力筋与盖梁连接成一个整体,更换方便且抗震性能优越,在主梁横向撞击力作用下挡块与盖梁接触位置可发生开口,撞击力消失后挡块在预应力筋的拉力作用下快速回到初始位置,具有良好的自复位能力.采用ABAQUS软件建立了可更换自复位摇摆挡块有限元模型,研究了预应力筋面积、初始张拉力和预应力筋布置形式对可更换自复位摇摆挡块抗震性能的影响.研究结果表明:可更换自复位摇摆挡块具有良好的自复位能力,当偏移率为9.3％时,残余位移几乎为0;可更换自复位摇摆挡块的屈服力随预应力筋初始张拉力的增大而增大,受预应力筋面积影响较小,张拉力提高1.00倍,屈服力提高约1.67倍,但挡块的屈服后刚度几乎与预应力筋初始张拉力无关,随预应力筋面积的增大而增大;不同预应力筋布置形式下可更换自复位摇摆挡块初始刚度相同,屈服后刚度四周布置相对于中心布置要大,预应力筋四周布置屈服后刚度值比预应力筋中心布置提高30％.相关结论为类似挡块的抗震性能设计提供了一定参考.
Abstract
To avoid severe damage and difficult repair of reinforced concrete blocks of small-medium bridge under the earthquake,a replaceable self-resetting swing block was proposed,which was connected to the cap beam as a whole by unbonded high-strength prestressed tendons,has excellent replacement and seismic performance.Under the horizontal impact force of the main beam,a joint opening between the main beam and the block was found.But the block quickly returned to its original position when the impact force was 0.It indicated that the proposed block had an excellent self resetting capacity.A finite element model was created by ABAQUS software to study the influence of the area,initial force and layout of prestressed tendons on the seismic performance of the replaceable self-resetting swing block.The results showed that the replaceable self-resetting swing block had an excellent self resetting capacity.The residual displacement was almost close to 0 when the drift ratio was 9.3％;The yield strength of the replaceable self-centering swing block increased with the increasing of the initial prestress.But it was almost unaffected by the area of the prestressed tendons.When the tension increased by 1 time,the yield strength increased by about 1.67 times.The initial prestress had little influence on the post-yield stiffness of the block,but increased with the increasing of the area of the prestressed tendon;Under different layout of prestressed tendons,the replaceable self-resetting swing block had the same initial stiffness.The surrounding layout of post-yield stiffness was larger than the center layout,the post-yield stiffness was improved by 30％larger than that of the block in the center.The relevant conclusions provide some reference for the seismic performance design of similar stoppers.
国家科技期刊平台
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