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为讨论摇摆–自复位(Rocking Self-Centering,RSC)桥墩在近断层地震动下的地震反应,基于Open Sees数值分析平台建立了RSC桥墩抗震分析模型。同时建立了普通钢筋混凝土(Reinforced Concrete,RC)桥墩,配置竖向无粘结预应力筋(Unbonded Prestressed Reinforced Concrete,PRC)桥墩的抗震分析模型作为对比。对各模型输入近断层地震动记录,进行增量动力分析。以墩顶最大位移角、残余位移角、预应力筋最大应力为考察目标,对比分析了不同墩高(剪跨比分别为2、4和6)、不同桥墩类型(RSC、RC和PRC桥墩)时各桥墩的地震反应。结果表明:随着耗能钢筋配筋率增加,RSC桥墩墩顶最大位移角和预应力筋最大应力均减小;RSC和PRC桥墩均可有效减少桥墩震后残余位移角。耗能钢筋配筋率与PRC桥墩纵筋配筋率接近的RSC桥墩,两者的最大墩顶位移角、残余位移角和预应力筋应力水平均接近。无论是RSC桥墩还是PRC桥墩,当剪跨比大于等于6.0时,易发生预应力筋失效。为避免预应力筋失效引起RSC桥墩产生过大的墩顶残余变形,RSC桥墩中耗能钢筋配筋率不宜低于0.75%。
In order to discuss the seismic response of Rocking Self-Centering (RSC) piers under near-fault ground motions, an aseismic analysis model of RSC pier was established based on the Open Sees numerical analysis platform. At the same time, the reinforced concrete (RC) bridge piers are set up, and the seismic analysis model of vertical unbonded prestressed reinforced concrete (PRC) piers is set up as a comparison. Input near-fault ground motion records for each model and perform incremental dynamic analysis. Taking the maximum displacement angle, the residual displacement angle and the maximum stress of prestressing tendons as the targets, the influences of different pier height (shear span ratios 2,4, 6, respectively) and different pier types (RSC, RC and PRC piers) Earthquake response of each piers. The results show that the maximum displacement of prestressed tendons and the maximum displacement of RSC piers decrease with the increase of the rate of reinforcement steel reinforcement. Both post-earthquake residual displacements of bridge piers can be effectively reduced by RSC and PRC piers. The maximum displacement angle, the residual displacement angle and the stress level of prestressing tendons of the maximum abutment are close to those of the RSC pier whose energy consumption ratio of reinforcement steel is close to that of PRC. Whether the RSC pier or the PRC pier, when the shear span ratio greater than or equal to 6.0, prone to prestress tendons failure. In order to avoid the failure of prestressing tendons causing excessive residual deformation of the abutments of RSC piers, the reinforcement ratio of energy consuming reinforcing bars in RSC piers should not be less than 0.75%.