Abstract

The re-centring ability and durability of important bridges have been the main objectives in recent provisions of seismic design codes. To achieve better recoverability and durability for piers, this article presents a double-reinforced pier configuration, in which the outer layer is reinforced with fibre-reinforced polymer (FRP) rebar and the inner layer is reinforced with steel rebar. An equal flexural capacity design method was used to determine the double-reinforced configurations. The effects of the potentially influential design parameters on the seismic response of piers were studied and compared to those of conventional RC piers. The results show that the proposed design method can satisfy the ultimate capacity and durability demands. The double-reinforced piers had a better performance than conventional piers in terms of the ductility, post-yield stiffness and residual deformation. The maximum deformation and energy dissipation capacity of the double-reinforced piers were comparable to those of the conventional RC piers. The results also demonstrated that the proportion of steel reinforcement had a clear effect on the performance of double-reinforced piers. However, FRP reinforcement with a high modulus of elasticity should be avoided due to the adverse effect on ductility.

摘要

重要桥梁的重新定心能力和耐久性一直是最近抗震设计规范规定的主要目标。为了使桥墩具有更好的可恢复性和耐久性，本文提出了一种双筋桥墩配置，其中外层采用纤维增强聚合物 (FRP) 钢筋加固，内层采用钢筋加固。采用等抗弯承载力设计方法来确定双钢筋配置。研究了可能有影响的设计参数对桥墩地震响应的影响，并将其与传统 RC 桥墩进行了比较。结果表明，所提出的设计方法能够满足极限容量和耐久性要求。双筋桥墩在延性方面比传统桥墩具有更好的性能，屈服后刚度和残余变形。双筋桥墩的最大变形和耗能能力与传统钢筋混凝土桥墩相当。结果还表明，钢筋的比例对双筋桥墩的性能有明显影响。然而，由于对延展性的不利影响，应避免使用具有高弹性模量的 FRP 增强材料。