钢筋混凝土矩形空心桥墩抗震性能

针对钢筋混凝土(RC)矩形空心桥墩基于性能抗震设计所需要的性能量化参数和抗震性能问题,该文对高宽比、轴压比、纵向和横向配筋率不同的12个约束良好的RC矩形空心桥墩,开展了恒定轴力作用下的水平循环荷载试验研究,并把试验观测到的桥墩主要损伤状态与工程设计参数联系起来,以满足基于性能抗震设计所需要的量化指标。在此基础上,基于OpenSees软件平台,采用纤维模型对试件体桥墩的滞回性能进行数值模拟,模拟结果与试验数据吻合良好。结果表明：使用累积概率曲线,可以较好地把混凝土开裂和剥落等主要损伤状态与混凝土压应变和纵向钢筋拉应变等工程极限状态联系起来,为基于性能的桥梁抗震设计提供量化指标。试件体桥墩的延性系数在3.71~8.29,等效粘滞阻尼比在0.19~0.31,延性系数和耗能指标均满足结构抗震设计要求。该横向配筋构型的RC矩形空心桥墩,可以作为当前我国公路桥梁抗震设计细则(JTG/T B02-01-2008)矩形空心截面横向配筋构型的一种补充。

SEISMIC PERFORMANCE OF REINFORCED CONCRETE RECTANGULAR HOLLOW BRIDGE COLUMNS

To investigate the seismic performance of hollow reinforced concrete (RC) bridge columns and obtain quantitative parameters for the requirements of performance-based seismic design, twelve specimens with rectangular cross section were tested under constant axial load and cyclic bending. Parametric studies were carried out on the aspect ratio, axial load ratio, longitudinal reinforcement ratio, and transverse reinforcement ratio. The key damage states from experimental observations can be related to engineering parameters, which can satisfy quantitative criteria of performance-based seismic design for bridges. The hysteretic behavior of specimens is simulated with a fiber model using OpenSees FE platform. The force-displacement relationship hysteretic curves of bridge column specimens derived from the fiber element model agree well with experimental results. Analysis of the experimental results suggested that key damage states of residual cracking, cover spalling, and core crushing can also be related to engineering parameters, such as longitudinal reinforcement tensile strain and concrete compressive strains, using cumulative probability curves. The experimental results showed that the ductility coefficient varies from 3.71 to 8.29 and the equivalent viscous damping ratio varies from 0.19 to 0.31, meeting the requirements of seismic design. The hollow RC rectangular bridge columns with configurations of transverse reinforcement in this paper have excellent performance, and may be considered as a substitute for current hollow RC rectangular section configurations described in Guideline for Seismic Design of Highway Bridges (JTG/T B02-01-2008).