采用板式橡胶支座的连续斜梁桥横向抗震行为研究

为了提高采用板式橡胶支座的斜梁桥横向抗震能力,揭示其在不同设计参数下的横向抗震行为,考虑板式橡胶支座的滑移、钢筋混凝土挡块的滞回力学性能、桥台-背土效应等非线性因素,采用OpenSEES建立某连续斜梁桥的三维分析模型,提出支座位移评价指标、主梁平面转角指标、墩柱曲率延性指标和抗剪指标,研究不同挡块强度和间隙组合下桥梁的横向抗震性能。研究表明:同时增大挡块强度和间隙,总体上会降低支座的横向变形,但会增加其纵向变形;挡块强度越高,主梁的横向位移有所下降,但平面转角越大,对两侧桥台处的支座抗剪越不利;挡块强度越高,间隙越小,墩柱越有可能进入弹塑性状态。在本文桥例中,当挡块强度取40%支反力,间隙取0.08m时,所有抗震指标都可满足规范要求。

Transverse Seismic Behavior of Continuous Skewed GirderBridges with Elastomeric Pad Bearings

To improve the transverse seismic capacity of continuous skewed girder bridges with elastomeric pad bearings and reveal their transverse seismic behaviors under different design parameters, the OpenSees was used to establish a three-dimensional finite element model of a typical continuous skewed girder bridge, while considering the sliding effect of elastomeric pad bearings, the hysteretic mechanical properties of reinforced concrete retainers, and the abutment-backfill interaction. The transverse seismic performance of the bridge was investigated for different combinations of retainer strength and gap. The results indicate that with an increase of both retainer strength and gap, the displacement of the bearings decreased in the transverse direction, but increased in the longitudinal direction. The transverse displacement of the main beams decreases with an increase of retainer strength. The increase of the plane rotation angle of the girder is detrimental to the shear safety of the bearings at the both sides of abutments. With greater strength and smaller gaps of retainers, the pier columns are more likely to be at an elastoplastic stage. In this paper, all the seismic performance indices of the modeled bridge satisfy the requirements in the design codes with a retainer strength of 40% of the reaction force and gap of 0.08 m.