基于A_p/V_p的双薄壁高墩刚构桥抗震性能研究  

Seismic Performance of Rigid Frame Bridge with Double Thin-walled High Piers based on A_p/V_p Characteristics

作　　者：乔万芝 徐略勤[1] 李建中[2] 腾杰[1] 

机构地区：[1]重庆交通大学土木工程学院,重庆400074 [2]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《防灾减灾工程学报》2017年第6期974-980,共7页Journal of Disaster Prevention and Mitigation Engineering

基　　金：重庆市基础与前沿研究计划项目(cstc2015jcyjA30014);交通运输部应用基础研究计划项目(2014319814210);国家自然科学基金项目(51408089);重庆交通大学研究生教育创新基金项目(2017S0102)资助

摘　　要：为了研究地震频谱特性对柔性桥梁抗震性能的影响,以正弦波为例推导了地震动能量与A_p/V_p的关系,基于能力需求比提出了桥梁抗震性能评估方法及计算公式。以某典型高墩连续刚构桥为工程背景,采用地震动参数A_p=0.4g的22条正弦波和7条实际地震记录,对比研究了桥梁纵、横向抗震性能随A_p/V_p的变化规律。结果表明:在地震动参数A_p相同的情况下,桥梁关键截面抗震能力需求比在纵、横桥向均随A_p/V_p的增大而呈现增长的规律,最大增幅超过12.92倍(正弦波)和2.31倍(实际波);按正弦波得到能力需求比普遍大于实际波,且随A_p/V_p增大而增大的规律更明显。研究发现将地震动参数A_p作为单一的抗震设计指标会导致桥梁抗震性能离散性很大,A_p/V_p可作为柔性桥梁抗震设计的补充指标。In order to investigate the effect of ground motion frequency contents on the seismic performance of flexible bridges, sine waves were used to deduce the relationship between the ground motion energy and the ratio of ground motion peak acceleration and peak velocity Ap/V, A process was proposed for seismic performance assessment of bridges based on capacity to de- mand ratio （C/D ratio） and the calculation methods were formulated to derive C/D ratios. In the background of a typical rigid frame bridge with high piers, 22 sine waves and 7 ground motion re- cords with a same round motion parameter Ap = 0.4 g were applied to examine the tendency of C/ D ratios in both longitudinal and transverse directions with respect to the parameter of Ap/Vp. The results show that in the same ground motion parameter Ap the C/D ratios for critical compo- nents of the illustrative bridge increases with an increasing Ap/Vp in both longitudinal and trans- verse directions. The maximum growth rate of C/D ratios reaches 1292% in the sine waves and 231% under the earthquake records, respectively. The C/D ratios obtained from the sine waves are in general larger than those from the earthquake records, and the growth trend of C/D ratios is more remarkable under the sine waves. It is found that the use of ground motion parameter A, as a single indicator for excitation input is insufficient to ensure the seismic safety of bridges and tends to produce divergent seismic designs. The parameter of Ap/Vp can be used as a supplemen- tary indicator for seismic design of flexible bridges.

关 键 词：桥梁工程 Ap/Vp 高墩刚构桥 能力/需求 正弦波 地震记录 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]