摘要
为研究不同水准地震下铁路圆端空心高墩震损模式和动力响应特征,以单线铁路40m圆端空心墩为研究对象,进行了3个1/6缩尺桥墩模型振动台试验,并与同类桥墩拟静力试验比较。结果表明:地震下桥墩损伤模式与拟静力结果存在显著差异,相同墩顶位移角下动力试件裂缝沿整个墩身分布,而拟静力试件裂缝主要集中在约2/3墩高范围内;振动台试件除在墩底倒角上缘附近形成明显塑性区域外,受高阶振型影响,墩身中上部仍出现较密集裂缝,为圆端空心高墩潜在塑性铰区;随着输入地震动PGA的增加,桥墩阻尼比、加速度、位移及应变响应增大,损伤累积导致自振频率和墩顶动力放大系数减小;桥墩在0.15g^0.2gPGA下开裂,0.45g^0.5g时首次屈服,0.55g^0.6g时进入等效屈服,最大工况0.8g或0.9gPGA下墩顶位移角为1.18%~1.48%,此时构件进入非线性状态;罕遇地震下试件DB-2(体积配箍率ρ_s=1.268%)抗震性能最优,试件DB-1(体积配箍率ρ_s=0.630%)次之,试件DB-3(体积配箍率ρ_s=0.270%)延性较差、易发生脆性破坏。
To study the seismic failure mode and dynamic response characteristics of round-ended hollow tall piers in railway engineering under different levels of earthquake,taking a typical single-track railway round-ended pier with the height of 40 m as the research object.The shaking table tests of three 1/6 scaled pier models were carried out,and the test results were compared with those of similar specimens by semi-static tests.The results show that great differences exist in seismic failure modes of the two kinds of specimens.Under the same tip drift ratio,the cracks of specimens under dynamic loading distribute along the whole pier body,while those of quasi-static ones mainly concentrate within the 2/3 of the pier height.In addition to the obvious plastic zone formed around the internal chamfering of dynamic specimens,there are still relatively dense cracks in the pier middle and upper part.It indicates that the higher-mode effects occur and act as the potential region of plastic hinge for the round-ended hollow tall piers.With the increase of input PGA,the damping ratio,acceleration,displacement,and strain responses increase,while the vibration frequency and dynamic amplification coefficient at pier top decrease owing to the damage accumulation.The pier specimens appear cracks under the PGA between 0.15g to 0.20g,yields between 0.45g^0.5g for the first time,emerges equivalent yielding at 0.55g or 0.60g,and enters into the nonlinear state under the final seismic excitation(PGA=0.8g or 0.9g)with drifts among 1.18%to 1.48%.Finally,the specimen DB-2(ρ_s=1.268%)owns the most excellent ductility performance under rare earthquake,then the 0.630%specimen DB-1,yet the DB-3(ρ_s=0.270%)has the poorest ductility due to brittle failure.
作者
邵长江
漆启明
韦旺
肖正豪
Shao Changjiang;Qi Qiming;Wei Wang;Xiao Zhenghao(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;National Engineering Laboratory of Geological Disaster Prevention Technology in Land Transportation,Southwest Jiaotong University,Chengdu 610031,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2020年第2期72-80,共9页
China Civil Engineering Journal
基金
国家自然科学基金(51178395,51978581)
四川省应用基础研究重点项目(2017JY0059).
关键词
圆端空心高墩
振动台试验
震损模式
高阶振型
动力响应
滞回特性
round-ended hollow tall piers
shaking table test
seismic damage mode
higher-mode shape
dynamic response
hysteresis property
作者简介
邵长江(1970—),男,博士,副教授。主要从事桥梁工程抗震研究;漆启明(1993—),男,硕士研究生。主要从事桥梁工程抗震研究;韦旺(1992—),男,硕士研究生。主要从事桥梁工程抗震研究;肖正豪(1992—),男,硕士研究生。主要从事桥梁工程抗震研究。
