振动与冲击
振動與遲擊
진동여충격
JOURNAL OF VIBRATION AND SHOCK
2014年
22期
58-66
,共9页
深水桥梁%等效单墩%近场地震%远场地震%流固耦合%动水压力%动力响应
深水橋樑%等效單墩%近場地震%遠場地震%流固耦閤%動水壓力%動力響應
심수교량%등효단돈%근장지진%원장지진%류고우합%동수압력%동력향응
deep-water bridge%equivalent pier%near-fault earthquake%far-field earthquake%fluid-structure interaction%hydrodynamic pressure%dynamic response
以某典型铁路深水桥梁等效单墩模型为对象，采用基于流固耦合理论的势流体计算方法，首次对近、远场地震作用下等效单墩结构振动特性及动力响应进行对比分析。结果表明，动水环境的存在会改变桥墩振动特性，随水深增加桥墩自振周期不断增大，30 m 水深时第一阶周期增长率达10．4％。墩周动水压力呈抛物线型分布，近场地震下大于远场地震，二者差别随水深增加而增大。近、远场地震下桥墩结构的动力响应存在明显差别，较无水环境，近场地震下墩顶位移、墩底弯矩及剪力峰值分别增大34．5％、37．8％及51．3％；远场地震下三项指标分别增大17．0％、21．8％及40．0％，具有明显速度脉冲的近场地震下结构动力响应显著大于远场地震。具有速度脉冲的近场地震破坏能力更强，在近断层区深水桥梁抗震设计中应特别重视。
以某典型鐵路深水橋樑等效單墩模型為對象，採用基于流固耦閤理論的勢流體計算方法，首次對近、遠場地震作用下等效單墩結構振動特性及動力響應進行對比分析。結果錶明，動水環境的存在會改變橋墩振動特性，隨水深增加橋墩自振週期不斷增大，30 m 水深時第一階週期增長率達10．4％。墩週動水壓力呈拋物線型分佈，近場地震下大于遠場地震，二者差彆隨水深增加而增大。近、遠場地震下橋墩結構的動力響應存在明顯差彆，較無水環境，近場地震下墩頂位移、墩底彎矩及剪力峰值分彆增大34．5％、37．8％及51．3％；遠場地震下三項指標分彆增大17．0％、21．8％及40．0％，具有明顯速度脈遲的近場地震下結構動力響應顯著大于遠場地震。具有速度脈遲的近場地震破壞能力更彊，在近斷層區深水橋樑抗震設計中應特彆重視。
이모전형철로심수교량등효단돈모형위대상，채용기우류고우합이론적세류체계산방법，수차대근、원장지진작용하등효단돈결구진동특성급동력향응진행대비분석。결과표명，동수배경적존재회개변교돈진동특성，수수심증가교돈자진주기불단증대，30 m 수심시제일계주기증장솔체10．4％。돈주동수압력정포물선형분포，근장지진하대우원장지진，이자차별수수심증가이증대。근、원장지진하교돈결구적동력향응존재명현차별，교무수배경，근장지진하돈정위이、돈저만구급전력봉치분별증대34．5％、37．8％급51．3％；원장지진하삼항지표분별증대17．0％、21．8％급40．0％，구유명현속도맥충적근장지진하결구동력향응현저대우원장지진。구유속도맥충적근장지진파배능력경강，재근단층구심수교량항진설계중응특별중시。
Taking the equivalent pier of a typical railway bridge built in deep-water as an example,the vibration characteristics and dynamic responses under near-fault and far-field earthquakes were contrasted by using the potential-based fluid method based on fluid-structure interaction theory.The results show that,the vibration characteristic of pier is changed due to the water around it.With the increase of the depth of water,the natural vibration period of pier becomes larger and the first period increases by 10.4% when the water depth is 30 m.The distribution of hydrodynamic pressure along the pier is in parabolic form,the pressure is larger by the near-fault earthquake than by the far-field and the difference becomes more obvious with the addition of water depth.There is also significant difference between the dynamic responses under near-fault and far-field earthquakes,in addition,the dynamic response under near-fault ground motions is greater than that under far-field earthquake.The diplacement at the top of pier,the moment and the shear force at the bottom of pier increase by 34.5%,37.8% and 51.3% respectively under near-fault earthquake;while these three indicators are 17.0%,21.8% and 40.0% for far-field earthquake.In summary,the destructive capacity of near-fault ground motions with obvious velocity pulse is far greater than that of far-field earthquake,so special attention should be paid to those bridges with piers surrounded by deep-water in near-fault zone.
