不同水深环境下桥梁群桩基础动力特性
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摘要
强烈地震作用下,水与群桩基础的互相作用问题一直没有得到很好解决。本文使用结构自由振动衰减力锤激励的方法对深水桥梁群桩基础考虑水影响下的动力特性进行了有益的探索与研究。以某深水桥梁群桩基础为工程背景,设计制作试验水池及缩尺比为1/30的九桩模型,介绍了在不同水深环境下进行模态试验的方法;同时利用有限元分析软件ADINA建立了水-结构相互耦合作用的三维实体有限元模型,对其动力特性进行了理论分析。通过比较不同水深环境下结构振动一阶侧弯与扭转阵型的试验与理论分析结果,验证了本文针对群桩基础结构模型所用的自由振动衰减模态试验方法是成功的;在考虑水-结构相互耦合作用后,结构的振型周期延长,频率减小;随着水深增加,结构频率变化越大。
The problem of water-structure interaction under strong earthquake is not well solved.Considering the water influence,the dynamic characteristics of deep-water bridge group foundation were experimentally studied by using the structural free vibration attenuation hammer excitation method.Taking a deep-water group pile foundation of bridge as an example,a test pool and a nine-pile model with the scale ratio of 1/30 were designed,and its method of modal test under different water depths was introduced.At the same time,the three-dimensional solid finite element model with water-structure interaction was built in finite element analysis program ADINA,and its dynamic characteristics were analyzed theoretically.Comparing the experimental and theoretical analysis results of the first lateral vibration and torsional modes under different water depths,it proves that the free vibration attenuation method of modal test for the group pile foundation model is feasible.The water-structure interaction results in the structural frequency to decrease and the structural frequency changes more significantly with the increase of the water depth.
The problem of water-structure interaction under strong earthquake is not well solved.Considering the water influence,the dynamic characteristics of deep-water bridge group foundation were experimentally studied by using the structural free vibration attenuation hammer excitation method.Taking a deep-water group pile foundation of bridge as an example,a test pool and a nine-pile model with the scale ratio of 1/30 were designed,and its method of modal test under different water depths was introduced.At the same time,the three-dimensional solid finite element model with water-structure interaction was built in finite element analysis program ADINA,and its dynamic characteristics were analyzed theoretically.Comparing the experimental and theoretical analysis results of the first lateral vibration and torsional modes under different water depths,it proves that the free vibration attenuation method of modal test for the group pile foundation model is feasible.The water-structure interaction results in the structural frequency to decrease and the structural frequency changes more significantly with the increase of the water depth.
引文
[1]高永.大型桥梁高桩承台群桩基础抗震能力研究[D].上海:同济大学,2009.
[2]Morrison J R,O'Brien M P,Johnson J W,et al.Theforce exerted by surface waves on piles[J].PetroleumTransactions,AIME,1950,189:149-154.
[3]Liaw C Y,Anil K C.Dynamics of towers surroundedby water[J].Earthquake Engineering&StructuralDynamics,1974,3(1):33-49.
[4]Oz H R.Natural frequencies of an immersed beam car-rying a tip mass with rotatory inertia[J].Journal ofSound and Vibration,1974,266(5):1099-1108.
[5]魏凯,伍勇吉,袁万城,等.桥梁深水群桩基础动力特性数值模拟[C]//第19届全国结构工程学术会议论文集(第Ⅲ册).北京:《工程力学》杂志社,2010:171-176.
[6]魏凯,伍勇吉,袁万城,等.桥梁群桩基础-水耦合系统动力特性数值模拟[J].工程力学,2011,28(s1):198-199.
[7]Pang Yutao,Yuan Wancheng,Wei Kai,et al.Nu-merical Simulation in Dynamic Analysis of DeepwaterGroup Pile Foundation of Bridges[C]//2011 Interna-tional Con-ference on Electric Technology and CivilEngineering(ICETCE),2011:492-495.
[8]Han R P S.A simple and accurate added mass modelfor hydrodynamic fluid--Structure interaction analysis[J].Journal of the Franklin Institute,1996,333(6):929-945.
[9]高学奎,朱熹.地震动水压力对深水桥墩的影响[J].北京交通大学学报,2006,30(1):55-58.
[10]赖伟.地震和波浪作用下深水桥梁的动力响应研究[D].上海:同济大学,2004.
[11]陈新.采用锤击法对24m预应力混凝土梁的模态试验分析[J].铁道标准设计,2008,(6):58-59.
[12]周勇军,贺拴海,宋一凡.基于锤击法的弯连续刚构模型桥动力试验[J].振动、测试与诊断,2007,27(3):1-5.
[13]章关永.桥梁结构试验(第二版)[M].北京:人民交通出版社,2010.
[14]赵迎祥,卢永智,隋峰.用共振法测定弹性梁固有频率及振型[J].陕西师范大学学报(自然科学版),1995,23(3):2-4.
[15]张宏斌,宋广君,张哲,等.模态分离法在拱桥动载试验中的应用[J].公路交通科技,2005,22(1):66-68.
[2]Morrison J R,O'Brien M P,Johnson J W,et al.Theforce exerted by surface waves on piles[J].PetroleumTransactions,AIME,1950,189:149-154.
[3]Liaw C Y,Anil K C.Dynamics of towers surroundedby water[J].Earthquake Engineering&StructuralDynamics,1974,3(1):33-49.
[4]Oz H R.Natural frequencies of an immersed beam car-rying a tip mass with rotatory inertia[J].Journal ofSound and Vibration,1974,266(5):1099-1108.
[5]魏凯,伍勇吉,袁万城,等.桥梁深水群桩基础动力特性数值模拟[C]//第19届全国结构工程学术会议论文集(第Ⅲ册).北京:《工程力学》杂志社,2010:171-176.
[6]魏凯,伍勇吉,袁万城,等.桥梁群桩基础-水耦合系统动力特性数值模拟[J].工程力学,2011,28(s1):198-199.
[7]Pang Yutao,Yuan Wancheng,Wei Kai,et al.Nu-merical Simulation in Dynamic Analysis of DeepwaterGroup Pile Foundation of Bridges[C]//2011 Interna-tional Con-ference on Electric Technology and CivilEngineering(ICETCE),2011:492-495.
[8]Han R P S.A simple and accurate added mass modelfor hydrodynamic fluid--Structure interaction analysis[J].Journal of the Franklin Institute,1996,333(6):929-945.
[9]高学奎,朱熹.地震动水压力对深水桥墩的影响[J].北京交通大学学报,2006,30(1):55-58.
[10]赖伟.地震和波浪作用下深水桥梁的动力响应研究[D].上海:同济大学,2004.
[11]陈新.采用锤击法对24m预应力混凝土梁的模态试验分析[J].铁道标准设计,2008,(6):58-59.
[12]周勇军,贺拴海,宋一凡.基于锤击法的弯连续刚构模型桥动力试验[J].振动、测试与诊断,2007,27(3):1-5.
[13]章关永.桥梁结构试验(第二版)[M].北京:人民交通出版社,2010.
[14]赵迎祥,卢永智,隋峰.用共振法测定弹性梁固有频率及振型[J].陕西师范大学学报(自然科学版),1995,23(3):2-4.
[15]张宏斌,宋广君,张哲,等.模态分离法在拱桥动载试验中的应用[J].公路交通科技,2005,22(1):66-68.
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