海冰对冰水域大跨拱桥地震动力反应的影响研究
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摘要
本文基于Croteau动冰力模型和动水附加质量建立冰水域墩柱结构地震反应简化计算模型,并进行大跨牛根拱桥分别被自由冰和固结冰包围时地震反应分析,通过对比分析拱桥主梁、拱肋内力响应及桥墩底部弯矩曲率响应,探讨自由冰和固结冰对大跨拱桥地震反应的影响。结果表明:无论是固结冰还是自由冰对牛根拱桥的自振频率影响不大,主要是由于桥墩结构刚度较大;地震作用下,自由冰和固结冰对主拱范围内的主梁和拱肋的内力影响较小,变化±3%左右,但对引桥端部和边拱端部处主梁的内力影响较大,可增大10%以上;而海冰对桥墩的地震反应的影响显著,海冰可使桥墩底部的弯矩和曲率增大数倍。因此,在进行冰水域大跨拱桥的抗震设计时,非常有必要考虑冰对桥梁结构内力的影响。
Based on Croteau ice force model and added mass method,the seismic response analysis model of a bridge pier surrounded by sea ice was put forward. Then the seismic responses of a long-span arch bridge were also studied with considering the effects of sea ice. By comparing the inner forces of bridge girder,arch rib and bridge pier,the effects of sea ice on seismic response of bridge were studied. The results show that no mater free sea ice or consolidated sea ice influences the natural frequency of the long-span arch bridge little,that mainly because the stiffness of bridge pier is too big. The sea ice influences the inner force of arch rib and bridge girder in the scope of arch rib little,and the change is about ± 3%,but influences the inner force of bridge girder at the end of bridge approach and subarch greatly,which can increase more than 10%. The sea ice can increase the curvature and flexural moment of pier bottom more than several times. So it is necessary to consider the effects of sea ice on long-span arch bridge in icy water in design.
Based on Croteau ice force model and added mass method,the seismic response analysis model of a bridge pier surrounded by sea ice was put forward. Then the seismic responses of a long-span arch bridge were also studied with considering the effects of sea ice. By comparing the inner forces of bridge girder,arch rib and bridge pier,the effects of sea ice on seismic response of bridge were studied. The results show that no mater free sea ice or consolidated sea ice influences the natural frequency of the long-span arch bridge little,that mainly because the stiffness of bridge pier is too big. The sea ice influences the inner force of arch rib and bridge girder in the scope of arch rib little,and the change is about ± 3%,but influences the inner force of bridge girder at the end of bridge approach and subarch greatly,which can increase more than 10%. The sea ice can increase the curvature and flexural moment of pier bottom more than several times. So it is necessary to consider the effects of sea ice on long-span arch bridge in icy water in design.
引文
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[2]American Petroleum Institute(API).Recommended practice for planning,designing,and constructing structures and pipelines for arctic conditions[S].USA:API,1995
[3]Hiroshi K.Evaluation of seismic load on the marine structure in ice-covered waters[C]//Proceedings of the Twelfth International Offshore and Polar Engineering Conference.Kitakyushu,Japan,2002
[4]Croteau P.Dynamic interactions between floating ice and offshore structures[D].Berkeley:University of California,1983
[5]佐藤貢一,中西三和,安達洋.氷海域と海洋構造物の地震における動的相互作用に関する研究:その21円錐形構造物の修正復元力モデルによる地震応答解析[C]//日本建築学会大会学術講演梗概集.日本:日本建筑学会,2001:265-266
[6]五十嵐康仁,佐藤貢一,等.氷海域における構造物の地震応答性状に関する研究:その23デッキ部分の回転慣性を考慮した構造物の地震応答性状[C]//日本建築学会大会学術講演梗概集.日本:日本建筑学会,2002:341-342
[7]Withalm M,Hoffmann N P.Simulation of full-scale ice–structure-interaction by an extended Matlock-model[J].Cold Regions Science and Technology,2010,60:130-136
[8]Song Bo,Qi Fuqiang.Study on effects of sea ice on nonlinear seismic responses of single-column pier subject to different types of earthquakes[J].Applied Mechanics and Materials,2012,166/167/168/169:2298-2303
[2]American Petroleum Institute(API).Recommended practice for planning,designing,and constructing structures and pipelines for arctic conditions[S].USA:API,1995
[3]Hiroshi K.Evaluation of seismic load on the marine structure in ice-covered waters[C]//Proceedings of the Twelfth International Offshore and Polar Engineering Conference.Kitakyushu,Japan,2002
[4]Croteau P.Dynamic interactions between floating ice and offshore structures[D].Berkeley:University of California,1983
[5]佐藤貢一,中西三和,安達洋.氷海域と海洋構造物の地震における動的相互作用に関する研究:その21円錐形構造物の修正復元力モデルによる地震応答解析[C]//日本建築学会大会学術講演梗概集.日本:日本建筑学会,2001:265-266
[6]五十嵐康仁,佐藤貢一,等.氷海域における構造物の地震応答性状に関する研究:その23デッキ部分の回転慣性を考慮した構造物の地震応答性状[C]//日本建築学会大会学術講演梗概集.日本:日本建筑学会,2002:341-342
[7]Withalm M,Hoffmann N P.Simulation of full-scale ice–structure-interaction by an extended Matlock-model[J].Cold Regions Science and Technology,2010,60:130-136
[8]Song Bo,Qi Fuqiang.Study on effects of sea ice on nonlinear seismic responses of single-column pier subject to different types of earthquakes[J].Applied Mechanics and Materials,2012,166/167/168/169:2298-2303
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