摘要研究目的:近年来,近断层地震对桥梁响应的影响日益引起研究者的注意,现有铁路规范对近断层效应的考虑较少。为研究方向速度脉冲效应对高速铁路桥梁地震响应的影响,基于Pacific Earthquake Engineering Research Center(PEER), Next Generation Attenuation Relationships for Western US (NGA West) 强震数据库,采用ANSYS分析软件、ANSYS-APDL语言和弯矩曲率关系计算程序,建立了高速铁路桥梁全桥模型,考虑了轨道不平顺的影响,计算了近/远断层地震作用下桥梁的弹塑性地震响应。
Abstract:Research purposes: Recently, the more attentions have been paid to the influence of the near-fault ground motion on the dynamic response to bridge, but there is a little concerns about the near-fault ground motion effect in the current railway codes. To investigate the influence of the seismic response of the near-fault ground motion on high-speed railway bridge, by using the Pacific Earthquake Engineering Research Center(PEER), the Next Generation Attenuation Relationships for Western US(NGA West)strong ground motion database, the ANSYS software, the ANSYS-APDL language and the moment-curvature program, the finite element model for the multi-span simply-supported bridge of the high-speed railway was built on consideration of the influence of the track irregularity to calculate the elastic-plastic seismic responses of bridge subjected to the near/far-fault ground motions.
Research conclusions:(1)Compared with far-fault ground motion and non-pulse-like motion, the directivity pulse-like Near-fault ground motion had a big influence on the seismic responses on the short-period structure, increased the displacement response of inelastic bridge structures and it also increased the structural and nonstructural damage because the hysteretic properties of the near-fault directivity pulse-type earthquake was characterized by the central strengthened hysteretic cycles.(2)The big vertical acceleration of near-fault directivity pulse-like motion could notably change the axial load of the bridge piers, resulting in big increase of vertical deflection in the mid-span of girder, but the vertical earthquake force is specified as 65% of the lateral earthquake in the 《Code for Seismic Design of Railway Engineering》 (GB 50111-2006) and it causes the smaller vertical deflection in the girder. (3)The calculation results could provide the reference to the seismic design of high-speed railway bridge, and provide the technical support for the revisions of the design specifications and standards.
[1] Somerville P G, Smith N F, Graves R W, etc. Modification of Empirical Strong Ground Motion Attenuation Relations to Include the Amplitude and Duration Effects of Rupture Directivity[J]. Seismological Research Letters, 1997(1):199-222.
[2] Alavi B and Krawinkler H. Consideration of Near-fault Ground Motion Effects in Seismic Design[C] // 12th World Conference on Earthquake Engineering, No. 2665, Auckland, New Zealand,2000.
[3]Choi H, Saiidi M, P. G. Somerville etc. Bridge Seismic Analysis Procedure to Address Near-Fault Effects[C] // Proceedings Caltrans Bridge Research Conference, Calif. Transportation Foundation and Calif. Dept. of Transportation, Sacramento, California, 2005.
[4]Alireza Mortezaei and Hamid Reza Ronagh. Plastic Hinge Length of Reinforced Concrete Columns Subjected to Both Far-fault and Near-fault Ground Motions Having Forward Directivity[J].The Structural Design of Tall and Special Buildings, 2013(12):903-926.
[5]Makris N and Black C. Dimensional Analysis of Rigid-plastic and Elastoplastic Structures under Pulse-type Excitations[J]. Journal Engineering Mechanics, 2004(9):1006-1018.
[6]Mavroeidis G P, Dong G and Papageorgiou A S. Near-Fault Ground Motions, and the Response of Elastic and Inelastic Single-degree-of-freedom (SDOF) Systems [J]. Earthquake Engineering & Structural Dynamics, 2004(9):1023-1049.
Chen Lingkun, Jiang Lizhong, Yu Zhiwu, etc. Study on Earthquake Characteristics of High-speed Railway Simply-supported Girder Bridge [J]. Journal of Vibration and Shock, 2011(12):216-222.
Chen Lingkun, Jiang Lizhong, Yu Zhiwu, etc. Numerical Analysis of Seismic Responses of High-speed Railway Bridge Round-ended Piers[J]. Journal of Hunan University (Natural Sciences).2012(4):19-25.
[9]陈琦. 荷麻溪大桥动力特性与地震反应谱分析[J].铁道工程学报,2012(5):22-34.
Chen Qi. Analyses of Dynamic Characteristics and Seismic Response Spectrum of Hemaav Bridge[J]. Journal of Railway Engineering Society, 2010(5):22-34.
Zhu Mengjun. Analyses of Modal and Earthquake Response of Twin Towers Single Cable-stayed Bridge[J]. Journal of Railway Engineering Society, 2009(10):37-40.
[11]Baker J W. Quantitative Classification of Near-fault Ground Motions Using Wavelet Analysis [J]. BuVetin of the Seismological Society of America, 2007(5):1486-1501.
[12] Applied Technology Council. Quantification of Building Seismic Performance Factors, ATC-63 Project Report (FEMA P695)[R]. Redwood City, CA: FEMA, 2008.
Chen Lingkun. Seismic Responses of High-speed Railway Train-ballastless Track-Bridge System and Train-running Safety During Earthquake [D]. Changsha: Central South University, 2012.
[14]GB 50111-2006, 铁路工程抗震设计规范[S].
GB 50111-2006, Code for Seismic Design of Railway Engineering [ S ].