不同边界约束对橡胶支座受力性能影响研究
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摘要
橡胶支座是连接桥梁上下部结构的重要构件,其力学性能对上下部结构地震响应有重要影响,但其力学性能会因安装时采用的锚固边界条件的不同而存在差异。为研究不同边界约束对橡胶支座受力性能的影响,利用有限元软件建立了顶底面锚固、顶面锚固和顶底面均不锚固(无锚固)3种不同边界约束的精细化橡胶支座有限元模型,并通过试验及理论计算验证了所建有限元模型的合理性。随后对具有不同边界约束的支座有限元模型施加竖向力及剪切变形,对比分析了不同边界约束对支座内部应力分布、应力响应值变化等力学性能的影响。结果表明,随剪切变形的增加,支座因受压面积减小而导致内部峰值压应力逐渐增加,不同边界约束下支座的内部峰值压应力增加幅值相差明显,其中采用顶底面锚固的支座增加幅值最大,无锚固边界支座增加幅值最小;在剪切变形作用下,对橡胶支座采取锚固措施会增加支座内部应力响应值,相同水平荷载下,顶底面锚固支座比无锚固支座更易发生橡胶层与钢板间的剥离、撕裂破坏,而且采取顶底面锚固边界约束会增大桥梁结构下部地震力,不利于结构抗震;对于采用无锚固边界约束的支座,随剪切变形的增加,其刚度退化明显,在设计时应考虑因支座支承面处卷曲而造成的有效剪切面减小的影响。
As an important component connecting the superstructure and the substructure of bridge, the mechanical property of rubber bearings has an important influence on the seismic response of the superstructure and the substructure, but the mechanical property is different depending on the anchorage boundary conditions adopted in the installation. In order to investigate the influence of different boundary conditions on the mechanical property of rubber bearings, a group of refined FE models of the bearing, which considering anchoring at top and bottom surfaces, only anchoring at top surface and without any anchoring, are developed using finite software. The rationality of all the finite models is verified by comparing with the experimental result and theoretical result. Then, vertical stress and shear deformation are applied on the verified models, the influence of different boundary conditions on the mechanical property, such as inner stress distribution and stress response value, is comparatively analysed. The result shows that(1) The compressive area of bearings decrease as shear deformation increase, which lead to the internal peak compressive stress increase gradually. The obvious different increases of peak compressive stress depend on the boundary condition. The bearing with anchoring at top and bottom surfaces increases the maximum amplitude, while the bearing without any anchoring increases the minimum amplitude value.(2)The internal stress value of bearings will be increased with anchoring application under shear deformation. The bearing with anchoring at top and bottom surfaces is more prone to peel and tear damage between rubber layer and steel plate than that without any anchoring under the same horizontal load, and the seismic force transferred to the substructure of bridge will be increased with anchoring application, which is not good for seismic performance of bridge.(3) For the bearing without any anchoring, the stiffness will be degraded as shear deformation increase. It is recommended that the decrease of effective shear area of bearings caused by roll-off at the supporting surfaces should be taken into consideration during bridge design stage.
As an important component connecting the superstructure and the substructure of bridge, the mechanical property of rubber bearings has an important influence on the seismic response of the superstructure and the substructure, but the mechanical property is different depending on the anchorage boundary conditions adopted in the installation. In order to investigate the influence of different boundary conditions on the mechanical property of rubber bearings, a group of refined FE models of the bearing, which considering anchoring at top and bottom surfaces, only anchoring at top surface and without any anchoring, are developed using finite software. The rationality of all the finite models is verified by comparing with the experimental result and theoretical result. Then, vertical stress and shear deformation are applied on the verified models, the influence of different boundary conditions on the mechanical property, such as inner stress distribution and stress response value, is comparatively analysed. The result shows that(1) The compressive area of bearings decrease as shear deformation increase, which lead to the internal peak compressive stress increase gradually. The obvious different increases of peak compressive stress depend on the boundary condition. The bearing with anchoring at top and bottom surfaces increases the maximum amplitude, while the bearing without any anchoring increases the minimum amplitude value.(2)The internal stress value of bearings will be increased with anchoring application under shear deformation. The bearing with anchoring at top and bottom surfaces is more prone to peel and tear damage between rubber layer and steel plate than that without any anchoring under the same horizontal load, and the seismic force transferred to the substructure of bridge will be increased with anchoring application, which is not good for seismic performance of bridge.(3) For the bearing without any anchoring, the stiffness will be degraded as shear deformation increase. It is recommended that the decrease of effective shear area of bearings caused by roll-off at the supporting surfaces should be taken into consideration during bridge design stage.
引文
[1] 庄卫林, 陈乐生. 汶川地震公路震害分析-桥梁与隧道[M]. 北京:人民交通出版社,2013.ZHUANG Wei-lin, CHEN Le-sheng. Analysis of Highways’ Damage in the Wenchuan Earthquake: Bridge and Tunnel[M]. Beijiing: China Communications Press, 2013.
[2] 王克海, 韦韩, 李茜, 等. 中小跨径公路桥梁抗震设计理念[J]. 土木工程学报,2012,45(9):115-121.WANG Ke-hai, WEI Han, LI Qian, et al. Philosophies on Seismic Design of Highway Bridges of Small or Medium Spans[J]. China Civil Engineering Journal, 2012,45(9):115-121.
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[4] 王东升, 孙治国, 郭迅. 汶川地震桥梁震害经验及抗震研究若干新进展[J].公路交通科技,2011,28(10):44-53.WANG Dong-sheng, SUN Zhi-guo, GUO Xun. Lessons Learned from Wenchuan Seismic Damages and Recent Research on Seismic Design of Highway Bridges[J]. Journal of Highway and Transportation Research and Development, 2011,28(10):44-53.
[5] CARDONE D, PERRONE G. Critical Load of Slender Elastomeric Seismic Isolators: An Experimental Perspective [J]. Engineering Structures, 2012, 40(7): 198-204.
[6] JAIN S K, THAKKAR S K. Experimental Investigations on Laminated Rubber Bearings [J]. Bulletin of Earthquake Engineering, 2005, 3(1): 129-136.
[7] WARN G P, WEISMAN J. Parametric Finite Element Investigation of the Critical Load Capacity of Elastomeric Strip Bearings [J]. Engineering Structures, 2011, 33(12): 3509-3515.
[8] GJORGJIEV I, GAREVSKI M. A Polynomial Analytical Model of Rubber Bearings Based on Series of Tests [J]. Engineering Structures, 2013, 56(6): 600-609.
[9] 聂利英,李建中,胡世德, 等. 地震作用下板式橡胶支座滑动引起的城市立交中的动力耦合作用[J]. 工程力学,2006, 23(11): 14-20.NIE Li-ying, LI Jian-zhong, HU Shi-de, et al. Dynamic Response Coupled by Rubber Bearing Sliding in Interchange Bridge under Earthquake [J]. Engineering Mechanics, 2006, 23(11): 14-20.
[10] 王常峰,陈兴冲. 竖向地震动对桥梁结构地震反应的影响[J]. 振动与冲击,2007, 26(6): 31-35.WANG Chang-feng, CHEN Xing-chong. Effect of Vertical Excitation on Seismic Performance of Continuous Bridge[J]. Journal of Vibration and Shock, 2007, 26(6): 31-35.
[11] 王克海. 桥梁抗震研究[M]. 2版. 北京: 中国铁道出版社, 2014.WANG Ke-hai. Seismic Research of Bridge[M].2nd ed. Beijing: China Railway Publishing House, 2014.
[12] STEELMAN J S, FAHNESTOCK L A,FILIPOV E T, et al. Shear and Friction Response of Nonseismic Laminated Elastomeric Bridge Bearings Subject to Seismic Demands [J]. Journal of Bridge Engineering, 2013,18(7):612-623.
[13] STEELMAN J S, FAHNESTOCK L A, LAFAVE J M, et al. Seismic Response of Bearings for Quasi-isolated Bridges: Testing and Component Modeling[C]// 2011 Structures Congress. Las Vegas: ASCE, 2011:164-178.
[14] 李冲, 王克海, 李悦, 等. 板式橡胶支座摩擦滑移抗震性能试验研究[J]. 东南大学学报: 自然科学版, 2014, 44(1):162-167.LI Chong, WANG Ke-hai, LI Yue, et al. Experimental Study on Seismic Performance of Laminated Rubber Bearings with Friction Slipping[J]. Journal of Southeast University: Natural Science Edition, 2014, 44(1):162 -167.
[15] 项乃亮, 崔侠侠, 李建中. 板式橡胶支座滑动摩擦性能试验及其力学模型[J]. 同济大学学报:自然科学版, 2016, 44(12):1828-1834.XIANG Nai-liang, CUI Xia-xia, LI Jian-zhong. Experimental Study on Sliding Friction Behavior of Laminated Rubber Bearing and Its Mechanical Model [J]. Journal of Tongji University:Natural Science Edition, 2016,44(12): 1828-1834.
[16] KONSTANTINIDIS D, KELLY J M, MAKRIS N. Experimental Investigations on the Seismic Response of Bridge Bearings, Report No. EERC 2008-02[R].Berkeley: University of California, 2008.
[17] 庄军生. 桥梁支座[M]. 3版. 北京:中国铁道出版社,2008.ZHUANG Jun-sheng. Bridge Bearings [M]. 3rd ed. Beijing:China Railway Publishing House,2008.
[18] 李枝军, 葛飞, 徐秀丽, 等. 板式橡胶支座性能有限元模拟与试验研究[J]. 东南大学学报: 自然科学版, 2013, 43(6):1299-1304.LI Zhi-jun, GE Fei, XU Xiu-li, et al. Finite Element Simulation and Experimental Study of Property for Elastomeric Pad Bearing[J]. Journal of Southeast University: Natural Science Edition, 2013, 43(6):1299-1304.
[2] 王克海, 韦韩, 李茜, 等. 中小跨径公路桥梁抗震设计理念[J]. 土木工程学报,2012,45(9):115-121.WANG Ke-hai, WEI Han, LI Qian, et al. Philosophies on Seismic Design of Highway Bridges of Small or Medium Spans[J]. China Civil Engineering Journal, 2012,45(9):115-121.
[3] 王克海, 李冲, 李茜, 等. 考虑支座摩擦滑移的中小跨径桥梁抗震设计方法[J]. 工程力学, 2014, 31(6): 85-92.WANG Ke-hai, LI Chong, LI Qian, et al. Seismic Design Method of Small and Medium Span Bridge Considering Bearing Friction Slipping[J]. Engineering Mechanics, 2014, 31(6): 85-92.
[4] 王东升, 孙治国, 郭迅. 汶川地震桥梁震害经验及抗震研究若干新进展[J].公路交通科技,2011,28(10):44-53.WANG Dong-sheng, SUN Zhi-guo, GUO Xun. Lessons Learned from Wenchuan Seismic Damages and Recent Research on Seismic Design of Highway Bridges[J]. Journal of Highway and Transportation Research and Development, 2011,28(10):44-53.
[5] CARDONE D, PERRONE G. Critical Load of Slender Elastomeric Seismic Isolators: An Experimental Perspective [J]. Engineering Structures, 2012, 40(7): 198-204.
[6] JAIN S K, THAKKAR S K. Experimental Investigations on Laminated Rubber Bearings [J]. Bulletin of Earthquake Engineering, 2005, 3(1): 129-136.
[7] WARN G P, WEISMAN J. Parametric Finite Element Investigation of the Critical Load Capacity of Elastomeric Strip Bearings [J]. Engineering Structures, 2011, 33(12): 3509-3515.
[8] GJORGJIEV I, GAREVSKI M. A Polynomial Analytical Model of Rubber Bearings Based on Series of Tests [J]. Engineering Structures, 2013, 56(6): 600-609.
[9] 聂利英,李建中,胡世德, 等. 地震作用下板式橡胶支座滑动引起的城市立交中的动力耦合作用[J]. 工程力学,2006, 23(11): 14-20.NIE Li-ying, LI Jian-zhong, HU Shi-de, et al. Dynamic Response Coupled by Rubber Bearing Sliding in Interchange Bridge under Earthquake [J]. Engineering Mechanics, 2006, 23(11): 14-20.
[10] 王常峰,陈兴冲. 竖向地震动对桥梁结构地震反应的影响[J]. 振动与冲击,2007, 26(6): 31-35.WANG Chang-feng, CHEN Xing-chong. Effect of Vertical Excitation on Seismic Performance of Continuous Bridge[J]. Journal of Vibration and Shock, 2007, 26(6): 31-35.
[11] 王克海. 桥梁抗震研究[M]. 2版. 北京: 中国铁道出版社, 2014.WANG Ke-hai. Seismic Research of Bridge[M].2nd ed. Beijing: China Railway Publishing House, 2014.
[12] STEELMAN J S, FAHNESTOCK L A,FILIPOV E T, et al. Shear and Friction Response of Nonseismic Laminated Elastomeric Bridge Bearings Subject to Seismic Demands [J]. Journal of Bridge Engineering, 2013,18(7):612-623.
[13] STEELMAN J S, FAHNESTOCK L A, LAFAVE J M, et al. Seismic Response of Bearings for Quasi-isolated Bridges: Testing and Component Modeling[C]// 2011 Structures Congress. Las Vegas: ASCE, 2011:164-178.
[14] 李冲, 王克海, 李悦, 等. 板式橡胶支座摩擦滑移抗震性能试验研究[J]. 东南大学学报: 自然科学版, 2014, 44(1):162-167.LI Chong, WANG Ke-hai, LI Yue, et al. Experimental Study on Seismic Performance of Laminated Rubber Bearings with Friction Slipping[J]. Journal of Southeast University: Natural Science Edition, 2014, 44(1):162 -167.
[15] 项乃亮, 崔侠侠, 李建中. 板式橡胶支座滑动摩擦性能试验及其力学模型[J]. 同济大学学报:自然科学版, 2016, 44(12):1828-1834.XIANG Nai-liang, CUI Xia-xia, LI Jian-zhong. Experimental Study on Sliding Friction Behavior of Laminated Rubber Bearing and Its Mechanical Model [J]. Journal of Tongji University:Natural Science Edition, 2016,44(12): 1828-1834.
[16] KONSTANTINIDIS D, KELLY J M, MAKRIS N. Experimental Investigations on the Seismic Response of Bridge Bearings, Report No. EERC 2008-02[R].Berkeley: University of California, 2008.
[17] 庄军生. 桥梁支座[M]. 3版. 北京:中国铁道出版社,2008.ZHUANG Jun-sheng. Bridge Bearings [M]. 3rd ed. Beijing:China Railway Publishing House,2008.
[18] 李枝军, 葛飞, 徐秀丽, 等. 板式橡胶支座性能有限元模拟与试验研究[J]. 东南大学学报: 自然科学版, 2013, 43(6):1299-1304.LI Zhi-jun, GE Fei, XU Xiu-li, et al. Finite Element Simulation and Experimental Study of Property for Elastomeric Pad Bearing[J]. Journal of Southeast University: Natural Science Edition, 2013, 43(6):1299-1304.