During past strong earthquakes, highway bridges have sustained severe damage or even collapse due to excessive displacements and/or very large lateral forces. For commonly used isolation bearings with a pure friction ...During past strong earthquakes, highway bridges have sustained severe damage or even collapse due to excessive displacements and/or very large lateral forces. For commonly used isolation bearings with a pure friction sliding surface, seismic forces may be reduced but displacements are often unconstrained. In this paper, an alternative seismic bearing system, called the cable-sliding friction bearing system, is developed by integrating seismic isolation devices with displacement restrainers consisting of cables attached to the upper and lower plates of the bearing. Restoring forces are provided to limit the displacements of the sliding component. Design parameters including the length and stiffness of the cables, friction coefficient, strength of the shear bolt in a fixed-type bearing, and movements under earthquake excitations are discussed. Laboratory testing of a prototype bearing subjected to vertical loads and quasi-static cyclic lateral loads, and corresponding numerical finite element simulation analysis, were carried out. It is shown that the numerical simulation shows good agreement with the experimental force-displacement hysteretic response, indicating the viability of the new bearing system. In addition, practical application of this bearing system to a multi-span bridge in China and its design advantages are discussed.展开更多
由于耐久性不足,常规黏滞阻尼器等动力控制装置不适用于双层钢桁梁斜拉桥减隔震设计。本文提出高性能的新型动力控制装置应用于双层钢桁梁斜拉桥抗震设计的研究思路,基于一座抗震设防烈度Ⅸ度区的跨径(90+128)m的双层钢桁梁斜拉桥,建立...由于耐久性不足,常规黏滞阻尼器等动力控制装置不适用于双层钢桁梁斜拉桥减隔震设计。本文提出高性能的新型动力控制装置应用于双层钢桁梁斜拉桥抗震设计的研究思路,基于一座抗震设防烈度Ⅸ度区的跨径(90+128)m的双层钢桁梁斜拉桥,建立三维有限元分析模型,进行地震动时程分析,应用两种新型动力控制装置-弹性索组合黏滞阻尼器以及拉索减隔震支座,进行地震作用下的结构受力分析及数值模拟,针对弹性索组合黏滞阻尼器的设计参数-弹性索水平刚度K及阻尼系数C进行优化设计。研究得出以下结论:(1)由弹性索组合黏滞阻尼器和拉索减隔震支座组合而成的动力控制系统既满足正常使用状态下的耐久性要求,又可以有效减少结构在地震作用下的动力响应。(2)纵向地震动作用下,组合动力控制系统对梁端位移减震率达75%,塔底弯矩减震率达60%;横向地震动作用下,组合动力控制系统对边墩底弯矩减震率达45%,同时可控制墩梁相对位移在0.3 m以内。(3)假定阻尼指数α=0.3,参数优化设计表明,针对场地类别Ⅰ0地区,阻尼系数C推荐值为2000 k N·s·m-1,弹性索水平刚度K推荐值为10000 k N/m;针对场地类别Ⅱ地区,C推荐值为4000 k N·s·m-1,K推荐值为50000 k N/m;针对场地类别Ⅳ地区,C推荐值为6000 k N·s·m-1,K推荐值为100000 k N/m。展开更多
基金Ministry of Science and Technology of China Under Grant No. SLDRCE09-B-08Kwang-Hua Fund for College of Civil Engineering, Tongji Universitythe National Natural Science Foundation of China Under Grants No.50978194 and No.90915011
文摘During past strong earthquakes, highway bridges have sustained severe damage or even collapse due to excessive displacements and/or very large lateral forces. For commonly used isolation bearings with a pure friction sliding surface, seismic forces may be reduced but displacements are often unconstrained. In this paper, an alternative seismic bearing system, called the cable-sliding friction bearing system, is developed by integrating seismic isolation devices with displacement restrainers consisting of cables attached to the upper and lower plates of the bearing. Restoring forces are provided to limit the displacements of the sliding component. Design parameters including the length and stiffness of the cables, friction coefficient, strength of the shear bolt in a fixed-type bearing, and movements under earthquake excitations are discussed. Laboratory testing of a prototype bearing subjected to vertical loads and quasi-static cyclic lateral loads, and corresponding numerical finite element simulation analysis, were carried out. It is shown that the numerical simulation shows good agreement with the experimental force-displacement hysteretic response, indicating the viability of the new bearing system. In addition, practical application of this bearing system to a multi-span bridge in China and its design advantages are discussed.
文摘由于耐久性不足,常规黏滞阻尼器等动力控制装置不适用于双层钢桁梁斜拉桥减隔震设计。本文提出高性能的新型动力控制装置应用于双层钢桁梁斜拉桥抗震设计的研究思路,基于一座抗震设防烈度Ⅸ度区的跨径(90+128)m的双层钢桁梁斜拉桥,建立三维有限元分析模型,进行地震动时程分析,应用两种新型动力控制装置-弹性索组合黏滞阻尼器以及拉索减隔震支座,进行地震作用下的结构受力分析及数值模拟,针对弹性索组合黏滞阻尼器的设计参数-弹性索水平刚度K及阻尼系数C进行优化设计。研究得出以下结论:(1)由弹性索组合黏滞阻尼器和拉索减隔震支座组合而成的动力控制系统既满足正常使用状态下的耐久性要求,又可以有效减少结构在地震作用下的动力响应。(2)纵向地震动作用下,组合动力控制系统对梁端位移减震率达75%,塔底弯矩减震率达60%;横向地震动作用下,组合动力控制系统对边墩底弯矩减震率达45%,同时可控制墩梁相对位移在0.3 m以内。(3)假定阻尼指数α=0.3,参数优化设计表明,针对场地类别Ⅰ0地区,阻尼系数C推荐值为2000 k N·s·m-1,弹性索水平刚度K推荐值为10000 k N/m;针对场地类别Ⅱ地区,C推荐值为4000 k N·s·m-1,K推荐值为50000 k N/m;针对场地类别Ⅳ地区,C推荐值为6000 k N·s·m-1,K推荐值为100000 k N/m。
