黏滞阻尼器在某大跨度钢桁架铁路梁桥中的应用研究

以某大跨度的铁路钢桁架连续梁桥为工程背景,基于有限元软件SAP2000建立其三维有限元模型,采用非线性动力时程分析方法分析了在罕遇地震作用下黏滞阻尼器对大跨度高墩连续钢桁架梁桥的减震效果,研究了黏滞阻尼器参数对减震效果的影响规律。研究结果表明:通过对黏滞阻尼器的合理布置和参数优化可以有效减小大跨铁路桥梁的主梁位移和墩底内力,显著改善其强震下的抗震性能。     

高墩大跨度铁路简支钢桁梁桥的减震性能分析

采用时程分析方法,研究了具有减隔震支座的铁路高墩大跨度简支钢桁梁桥的减震性能,探讨减隔震技术在高墩桥梁中的适用性.通过数值分析研究了采用铅芯橡胶支座、盆式橡胶支座和双曲面支座时的减震效果.计算结果表明,在铁路高墩大跨度简支钢桁梁桥上使用减隔震支座具有一定的减震效果.     

在振动台模型试验中黏滞阻尼器的设计方法

通过有限元分析,计算出原型结构中黏滞阻尼器的合理参数,然后利用阻尼力相似原则,对原型结构中黏滞阻尼器参数进行相似比运算,转化为模型结构中的黏滞阻尼器参数.运用该方法,在连续梁桥纵向消能减震振动台试验中设计模型黏滞阻尼器,从试验结果来看,黏滞阻尼器发挥了良好的消能减震效果.     

黏滞阻尼器对拉索参数振动的控制分析

提出采用黏滞阻尼器对拉索参数振动进行控制,建立了黏滞阻尼器控制拉索参数振动的运动方程。从频域和时域以及起振幅值等角度,研究了最优黏滞阻尼器对不同垂度拉索参数振动的控制效果;此外,还研究了最优黏滞阻尼器安装位置对拉索参数振动控制效果的影响。研究表明,黏滞阻尼器可以有效控制拉索的参数振动,控制效果与拉索的激励幅值、最优阻尼器的安装位置和斜拉索的垂度有关。激励幅值越大,控制效果一般越差;最优阻尼器的安装位置越靠近跨中,则控制效果越好;黏滞阻尼器对大垂度拉索的控制效果不及对小垂度拉索的控制效果。     

独塔自锚式悬索桥纵向设置黏滞阻尼器参数分析

以鼓山大桥为工程背景,研究黏滞阻尼器对该桥抗震性能的影响。利用非线性动力时程分析的方法讨论了黏滞阻尼器参数C及ξ的不同组合对该桥塔底、墩底、梁端及塔顶等关键部分内力及变形的影响规律。综合考虑桥梁结构各个关键部位的反应情况,得出该桥的拟安装阻尼器的最优参数约为C=1500kN／（m·s）^0.3,ξ=0．30左右。分析结果表明：在纵桥向设置适当参数的阻尼器可有效减小纵桥向位移的同时改善关键构件受力。     

黏滞阻尼器在单层网壳结构中的优化布置

目前采用黏滞阻尼器对单层网壳结构进行减振控制时,阻尼器最优布置位置通过试算确定。针对此问题,推导了地震作用下黏滞阻尼器耗能公式,提出了以能量比例系数为评价指标的阻尼器优化布置准则。以单层球面网壳和单层柱面网壳为例,对比分析了地震作用下分别采用优化布置准则与现有布置方式布置阻尼器时结构最大节点位移减振系数,验证了所提出优化布置准则的正确性及在单层球面网壳和单层柱面网壳中的适用性。     

FVD与FPB在大跨长联减隔震体系梁桥中的联合作用机理研究

为验证液体黏滞阻尼器(FVD)与摩擦摆支座(FPB)组合在大跨长联减隔震体系梁桥中的应用效果,以一联(50+8×100+50) m预应力混凝土连续梁桥为工程背景,建立全桥有限元模型,通过输入场地地震安评报告提供的50年超越概率为2%的三条人工模拟地震波,开展单独及组合使用液体黏滞阻尼器和摩擦摆支座的大跨长联梁桥减隔震研究,从能量耗散的角度揭示液体黏滞阻尼器与摩擦摆支座组合在大跨长联减隔震体系梁桥中的联合作用机理。结果表明,大跨长联梁桥仅使用黏滞阻尼器,其长周期特性激发黏滞阻尼器充分发挥耗能,但无法避免对固定墩的地震损伤;仅使用摩擦摆支座隔震在纵(横)向强震下会引起支座位移超限;摩擦摆支座与黏滞阻尼器组合的减震机理为摩擦摆支座提供墩梁间的弱连接,激发墩梁间的相对速度,促进黏滞阻尼器(速度型)充分发挥阻尼耗能作用。另外,组合减震方案中摩擦摆支座为辅助耗能装置,黏滞阻尼器为主要耗能装置,且主控梁体位移;相比仅使用摩擦摆支座隔震,由于黏滞阻尼器激发的阻尼力增强了墩梁间约束,这种组合减隔震可能使结构输入能量增加,从而导致地震反应加剧。     

设置黏滞阻尼器的钢结构实用减震设计方法

黏滞阻尼器作为一种有效的消能减震装置,已在钢结构建筑中得到了大量应用.然而由于钢结构的延性和阻尼特征,实用的钢结构附加黏滞阻尼器设计方法仍需深度探讨.文中提出一种基于黏滞阻尼器延性需求的减震设计方法.首先,根据钢结构需求量化层间位移角性能目标及目标附加阻尼比,计算黏滞阻尼器延性需求,并确定黏滞阻尼器布置数量、进行控制效...     

超高墩大跨铁路连续钢桁梁桥粘滞阻尼消能减震研究

针对某超高墩大跨铁路连续钢桁梁桥,建立了考虑桩-土动力相互作用、超高墩几何非线性P-Δ效应的全桥空间有限元模型,考虑了由于粘滞阻尼的非比例阻尼影响,并通过应变能理论将结构不同部位的振型阻尼引入到分析模型中。基于确定的粘滞阻尼器布置方案,研究了阻尼指数和阻尼系数对结构减震的影响规律,采用参数敏感性分析方法对阻尼器参数进行优化,并分析了其减震性能。研究表明:对于文中分析的桥梁,采用速度指数为0.4的粘滞阻尼器可达到最优的减震效果,能够有效降低各墩水平地震作用,并使高度相近的1、4号墩,以及2、3号墩墩底弯矩和墩顶位移趋于均匀;由于固定墩墩底纵向剪力峰值和非减震模型接近,该类型桥的减震控制应以墩底弯矩和墩顶位移为控制目标;对比基于比例阻尼和非比例阻尼分析模型的地震反应,发现考虑非比例阻尼后超高墩大跨桥梁墩底弯矩和墩顶位移均有所增大,且固定墩墩底弯矩增大更显著,建议进行超高墩大跨粘滞阻尼减震桥梁抗震分析时应考虑非比例阻尼。     

粘滞阻尼器在高墩连续梁桥抗震设计中的应用

以大理州鸡足山旅游公路宝丰寺大桥为工程背景,基于桥梁地震动方程建立了空间非线性有限元模型,研究粘滞阻尼器参数及其设置位置对山区高墩连续梁桥减震效果的影响,并同其他减震措施进行了比较,以分析进行高墩连续梁桥减震设计的合理方法.计算结果表明,粘滞阻尼器在高墩连续梁桥的抗震设计中具有优越的性能,对结构的位移控制以及内力的耗散作用非常明显,而铅芯橡胶支座由于附加刚度的影响造成边矮墩内力过于集中,在减震性能上不及粘滞阻尼器;粘滞阻尼器的安装位置对结构减震性能具有较大的影响,设计时须充分考虑,以确保结构的减震性能和工程的经济性.     

大跨铁路钢桁连续梁桥减隔震方案比较研究

为研究适用于大跨铁路钢桁连续梁桥的减隔震方案及合理优化参数,以一座全长504 m的三跨铁路钢桁连续梁特大桥为工程背景,使用非线性结构分析软件SAP2000建立有限元模型,采用快速非线性分析方法分析对比摩擦摆、阻尼器、速度锁定器等减隔震方案在各种装置参数下的减震效率。研究表明:由于大跨铁路钢桁连续梁桥墩身自振导致的地震力较大,摩擦摆方案内力减震效率一般,同时墩底内力对滑动面半径变化并不敏感,在选取滑动半径时应更多地考虑行车平顺性和梁端位移值的限制。速度锁定器会极大地增加此类桥梁地震输入能量,不适用于此类桥型。阻尼器方案对活动墩内力减震效果明显,但不能有效降低固定墩内力。摩擦摆支座附加阻尼器组合减震方案能有效控制此类桥梁的内力和位移响应。研究结论可为大跨度钢桁连续梁桥减隔震设计提供参考。     

高烈度区大跨度桥梁粘滞阻尼器减震研究

高烈度地震对铁路桥梁安全造成巨大隐患,且次生灾害将引起较大经济损失。该大跨连续梁桥所处地震带正进入活跃期,未来有发生较大规模强烈地震的可能,但桥梁自身不具备高烈度抗震能力,需利用粘滞阻尼器对其进行减震处理。采用斜向设置阻尼器并配合双曲面球型支座,来控制可能发生的纵向和横向地震。通过数值模拟进行阻尼器参数敏感性分析以及减震效果讨论,进而确定其最优设置方案。选取相关参数作为评价指标,对比加设阻尼器前后易损部位的地震响应,确定其在高烈度地震荷载激励下的减震效果。研究结果表明:在液体粘滞阻尼器的作用下,使得各墩协同受力,大大增加了结构的整体性,同时能很好弥补减隔震支座不能很好的控制上部结构位移的缺点,同时能降低罕遇地震力对桥墩的冲击损伤。因此,在高烈度区大跨度桥梁中更有必要设置阻尼器来抗震。     

基于粘滞阻尼器的元江大桥减震设计方案

为了提高大跨度桥梁的抗震性能水平,基于粘滞阻尼器的结构减震控制技术成为专家学者研究的重点和工程设计人员首先考虑的抗震设防措施。现有成果主要集中在大跨度公路斜拉桥的研究和应用,在山区的非规则高墩钢桁连续梁桥研究的较少。以云南省元江大桥为例,采用Midas/civil建立弹性分析的有限元模型,对元江大桥进行了动力特性分析。采用快速非线性时程分析方法对粘滞阻尼器参数进行了优化分析,并且总结了粘滞阻尼器参数对高墩连续梁桥的减震作用规律。最后,通过有控和无控结构的地震动响应对比分析,评价了安装阻尼器后的结构主控部位的减震效果。结果表明:减震控制提高了结构的安全性。     

铅阻尼器在自锚式悬索桥横向减震设计中的应用研究

某自锚式钢桁架悬索桥结构主跨408m,采用双层桥面,2根主缆为空间线形布置。本文根据自锚式悬索桥独特的动力特性,提出在悬索桥主梁与过渡墩、辅助墩之间沿横向设置铅挤压阻尼器的消能减震设计方案,以控制悬索桥的横向地震反应。根据风、行车和地震荷载等各种工况可能引起的支座剪力值,提出了铅挤压阻尼器临界滑移荷载值的确定方法。研究表明,同时采用铅挤压阻尼器和粘滞阻尼器的消能减震技术,可以有效地减小悬索桥的横向地震反应,可供工程实践参考。     

大跨径钢管混凝土拱桥减震控制装置参数的研究

大跨度桥梁结构的减震控制研究对于桥梁结构的抗震安全具有重要意义。本文以主跨368m的茅草街大桥为研究对象,基于ANSYS建立了该桥的三维有限元模型,并采用子空间迭代法分析了该桥的动力特性。在此基础上进行了大跨度钢管混凝土拱桥的地震响应及减震控制研究,重点进行了弹性连接装置和粘滞阻尼器减震效果的参数敏感性分析,并对比分析了不同位置布设减震装置时的效果。结果表明,纵飘振型对该桥肋纵向相对位移的贡献最大;弹性连接装置和阻尼器均能有效减小地震作用下该桥的肋梁纵向相对位移;综合考虑各关键部位的地震响应时,同时采用两类减震装置并将其分散布置时的减震效果最佳。结论可供大跨度中承式钢管混凝土系杆拱桥的抗震设计参考。     

Shake-table tests and numerical simulation of an innovative isolation system for highway bridges

Damage investigation of small to medium-span highway bridges in Wenchuan earthquake revealed that typical damage of these bridges included: sliding between laminated-rubber bearings and bridge girders, concrete shear keys failure, excessive girder displacements and even span collapse. However, the bearing sliding could actually act as a seismic isolation for piers, and hence, damage to piers for these bridges was minor during the earthquake. Based on this concept, an innovative solation system for highway bridges with laminated-rubber bearings is developed. The system is comprised of typical laminated-rubber bearings and steel dampers. Bearing sliding is allowed during an earthquake to limit the seismic forces transmitting to piers, and steel dampers are applied to restrict the bearing displacements through hysteretic energy dissipation. As a major part of this research, a quarter-scale, two-span bridge model was constructed and tested on the shake tables to evaluate the performance of this isolation system. The bridge model was subjected to a Northridge and an artificial ground motion in transverse direction. Moreover, numerical analyses were conducted to investigate the seismic performance of the bridge model. Besides the test bridge model, a benchmark model with the superstructure fixed to the substructure in transverse direction was also included in the numerical analyses. Both the experimental and the numerical results showed high effectiveness of this proposed isolation system in the bridge model. The system was found to effectively control the pier-girder relative displacements, and simultaneously, protect the piers from severe damage. Numerical analyses also validated that the existing finite element methods are adequate to estimate the seismic response of bridges with this isolation system.     

Design formulations for supplemental viscous dampers to highway bridges

Design formulas for supplemental viscous dampers to building structures are readily available in FEMA provisions and MCEER research reports. However, for the design of supplemental viscous dampers corresponding to a desired system damping ratio of highway bridges, there exist, if any, few design guidelines. This is particularly true if the bridge components such as elastomeric bearings, piers and abutment possess different damping ratios, stiffnesses, and lumped masses. In this paper, the design formulas for supplemental viscous dampers to highway bridges have been derived based on the concept of ‘composite damping ratio’. The design formulas can be used to determine the damping coefficients of the dampers corresponding to a desired system damping ratio of the bridge in which different component damping ratios may be assumed for the elastomeric bearings, piers and abutments. The proposed design formulas are numerically validated by comparing the seismic responses of a three‐span bridge equipped with viscous dampers with those of the same bridge without viscous dampers but with an assigned inherent system damping ratio equal to the target system damping ratio. Copyright © 2005 John Wiley & Sons, Ltd.     

大跨度拱桥地震动输入模式研究

地震动输入是大跨度桥梁地震反应分析的重要一环。从明确大跨度拱桥的临界跨度入手,探讨了大跨度拱桥地震动输入模式中的行波效应、三向输入及其地震动选取问题。基于某大跨度钢管混凝土拱桥,建立了有限元分析模型,考查了行波效应及三向地震动输入对拱关键截面内力、减隔震支座位移及粘滞阻尼器冲程的影响。结果表明:给出的大跨度拱桥临界跨度确定方法合理,行波效应对拱顶轴力有重要影响,不考虑三向地震动同时作用会明显低估大跨度拱桥的地震反应。确定大跨度拱桥地震动输入模式时需考虑行波效应与三向地震动同时输入。     

Effects of seismic devices on transverse responses of piers in the Sutong Bridge

The Sutong Bridge in China opened to traffic in 2008, and is an arterial connection between the cities of Nantong and Suzhou. It is a cable-stayed bridge with a main span of 1,088 m. Due to a tight construction schedule and lack of suitable seismic devices at the time, fixed supports were installed between the piers and the girder in the transverse direction. As a result, significant transverse seismic forces could occur in the piers and foundations, especially during a return period of a 2500-year earthquake. Therefore, the piers, foundations and fixed bearings had to be designed extraordinarily strong. However, when larger earthquakes occur, the bearings, piers and foundations are still vulnerable. The recent rapid developments in seismic technology and the performance-based design approach offer a better opportunity to optimize the transverse seismic design for the Sutong Bridge piers. The optimized design can be applied to the Sutong Bridge(as a retrofit), as well as other bridges. Seismic design alternatives utilizing viscous fluid dampers(VFD), or friction pendulum sliding bearings(FPSB), or transverse yielding metallic dampers(TYMD) are thoroughly studied in this work, and the results are compared with those from the current condition with fixed transverse supports and a hypothetical condition in which only sliding bearings are provided on top of the piers(the girder can move "freely" in the transverse direction during the earthquake, except for frictional forces of the sliding bearings). Parametric analyses were performed to optimize the design of these proposed seismic devices. From the comparison of the peak bridge responses in these configurations, it was found that both VFD and TYMD are very effective in the reduction of transverse seismic forces in piers, while at the same time keeping the relative transverse displacements between piers and the box girder within acceptable limits. However, compared to VFD, TYMD do not interact with the longitudinal displacements of the girder, and have simpler details and lower initial and maintenance costs. Although the use of FPSB can also reduce seismic forces, it generally causes the transverse relative displacements to be higher than acceptable limits.