【作者】 于芳；

【导师】 周福霖；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2011， 博士

【摘要】 目前隔震技术主要应用于结构和公路桥梁中,能够起到隔离地震并且消耗传到结构上的地震能量的作用,有效减小地震作用下结构的加速度响应,但一直很少应用于铁路桥梁中。铁路桥梁是有轨线路,车辆的编组形式和车辆运行速度等影响因素众多,分析复杂,关于隔震铁路桥梁在列车作用下和地震作用下的动力性能还不够明确。目前中国铁路列车不断提速,列车对轨道的平顺性要求更加严格。为使隔震技术能够应用于高速铁路桥梁,使桥梁在地震作用下满足安全性要求,并满足列车运行的安全性和舒适性的要求,本文做了如下几方面研究:1建立了隔震铁路桥梁纵桥向的车桥动力分析模型,将列车简化为多质点模型,隔震桥梁采用空间有限元模型,通过轮对与轨道的纵桥向相互作用力将车辆系统和桥梁系统联系起来。通过力的平衡关系,建立列车的动力平衡方程,用四五阶龙格库塔方法进行求解得到轮对制动力时程,采用二次离散方法将移动轮对制动力时程转换为结构固定节点的制动力时程,实现空间离散过程;通过通用有限元软件ANSYS对桥梁进行了动力响应分析,完成时间离散过程。分析结果表明:采用隔震设计的铁路桥梁,在纵桥向制动力作用下,桥梁的纵向位移响应大于非隔震桥梁的位移响应,隔震设计后可以使制动力在各个墩台间的分布更加合理。列车最不利的停车位置位于列车第一轮对出桥时。2采用模态综合法建立了车桥耦合振动模型,利用MATLAB软件编写了垂横向的车桥耦合动力响应分析程序,进行了铅芯橡胶双向隔震支座铁路桥梁的横桥向和竖向的车桥耦合振动响应分析,分析中采用27个自由度的车辆模型,分析了在轨道的不平顺和轮对的蛇形运动激励下,隔震桥梁的隔震周期和弹性隔震度、以及车辆行驶速度等因素对振动响应的影响。分析结果表明,采用常规的铅芯橡胶支座的设计方法的隔震铁路桥梁,在列车过桥时产生较大的横向动位移,不能满足列车运行安全性的要求。要使双向隔震技术应用于铁路桥梁需要对铅芯橡胶支座进行限位。3采用有限元软件ANSYS进行了铅芯橡胶支座双向隔震桥梁在设计地震和罕遇地震作用下纵桥向和横桥向的时程响应分析,分析结果表明,采用铅芯橡胶支座隔震铁路桥梁,在强震作用下取得了较好的隔震效果,但在设计地震和多遇地震作用下,隔震支座发生屈服,产生较大的位移,对于铁路桥梁容易引起轨道设备的破坏,严重影响列车运行的安全性,增加的对轨道维护的难度和工作量,带来不必要的经济损失。4为了限制铅芯橡胶支座隔震铁路桥梁在多遇地震和设计地震作用下桥梁上部结构的位移,设计了耗能型限位装置和非耗能型限位装置,为隔震支座提供足够的初始刚度和屈服强度,两类装置主要具有如下特点:a.耗能型限位装置:在设计地震和多遇地震作用下,限位器和铅芯橡胶支座处于弹性工作阶段,限位装置起到理想的限位作用,在罕遇地震作用下,限位装置先于铅芯橡胶支座进入屈服阶段,组合隔震支座起到隔震耗能作用。耗能型限位装置主要研究了X形钢板耗能限位器和X形钢棒双向耗能限位器。b.非耗能型限位装置:不具有塑性发展阶段,达到弹性极限即破坏。在设计地震和多遇地震作用下,限位装置和铅芯橡胶支座处于弹性工作阶段,罕遇地震作用下,限位装置发生破坏,退出工作,由铅芯橡胶支座单独工作,充分发挥铅芯橡胶支座的隔震减震作用。非耗能型限位器主要研究了X形脆性钢板和细长颈部的X形钢棒。5.分别对以上几种限位器进行了材料性能和构件的力学性能静力试验研究,为模型桥梁有限元分析中的模型本构关系和滞回关系的输入提供的试验依据。设计了三跨连续隔震铁路桥梁模型,对采用铅芯橡胶支座和三种组合隔震支座的桥梁模型在纵桥向进行了振动台试验研究,试验结果验证了设计方法的合理性以及桥梁模型有限元的模型简化和分析结果的的正确性,通过原型桥梁模型的分析,证明了组合隔震支座限位和隔震的有效性。更多还原

【Abstract】 Seismic isolation technology is usually used in structures and bridges. This method can prevent and dissipate the input energy of earthquake and reduce the acceleration response of structures effectively. However the LRB is rarely used in railway bridges. The railway bridge with tracks is hardly to analysis for several reasons such as vehicle structure, groups organizing and velocity of vehicles. So far, the performance of railway bridge under train load and earthquakes is not clear. And in China the velocity of trains is frequently accelerated, the smooth of tracks is restricting restrained. In order to apply the seismic isolation technology to high speed railway bridge and to insure the safety and satisfaction, the following content had been studied:1. The vertical and longitudinal coupling oscillation between train and railway bridge had been analyzed. It is simplified to be the multi-particle model. The isolated bridge using finite element model connect the vehicle and bridge system together through the longitudinal interaction force between the wheel and rail. Set up the train’s dynamic equation through the force balance. The interaction force time history between wheels and tracks had been obtained. Multi degree of freedom model and forth and fifth order Runge-Kutta method is adopted when calculating the braking force time history. The bending and braking force time history had been second discrete transferred to braking force time history fixed node of structure to realize the space discrete. The time discrete is realized for the bridge dynamic analysis by the ANSYS. The result show that, when the train pass by the bridge, the vertical displacement response of isolation bridge is larger than non-isolation bridge. Longitudinal displacement response is smaller than non-isolation bridge. When brake at single pier the braking force is uniformly distributed to each pier. So the longitudinal displacement response of deck can be diminished effectively and the force distribution reasonably. The most unfavorable position of the train at the train stop on the bridge when the first pair of wheels go out of the bridge.2 Dynamic coupling responses between vertical and transverse dimension analysis program by composite mode method had been written by MATLAB. The vertical and transverse coupling response between train and bridge of bidirectional seismic isolation railway bridge with LRB had been analyzed. The analysis take into account the non-smooth of track and the snake moving of wheels and the vehicle is simulated by 27 DOF model. The influence of isolation period, isolation damp ratio, the initial stiffness and yield load to oscillate response had been studied. The result show that the train passes by the bridge with normal LRB the transverse displacement is large which can not satisfy the safety demand and the displacement of LRB must be restrained.3 The longitudinal and transverse time history response under designed and rare earthquakes of bidirectional seismic isolation bridge had been analyzed by FEM software ANSYS. The result show that the there will be good seismic isolation effect of railway bridge with LRB. Under occasional and design earthquakes the LRB yield and the displacement will be beyond the allowable value, which may cause the damage of track equipments. The large displacement have serious influence to the safety and increase the difficulty and work to the maintenance and economic loss.4 In order to restrain the displacement of bridge deck under occasional and frequency earthquakes, a composite bearing which is combined by LRB and displacement restrainer had been approved here to provide enough initial stiffness and yield strength for isolation bearings. There are totally two types of displacement restrainer:a. Energy dissipation and deform restrain damper: In the design and occousional earthquake the damper and LRB remain elastic state and restrain the deformation effectively. And under rare earthquakes the dampers yield and the composite bearing can isolate the earthquake and dissapate energy. In this section X shape steel plate damper and X shape steel rob had been studied.b. Non-energy dissipation deform restrainer: This restrainer has no plastic stage and when reach elastic limitation the restrainer crack. Under design and occousional earthquake, both of the deform restrainer and LRB remain elastic state. Under rare earthquake the deform restrainer quit and LRB works solely. In this section X shape brittleness steel plate and long neck X shape steel rob had been strudied.5 The material characteristics and mechanical static test is done for the above restrainers. The constitutional relationship and hysteretic relationship had been got by test for FEM simulation. A three spans continuous railway bridge with seismic isolation bearings had been designed. And the shake table test had been taken to the railway bridge, and the test verified the design method is reasonable and the FEM analysis result is right and proved the theory and test demonstration for the practice use of the three composite bearings.更多还原