客运专线无砟轨道梁端扣件上拔力研究

针对客运专线无砟轨道梁端转角和竖向相对位移对梁端轨道结构设计的影响,分析了无砟轨道梁端扣件上拔力产生的机理。建立了无砟轨道梁端扣件上拔力计算的有限元模型。分析了梁端转角、竖向相对位移、梁缝处扣件间距、梁端悬出长度、梁高等对扣件上拔力的影响规律,为客运专线梁端无砟轨道结构设计提供理论参考。     

港珠澳大桥的非线性地震响应分析

根据隔震连续桥梁的设计特点,利用2个正交的非线性水平弹簧单元来模拟铅芯橡胶支座的双向非线性特性,基于大型有限元软件,合理选取了强震记录作为地震输入,建立了加设隔震支座的港珠澳大桥有限元模型,并进行了强地震动作用下的地震响应分析。分析结果表明:采用减隔震支座后,桥梁结构通过延长自身的自振周期避开了地震的卓越周期;同时依靠减隔震支座的滞回耗能,有效地减少了输入到桥梁结构中的地震能量,降低了桥梁结构的地震响应,使大部分构件处于弹性工作阶段,从而达到保护主体结构的目的。     

车桥撞击动力学分析模型

针对频发的车桥撞击事故,采用落锤冲击试验装置,进行了钢筋混凝土圆形桥墩模型在静力及侧向撞击荷载下的力学性能试验,建立了车桥撞击动力学分析模型。试验结果表明:桥墩撞击荷载下破坏模式与撞击力及材料动态性能相关;基于达朗贝尔原理建立的车桥一维碰撞的单自由度、双自由度模型求解撞击力与试验值基本吻合,峰值及平均值误差分别为-15.4%和14.5%。     

流线型桥梁断面颤振稳定性数值模拟

对于流线型桥梁断面颤振稳定性,采用动网格实现结构分状态强迫振动法,提取稳定的气动力,按照最小二乘法求得不同折减风速的颤振导数。研究了理想薄平板的8个颤振导数,并将数值计算结果与Theodorsen理论解进行对比,发现采用该方法识别颤振导数与理论解吻合得很好。采用该方法计算了3种不同流线型桥梁断面的颤振导数,并计算了颤振临界风速。结果表明:增大主梁的宽高比,可以提高主梁的颤振稳定性;宽高比相同时,主梁底板采用折线形状要比圆弧线颤振稳定性好。     

Design of Unballasted Track Bridges on Beijing-Tianjin Intercity railway

Beijing-Tianjin intercity railway is the first newly-built passenger dedicated line with operating speed of 350 km/h in our country. During design,new ideas of bridge construction were carried out to ensure the requirements of safety,comfort and stability of the train under high-speed condition. At the same time,concepts of environmental adaptability,service to transportation and comprehensive benefits were observed. On the whole line,long-bridge schemes were adopted and the most advanced technologies of unballasted track were utilized on bridges,the length of which accounts for 87.7 % of the total line. The success of design and construction of the bridges on this rail has accumulated valuable experience for high-speed railway construction on a large scale in the future,and made it a marking,demonstrating,and model project to follow.     

Energy conservation research of dehumidification system for main cable anticorrosion of suspension bridge

The necessity of the main cable anticorrosion for suspension bridge is described, and operating principles and composition of main cable dehumidification system are analyzed. An idea using the waste heat of high temperature outlet air of dehumidification system to heat up regeneration air of rotary-type dehumidifier is put forward in this paper. The concrete scheme is to install a heat exchanger on air-out pipeline of roots blower and air-in pipeline of regeneration electric heater of rotary dehumidifier. Air preheated by the heat exchanger enters regeneration electric heater of rotary-type dehumidifier. Energy conservation of main cable dehumidification system for the Yangtze River highway bridge is calculated, and the results show that energy conservation rate can reach 44 %.     

桥台后路堤多级加载下黏弹性饱和成层软土地基一维固结分析

将桥台后路堤荷载简化为横截面梯形分布的半无限条形荷载,基于Boussinesq弹性力学解答推导得到桥台后软土地基内竖向附加应力计算公式,由此考虑初始孔隙水压力非均匀分布特性.结合桥台后路堤多级加载的Laplace变换递推公式,运用Laplace变换及其逆变换方法求解Terzaghi固结与Kelvin黏弹性应力应变联合微分方程,获得桥台后路堤多级加载条件下黏弹性饱和成层软土地基固结变形解答.算例分析结果表明:该解答具有合理性和可靠性,计算结果可为桥台后软土地基沉降分析提供参考.     

桥梁纠偏技术在平定大桥中的应用研究

近人类经济工程活动也使得地质灾害的发育日趋加剧,这些自然灾害对桥梁结构的影响巨大,造成大量桥梁被掩埋,或者出现了墩台沉降、横向偏移及墩柱压溃等严重病害。本文就甘肃罗定大桥通过单墩顶升逐调法对其进行了成功纠偏,为类似桥梁纠偏提供了参考。     

京沪高速铁路某特大桥墩身混凝土外观质量控制方法研究

分析了京沪高速铁路某特大桥墩身混凝土常见外观质量问题及其产生原因,提出了相应的控制方法及措施。     

公路装配式空心板桥加宽预压施工新工艺研究与应用

针对公路装配式空心板桥,在分析影响桥梁加宽效果关键因素的基础上,提出了预压加宽施工新工艺,并在工程实例桥加宽改造施工中进行的应用验证,该施工工艺可用于类似桥梁的加宽改造.