高架浮动门桥水动力特性研究

发布时间：2018-09-07 18:22

【摘要】：用于交通应急用的高架浮桥以浮动基础代替固定基础,是战时克服跨水体障碍进行人员快速投送以及后勤物资运输的重要保障手段。而分析浮桥的通载能力是重要一步,虽然试验是验算浮桥通车能力的最理想方法,但因试验成本大、耗时长等特点,故往往采用计算机有限元软件模拟分析浮桥的动力性能。本文以长江上某一垮塌桥梁为研究背景,采用浮桥替代坍塌桥跨,结合长江内河特殊水文条件和《铁路桥梁抢修规范》,分析了高架门桥的稳性、水动力特性和结构强度,对铁路浮桥的设计与验算提供一定的参考。首先进行1 500 t方驳的设计,基于SESAM软件进行数值模拟,对比分析梁与墩在三种支座约束下的稳性,得出支座约束的最佳形式;根据门桥的实际长度,验算不同浮墩间距下门桥自身的稳性,得出最不利的墩距;研究梁上列车荷载的不同位置对门桥完整稳性的影响,得出最不利的加载位置,作为后续计算分析的基础;对比分析不同的风速对门桥倾覆力矩的影响及验算六级风荷载作用下门桥系统能否达到稳性标准要求。其次,概述门桥浮体结构水动力及运动响应的计算理论,并进行波浪搜索下高架门桥的水动力及运动响应研究;根据门桥在微幅波浪诱导下的水动力计算结果,分析了频幅响应内不同水深、不同波浪入射角条件下门桥附加质量、辐射阻尼、一阶波激力、平均二阶漂移力的变化规律。最后,应用基于谱分析的设计波法完成了浮式门桥波浪诱导载荷的长期预报,该方法关键之处在于确定具有代表性的剖面波浪载荷。以规则波下计算出的载荷传递函数为基础,创建波浪散布图,定义超越概率水平和重现周期,进一步阐述了波浪载荷控制参数长期预报的计算过程,得到一定超越概率水平波浪载荷,从而得出设计波参数,实现单位波幅下的结构响应。与此同时,将实际波幅与相位角进行结果组合得出实际浮桥结构应力,并根据《铁路桥梁抢修规范》,对梁进行了强度验算。最后进行不同浮墩间距下梁的内力计算,得出门桥合理的浮墩间距。
[Abstract]:The floating foundation is used to replace the fixed foundation of the elevated floating bridge which is used for traffic emergency. It is an important guarantee means to overcome the obstacle of crossing the water for the rapid delivery of personnel and the transportation of logistics and materials in wartime. It is an important step to analyze the loading capacity of floating bridge. Although the test is the most ideal method for checking the capacity of the floating bridge, because of the characteristics of high test cost and long time consuming, the finite element software of computer is often used to simulate and analyze the dynamic performance of the floating bridge. Taking a collapsing bridge on the Yangtze River as the research background, the floating bridge is used to replace the collapsed bridge span, combined with the special hydrological conditions of the Yangtze River and the Code for the urgent repair of Railway Bridges, the stability, hydrodynamic characteristics and structural strength of the elevated gate bridge are analyzed. It provides a certain reference for the design and checking calculation of railway floating bridge. Firstly, the design of 1 500t square barge is carried out, and the numerical simulation based on SESAM software is carried out, and the stability of beam and pier under three kinds of support constraints is compared and analyzed, and the optimum form of support constraint is obtained, according to the actual length of gate bridge, By checking the stability of the portal bridge under different floating pier spacing, the most unfavorable pier spacing is obtained, and the influence of the different position of train load on the beam on the integrity stability of the portal bridge is studied, and the most unfavorable loading position is obtained, which is the basis of subsequent calculation and analysis. The influence of different wind speed on the overturning moment of the portal bridge and the checking calculation of whether the gate-bridge system can meet the stability standard under the action of six-stage wind load are compared and analyzed. Secondly, the calculation theory of hydrodynamic and motion response of floating structure of portal bridge is summarized, and the hydrodynamic and kinematic response of elevated portal bridge under wave search is studied, according to the hydrodynamic calculation results of portal bridge induced by micro-wave, The variation of the additional mass, radiation damping, first-order wave-induced force and average second-order drift force of the gate bridge under different water depths and different wave incident angles in the frequency amplitude response are analyzed. Finally, the design wave method based on spectral analysis is used to complete the long-term prediction of wave induced loads of floating gate bridges. The key point of this method is to determine the representative wave loads in the profile. Based on the load transfer function calculated under the regular wave, the wave scatter diagram is created, the level of surpassing probability and the recurrence period are defined, and the calculation process of the long-term prediction of wave load control parameters is further expounded. The horizontal wave loads with a certain transcendence probability are obtained, and the design wave parameters are obtained to realize the structural response under the unit wave amplitude. At the same time, the actual structural stress of floating bridge is obtained by combining the results of actual wave amplitude and phase angle, and the strength of the beam is checked according to the Code of Railway Bridge repair. Finally, the internal force of the beam under different floating pier spacing is calculated, and the reasonable floating pier spacing of the exit bridge is obtained.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441;U448.19

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