【作者】 王子健；

【导师】 肖盛燮；

【作者基本信息】 重庆交通大学 ， 道路与铁道工程， 2013， 博士

【摘要】 随着我国经济建设和交通事业的快速发展,区域性交通网络的建立已经迫在眉睫,必须加快跨江跨海大桥的建设和发展步伐。然而作为危及人类生命财产最为严峻的自然灾害之一——波浪荷载是跨江、跨海大桥结构设计中必须考虑的外荷载。因此开展波浪激励下桥墩振动问题及防护措施的研究有着非常重要的科学价值和实践意义,也是桥梁学者与设计者所面临的现实问题。本文的研究内容涉及多门学科的交叉与渗透,涵盖了海洋工程波浪力学、桥梁工程、桥涵水文及水力学、结构动力学、振动力学、随机振动与谱分析概论、概率统计学、流体力学、数值分析、结构有限元分析、防灾减灾工程学、流固耦合动力学等多学科。本文主要的研究内容和研究成果如下：(1)基于线性叠加法建立了以波浪谱为基础的单自由度波浪力时程曲线,由孤立墩柱悬臂梁的受力特征,建立了折算等代波浪力数值计算简化公式。通过验证,该简化公式计算的波浪力满足精度要求,可用以求解墩柱的动力响应,为随机波浪力研究提供了一种方便、简捷的计算方法。(2)借鉴国内外求解反应谱内插法的基本思路,并结合波浪力时程曲线的特点进一步分析了波浪反应谱的求解方法,建立了等时间间隔内按三角函数变化的振动反应谱连锁递推公式,对实际和人工模拟的波浪时程曲线进行波浪反应谱精度分析,结果表明该法计算简捷精确,为桥墩抗波浪设计提供了有效的计算分析方法。(3)首次将全量补偿复合反演法运用于桥梁墩柱在部分未知波浪输入条件下的参数识别与未知波浪力的反演,进而推导了不考虑墩柱波浪拖曳力时,作用于各节点上的波浪力时程为完全时域相关,并结合概率“统计平均法”与“消去法”构建了未知波浪输入及顶点未知水平荷载作用下的改进复合反演算法,开拓了桥梁损伤识别的新方法。(4)为真实反应深水桥墩在各种环境荷载作用下的动力响应特点,在考虑附加质量和流固耦合效应下,运用有限元软件ANSYS的流固耦合模块对深水桥墩进行地震、流速及风荷载影响下的波浪力响应分析,并探讨各环境荷载对深水桥墩的影响程度,使桥墩设计更加趋于安全经济合理。(5)以弱势环节断链减灾思想为导向,以流体理论为基础,并借鉴结构抗风和桥墩防冲刷机理,将抑制跨江跨海的桥墩受波浪等环境荷载损伤的防护措施放在降低圆柱绕流的阻力和升力上,提出了控制圆柱桥墩绕流的三项措施,并验证了三项措施的有效性和适用性,为涉水桥墩防护对策提供借鉴。更多还原

【Abstract】 With the rapid development of economy and transportation industry in our country, the establishment of regional transportation network becomes urgent. Therefore construction and development of sea or river crossing bridge should be accelerated. However, wave load becomes external load has to be considered in the structural design of sea or river crossing bridge as it is one of the most serious natural disasters for human life and property security. Therefore it is significant to carry out the analysis of pier vibration under wave excitation and braking measure which is also scientific research personnel and bridge designers will face.This article refers to several subjects which covers ocean engineering wave mechanics, bridge engineering, bridge hydrology and hydraulics, structural dynamics, vibration mechanics, introduction to spectral analysis and the random vibration, fluid dynamics, numerical analysis, probability statistics, structure finite element analysis, disaster prevention and mitigation engineering, fluid-structure interaction dynamics and etc. Its main research contents and achievements are shown as follows:1) Establish single degree of freedom wave force time history curve on the basis of the wave spectrum on account of the linear superposition method. Meanwhile, converting equivalent wave force numerical calculation simplification formula is established taking isolated pier cantilever beam as mechanics characteristic. By means of examples proving, wave force calculated by this simplified formula could cater for accuracy requirement which provides a convenient and simple calculation method for the random wave force research.2)Vibration response spectrum chain recursion formula changing with trigonometric function in equal time intervals is established by reference to the basic ideas of solving response spectrum interpolation method at home and abroad and combining with the characteristics of wave force time-history curve so that practical wave is simulated to do contrastive analysis on response spectrum accuracy. It shows that this method is of simplicity, speediness and accuracy which will provide effective calculating analysis method for the wave resistance design of bridge piers.3) Use full amount compensation composite inversion method for the first time to do physical parameters identification and unknown wave force inversion on bridge pier under the condition of some unknown wave input. It further deduces that wave force time-history acting on each node is approximate to be complete domain correlation leaving out wave drag force. The improved composite inversion algorithm is constructed under the condition of unknown wave input and unknown load effect on the peak combining probability "statistical averaging method" and "elimination method" with it. Through verification, this provides reference for bridge damage identification.4) In order to comprehensively discuss the force and response features of deepwater pier under various environmental load effects, fluid-structure coupling model of finite element software ANSYS is applied to analyze the wave force response of deepwater pier under the influence of earthquake, flow velocity and wind load. Additional mass and fluid-structure coupling effect are also taken into account. Analysis and comparison results show that comprehensive consideration of influences of all environmental factors on deepwater bridge pier makes structural design be safer, more economical and reasonable.5) Take the weak link chain-cutting disaster mitigation idea in the chain-styled theory of the disaster as orientation and fluid theory to be basis, this paper refers to structural wind resistance and bridge pier scour prevention mechanism, puts protective measure which protects bridge piers spanning rivers and seas from damaging of wave and other environmental loads on reducing resisting and elevating force of cylinder streaming around and proposes three pieces of measures to prevent cylinder piers from flowing around. It verifies that these three measures are effective and applicative and provide reference for wading bridge pier protection.更多还原