【作者】 丁凯；

【导师】 程永春；

【作者基本信息】 吉林大学 ， 工程硕士（专业学位）， 2018， 硕士

【摘要】 为了使截面抗力分配合理,并兼顾桥梁外观,桥梁结构通常被修建成各种各样的变截面形式,变截面形式的多样性决定了桥梁结构理论计算的复杂性。由于动力荷载试验具有客观性强、不会引起附加损伤以及能够发现隐蔽部位病害等优点;且动力特性对桥梁结构的损伤具有一定的敏感性,因此,基于动力特性的桥梁状态评估备受人们的青睐。在简支梁桥的动力荷载试验中,以获得良好的激振效果,往往采用车辆对其进行激振(例如跳车试验和跑车试验)。有关研究资料表明:车辆作用会导致桥梁结构的动力特性发生变异,这种变异甚至会掩盖桥梁损伤导致的动力特性变化。因此,对车辆作用下的桥梁动力特性进行分析,并准确把握其变异规律显得尤为重要。由于桥梁在服役期间需要经受移动车辆的往复作用,在以静力分析为基础的桥梁设计中需要考虑移动车辆引起的动力效应。再者,桥梁结构的动力响应也是评定桥梁服役性能的一项重要指标。因此,对车辆作用下的桥梁动力响应进行计算意义重大。综上所述,开展车辆作用下变截面简支梁桥动力特性及动力响应分析的研究工作具有重要的理论意义和很强的工程应用价值。本文开展的具体研究工作如下:1、基于传递矩阵法的基本原理,建立了任意变截面形式的简支梁桥的动力特性计算模型,提出采用龙格-库塔和半区间迭代法来求解动力特性。2、建立了车辆作用下变截面简支梁桥自振频率的计算方法,讨论了车体质量、悬架质量、悬架刚度和车轮刚度对简支梁桥频率的影响规律,并剖析了车辆对桥梁频率的影响机理。3、采用三次样条插值方法把离散振型数值转化为连续的振型函数,基于模态叠加法的基本原理,建立了移动车辆作用下变截面简支梁桥的分析模型,并形成了其求解方法。基于建立的分析模型,探讨了不平整度、车速、车体质量、悬架刚度以及车轮刚度对简支梁桥冲击系数的影响规律。更多还原

【Abstract】 Bridge structures are usually designed to variable cross-section forms for the bridge appearance and reasonable distribution of cross-section resistance,whose diversity determines the complexity of the bridge structural theoretical calculation.As dynamic load test has the advantages of strong objectivity,no additional damage,finding hidden disease and so on,and dynamic characteristics has a certain sensitivity to the bridge structural damage,dynamic characteristics have been widely used for bridge condition assessment so far.Traffic-induced excitation,such as vehicle bump test and vehicle travelling test,is often adopted to obtain good dynamic results for simply supported beam.The previous researches show that traffic will lead to variation in dynamic characteristics of bridges,which may completely cover the variation caused by structural damage.Thus,it’s necessary to analyze the dynamic characteristics of bridge under vehicle and its variation pattern.Besides,due to the repeated actions of moving vehicles during the bridge service,bridge design based on static analysis needs to consider the dynamic response by moving vehicles,which is also an important index to evaluate the bridge service performance.Therefor,it’s of great importance for analyzing dynamic response of bridges subjected to vehicles.In summary,study on dynamic characteristics and response of simply supported bridge with variable cross section subjected to vehicle action has important theoretical significance and high engineering application value,the main research in this paper has been carried out as follow:1.Dynamic characteristic calculation model of simply supported bridge with arbitrary variable cross-section is established based on transfer matrix method and dynamic characteristic could be solved by Runge–Kutta method and half interval iterative method.2.An approach to natural frequency of simply supported bridge with variable cross-section under vehicle action is presented.Then the influences of vehicle mass,sprung mass,suspension spring constants and tyre stiffness coefficients on the natural frequency are discussed and the influence mechanism is also analyzed.3.Cubic spline interpolation method is adopted to make the discrete mode data into continuous modal function.By using the mode summation method,the analysis model of simply supported bridge with variable cross-section subjected to a moving vehicle is established and solved.Next,the influences of roughness,speed,vehicle mass,suspension spring constants and tyre stiffness coefficients on the impact coefficient of simply supported bridge are also discussed.更多还原