三跨变截面波形钢腹板连续梁桥挠度及动力特性分析

发布时间：2018-04-04 23:13

本文选题：波形钢腹板　切入点：剪力滞　出处：《兰州交通大学》2017年硕士论文

【摘要】：波形钢腹板箱梁桥作为一种新型钢混组合结构在国内外使用频率越来越高。其拥有很多优点,诸如结构自重低、预应力施加效率高、施工简便、跨越能力突出以及造型美观等。从20世纪80年代这种结构首先在法国出现以后,很快便得以在日本德国等国家得到推广,相应的研究也逐步深入。近年来,国内也出现大量的该类型箱梁桥。随着桥梁结构愈加复杂化,所需研究内容也大大增加。本文以国内一座大跨度变截面波形钢腹板连续梁桥为依托进行了一些研究。主要内容是在考虑剪切变形及剪力滞效应的共同作用下,对波形钢腹板大跨度变截面连续梁挠度计算方法的探讨。研究的过程主要运用到能量变分法对其挠度计算公式进行了推导,并对波形钢腹板截面惯性距的计算方法进行了简化。同时使用ANSYS软件建立三维有限元模型对该计算方法进行了验证。最终结果表明,该计算方法能较为准确的求解出荷载作用下箱梁各位置处挠度,能为施工设计起到指导作用。本文还对波形钢腹板箱梁的动力特性进行了研究,并分别建立梁单元与实体单元模型,对比分析了各自的特点。通过对比实体模型与梁单元模型后我们可以知道,在满足工程精度要求的前提下,计算箱梁自振特性时可以用工程师熟练掌握的梁单元建立模型而不必用建立复杂的实体模型,梁单元模型同样能够达到较为精确的结果。此外,还建立了跨径布置相同的普通腹板箱梁。对两者的自重、墩顶和跨中弯矩、截面特性以及动力特性进行了对比分析。结果表明普通混凝土箱梁相比波形钢腹板梁体自重减轻了约20%,跨中最大正弯矩降低11.7%,墩顶最大负弯矩降低20.7%,这有利于提高结构经济性。两者的纵横向抗弯刚度相差都不是很大,但是抗扭刚度降低较多,需要特别注意。并研究跨中横隔板对于抗扭刚度的影响,得出其虽然能够提高结构抗扭性能但是提高幅度有限的结论。在对自振频率进行研究后发现,波形钢腹板箱梁扭转频率主要发生在高阶,高于结构主频,可认为其仍旧具有较高抗扭刚度。
[Abstract]:As a new type of steel-concrete composite structure, box-girder bridge with corrugated steel web is used more and more frequently at home and abroad.It has many advantages, such as low weight of structure, high efficiency of prestress application, simple construction, outstanding span ability and beautiful shape.Since the first appearance of this structure in France in the 1980s, it has been popularized in Japan and Germany, and the corresponding research has been gradually deepened.In recent years, there are a large number of box girder bridges in China.With the increasing complexity of bridge structure, the research content is greatly increased.In this paper, a large span corrugated steel web continuous beam bridge with variable cross section is studied.The main content of this paper is to discuss the deflection calculation method of long-span continuous beam with variable cross section of corrugated steel web under the joint action of shear deformation and shear lag effect.The calculation formula of deflection is deduced by energy variational method, and the calculation method of inertia distance of corrugated steel web section is simplified.At the same time, the three-dimensional finite element model with ANSYS software is used to verify the method.The final results show that the calculation method can accurately calculate the deflection of the box girder under load, and can play a guiding role in the construction design.The dynamic characteristics of corrugated steel web box girder are also studied in this paper. The model of beam element and solid element are established, and their characteristics are compared and analyzed.After comparing the solid model with the beam element model, we can know that, on the premise of meeting the requirement of engineering precision, the model can be established by using the beam element which the engineer is familiar with, but not the complicated solid model, when calculating the natural vibration characteristics of the box girder.The beam element model can also achieve more accurate results.In addition, the common web box girder with the same span arrangement is also established.The weight, bending moment of pier top and span, cross-section characteristic and dynamic characteristic are compared and analyzed.The results show that compared with corrugated steel web beam, the weight of ordinary concrete box girder is reduced by about 20 percent, the maximum positive moment of span is reduced by 11.7m and the maximum negative moment of pier top is reduced by 20.7. this is beneficial to improve the structure economy.The difference of longitudinal and transverse flexural stiffness is not very big, but the torsional stiffness is much lower, so special attention should be paid to it.The effect of straddle plate on torsional stiffness is studied, and the conclusion is drawn that although it can improve the torsional performance of the structure, the range is limited.It is found that the torsional frequency of the corrugated steel web box girder mainly occurs in higher order, which is higher than the main frequency of the structure, so it can be considered that it still has high torsional stiffness.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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