考虑剪切变形效应的单跨斜梁桥受力特性研究

发布时间：2018-06-11 15:49

本文选题：斜梁桥 + Timoshenko深梁理论　；参考：《长沙理工大学》2015年硕士论文

【摘要】：高等级公路及铁路线上的中、小型桥梁,往往采用服从线路走向的设计方式,将中轴线与支承线、水流方向等斜交的桥梁设计成斜梁桥。随着我国交通运输事业的迅猛发展,中、小跨径的斜梁桥结构应用越来越广泛,国内外学者也进行了广泛而深入的研究,其内力、变形等静力特性方面的研究较为系统。但以往研究的理论基础大多为初等梁理论,认为剪切效应对内力、变形的影响较小,因而被忽略。剪切效应对斜桥内力、变形的影响规律如何、如何进行力学分析,目前的研究工作还不是非常深入,值得进一步探讨。故本文基于Timoshenko深梁理论的力法及图乘法,做了以下工作:(1)建立了考虑剪切变形影响的单跨静定斜梁计算方法,推导了静定斜深梁桥在常见荷载作用下的变形计算公式,分析了一座单箱单室无悬臂斜梁桥随斜交角、平面形状、弯剪刚度比变化时剪切效应对其内力的影响规律。(2)建立了考虑剪切变形影响的单跨超静定斜梁计算方法,推导了超静定斜深梁桥在常见荷载作用下的反力、内力及变形计算公式,并对A型斜箱梁桥的跨径、斜交角、平面形状等参数进行变化,分析剪切效应对其反力、内力及变形计算的影响;得到了跨径越小、斜交角越大,剪切效应对斜梁挠度的影响越大,但对挠角和扭角的影响较小等结论。(3)针对工程上常见的四种特殊斜梁(简支正梁、平行四边形斜梁、直角梯形斜梁、等腰梯形斜梁),分析了剪切效应对其内力、变形计算的影响;提出中、小跨径斜梁桥挠度计算时应采用考虑剪切变形影响的Timoshenko深梁理论,否则低估挠度计算结果;(4)建立了考虑剪切变形与支承刚度共同影响下的斜梁桥内力计算方法,分析了剪切变形及支承刚度对斜梁桥内力计算的影响;并用有限元软件对所推导的计算公式进行了验证,得出了剪切变形与支承刚度对单跨斜梁桥内力计算的影响较小;所推导的斜深梁桥内力与变形计算公式方便设计人员的计算,有促于推动斜桥计算理论的深化和拓展,丰富斜梁的计算方法。
[Abstract]:Medium and small bridges on high grade highways and railway lines are often designed by the way of design from line to line. The bridge with skew intersection of central axis and supporting line and direction of water flow is designed into oblique beam bridge. With the rapid development of transportation in China, the small span oblique beam bridge structure is more and more widely used. Scholars at home and abroad have also carried out extensive and in-depth research, its internal force, deformation and other static characteristics of the research is more systematic. However, most of the previous studies are based on the elementary beam theory, and it is considered that the shear effect has little effect on the internal force and deformation, so it is neglected. The influence of shear effect on the internal force and deformation of the inclined bridge and how to carry out mechanical analysis are not very deep at present, so it is worth discussing further. Therefore, based on the force method and graph multiplication of Timoshenko deep beam theory, the following work is done: 1) the calculation method of single-span statically indeterminate oblique beam considering the effect of shear deformation is established, and the formula for calculating the deformation of statically inclined-deep beam bridge under common loads is derived. In this paper, the influence of shear effect on the internal force of a single-box single-chamber non-cantilever beam bridge with the angle of skew, plane shape and the ratio of bending to shear stiffness is analyzed. The calculation method of single-span statically indeterminate oblique beam considering the effect of shear deformation is established. The formulas for calculating the reaction force, internal force and deformation of a statically indeterminate skew deep beam bridge under common loads are derived. The parameters such as span, diagonal angle and plane shape of A type inclined box girder bridge are changed, and the reaction force of shear effect on the bridge is analyzed. The results show that the smaller span, the greater the angle of oblique intersection, the greater the influence of shear effect on deflection of skew beam, but the less effect on deflection angle and torsion angle of skew beam. In this paper, the influence of shear effect on the calculation of internal force and deformation of skew beam with parallelogram, right angle trapezoid beam and isosceles trapezoid beam is analyzed, and the Timoshenko deep beam theory considering the influence of shear deformation is put forward in the deflection calculation of small span skew beam bridge. Otherwise, the calculation results of undervalued deflection are as follows: (1) the calculation method of internal force of oblique beam bridge considering the influence of shear deformation and supporting stiffness is established, and the influence of shear deformation and supporting stiffness on the calculation of internal force of oblique beam bridge is analyzed. The calculation formula is verified by finite element software, and it is concluded that shear deformation and supporting stiffness have little influence on the calculation of internal force of single-span inclined beam bridge, and the deduced formula is convenient for designers to calculate the internal force and deformation of inclined deep beam bridge. It promotes the deepening and expanding of the theory of skew bridge calculation and enriches the calculation method of skew beam.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441

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