混凝土连续曲线箱梁桥内力与设计参数因素研究

发布时间：2018-08-14 09:07

【摘要】：预应力混凝土曲线梁桥由于其线型优美且与环境协调、经济性好、抗扭刚度大等一系列优点已经成为现代交通工程中一种重要的桥型。但在营运过程中也出现了大量的病害，恶性事故频有发生。因此对连续箱梁桥的力学性能的研究非常必要。本文首先讨论了弯桥的几种基本理论与计算方法，包括弗拉索夫弹性薄壁结构理论，平面曲梁的平衡微分方程，力与应变关系的圆弧微分方程等。然后采用结构有限元理论基础，以某一座实际工程中的曲线梁桥为例，利用有限元分析程序建立结构模型，采用单参数影响分析法对影响曲线梁桥的几个重要因素（曲率半径，支撑方式，支撑偏移，预应力钢绞线张拉顺序等）进行分析计算比较与归纳。具体内容如下： 1）通过对不同曲率半径的曲线梁桥进行计算分析可知，曲率半径越大，曲线梁桥y方向的位移会减小，最大主拉应力有所减小，最大主压应力有所增大。支座的受力也更加均匀合理。故在做曲线梁桥设计时，尽量采用曲率半径比较大的曲线。这样不仅桥梁美观，其受力也会更加合理。 2）通过对不同支撑方式的曲线梁桥进行对比分析，可以得出抗扭支撑与点铰支撑相比其z方向最大挠度值减小20.6%，，最小挠度值的绝对值减小43.3%。这说明设置抗扭支撑可以有效控制曲线梁桥的竖向变形。另外点铰支撑桥台支座会受到更大的扭矩。而且，相对点铰支撑，抗扭支撑梁体内力值也会更加均匀。 3）通过对曲线梁桥点铰支撑偏移与抗扭支撑偏移可以得出，对于本桥，若跨中采用点铰支撑则向外偏移25cm左右最为合适。此时桥台支座所受到的扭矩与支反力最为均匀，差值最小。曲线梁桥y方向变形也有一定程度地减小。若跨中采用抗扭支撑，支座偏移对曲线梁扭矩内力有一定影响，对其余因素无明显影响，考虑扭矩因素向外偏置15cm比较合适。 4）通过模拟曲线梁桥施工阶段预应力钢绞线不同张拉顺序，可以得出不同张拉顺序对主梁最大主拉应力有一定影响，对其余因素无明显影响。综合考虑，建议此曲线箱梁桥采用先外侧后内侧的张拉顺序。
[Abstract]:The prestressed concrete curved girder bridge has become an important bridge type in modern traffic engineering because of its good alignment and coordination with the environment, good economy, high torsional stiffness and so on. However, a large number of diseases also appear in the course of operation, and malignant accidents occur frequently. Therefore, it is necessary to study the mechanical properties of continuous box girder bridge. In this paper, several basic theories and calculation methods of curved bridge are discussed, including Vlasov elastic thin-walled structure theory, equilibrium differential equation of plane curved beam, circular arc differential equation of the relationship between force and strain, etc. Then, based on the theory of structural finite element, taking a curved beam bridge in a practical project as an example, the structural model is established by using finite element analysis program, and several important factors (radius of curvature) affecting the curved beam bridge are analyzed by single parameter influence analysis method. Support mode, support offset, tension sequence of prestressed steel strands, etc.) are analyzed, compared and summarized. The main contents are as follows: 1) through the calculation and analysis of curved girder bridges with different radius of curvature, it can be seen that the larger the radius of curvature, the smaller the displacement in the y direction and the smaller the maximum principal tensile stress of the curved girder bridges. The maximum principal compressive stress increases. The bearing force is more even and reasonable. Therefore, in the design of curved girder bridge, the curve with larger radius of curvature should be used as far as possible. In this way, not only is the bridge beautiful, but its force will also be more reasonable. 2) through the comparative analysis of curved girder bridges with different supporting modes, It can be concluded that the maximum deflection value in z direction and the absolute value of minimum deflection value in torsional bracing are reduced 20.6and 43.3% respectively compared with point hinge bracing. This shows that torsional bracing can effectively control the vertical deformation of curved girder bridge. Another point hinge support abutment support will be subjected to greater torque. Moreover, the force value of torsional bracing beam will be more uniform than that of point hinge bracing. 3) it can be obtained from the offset of point hinge support and torsional bracing of curved girder bridge. If point hinge bracing is adopted in the middle of span, the 25cm is most suitable to shift outward. At this time, the bridge abutment bearing is subjected to the most uniform torque and supporting reaction force, and the difference is minimum. The y direction deformation of curved girder bridge is also reduced to a certain extent. If torsional bracing is adopted in the middle of the span, the bearing offset has a certain influence on the internal force of the torque of the curved beam, but has no obvious effect on the other factors. Considering the torque factor, it is more appropriate to bias 15cm out. 4) by simulating the different tension sequence of prestressed steel strand in the construction stage of curved girder bridge, it can be concluded that different tension sequence has certain influence on the maximum main tensile stress of the main girder. There was no significant effect on other factors. Considering comprehensively, it is suggested that this curved box girder bridge should use the tension sequence of the first outer side and the inner side.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.5;U448.213

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