【作者】 王剑；

【导师】 许颖； 吴红军；

【作者基本信息】 哈尔滨工业大学 ， 土木工程， 2010， 硕士

【摘要】 预应力混凝土连续曲线梁桥以占地面积小、线形流畅、造型优美、意境生动等优点在立交桥、高速公路及高架桥等实际工程中被广泛运用。而曲线梁桥因曲率的存在,导致结构体积重心偏心,产生弯扭耦合作用,使得其力学性能和变形与直线梁桥相比更为复杂。由于缺少可靠的理论分析和完善的技术规范,曲线梁桥多次在施工及运营中出现固结墩墩身开裂、梁端翘曲、梁体向弯道外侧“爬移”、梁体与支座脱离(即“支座脱空”)、垮桥等病害现象。本课题以深圳市梧桐山立交桥工程为背景,研究曲线梁桥以直代曲的判别条件和多因素综合分析。以直代曲就是将曲线梁桥展开,按照中心线长度一致的直线桥进行设计计算的方法。本文对以直代曲判别条件进行研究,简化了曲线梁桥的设计过程,并提供了以直代曲判别公式。另外,本文多因素综合分析研究了曲线梁桥的最不利荷载组合,为在设计过程中设计荷载的取值提供了一定的理论依据,也为曲线梁桥规范的制定和完善提供依据。本文的研究内容和主要成果如下:(1)分别分析曲线梁桥的桥面宽、半径、桥长和桥墩高这四个几何参数对曲线梁桥力学性能和变形的影响。得出本论文以直代曲的研究方法是寻找一个临界半径R临界,当实际曲线桥梁的设计半径小于R临界时,不能以直代曲;当实际曲线桥的设计半径大于或等于R临界时,能够以直代曲。(2)在最大主压应力5%和10%风险控制率下,求得在已知桥面宽、桥长和桥墩高条件下的能够以直代曲的临界半径,数值拟合出适用于三跨曲线梁桥的以直代曲判别公式。并用此判别公式与国内外权威的以直代曲研究成果进行对比,验证其对单跨和三跨曲线桥的正确性。得出5%风险控制率的判别公式对单跨和三跨曲线梁桥的适用性较好,10%风险控制率的判别公式不适用于单跨曲线梁桥,对三跨曲线梁桥的适用性较好。(3)在多因素综合分析中,把曲线梁桥经常受到的荷载进行荷载组合,求得最不利荷载组合工况及各荷载单独作用产生的力学效应所占最不利荷载组合产生力学效应的比例。按承载能力极限状态基本组合设计时,改变半径,汽车荷载产生的峰值扭矩的变化小于其他荷载产生的峰值扭矩的变化;改变桥墩预偏心,重力+附加扭矩产生的峰值扭矩的变化小于其他荷载产生的峰值扭矩的变化。按正常使用极限状态作用短期效应组合设计时。改变半径,预加力产生的峰值扭矩的变化小于其他荷载产生的峰值扭矩的变化;改变桥墩预偏心时,重力+附加扭矩产生的峰值扭矩的变化小于其他荷载产生的峰值扭矩的变化。更多还原

【Abstract】 Prestressed concrete continuous curved girder bridge with small footprint, linear smooth and elegant, vivid conception and so on advantages in overpass, highway and viaduct is widely used in practical projects. However because of radius of curvature curved girder bridge results eccentric of structural volume center of gravity, leads to the coupling effect of bending and torsion, and makes its mechanical properties and deformation more complex than straight bridge.The absence of reliable theoretical analysis and perfect technical specifications, in the construction and operations curved girder bridge appears so many times consolidation Pier Body cracking, end of the beam warping, beam“climb shift”to the outside corner, beam and bearing voiding(that is“bearing separation)bridge collapsing and so on bridge diseases. The topic makes Shenzhen Wu tong Mountain Interchange Project as the background, analysis of formula of how to replace the curved girder bridge by the straight bridge and comprehensive analysis of multi-factor. The meaning of replacing the curved girder bridge by the straight bridge is that curved girder bridge will be unfolded, design and calculate in accordance with straight bridge that has the equivalent centerline length. In this text, I analysis the criterion of replacing the curved girder bridge by the straight bridge in order to simplify the design process of curved girder bridge and provide a discriminant formula of replacing the curved girder by the straight bridge. In addition, in the comprehensive analysis of multi-factor I combine the load which curved girder brider is often taken in order to provider a theoretical basis of values of design load in the design process and a basis of specification formulating and improvement for curved girder bridge. The contents and main results of this study as followings:(1) This topic firstly analysis the influences that the four geometric parameters to the mechanical properties and deformation of curved girder bridge. The method of replacing the curved girder by the straight bridge is finding a critical radius Rcritical. When the design radius is less than Rcritical, it can not replace the curved girder by the straight bridge. When the design radius is greater than or equal to Rcritical, it can replace the curved girder by the straight bridge.(2) Under the risk control rate of the maximum principal stress is equal to 5% and 10%, I obtain the critical radius with the known bridge width, bridge length and high of bridge piers, then numerical fit formula for replacing the curved girder bridge by the straight bridge. Above formulas only fit to three-span curved girder bridge. Finally I verify the formula of this topic compared with the authoritative research results of replacing the curved girder bridge by the straight bridge. The formula under 5% the risk control rate apply well to single-span and three-span curved girder bridge. The formula under 10% the risk control rate do not apply to single-span curved girder bridge but apply well to three–span curved girder bridge.(3) In the comprehensive anysis of multy-factor, I combine the load which curved girder bridge is often taken, then obtain the worst load combination and a ratio that the mechanical effect of a alone load dividing mechanical effect of the worst load combination. When according to the design of basic combination of the carrying capacity ultimate state, changing the radius, the change of peak torque generated by vehicles load is less than the change of peak torque generated by other loads; Change the pre-eccentric pier, the change of peak torque generated by gravity + additional torque is less than the change of peak torque generated by other loads. When according to the design of the design of short–term effect combination of the normal use limit state, changing the radius, the change of peak torque generated by pre-tension is less than the change of peak torque generated by other loads; Change the pre-eccentric pier, the change of peak torque generated by gravity + additional torque is less than the change of peak torque generated by other loads.更多还原