预应力混凝土斜交连续箱梁设计

发布时间：2019-01-19 19:47

【摘要】：研究目的:娄底市共荣路上跨娄邵铁路采用(25+40+25)m预应力混凝土斜交连续箱梁,斜交角度为55°,支架现浇施工方法。由于该梁桥面较宽,斜交角度较大,为了对实际结构进行更准确的模拟,本文采用空间梁格及平面单梁两种有限元分析方法对预应力混凝土斜交连续梁进行对比分析研究。研究结论:(1)为方便预应力混凝土斜交连续梁设计,建议采用单梁法设计,空间梁格法进行验证;(2)大角度斜交连续梁跨中最大正弯矩和中支点负弯矩在恒载作用下均小于正桥,但剪滞效应比正交箱梁更为显著,设计时必须充分考虑其剪滞效应;(3)斜交连续梁钝角边侧支点反力比锐角边侧支点反力要大15%左右,设计时特别注意支座的选择及下部结构设计;(4)为增加各箱室之间横向刚度,建议在边跨及中跨设置几道横隔板;箱内可采用两次倒角使其不出现锐角,以消除应力集中现象;梁体建议采用全预应力结构设计,并将梁体普通钢筋适当加强;(5)本研究结论可为预应力混凝土大跨度斜交连续梁桥设计提供参考。
[Abstract]:Research purpose: the continuous box girder of (25 4025) m prestressed concrete skew continuous box girder is adopted in Tongrong Road, Loudi City, with an angle of 55 掳, and the construction method of cast-in-place support is adopted. In order to simulate the actual structure more accurately, the prestressed concrete skew continuous beam is studied by two finite element analysis methods, spatial beam lattice and plane single beam, because of its wide deck and large skew angle. The conclusions are as follows: (1) in order to facilitate the design of prestressed concrete skew continuous beams, the single beam method is recommended, and the spatial beam method is used to verify the design; (2) the maximum positive moment in span and negative moment of middle fulcrum of large-angle skew continuous beam are smaller than that of positive bridge under dead load, but the shear lag effect is more obvious than that of orthogonal box girder, so the shear lag effect must be fully considered in design. (3) the reaction force on the side of obtuse side of oblique continuous beam is about 15% greater than that on the edge of sharp angle, so special attention should be paid to the selection of support and the design of substructure. (4) in order to increase the transverse stiffness of each box room, it is suggested that several transverse spacers should be arranged in the side span and the middle span, and two chamfering angles can be used to avoid the sharp angle in order to eliminate the stress concentration phenomenon. It is suggested that the whole prestressed structure should be designed and the normal reinforcement should be strengthened properly. (5) the conclusion of this study can be used as a reference for the design of prestressed concrete long-span skew continuous beam bridge.
【作者单位】：中铁第四勘察设计院集团有限公司;
【分类号】：U448.35

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