简支变连续桥梁配筋方案比较

Comparison of Different Arrangements of Reinforcements in Bridges Transforming from Simply-Supported into Continuous Girders

简支变连续桥梁随着施工进展而发生体系转换,且兼具简支梁和连续梁的特点而导致其正负弯矩区的配筋形式多种多样。采用有限元软件对一座三跨简支变连续梁桥进行计算分析,对正负弯矩区配筋量不同的三种方案,从应力状态、成桥初期及10年徐变弯矩和应力、截面承载力三个方面进行比较,找出了应力、弯矩分布均匀,截面承载力较高的配筋方案,并对该体系的配筋提出一种实用简便的方法,即由构件截面抗裂性控制配筋,适当调整正负弯矩区预应力钢筋量,最后验算其截面承载力。

Transformation is usually occurred with the construction process and the characteristics of simply supported and continuous beams are shared for bridges transforming from simply-supported into continuous girders,which will result in a variety of arrangements of reinforcements in positive and negative bending moment regions.Numerical simulation of a three span bridge transforming from simply-supported into continuous girders was carried out by the finite element software.The stress situation,moments and stresses when erected and after ten years,and bearing capacities of three proposals with different reinforcements were compared.The scheme inducing well distributed stresses,moments and high bearing capacities was found out,a useful method for the arrangement of reinforcements was proposed,that is,the arrangement of reinforcements is firstly controlled by members＇ crack resistance,then the quantities of reinforcement in positve and negative moment bending regions are adjusted,finally bearing capacity is checked.