基于极限状态法预应力混凝土桥枕设计方法研究

Research on Design Method of Prestressed Concrete Bridge Sleeper Based on Limit State Method

现行规范中仅对普通轨枕进行了设计方法说明,但对于带有护轨的桥枕设计还无明确规定。本文通过分析桥枕实际受力状况,建立弯矩和受力平衡方程,推导出桥枕荷载弯矩计算公式,并利用极限状态法对桥枕进行了承载力检算。结果表明:桥枕的设计弯矩值相对普通轨枕较大,对桥枕跨中和轨下有不利影响,因此在桥枕设计中不宜采用普通轨枕设计方法。采用本文推荐的桥枕设计方法,桥枕的承载力极限状态、正常使用极限状态和疲劳极限状态满足承载力的检算要求,且更加合理。

The design method of the ordinary sleeper is described only in the current specification, but there is no clear regulation for the design of the bridge sleeper with guard rail. This paper analyzes the actual stress state of the bridge sleeper, establishes the bending moment and force balance equation, derives the calculation formula of the bending moment of the bridge sleeper, and checks the bearing capacity of the bridge sleeper by the limit state method. The results show that the design bending moment value of the bridge sleeper is larger than that of the ordinary sleeper, which has an adverse effect on the middle and lower rails section of the bridge sleeper, Therefore, the design of the bridge sleeper should not adopt the ordinary sleeper design method. According to the bridge sleeper design method recommended in this paper, the bearing capacity limit state, the normal use limit state and the fatigue limit state satisfy the requirements of bearing capacity check.