D型施工便梁动态特性的有限元分析

研究目的:D型施工便梁常作为一种临时结构加固既有线路,《铁路工务安全规则》中规定列车通过便梁时限速45 km／h,而实际上为减少施工对运输的干扰,往往需将限速值提高至60 km/h及以上。本课题为其提供理论依据。研究方法:运用有限元的分析方法,通过建立数学模型,对使便梁所受载何进行力学分析。研究结论:便梁在实际荷载作用下实测的竖向挠度值与利用本研究方法在考虑了冲击系数后得到的计算结果十分接近;便梁跨中横向位移实测结果与计算结果也十分接近,略小于计算值;实测D24便梁的频率为 3．723 6 Hz,比理论计算结果大8．8％,便梁具有足够的刚度。

FINITE-ELEMENT ANALYSIS OF DYNAMIC CHARACTERISTICS OF TEMPORARY BEAM MODEL D FOR CONSTRUCTION

Research purpose: The Temporary Beam Model D for construction is often as temporary str(?)eture for reinforcing existing railway line. The sped of train is limited to 45 km/h on the temporary beam aecording to the rule stipulated in "Rules of Railway Engineering and Maintenance Safety" , but in fact, the speed of train on the temporary beam is often increased to 60 km/h or more in order to reduce the influence on traffic by construction. This research is for providing theoretical basis for speed-raise. Research method: The mechanics analysis is made to the load born by temporary beam by adopting the method of finite-element analysis and establishing mathematics model. Research conclusion: The vertical deflection value of temporary beam under effect of real load is very close to the calculated result after considering the impact factor by adopting the research method. The sample result of displacement in span of temporary beam is also very close to the calculated result, only a little smaller than the calculated result. The freauency of sample D24 temporary beam is 3.7236 Hz and is larger than theoretically calculated result by 8.8 percent. Therefore, it shows the temporary beam has enough rigidity.