Study On The Pile Connection Process Of The W-beam Guardrail In Maintenance Project Of Freeway

Recently,due to the reconstruction and extension project of freeway,the height of guardrail can not meet design requirements,which led to amount of crossing guardrail traffic accident increased greatly and affect the freeway safety.Research on modification scheme of W-beam guardrail pile connection process had great significance to improve safety and reduce accident.Through a large number of researches and tests on the traditional forms of pile connection,with the construction convenience and cost of pile connection,inlaid pile connection was proved to be best choice.Based on the mechanical principle,using structural solver method and parallel test method of embedded component to analyze the mechanical properties,the structure parameters of embedding component was initially calculated out;Using the nonlinear finite element code LS-DYNA respectively to different height parapet scheme of dynamic static simulation analysis,the member of embedded component in the structure parameters are obtained;From the perspective of economy,technology and other aspects of the optimization analysis,the construction of the geometric size of the guardrail using the pile connection was finally determined.Secondly,by establishing the LS-DYNA model of truck and the structure model of the guardrail,the dynamic deformation curve and the maximum displacement value of the pile guardrail are obtained by using computer simulation;Based on Newmark theory,the theoretical model of the vehicle impact W-beam guardrail is established,and the time history analysis of guardrail collision was carried out,the displacement--time relationship model is constructed,which provides a theoretical basis for computer simulation.In the end,the load--displacement relationship curve is obtained by making static loading test on pile guardrail and standard guardrail;The pile guardrail ' s maximum dynamic deformation value of 856 mm is obtained by using pile guardrail and standard guardrail to conduct the real vehicle crash simulation test.The process flow chart of the pile connection process of W-beam guardrail is put forward in view of the manufacturing process and the characteristics of the embedded component.The application of the research results not only improves the safety of the freeway,but also saves the cost of maintenance,which embodies the concept of energy saving andemission reduction,it will produce huge economic and social benefits.In the research process,the support of the science and technology project of Hebei provincial transportation department is obtained.