Study Of Guardrail Under Impact Load

As an important traffic safety facility, w-beam guardrail is the most widely used at present. But the specification of w-beam guardrail is mostly confirmed referring to foreign similar specifications, and the level of guardrail don’t achieve the optimum, and concrete foundation of guardrail is set up by virtue of experience. Based on these problems, this thesis study the design about concrete foundation of guardrail by means of theoretical analysis and study the influence of guardrail components variation on guardrail performance by means of computer simulation experiment. The main research work is as follows:(1) Referring to Japanese specification and ensuring sliding stability of post after vehicle’s collision, the design method of concrete foundation coinciding with w-beam guardrail stipulated in our country’s specification was established.(2) A dynamic analysis model simulating vehicle-guardrail collision was established taking material nonlinearity and complicated contact between components into account. The dynamic response of w-beam guardrail under certain conditions was computed using the dynamic analysis model.(3) The performance of guardrail was analyzed from several aspects of energy absorption characteristics, vehicle running track and collision damage of wave plate. Results show that except for the standard w-beam guardrail, guardrail with plate thickness3.5mm and guardrail with post thickness4.0mm satisfies performance evaluation criterion, and the new-type block designed can make guardrail have better performance.(4) Comparing with the standard w-beam guardrail, material cost of guardrail with plate thickness3.5mm and guardrail with post thickness4.0mm economize by12.5%and11.2%respectively. The material cost of guardrail with new-type block designed is equivalent to that of standard guardrail.The research achievements presented in this thesis not only provide reference for setting up reasonable foundation of w-beam guardrail, but also provide reference for design optimization and specification revision of w-beam guardrail.