Simulation Of Collision Safety Erformance Of New Double-beams Guardrail Used On Central Separate Belt Of Expressway

Central median guardrail is a highway traffic safety measures and an important guarantee for the safety of the car. Currently separate unilateral guardrail is widely used. However foreign countries have large-scale application of the combined guardrail. The design of combined guardrails which meets the China’s national conditions has a very realistic meaning. The main work of this paper is as follows:(1) Two modular guardrails are designed and the collisions are simulated. The finite element models of two types of guardrail and a bus model are established by FEM which based on the protective performance requirement of guardrail Am stipulated in the relative bus collision specification. Although the collision simulation results of combined guardrail which meet old standard meet the security evaluation criteria,collision occurred straddle phenomenon and the combined guardrails which meet old standard did not meet the safety standards. The combined guardrails which meet new standard meet the safety standards.(2) Because the combined guardrails which meet old standard did not meet the safety standards. This paper proposed three guardrails reinforcement schemes: thickening wave beam、adding horizontal beams、increasing the column. Crash simulations of these schemes are completed. According to the simulation results, three improvement programs have improved the risk of snagging and straddle phenomenon,reaching a standard of vehicle collision. The reinforcement schemes of thickening wave beam and adding horizontal beams have reached the target and especially the scheme of adding horizontal beams has better economic efficiency.(3) The effect of column spacing on security of guardrail is analyzed. For newly-built guardrail, the impact of column spacing including 2.4m,2.8m,3.0m,3.1m,3.2m,3.6m to defensive capability is analyzed. The results showed that as the column spacing increases guardrail crash performance decreases and column spacing from 3.1m to 3.2m is a range that guardrail is qualified to unqualified.Analytical methods and conclusions mentioned in the paper have reference value about further optimization design of the modular fence.