Research On Cable Guardrail Applied To Mountain Expressway

Road accident has become a headache problem in worldwide.With the vigorous development of China's transport,the accidents also grow rapidly. As an important traffic safety facilities of expressway,guardrail plays a key role in reducing the damage and property losses of road accident.At present,the guardrail form commonly used is rigid guardrail and semi-rigid guardrail.For cable guardrail,seldom research has been carried on,may it can be say no study have been conducted.So the relative specification is mostly based on foreign studies and the experience gained from the using of some expressway.In this paper,firstly give a summarization of the phylogeny,current research situation and commonly used research method of road side barrier,then make a decision for the content of this paper.I choose a digital simulation method as the research direction for this paper,by FEA software LS-DYNA,I give the mainly factor that should be considered in structure design through changing the structure parameter.Analyzing the results,it founds that the maximum dynamic displacement of the guardrail is an important criterion to evaluate the roadside barrier,during the impacting process .it changes with the space between the posts,the initial tension stress of the cable and the guardrail's installation length.it is sensitive to the first factor,then to the cable's initial stress,and the sensitivity to the installation length less than formers.When reference to the maximum acceleration,it's sensitive to all the factors above.Also the impacting force is another important indicator to evaluate the guardrail,for it's directly affluent the vehicles'damage and people's safety.The results reflect the impacting force far less than the car impact to a rigid guardrail with same kinetic energy.During the impact process,most of the car's kinetic energy convert into the guardrail's internal energy and seldom other energy forms were converted.The internal energy of the guardrail is mainly distribute by the post and cable,and the distribution not sensitive to the factor above.In the figure of resultant force,we found that the value changed with the initial condition and far less than that of a vehicle impact rigid guardrail.To sum up, when designing a cable guardrail,it should consider the space between the post first then the cable's initial stress and then the installation length.Some accident-prone sections of the mountains expressway which have sufficient clearance to install cable guardrail will play better security results.