Research On The Protective Ability Of Thin-walled + Concrete Combined Roadside Semi-rigid Guardrail

With the rapid development of China’s transportation construction,the demand for road safety is also increasing,and the research on road safety facilities has gradually become extensive.As an important part of road safety facilities,roadside guardrails are the last barrier to road safety,and their safety design is crucial.As a common form of expressway guardrail,corrugated beam guardrail is often used as the object of guardrail safety research,but the current related safety research is mainly through the transformation of the structural size and structural form of corrugated beam guardrail,which will lead to an increase in steel consumption,which is not in line with the current concept of green construction and development of engineering.Based on this,this thesis proposes a new type of combined guardrail with thin-walled column and concrete,that is,under the condition of reducing the thickness of the column,the corresponding protection ability of the corrugated beam guardrail is improved by combining concrete and column,which has certain theoretical and research significance for convenient construction technology and improving green engineering construction.At the same time,in order to further verify the applicability of the combined guardrail scheme,the corresponding combined scheme transformation design of SB-class and A-class corrugated beam guardrails is carried out,and the protective capacity of the traditional corrugated beam guardrail structure is compared and analyzed,and the specific research content is as follows:Firstly,through domestic and foreign literature research,the research methods,structure types and setting requirements of corrugated beam guardrails are summarized,and the finite element theory of guardrail-vehicle collision is analyzed,and the key points of automobile-guardrail model parameter setting are expounded.Then,the frontal collision simulation research of 1.5t small bus,10 T medium bus and 10 T medium truck was carried out to verify the accuracy of the vehicle model,and the accuracy of the simulation calculation results of the coupling model was verified by comparing the actual vehicle collision report data with the established guardrail-collision coupling model.In order to verify the protective performance of the thin-walled column and concrete transformation scheme design at different levels,the protective performance of the Aclass corrugated beam combined transformation guardrail and the SB-class corrugated beam combined transformation guardrail were compared with the corresponding standard guardrails,and the vehicle driving process,vehicle trajectory,center of gravity elevation value,vehicle camber value,guardrail lateral displacement,collision force and the center of gravity velocity and acceleration index of the trolley were analyzed in detail,and the specific analysis conclusions are as follows:(1)The A-class corrugated beam combined transformation guardrail can smoothly export three kinds of vehicles,meet the requirements of the expressway guardrail safety performance evaluation standard(JTG B05-01-2013),the safety indicators of cars,buses and trucks have been improved,the camber value and center of gravity lift value of the truck are significantly reduced,the guardrail system of the bus absorbs energy significantly,the degree of vehicle collision damage is lighter,and the safety of the combined modified guardrail is stronger than that of the A-class corrugated beam standard guardrail.(2)The collision process of the three models of SB-class combined transformation guardrail meets the functions of blocking,guiding and buffering(the safety performance evaluation standard of expressway guardrail).Among them,the camber value and lift value of the truck are greatly reduced,the energy absorption value of the truck guardrail system increases significantly,the speed of the center of gravity of the trolley is reduced,and the SB-level wave beam combined transformation scheme design can effectively inhibit the overturning of the truck,improve the safety of the occupants of the small bus,and the safety performance of the modified guardrail is stronger than that of the standard guardrail.(3)The design of thin-walled column and concrete transformation scheme can effectively improve the protection ability of class A and SB corrugated beam guardrails,and the combined transformation scheme has certain applicability,which can be well applied to the transformation design of corrugated beam protection capacity in actual engineering.