Laboratory Simulation Test Planning And Equipment Research On Post-foundation Relationship Of Road Anti-collision Structure

The safety performance of the anti-collision structure is uncertain in practical application which caused by detecting the relationship between guardrail post and foundation of the road anti-collision structure difficultly.In order to solve the difficulty,on the basis of learning from foreign mature dynamic impact test technology of anti-collision structure post,methods and related equipment for laboratory and finite element simulation test,which is for the relationship between post and roads in the road anti-collision structure,were researched based on the large structure crash center of Changsha University of Science and Technology and the standard Safety Performance Evaluation Criteria of Highway Barriers and Design Rules for Highway Traffic Safety Facilities.In addition,using finite element crash analysis method and moment equivalent method to plan the laboratory simulation test of the post-foundation relationship for the road anti-collision structure.Firstly,taking the relevant parameters of test vehicle in standards JTG B05-01-2013 and NCHRP Report 350 as reference,and taking the design concept of private customization of Industry 4.0 integrating into the new bogie design which is for dynamic impact test of the road anti-collision structure,then the limit condition of new bogie and the comparison to traditional bogie are analyzed by the finite element crash analysis.Secondly,considering the difference between central separation strip and the roadside installation environment of anti-collision structures in highway,researches on post-foundation laboratory and finite element simulation method was carried out base on the new bogie respectively,and the finite element crash analysis was performed on the relationship of post-foundations under different posts and different foundations.Finally,on the basis of the laboratory and finite element simulation method for the anti-collision structure post-foundation relationship,the collision performance of different actual vehicles to road anti-collision structures posts was studied,and the collision between the actual vehicles and the posts were equivalent to the new bogie using the moment equivalent method which is for planning the laboratory simulation test of the anti-collision structures post-foundation relationship under different grades.This study obtains the following conclusions:(1)The best way to research the relationship between posts and foundations of anti-collision structures is dynamic impact test,and the preferred test equipment for test is the new bogie with variable mass.(2)The new bogie with variable mass,which can be adjusted in the range of 1.1t to 1.8t according to test requirements,is designed based on the private customized design concept,it can complete the dynamic impact test for all post of anti-collision structure in the standard and the frontal crash test with the maximum collision speed of 100 km/h for other anti-collision structures which has good crashworthiness and applicability.(3)When carrying out the laboratory and finite element simulation test for post-foundation of central separation strip anti-collision structure,cylindrical foundation with diameters and depths of at least 3000mm and 2010mm should be established;and from simulation test we find that the relationship of concrete post-foundation is firmest and the rigidity of the rectangular post is maximum.(4)When carrying out the laboratory and finite element simulation test for post-foundation of roadside anti-collision structure,slope foundations with a slope of 1:1.5 should be established with a minimum length and width of 4000 mm and a depth of at least 2500 mm;and from simulation test we conclude that the relationship of post-foundation in central separation strip is stronger than the roadside under same conditions.(5)The laboratory simulation test planning table for post-foundation with different protective grades for central separation strip and roadside are obtained based on the new bogie.The laboratory and finite element simulation test method and planning based on the new bogie for the post-foundation relationship can study the anti-collision structure of highway scientifically and specifically,and can provide powerful support for solving the difficulty of uncertain safety performance of the anti-collision structure that caused by difficult detection in the constraint relationship of post-foundation in practical applications,and be of practical significance to improve the road traffic safety.