Improving Measures for Transition Sections of Barriers at Tunnel Entrances in Expressways

The semi-rigid barriers were generally used in tunnel entrance. When impact occurred, some deformation of facilities could cause vehicles’ rolling or impacting on tunnel wall, effective protection would not be provided. New transition structures combining connection sections with strengthen lap beams between standard barriers and tunnel were set to solve the above problems. According to new standards, crash simulation tests were analyzed, which small passenger car, medium truck and bus with impact angle (20°) and impact velocity on transition structures. By analyzing vehicle tracks, the buffering and redirective performances, maximum dynamic lateral deflection (D), the maximum dynamic widening distance of lateral deflection (W), and maximum dynamic vehicle incline-out distance (VI), the results showed that the improved barriers with transition structures met the anti-collision requirements.