Abstract：To improve traffic safety of continuous long downgrade section in expressway, one type of combined barrier was designed with an energy-absorbing steel pipe settled along the steel beam, which had the double function of crashworthiness and vehicle speed-reducing. Based on the design of flange slab for local bridge, the anchoring strength was checked for barrier foundation and the flange slab was strengthened through the additional steel bars in the deck. Full-scale impact tests were conducted to validate safety performance of this barrier. The crashworthiness of this barrier can reach SS level. The energy absorbing pipe deforms while vehicles pass along this barrier. The vehicle kinetic energy is changed into internal energy of energy absorbing pipe and the speed of vehicle is reduced effectively. Because of the settlement of energy absorbing pipe the steel beam has little deformation, which helps to reduce the maintenance workload after crash. Energy absorbing pipe does not cause adverse effect on vehicle running posture or cause the vehicle to snagging. The strain maximum of steel in deck and flange slab lies in the position of barrier traffic side bottom. The additional steel bars in the deck can participate in carrying the impact load and the anchoring strength of barrier foundation is proved to be enough.
2013, Vol. 32 
