Development of Design Guidelines for Soil Embedded Post Systems Using Wide-flange I-beam to Contain Truck Impact

摘要

Anti ram perimeter barriers are part of the protection of important facilities such as power plants, air ports and embassies against unrestricted vehicle access. Many different systems can be used to achieve the containment goal. One of these systems makes use of soil embedded posts either single posts if the soil is hard enough or groups of soil embedded posts tied together by beams if the soil is not hard enough for a single post to stop the in-coming truck. The design of these soil embedded posts needs to take account a number of influencing factors which include the soil strength and stiffness, the post strength and stiffness, the mass of the vehicle and its approach velocity.This dissertation describes the work done to develop a set of design recommendations to select the embedment of a single post or group of posts. The post is a steel beam with an H shape cross section: W14X109 for the single post system and W14X90 for the group system with a double beam made of square hollow steel section HSS8X8X1/2. The spacing of the posts for the group includes 2.44 m, 4.88 m, and 7.32 m. The soil strength varies from loose sand and soft clay to very dense sand and very hard clay. The vehicle has a mass of 6800 kg and the velocities include 80 km/h, 65 km/h, and 50 km/h.The design guidelines presented here are based on 10 medium scale pendulum impact tests, 2 medium scale bogie impact tests, 1 full scale impact test on a single post, 1 full scale impact test on a group of 8 side by side posts with a 5.2 m spacing and connected with two beams, approximately 150 4-D numerical simulations of full scale impact tests using LS-DYNA, as well as fundamental theoretical concepts.