New Shallow Foundation Security Barriers for Urban Applications: FEA and Certified Actual Crash Test

Providing an accurate and reliable design or analysis of complex physical security systems has been a great challenge for several years. To meet this challenge, the latest and most advanced engineering techniques proved to be necessary. Among them is the Finite Element Analysis (FEA) computational method. FEA is recognized today within the engineering and scientific community to be a very powerful tool in solving the most complex structural analysis, crash and impact-related problems. Due to the significant improvements in computer technology and software developments, FEA can now provide excellent support to the design, analysis, evaluation and improvement of all security barriers. In the current research, a new shallow-foundation bollard system design has been conceived and analyzed using nonlinear FEA. This design is appropriately suitable for urban applications since its foundation is a mere 18 inches deep and can be installed within a few hours. Further optimization led to the utilization of the most appropriate commercial steel-structural elements with the objective of reducing material, manufacturing and installation costs. The system has proven to be capable of sustaining severe impacts by spreading a portion of the induced energy throughout the entire structure and the supporting soil/concrete. This was possible through a process of FEA iterations that resulted in the refinement of the initial bollard concept. Subsequently, a five-bollard full-scale module was constructed and tested under K12 impact conditions as defined by the Department of State (DOS) guidelines (SD-STD-02.01). According to the DOS guidelines, a K12 rated barrier must be able to stop a 15,000 lb single unit truck at an impact speed of 50 mph. The system successfully stopped the truck with negative cargo penetration and less than 5 inch bollard deformation. In the final step, the FE model of the tested bollard system was validated by simulating the crash at the exact test speed (47.4 mph). The FE simulation results showed excellent correlation with the actual test output.Copyright © 2009 by ASME