Case Study: Implications of Installing Vehicle Security Barriers in Elevated Structural Slabs

Abstract

Vehicles of all types are increasingly being used as a hostile threat in public and urban environments. While vehicle barriers have been designed, manufactured, and installed for highsecurity applications in the government, military, and energy sectors, there is a growing need to provide hostile vehicle mitigation for commercial property. Though there are many suppliers of vehicle barriers in the U.S. and abroad, impact test certification is typically only applicable to a single configuration. Oftentimes there are site constraints that prevent barrier installation in the tested configuration. One specific and common variance that arises is the use of surface-mounted barrier systems installed atop an existing, elevated structural slab. Though the need for a deep foundation is avoided with this barrier type, there remains a strong assumption that the barrier is continuously supported by the soil beneath. When barriers are mounted above basements or in parking structures, the existing structural slab is vulnerable to failure from vehicle impact loads and providing an anchorage design can be challenging. The aim of this case study is to evaluate the performance of typical elevated, reinforced-concrete slabs for surface-mounted vehicle barrier designs currently available for procurement. Finite element analysis is employed to assess the load transfer to and behavior of the slab and anchorage in the event of an impact. Key implications and design challenges are documented.

Strategy investments in zero-sum games

“…In addition to the screening technologies varying in price and effectiveness (e.g., basic x-ray machines versus new 3D computational tomography scanners), there may also be available investments which (at a cost) serve to remove certain feasible actions of the attackers. For instance, investment in high compound walls or vehicle security barriers may remove the possibility of certain perimeter breaches [12]. With a given budget, the airport must first choose which security measures to make available and/or which actions of the attackers to eliminate.…”