Securing the Nation's Bridges

Securing the Nation's critical infrastructure, including bridges, emerged as a major issue after the terrorist attacks of September 11, 2001. This article discusses the Federal Highway Administration’s (FHWA) research and development efforts to protect bridges from acts of terrorism. Responding to the security threat has required collaboration among numerous public agencies, the military and the private sector. The FHWA has conducted field evaluations to assess potential targets and analyze vulnerabilities. Research directed toward technology assessment as well as mitigation efforts has been conducted, including an ongoing research effort on steel bridge towers subjected to blast loadings. The FHWA has identified nine areas for future research regarding bridge and tunnel security. Although researchers have learned much about how to protect the Nation's infrastructure in the decade since the September 11 attacks, much work remains. Ever-changing threats and the inherently low probability of an attack at any one location make decision making about mitigation measures difficult. Security mitigation is easier when the target and consequences are clear. With changing threats and so many potential targets, there are limitations on what can be done in terms of structural retrofits and designing for security. An effective security plan must be developed to detect, delay, and deter attacks and to defend when possible. A plan for organized and rapid response and recovery may be the most appropriate and effective security action for most of the Nation's bridges and tunnels. FHWA will continue to conduct research designed to provide highway structures that are safe and reliable for all service conditions. In the process of rehabilitating existing structures, steps will be taken to incorporate designs and mitigation measures to secure against potential hazards. Even after the bridge of the future delivers high performance with low maintenance, eliminating hazards will continue to be an agency goal.