The terrorist attacks of 1995 (Murrah Federal Building) and 2001 (World Trade Center) focused attention on structural design requirements to prevent the catastrophic damage caused by these events. However, creating practical design requirements for such severe loading proved to be an extremely difficult task. Because prescriptive and performance requirements for blast and progressive collapse mitigation do not appear in the design codes they are not codified into law. The owner, architect and structural engineer are the key stakeholders who carry the responsibility in deciding if the need for blast and progressive collapse resistance is necessary. Generally prescriptive design procedures for blast and progressive collapse resistance result in inefficient costly construction and limitations on the architectural design of such buildings thus are rarely implemented on a project that doesn’t have GSA, DoD or State Department requirements.
The current blast effects/progressive collapse market is relatively small and is primarily government driven. The desire for this type of protection is significant however high cost, difficulty in structural design and impact on program flexibility pushes it into an impractical requirement. We believe that this market will undergo a paradigm shift in growth when resistance to blast effects and progressive collapse can be attained with practical cost effective designs.
With the ConX™️ System, the key stakeholders now have the option of specifying a structural framing system that will carry gravity, wind and seismic loading and, at no additional cost, also provide resistance to blast and progressive collapse, all in one efficient structural framing system. The innovative and highly robust ConX framing system provides a cost effective and easily configurable biaxial moment frame connection that also provides blast and progressive collapse resistance.
In 2004, Ronald Hamburger of Simpson Gumpertz & Heger wrote an article discussing the high costs and architectural limitations of current prescriptive design methods. He felt there was a much more cost effective performance based design method, but the industry needed “a program of research and development similar to that conducted after the 1994 earthquake to determine the types of connection technologies that can be effective in resisting progressive collapse so that less conservative but more reliable approaches to blast-resistant design can be adopted by the community.”
The ConXtech ConXR™️ framing connection debuted in 2004 and the ConXLT™️ connection in 2008. In 2009 Ronald Hamburger wrote “The ConXR and ConXL systems are ideal for building applications that must be designed to resist progressive collapse resulting from vehicle impact, incendiary or explosive device attack.”
“The ConX Connection: A Bolted Special Moment Frame Connection for Seismic and Structural Integrity Applications” March 2009
Ronald O. Hamburger, Simpson Gumpertz & Heger
“Design of Steel Structures for Blast-Related Progressive Collapse Resistance”
Modern Steel Construction, March 2004
Ronald O. Hamburger, Simpson Gumpertz & Heger Andrew Whitaker, University at Buffalo, NY