Blast resistant design for roof systems

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The design of structures to resist explosive loads has become more of a concern to the engineering community. This research focuses on the design techniques for the loading on roof structures and the resistance of open web steel joists. A procedure has been developed to devise a uniform dynamic load on a roof that matches the response from blast loads. This research uses finite element analysis to evaluate the responses from numerically calculated blast loads and compares them to the equivalent loading response and the response of experimentally measured roof blast pressures. While the responses from finite element modeling matched the experimental responses, the equivalent loading procedure did not adequately predict the initial peak deflection or the maximum deflection. The response of several structural members used in roof construction, such as hot-rolled steel beams and reinforced concrete slabs, are well documented and understood. Open web steel joists (OWSJ) are other types of common roof components. Their responses under loading are not clearly defined, and current methods extrapolate techniques used in the design and analysis of hot-rolled steel beams and reinforced concrete. It is believed that the failure mechanisms of OWSJ significantly are not accurately being taken into account. The resistance function is computed from three tests and compared to current methodologies. It is recommended that an analytical resistance function for OWSJ be clearly defined, which includes all failure limit states.