Inelastic Dynamic Response of Curtainwall Systems to Blast Loading

Blast resistant curtainwall systems require the use of laminated glass that is adequately adhered within the frames to develop the membrane capacity of the glazing and mullions that are capable of transferring the collected forces to the structural slabs. Dynamic inelastic analyses are required to determine the response of these curtainwall systems to highly impulsive blast loading. The most economical design of these systems to minimize the hazard to the occupants allows the components to undergo large deformations prior to dismemberment and fragmentation. Often, the performance of these systems are evaluated using a sequence of single-degree-of-freedom (SDOF) analyses; the glass is represented as a SDOF to determine the reaction forces which are subsequently applied to the SDOF analyses of the mullions. While these individual calculations attempt to represent the dynamic inelastic response of the components, it often neglects interaction and phasing of the components. As a result, the SDOF methods very often over predict the response of the individual members and produce an uneconomical design. Dynamic inelastic finite element analyses that account for the interaction of the various components and accurately represents the potential failure mechanisms provide the most accurate and economical design for blast resistant curtainwall systems. In addition to material nonlinearities, the finite element approach also accounts for geometric stiffening of the different components and therefore produces more accurate anchorage forces that must be developed at the slabs.