Experimental and numerical investigations of glass curtain walls subjected to low- level blast loads

Abstract

A series of three full-scale, nearly-conventional, curtain wall specimens were blast tested in the open arena of the Infrastructure Security and Emergency Responder Research and Training (ISERRT) Facility in Gastonia, NC. The specimens were subjected to low-level blast loads produced from the detonation of high explosives. Low-level blast loads, similar to those produced during the tests, are typical of small charge weights (i.e. satchel charges) at short-to-moderate standoffs. A simple finite element (FE) model that effectively represents the nonlinear dynamic response of glass curtain walls subjected to blast loads was developed, and simulation results were compared with the test results. It was shown that, with the judicious choice of modeling parameters, the FE model effectively represents the response of glass curtain walls subjected to blast loads while being computationally economical. The calibrated FE model was used to evaluate the efficacy of a nonlinear single-degree-of-freedom (NSDOF) design expression for analytically approximating the blast resistance of curtain wall systems. The design expression is based on a procedure in which a nonlinear resistance function of the system is input to an energy expression that models the maximum nonlinear dynamic deflection due to an ‘impulsive’ loading. It was shown that the maximum impulse predicted by the design expression, when the expression was used in conjunction with a satisfactory resistance function, compared reasonably well with the FE simulation results. The expression could be used as a starting point for design or to supplement more advanced models of curtain walls subjected to blast loads.