Structural Performance of Double-Skin Façade Systems Subjected to Blast Pressures

Abstract

The main function of a building façade system is to provide comfort and protection to interior building spaces. In a blast event, façade components become the weakest part of a building and the blast-induced shock wave may breach the facade and injure building occupants due to flying debris. There is increasing popularity in the use of double-skin façade systems (DSFSs) in modern façade construction because of their energy efficiency advantages. In addition to their improved energy performance, DSFSs can increase the blast-resistant capacity of a building. However, due to the complex structural interactions between DSFSs and blast-pressure waves, there is a lack of design codes that account for the performance of DSFSs under blast loading. This paper reports on an experimental program of analogical DSFSs that consist of steel panels as opposed to glass panels, subjected to a 250 kg equivalent TNT charge weight at a stand-off distance of 52 m (250 kg @ 52 m). Three different DSFS compartments with varying ventilation areas were tested. Numerical analyses of the structural responses of a DSFS were then conducted based on the pressures recorded in the experiment. A comparative study was conducted on the blast performance of glass panels, based on the design procedures of current standards and numerical techniques. It was found that the current standards for double-glazed insulating glass (IG) units greatly overestimated the blast performance of DSFSs by simplifying the load-sharing factors. This paper further identifies the critical parameters of DSFSs when assessing their responses to blast pressures.