Deformed Shape Analysis of Coupled Glazing Systems
PROTECTION ENGINEERING CONSULTANTS LLC AUSTIN TX
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Glazing in storefront and curtain wall configurations is increasingly used in areas subjected to blast load. Current design approaches typically use single-degree-of-freedom SDOF methods to analyze the performance of both the glazing and mullions. The flexural resistance and mass of each component must be identified to solve the SDOF. The resistance is calculated based on span, support conditions, cross sectional stiffness and an assumed deformed shape. Dynamic verification of deformed shape is difficult to assess through testing and has historically been calculated through analytical and numerical methods. However, new measurement methods provide high resolution, high speed deformation measurements through the use of Digital Image Correlation DIC, which is a stereoscopic, high speed camera setup capable of measuring the strain and deflection of both the glazing and mullions simultaneously in three dimensions. Protection Engineering Consultants PEC conducted a shock tube test series and two blast tests using DIC to measure glazing and mullion deformation for high strength glass. DIC data from the shock tube tests was used to determine the deformed shape and corresponding strain and stress states of the glass to improve the resistance curve used in the SDOF model. In the blast tests, the windows were installed in a storefront configuration and DIC was used to measure the deformation of the glazing and the mullions simultaneously such that effects from the coupled movements of the windows and mullions could be assessed. The validated SDOF models of the glazing and mullions were used to compare coupled versus uncoupled analysis to identify potential improvements. Coupled analysis has the potential to create significant material and connection efficiencies in design to resist blast loads.
- Construction Equipment, Materials and Supplies
- Structural Engineering and Building Technology