Strain measurements in monolithic and laminated glass

As the uses of laminated glass (LG) become more prevalent, the need to better understand LG behavior increases. Due to the variation in shear transfer capability of the interlayer with temperature, the behavior of LG is poorly defined. LG behaves similarly to monolithic glass at room temperature, but behaves differently at elevated temperatures. The objective of the research presented herein is to gain insight into the behavior of LG subjected to uniform load as temperature varies from room temperature to 158°F (70°C). The research consisted of measuring flexural strains and center deflections at the full design load and one-half design load. Glass Research and Testing Laboratory (GRTL) staff, at Texas Tech University, tested one LG specimen and one monolithic glass specimen for each of five geometries.

The data collected indicates, in general, that LG having a low flexibility ratio displays different behavior from monolithic glass at room temperature and above. This conclusion falls in line with aspects of ASTM E 1300 (2000), although the flexibility ratio at which the behavior deviations become significant may differ from 150.