Approximate Solution on Large Deflection of Glass Panels Subjected to Uniform Pressure

The estimation of the deflection of glass panels under wind pressure is important in designing external facades of buildings. A direct method to compute the large deflections of glass panels under uniform loads such as wind pressure is presented. The model allows for derivation of the load-deflection response of square or rectangular multilayered glass panels subject to uniform loads. The boundary conditions examined are those of four-point discontinuous supports or continuous supports along the four sides. With some assumptions on bending and membrane action of flat glasses, simple analytical expressions were derived from the elastic theory. Viscoelastic effects for multilayered glass panels with a thin interlayer of PVB were taken into account by introducing a time-dependent equivalent thickness, as suggested in the literature. The mechanical model based on the structural behavior of equivalent beams is also able to account for the flexural and membrane actions. Different experimental results available in the literature and relative to flexural tests on out-of-plane loaded, large-scale panels made of laminated structural glass were utilized to validate the model. The model was compared satisfactorily with numerical results obtained by using nonlinear FEMs and with existing analytical models. In almost all cases, the comparison was satisfactory, and the proposed model provides a useful design instrument that allows one to determine the minimum thickness of multilayered glass panels while respecting maximum allowable deflection and strength criteria.