Insulating Glazing Units (IGUs) consist of glass panes held together by structural edge seals, entrapping a gas for thermal and acoustic insulation. Changes in temperature and barometric pressure unbalance the external and internal pressures, developing effects in the panes. When external actions are applied, the bending of one pane induces gas pressure variations, redistributing the loads among the panes and providing a load-sharing effect, depending upon the flexural stiffness of the panes and the gas compressibility. While the calculation of IGUs under climatic loads is quite straightforward, methods proposed by Standards to evaluate the load-sharing under external actions usually allow to consider only uniformly distributed loads. The cases of line distributed and concentrated load usually require FEM analyses.

Recently, an analytical method based on Betti’s Reciprocal Work Theorem (Betti’s Analytical Method – BAM) has been proposed. This allows to evaluate the gas pressure variation in IGUs of any shape, composed by an arbitrary number of glass panes, under the most general loading conditions. Simple expressions can determine the pressure as a function of a universal shape function, correspondent to the deformed surface of a simply supported plate of the same shape of the IGU, under uniform pressure. Remarkably, only one table is sufficient to consider many cases in terms of loads and boundary conditions. Here, the accuracy of the BAM is demonstrated via comparisons with numerical analyses, illustrating the influence on the load-sharing of the size and shape of the IGU, glass and spacer thickness and type of loading.