Finite element analysis of thin-walled composite two-span wood-based loadbearing stressed skin roof panels and experimental validation

The aim of this work is to study the structural behavior of prefabricated thin-walled wood-based loadbearing stressed skin panels for use in roofs. These stressed skin panels are composed of double thin skins, made of waterproof agglomerate and oriented strandboard, with a rigid insulating core made of extruded polystyrene without a vapor control layer or breather membrane. Current design criteria for these panels are often governed by calculating shear strength rather than bending strength. However, bending is often observed as the controlling factor in real structures and experimental studies. This work describes a design procedure based on predicting whether bending or shear will control their structural behavior. In order to get this purpose, we have studied both experimentally and theoretically the different elements that constitute this construction system to determine accurately its response in the presence of the external loads. The numerical analysis of the different variables using the finite element method (FEM) was validated by means of real tests on prototypes. The biggest difficulties in the simulation were found in the supports, due to the contacts between the different elements that compose them, and in the orthotropic material properties. Finally, the conclusions and suggested simplified procedures of calculation to be applied in similar structures are given. Comparisons with experimental data and with predictions using the quasi-analytic formulas are provided in order to support the validity of the proposed models.