Proposal for Correction on the Gamma Method for Estimating the Displacement of CLT Plates

The determination of bending stiffness of Cross Laminated Timber (CLT) can be carried out using several calculation methods, such as the Gamma method, a standardized approach. Each method has its own considerations as a 1D or 2D element, along with limitations on stiffness assessment, mainly for shear displacement contributions on short spans. These limitations can lead to an unsafe structural design. Therefore, this research proposes a correction factor (α) for bending stiffness obtained by the Gamma method, based on a parametric study using finite element analysis (240 simulations). Variables such as length, number of layers, wood species, total height, and load application were varied, considering elastic properties and wood orthotropy. The α factor was determined through multivariable regression models to relate the analytical value (Gamma method) to the numerical value of bending stiffness. The model considering all parameters resulted in a MAPE and CV lower than 2% and 17%, respectively.