Numerical Investigation of Effective Flange Width in the CLT-GLT Composite T-beams

This paper deals with the structural behavior of CLT-GLT composite T-beams which is made up of a Cross Laminated Timber (CLT) panel attached to a Glue Laminated Timber (GLT) beam. The technical research paper explores the effect of the CLT panel and GLT beam configuration on the effective flange width of CLT-GLT composite T-beams, which is an important requirement for simplified structural analysis and design. When the CLT-GLT composite T-beams are under positive bending moment, part of the CLT panel will act as the flange of the GLT beam resisting compression. From shear lag, the compressive stress in the CLT flange will differ with the distance from the GLT beam. When the spacing between the GLT beams becomes larger, the CLT flange becomes more highly stressed over the GLT beam than in the extremities edges of the CLT flange. Despite a large number of studies regarding steel-concrete composite structures for design purposes, there has not been comprehensive comparative research on structures that are constructed by engineered wood products. In this study, a finite element (FE) model which is experimentally verified is used to analyze the CLT-GLT composite T-beams and obtained effective flange width results are presented by tables, bar charts, and normal stress distribution figures. Based upon a detailed parametric study, it is concluded that the layer arrangement of the CLT panels and its material properties have a significant influence on the effective flange width of the CLT-GLT composite T-beams. Any changes that increase the ratio of the transverse layer’s depth to the longitudinal layer’s depth result in an increase of the effective flange width. FE Parametric study on conventional layers configurations of the CLT panels showed that when the boards in transverse layers replaced by two times thicker boards, the effective flange width of CLT-GLT composite T-beams increases at least 85 percent.