Behavior of timber-timber composite structure connected by inclined screws

The behavior of timber composite structure made of cross laminated timber (CLT) panel and glued laminated timber (GLT) beam was considered in this paper. Bending tests of a CLT-GLT composite structures with and without fasteners were conducted. CLT panel and GLT beam were connected by screws installed at a 45° angle to the GLT axis grain. It was experimentally proved that the application of inclined screws increases the strength of the CLT-GLT composite structure by 1.3 and 1.6 times, stiffness – by 1.6 and 2.1 times, shear capacity – by 2.1 and 3.5 times for two orientation types of CLT panel (CI and CII), respectively. Two types of CLT panel orientations were considered: with the top layer oriented parallel to the GLT axis (CI) and oriented perpendicular to the GLT axis (CII). The CLT-GLT composite structure with the top layer oriented parallel to the axis of the GLT beam has 50 % more strength and 14 % more stiffness than a composite structure with the top layer oriented perpendicular to the GLT axis. Based on numerical and experimental results, a design procedure was suggested to determine the strength and strain characteristics of the CLT-GLT composite structure connected by inclined screws.