Bending Behavior of Separable Glued-Laminated Timber (GLT)-Steel Beam Combined with Inclined Screws

Abstract

A separable glued-laminated timber (GLT, Larix kaempferi Carr.)-steel beam system is presented in this work for easy recycling at the time of disposal. The minimum thickness of steel required to induce compressive GLT failure was assembled with GLT by inclined screws. In a total of 8 GLTs, 3 GLTs were not reinforced (control group), and 5 GLTs were reinforced with steel plates (comparison group). In the GLT in the comparison group, a steel plate (SPHC, yield strength: 227 MPa, modulus of elasticity 166.33 GPa) was installed with screws (∅9x160mm, 45°). The deflection and load of specimens were measured by a third-point bending test to derive their bending stiffness and load-carrying capacities. All specimens in the control group showed brittle tensile failure, but all specimens in the comparison group showed ductile behavior and maintained a load-carrying capacity of about 30 kN. After the compression failure of the GLT, there was no damage to the screw connection, while the steel plate was extended. Based on the behavior of the steel, a GLT-steel beam prediction model was developed, similar to the structural design method for reinforced concrete.