Experimental and theoretical investigation of the structural behavior of reinforced glulam wooden members by NSM steel bars and shear reinforcement CFRP sheet

Abstract

Abstract The current investigation is an attempt to evaluate the effectiveness of utilizing steel bars as reinforcements in glulam timber beams using the near-surface-mounted (NSM) technique. A series of flexural testing was carried out until failure for both reinforced and unreinforced glulam members in a simple support system. Eleven specimens were examined in two groups to compare with the controlled beam. Five reinforced glulam beams of the first group were reinforced with different schemes at tension and compression zones using the same bar size, while other five specimens of the second group were reinforced in addition to the same flexural reinforcement schemes, the shear reinforcement using fully wrapping strips made of CFRP sheet. Each glulam beam has a span of 1.35 m and a rectangular section sized 85×175 mm. Experimental results presented, that the reinforced glulam beams performed much better than unreinforced reference beams in terms of structural behavior with improvements in ultimate load capacity ranging from 16 to 49%. Based on experimental outcomes, theoretic modeling was provided to estimate the ultimate load capacity and bending rigidity of reinforcing glulam members. Though several theoretical predictions of flexural capacity were overstated when compared to experimental predictions, these disparities were frequently about 10%, confirming that the proposed theoretical model was accurate and the mean of ultimate loading capacity and deflection between experimental and theoretical results were 1.01 and 1.09, respectively, while the shear reinforcement for reinforced glulam members slightly improved flexural performance and ultimate load capacity increased by 2–7%.