Numerical study on the serviceability performance of reinforced glulam beams with different steel arrangements

Abstract

Glued laminated timber (glulam) beams manufactured with glued steel bars can achieve improvements in their mechanical performance and the effects of the arrangement of steel bars in the cross-section are of technological interest. This study aimed to evaluate the mechanical behavior of beams with symmetric reinforcements (compression and tension zones) and beams with asymmetric reinforcements (compression zone), under loading imposed at the serviceability limit state. To achieve this goal, glulam beams with reinforcement ratios ranging from 0.5% to 4% were simulated using the finite element method. When compared to the nonreinforced beams it was found for the deflections that the asymmetric reinforcements provided reductions of up to 31.5% and the cases with symmetric reinforcements were more efficient, with deflection reductions of up to 45%. In comparison to the symmetric arrangement of the bars, the asymmetric distribution provided a reduction of up to 10.5% in the normal stress of the glulam beam compression zone. The asymmetrically arranged reinforcement effectively contributed to increasing the stiffness of the beam and was more efficient in reducing normal stresses in the compressive zone, thus preventing the initial yielding of the wood.