Experimental and numerical analysis of compression and bending strength of old wood reinforced with CFRP strips

Abstract

The reinforcement and repair of historical wooden structures is very important because they reflect the socio-economic structure and architectural construction techniques of the period it was built. In this study, carbon fiber-reinforced polymer (CFRP) strips were used to improve the mechanical behaviors of old wood (OW) samples that were damaged over time because of various environmental effects and biological factors. To determine the effect of reinforcement on the strength values of OW and new wood (NW) samples under bending and compression loads, CFRP strips were applied at tension surfaces of bending samples and around the perimeter of compression samples. The effect of reinforcement on mechanical properties of OW and NW samples was evaluated with a statistical analysis program. Moreover, the ductility and energy dissipation capacities of experimental samples was calculated from the load-deflection curve obtained under bending loading. Reinforcement with CFRP has significantly improved the mechanical strength and stiffness of OW samples. The bending strength values increased 28%, 34% and 59% for new wood (NW), reinforced old wood (FROW) and reinforced new wood (FRNW) with respect to the non-reinforced OW, respectively. The modulus of elasticity values of NW, FROW and FRNW were 15%, 19% and 34% higher than OW, respectively. The 3-dimensional numerical model was developed and validated by experimental tests carried out on wood samples with and without reinforcement arrangements. Wood behaviors were modeled using uniaxial stress-strain curves. In numerical analysis, load-deflection curves, equivalent stresses and normal stresses of the beams were obtained. A good correlation was obtained between numerical and experimental results.