Reinforcement of flexural performance of screwed cross laminated timber (CLT) panels constructed of poplar by aluminum sheet and glass fiber reinforced polymer wrap

In this study, flexural reinforcement of 3-layer screwed CLT made of poplar (Populous alba) and polyurethane glue was investigated. Static bending test was performed by Instron according to ASTM D4761. The variables of this study were types of reinforcing (aluminum sheet and glass fiber reinforcement polymer (GFRP) wrap) and arrangements of reinforcers (no.1: bonded on the bottom (tension) side; no.2: bonded on the bottom and top (tension and compression side); no.3: bonded on the bottom, top and between two bottom layers; no.4: bonded on the bottom, top and among layers). The results showed that the higher MOR and MOE were related to major direction of CLT reinforced with aluminum with configuration of no.1. The lower MOR and MOE were observed in minor direction of CLT reinforced with GFRP with configuration of no.1. The increasing percentage of the MOR and MOE in minor direction of CLT reinforced with aluminum were 195.1 and 344.6% and in major direction of them were 89.3 and 50.8%, respectively in comparison with control specimens. When CLT panel were reinforced with GFRP, the increasing percentage of MOR and MOE in the minor direction of CLT were 42.8 and 21.3% and in major direction of CLT were, respectively 46.1 and 12.7% in comparison with control specimens. The results showed that MOR and MOE of CLT reinforced with aluminum sheet were higher than those reinforced with GFRP wraps. Failure modes of CLT were changed by reinforcing from brittle to ductile and consequently increased their flexural strength.