Steel‐Reinforced Glued Laminated Timber

Abstract

A possible candidate for replacement of tension laminations in glulam beams is examined. The replacement is a composite of concrete‐reinforcing steel embedded in oriented flakeboard. Pullout tests were used to select the best of three possible furnishes for the composite. After this selection, 2in.6in.×9ft(50.8mm×152.4mm×2.74m) beams were fabricated. Control beams with no reinforcing and beams with one lamina replaced with the steel‐wood composite were tested. The beams were tested both dry (50% RH) and wet (90% RH). The dry beams exhibited increases in stiffness of 24% and 32% and increases in ultimate moment capacity of 29% and 30% for one number 3 or number 4 bar, respectively, in the beam. The wet beams also showed increases in stiffness on the order of 30% but showed no significant increases in strength. This lack of reinforcing effect is likely to be a combination of increased steel stress due to reduced wood modulus of elasticity with increased moisture content and decreased flakeboard internal bond strength due to increased moisture content.