Mechano-sorptive creep in reinforced glulam

Abstract

An investigation was carried out to examine the effect of reinforcement on the creep behaviour of FRP reinforced timber elements in a controlled variable climate. Creep is accelerated by moisture variations due to a variable climate. This is termed the mechano-sorptive effect. In this paper, both unreinforced and reinforced beams are subjected to long-term creep tests loaded to a common maximum compressive stress of 8 MPa. The relative humidity of the variable climate was cycled between 65 ± 5% and 90 ± 5% every four weeks while the temperature remained constant at 20 ± 2°C. After 75 weeks, the total deflection and creep deflection of the reinforced beams was reduced by 16.46% and 8.37%, respectively, compared to the unreinforced beams. The results have shown that the creep behaviour of the unreinforced and reinforced beams is heavily influenced by the variable climate and it was found that the reduction in total deflection and creep deflection is statistically significant after just the first relative humidity cycle.