Residual performance of a prototype hybrid Timber-FRP glulam beam after fire

Abstract

Within the scope of this work, a prototype hybrid Timber-FRP (Fibre Reinforced Polymer) Glulam (Glued Laminated Timber) beam was conceived for developing timber floor systems that have an enhanced load-bearing structural performance during and after fire. To better understand the response of this hybrid Timber-FRP Glulam at elevated temperatures, this research study describes two fabrication techniques using Carbon FRP (CFRP), aiming to increase the bending moment capacity of the hybrid Timber-FRP during and after fire. Both fabrication techniques comprise of introducing CFRP fabric or strips near the areas in tension (i.e. near the soffit). The increase in bending strength and stiffness of the beams through the inclusion of a relatively rigid CFRP element has been investigated through an experimental approach based on residual strength tests on beams under four-point bending (normal Glulam and including CFRP). Results show that beams incorporating CFRP have an increased bending moment capacity and stiffness at ambient conditions. They also exhibit a significant increase in the bending moment capacity after heating and cooling (i.e. residual conditions).