Damage tolerance and residual strength of hybrid FRP–UHPC beam

This paper focuses on the results and analysis performed on two types of hybrid FRP–UHPC beams, reinforced with either CFRP or SFRP tension sheets. The experimental program was conducted in two stages with a total of six beams tested. In Stage 1, six full length hybrid beams were tested until failure under four-point loading using both monotonic static and fatigue loading regimes. Then in Stage 2, the same beams were shortened to eliminate the sections of major damage and re-tested to determine the post-damage residual strength and behaviour due to flexural loading. The results showed that there was no detectable difference in the amount of damage sustained under similar loading for the two types of hybrid beams tested. Testing of post-damaged beams showed a performance level of at least 74% of the pre-damaged beams, thus demonstrating that the hybrid beams are capable of supporting considerable loads after sustaining significant damage. Additionally, the introduction of compressive clamping forces was found to enhance the bond behaviour at material interfaces by promoting frictional forces. More experimental testing with additional hybrid beam specimens is strongly recommended.

► Hybrid beams capable of supporting load after sustaining damage. ► A maximum of 85% of initial flexural capacity was achieved in post-damaged beams. ► No discernible difference in post-damage performance between two types of hybrid beams. ► Clamping forces can be used to partially restore bond with frictional forces.