Experimental investigation of full scale underground concrete chambers reinforced with GFRP bars

Fibre reinforced polymer (FRP) reinforcing bars is being extensively used as a promising substitute for conventional steel bars in corrosion environment. In a comparative investigation, this paper presents the results of an experimental investigation on the structural performance of full scale underground concrete chambers reinforced with either glass fibre reinforced polymer (GFRP) bars or conventional steel reinforcement. The experimental campaign was aimed at evaluating the possibility of reinforcing underground concrete chambers commonly used by Hydro-Quebec with GFRP bars. Therefore, the reinforcement details and dimensions of all specimens were selected to be identical to the common practice of Hydro-Quebec steel reinforced chambers regardless of its optimal design. Consequently, the only difference in two types of chambers was the type of reinforcement (i.e. GFRP or steel bars). Each chamber specimen measures 2300 mm wide by 3800 mm long with walls of 2800 mm high. The experimental results were reported in terms of strains in concrete and reinforcing bars, loading capacity, deformation, and cracking behavior. The findings illustrated the high strength of both types of chambers highlighting the initial conservative design of chambers. Comparing the results of steel and GFRP reinforced specimens, GFRP reinforcing bars can be reliably introduced as a premium corrosion resistant alternative to steel reinforcement in construction of underground reinforced concrete chambers.

Keywords:

Underground concrete chambers , GFRP bar , Steel bars , Compression loading , Strength