Seismic behavior of ultra-high performance concrete columns with GFRP bars under different loading directions

Abstract

The combination of ultra-high performance concrete (UHPC) and glass fiber reinforced polymer (GFRP) bars offers a promising and viable design option for future infrastructure in the extremely harsh environment. However, studies carried out on this kind of structure are rather limited, especially for its seismic behavior under non-principal bending. This paper presents an experimental program on eight columns (four UHPC-GFRP hybrid columns, three UHPC columns and one reinforced concrete column) tested under lateral displacements with loading angles of 0° and 45°. Other changes of interest include types of concrete, types of reinforcement, and longitudinal reinforcement ratios. The seismic responses of specimens were discussed and analyzed in detail from various aspects, including cracking patterns, failure modes, hysteretic responses, and strain profiles. The experiment results reveal that the introduction of GFRP bars is effective in restricting the development of cracks while having limited negative influence on the seismic performance of UHPC columns, demonstrating the practicability of the UHPC-GFRP hybrid column. Furthermore, in contrast to reinforced concrete columns, it has been observed that UHPC specimens exhibit a low sensitivity to the direction of lateral loading with regard to cracking patterns and energy dissipation capacity.