Seismic Performance of Steel Fiber Reinforced High-Strength Concrete Beam-Column Joints

In high-strength concrete, the reinforcement concentration will cause some problems in the beam-column joints (BCJs) due to a large amount of transverse reinforcement. Hence, the main object of this paper is to prevent the reinforcement concentration and reduce the amount of transverse reinforcement in the BCJs through the ideal usage of steel fibers and reinforced high-strength concrete. Pseudo-static tests on seven specimens were carried out to investigate and evaluate the seismic performance of beam-column joints in steel fiber reinforced high-strength concrete (SFRHC). Test variables were steel fiber volume ratio, concrete strength, the stirrup ratio in the core area, and an axial compression ratio of the column end. During the test, the hysteresis curves and failure mode were recorded. The seismic indicators, such as energy dissipation, ductility, strength, and stiffness degradation, were determined. The experimental results indicated that the failure modes of SFRHC beam-column joints mainly included the core area failure and the beam end bending failure. With the increase in stirrup ratio, volume ratio of steel fiber, and axial compression ratio in the core area, both the ductility and energy consumption of beam-column joints increased, while the opposite was true for concrete strength.

Automated summary

This study aimed to improve the seismic performance of beam-column joints by reducing the concentration of reinforcement and utilizing steel fibers and reinforced high-strength concrete effectively. Experimental results showed that increasing the stirrup ratio, steel fiber volume ratio, and axial compression ratio in the core area can enhance the ductility and energy consumption of the joints, while the opposite is true for concrete strength.