Development and testing of precast concrete-filled square steel tube column-to-RC beam connections under cyclic loading

摘要

Compared with the cast-in-place construction technique, the precast structure has advantages such as high industrialization, good quality, and environmental protection. Previous studies and investigations have shown that fabricated structures require secure connection technology, which could solve critical seismic problems associated with structures. The complex reinforcement layout in joint zone and the inefficient connection processes erode the economic value of the fabricated structure. This paper presents a novel precast concrete-filled square steel tube (CFSST) column-to-RC beam connection with energy dissipating (ED) bolts and prestressing tendons. In total, eight precast specimens with different axial compression ratios, ED bolt diameters, steel tube thicknesses, and beam end arrangement were tested under cyclic loading. The results show that the structural drift ratio obtained is up to 5.75%. The hysteresis curves of all specimens are plump. Even the specimen with the smallest diameter ED bolts can reach twice the energy dissipation capacity of the cast-in-place frame RC joint. The average ductility coefficients of all models are greater than 5. The precast CFSST column has good integrity and less damage after the earthquake. The final failure modes of the fabricated connections are governed by the plastic hinges at the beam. Besides, a calculation method for the flexural bearing capacity of the novel joint is developed and compared with the test results, which verified the feasibility of the model. The proposed precast connections exhibit superior resilience against earthquakes and can be used in active seismic regions. (C) 2021 Elsevier Ltd. All rights reserved.