Structural Behaviour of Precast Beam-Column Sub-Assemblages with Cast-In-Situ Engineered Cementitious Composites under Column Removal Scenarios

Abstract

This paper presents an experimental study on the structural behaviour of precast beam-column sub-assemblages under column removal scenarios, in which conventional concrete and engineered cementitious composites (ECC) were used in the cast-in-situ concrete topping and the beam-column joint. The specimens were restrained by horizontal and vertical load cells and tested under quasi-static loading condition. Experimental results indicate that at the initial stage ECC and steel reinforcement sustained tensile stresses compatibly and multiple cracking was observed in the ECC topping. When the tensile strain capacity of ECC was exhausted, major cracks were formed in the plastic hinge region, whereas at other sections ECC remained intact to transfer tensile stresses across cracks. Compared to conventional concrete, ECC resulted in more severe localisation of rotations in a limited region due to its tension-stiffening behaviour. Conclusions are drawn that application of ECC to structural topping and beam-column joints did not significantly enhance structural resistance of sub-assemblages under column removal scenarios. However, the calculated pseudo-static resistance of ECC sub-assemblage is greater than that of concrete specimen due to better energy-absorption capacity of ECC.