Experimental and numerical investigations on interaction between reinforced‐concrete grid frame and ceramsite foam concrete infill

Abstract

AbstractExperimental and numerical studies were conducted to investigate interaction between reinforced‐concrete grid frame (CGF) and ceramsite foam concrete (CFC) infill. In the experiments, compressive tests were performed on the CGF and RC grid frame filled with the CFC which forms a composite wall, namely CGFW. To investigate the mechanical properties of the CGFW and the interactions between the CGF and CFC infill, the failure modes, integral stiffness, local strains, and load distribution coefficients of the composite wall were analyzed. The experimental results indicated that the CFC infill could uniformly transmit loads and significantly improve the bearing capacity and vertical stiffness of the CGFW while reducing the ductility of the composite wall. The load distribution coefficients of the CFC infill were stable at 0.51 ± 0.06 before peak load and damage evolutions in concrete columns were effectively alleviated due to obvious interactions between the CGF and CFC infill. To evaluate the interaction mechanisms of the two, numerical analysis was carried out by changing the sizes of central grid, opening rates, and reinforcement ratios of the composite walls. The finite element model with plastic damage constitutive of concrete was calibrated by comparing the experimental results. The numerical results indicated that the interaction between the CGF and CFC infill was insensitive to changes in grid sizes, and the interaction between the two was significantly different with the same reinforcement method of frame beams and columns. In addition, the CFC infill played an important role in the stability of CGF as the opening rate significantly affected the mechanical properties of the CGFW, and a stable path of load transfer was the key factor to ensure the interaction between the CGF and CFC infill.