Seismic Safety Evaluation of a Full-Size Reinforced Concrete Frame Infilled With Precast Modular Reinforced Blocks Using Pseudo-Dynamic Testing and Nonlinear Dynamic Finite Element Analysis

Abstract

This study proposes a novel seismic retrofitting method involving a reinforced concrete (R/C) frame infilled with precast modular reinforced blocks (PMRBs) to address the limitations of conventional infilling techniques. The retrofitting system for the R/C frame infilled with PMRB maximizes the advantages of factory-produced modular reinforcement blocks, considerably improving the constructability and joint integrity between the existing frame and the reinforcement, without substantially increasing the structural weight. Moreover, this approach uses a typical frame-infilling method to enhance lateral load capacity, simplifying the calculation of the required amount of seismic reinforcement; thus, it is ideal for R/C buildings with non-seismic detailing dominated by shear failure because it helps secure the necessary strength. A pseudo-dynamic test was conducted using a full-scale two-story frame test specimen, based on an existing R/C building with non-seismic detailing, to verify the restoring force characteristics, strength-increasing effects, reinforcement strain and seismic response control capabilities of the PMRB frame-infilling system. Nonlinear dynamic finite element analysis (FEA) was performed to compare and estimate the results of the pseudo-dynamic test. The study results showed that the average deviation ratio for the seismic response load and displacement between the nonlinear dynamic FEA and the pseudo-dynamic test was approximately 10%, indicating similar outcomes. Under a design basis earthquake of 200 cm/s² in seismic intensity, the unreinforced R/C frame experienced shear failure, whereas the PMRB-reinforced frame sustained only minor earthquake damage, even under seismic accelerations of a maximum considered earthquake of 300 cm/s² and a large-scale earthquake of 400 cm/s². Thus, the newly developed PMRB frame-infilling system shows great promise for seismic reinforcement.