Seismic performance of RC-ECC composite frame by eliminating shear reinforcement in beam-column joint: Shake table tests

Abstract

The inherent vulnerability of beam-column joints to seismic loading and steel congestion are two major research problems connected with beam-column joints of moment-resisting frames. The experimental study presented herein addresses these research questions and seeks to solve them by using Polyvinyl Alcohol based Engineered Cementitious Composite (PVA-ECC) in beam-column joints without transverse shear reinforcement. The study included the manufacture and shake table testing of two 1:3 reduced scale one bay two-story moment-resisting frame models using simulated earthquake motions. To evaluate the performance of ECC beam-column joints without shear reinforcement, two frame models, one with and the other without shear reinforcement in the beam-column joints, were prepared and tested. The acceleration time history record of the 1994 Northridge Earthquake USA was used for the excitation of specimens at different levels to produce progressive damage up to the near collapse state. The observed damage mechanism of tested models was recorded, and the response parameters, including floor displacement and acceleration, were measured. The measured data was processed to develop a lateral force-displacement envelope curve for the supposed prototype frames and calculate their seismic design factors (ductility, overstrength, and response modification). Comparison of the seismic performance parameters of the two prototype frames reveal that the ECC beam/column joint without shear ties performed marginally inferior to the ECC beam-column joints having shear ties but it still achieved a 75% larger R-factor compared with the code specified value.

Research on Optimization Design of Prefabricated ECC/RC Composite Coupled Shear Walls Based on Seismic Energy Dissipation

“…Cai et al [33] investigated the ductility, stiffness, and energy dissipation of ECC/RC composite frames compared to RC frames, noting significant improvements in the ECC/RC frames. Khan et al [34,35] demonstrated that ECC beam-column joints without shear reinforcement still surpassed the code-specified shear resistance. Ye et al [36] and Yang et al [37] conducted low cyclic loading experiments on RECC-coupled shear walls, finding that using ECC materials in cast in situ connection areas significantly improved the seismic energy dissipation capacity compared to specimens without ECC.…”

Numerical and experimental analysis in seismic performance of post-earthquake reinforced concrete frame retrofitted with ECC

“…However, due to the relatively small lateral stiffness, damage often occurs after strong earthquake actions (Civil et al, 2008; Gong et al, 2013; Kamogawa et al, 2005). For those post-earthquake damaged structures, it would be too costly to totally rebuild, while the option of strengthening and repairing can improve the seismic performance of the structure with a smaller increase in investment (Khan et al, 2022; Prota et al, 2004; Yuan and Hu, 2021). Therefore, the importance of post-earthquake strengthening research has been attracted much attention (Fischer and Li, 2003; Mosallam et al, 2019).…”