Study on seismic behavior and damage models of BFRC and RC/ECC piers

This study investigates the use of highly ductile engineered cementitious composites (ECC) to replace ordinary concrete pier in the plastic hinge zone and compares them with basalt fiber reinforced concrete (BFRC) pier, with the aim of analyzing the difference in seismic performance between these two types of pier models (Reviewer #1, question 1). The seismic performance differences between these two types of piers were investigated and compared through quasi-static experiments and numerical simulations. Seismic performance indicators, such as experimental failure mode (Reviewer #1, question 3), hysteretic behavior, pier ductility, and energy dissipation capacity, were used to analyze the seismic performance differences between BFRC and RC/ECC composite piers. According to the experimental findings, the BFRC pier’s peak load capacity exceeds that of the RC/ECC composite pier by 15.1%, while the latter shows a 30.7% greater ultimate displacement compared to the BFRC pier. Numerical simulations, based on the experimental data, were performed, and the results demonstrated a high degree of agreement with the experimental observations. Numerical simulations show that increasing the axial load ratio leads to a marked decrease in the pier model's ultimate displacement. Moreover, at higher axial load ratios, the RC/ECC composite pier performs worse seismically than both the BFRC and RC piers. As the shear-span ratio increases, the ductility factor of the RC and RC/ECC composite piers first grows and then diminishes. However, the seismic performance of the BFRC pier is negatively affected by an increase in the shear-span ratio throughout. From the failure modes identified in the quasi-static tests, new damage models for RC, BFRC, and RC/ECC piers were suggested. The modified damage models were validated by comparing them with the observed damage curves, demonstrating their practicality and applicability.