Investigation on drift ratio limits of PVA fiber reinforced concrete columns under different performance levels based on the Kunnath damage model

Within the context of the performance-based seismic design (PBSD), it is crucial to determine the drift ratio limits of PVA-FRCs under different performance levels. In this article, seven PVA fibers and high strength steel bars reinforced concrete columns were designed, and the quasi-static test was carried out to investigate their failure models and hysteretic loops. The calculated damage indexes using the Kunnath damage model were compared with the measured damage index ranges. The results indicated that the Kunnath damage model could accurately calculate the damage indexes of PVA-FRCs. According to the failure process of columns, the cracking point, yield point, peak point and ultimate point were used as the performance level control points of PVA-FRCs. Based on the idea of PBSD, the seismic performance levels of PVA-FRCs were divided into normal operation performance level, temporary operation performance level, reparable operation performance level, life safety performance level and collapse prevention performance level. Combined with the fiber concrete column test data in the references, the relative frequency statistics of the drift ratios of 38 PVA-FRCs at each feature point were carried out. The drift ratio limits under different performance levels and the corresponding damage indexes for PVA fiber reinforced concrete columns were established. Through the statistical analysis of relative frequency, the drift ratio limits of PVA-FRCs under different performance levels with more than 85% safety assurance rate were obtained, which were 1/300, 1/150, 1/80, 1/55 and 1/40, respectively. The performance level, damage state, lateral drift ratio limit and damage index were combined to form a relatively complete system to provide a reference for the anti-seismic repair of PVA fiber reinforced concrete structures.