Seismic performance of local prestressed concrete joint with interior anchorage in the core region

Local prestressing technology is widely used in large public and industrial buildings due to its flexible spatial arrangement and significant improvement of structural serviceability. However, owing to limited experimental research, the effects of asymmetry and anchorage characteristics in the core zone on the seismic performance of joints and the mechanical behavior of the core region remain unclear. This study conducted quasi-static tests on five local prestressed concrete (LPC) joints and one reference RC joint, supplemented by finite element parameter extension analysis. The influences of prestressing degree, beam depth ratio, joint stirrup ratio, and axial compression ratio on the seismic performance of the joints were investigated. The results indicate that LPC joints exhibit satisfactory ductility and energy dissipation capacity within prestressing degrees, beam depth ratios, and axial compression ratios of 0.8, 1.5, and 0.4, respectively. Based on the analysis of the mechanical mechanism of core concrete under the influence of anchorages, a modified softened strut-and-tie model suitable for asymmetrical internally anchored joints was developed. The model predictions show good agreement with experimental results and collected data, with errors within ±12.1%. Parameter analysis based on this method reveals the influence patterns of various parameters on the seismic bearing capacity of LPC joints.