Experimental evaluation of multi-story self-centering prestressed concrete frames with web friction devices under cyclic loading

The self-centering prestressed concrete (SCPC) frame with web friction devices is a novel resilient structural system capable of achieving minimal post-earthquake residual displacement. However, present research on its seismic performance under cyclic loading is primarily focused on single-story structures, with little consideration given to the influence of web friction device performance deterioration induced by variations in clamping force applied through bolts. Because of more complicated mechanical systems, multi-story structures' seismic performance may differ from that of single-story ones. Given this, this study performed a thorough investigation of the seismic performance of a multi-story SCPC frame through quasi-static tests. To further detect the variation in the performance of the web friction device during the test, clamping forces were monitored. The experimental results reveal that structural behavior may not scale linearly with structure size, while the multi-story frame exhibits notable displacement-dependent behavior. The lagging effect of the web friction device was observed, where the frame with lower clamping forces (or friction forces) demonstrates a higher energy-dissipating capacity under small drift levels. Simultaneously, higher energy-dissipating capacity is accompanied by greater residual displacement. Besides, higher post-tensioning (PT) forces provide better stability and more consistent clamping forces, whereas lower PT forces result in greater variability in bolt clamping. While limited cracking patterns were observed, the study notes concern about PT tendon anchorage abrasion. These findings offer crucial insights for optimizing SCPC frames across various structural sizes, underscoring the importance of a balanced design approach that considers energy dissipation, self-centering capabilities, and structural complexity. •Friction devices guide vertical and shear cracks at the beam-column joint area.•Web friction devices show a lagging effect caused by static frictional forces•High-friction devices show high efficacy in severe versus regular seismic events.