Resilient slip-friction connection-enhanced self-centering column for the low-damage prefabricated underground structures

The application of prefabricated assembly technology in underground structures has increasingly garnered attention due to its potential for urban low-carbon development. However, given the vulnerability of such structures subjected to unexpected seismic events, a resilient prefabricated underground structure is deemed preferable for mitigating seismic responses and facilitating rapid recovery. This study proposes a resilient slip-friction connection-enhanced self-centering column (RSFC-SCC) for prefabricated underground structures to promote the multi-level self-centering benefits against multi-intensity earthquakes. The RSFC-SCC is composed of an SCC with two sub-columns and a series of multi-arranged replaceable RSFCs, intended to substitute the fragile central column. The mechanical model and practical manufacturing approach are elucidated, emphasizing its potential multi-level self-centering benefits and working mechanism. Given the established simulation model of RSFC-SCC-equipped prefabricated underground structures, the seismic response characteristics and mitigation capacity are investigated for a typical underground structure, involving robustness against various earthquakes. A multi-level self-centering capacity-oriented design with suggested parameter selection criteria is proposed for the RSFC-SCC to ensure that prefabricated underground structures achieve the desired vibration mitigation performance. The results show that the SCC with multi-arranged replaceable RSFCs exhibits a significant vibration isolating effect and enhanced self-centering capacity for the entire prefabricated underground structure. Benefiting from the multi-level self-centering process, the RSFC-SCC illustrates a robust capacity that adapts to varying intensities of earthquakes. The multi-level self-centering capacity-oriented design effectively facilitates the target seismic response control for the prefabricated underground structures. The energy dissipation burden and residual deformation of primary structures are mitigated within the target performance framework. Given the replacement ease of RSFCs and SCC, a rapid recovery of the prefabricated underground structure after an earthquake is ensured.