Experimental study on the structural performance of RCP rehabilitation by spraying method under preloading

In this study, an investigation was conducted on the rehabilitation of longitudinally cracked reinforced concrete pipes (RCPs) under preloaded conditions using the spraying method, based on TEB tests. The effects of sustaining preload and not sustaining preload on the performance of the rehabilitated pipes were examined, alongside the relationship between external loads and pipe displacement, strain, and cracks. The results revealed that the bearing capacity of the rehabilitated pipe increased by 5.6% in Specimen B, which was unloaded after preload, and by 22.7% in Specimen C, which maintained preload, compared to the pre-rehabilitation pipe. Compared with Specimen B, the ultimate bearing capacity of the repaired pipe in Specimen C increased by 12.8%, although the displacement at failure was significantly reduced. The failure of the repaired pipe-lining structure primarily occurred through longitudinal cracking and interfacial detachment of the lining. The application of spray lining improves the structural performance of damaged pipe, especially for specimens that maintain preloading.