Cracking characteristics and axial capacity degradation of precast segmental bridge piers connected with corroded tapered sleeve locking-type splicing

Abstract

The tapered sleeve locking-type splicing (TSLTS) reinforcement joint is a new method of steel mechanical connection. When applying the TSLTS reinforcement joints to precast segmental bridge (PSB) piers in coastal environments, the durability need to be taken into account. After the TSLTS reinforcement joint is corroded, the connection performance of the TSLTS reinforcement joint is degraded. Therefore, the mechanical properties of PSB piers decrease due to the corrosion of the joints, which brings some potential hazards. In this paper, the durability of PSB piers with TSLTS reinforcement joints in coastal environments was studied. The corrosion-induced cracking characteristics, failure mode and axial capacity of PSB piers with TSLTS reinforcement joints were investigated by means of accelerated corrosion test and axial loading failure test. The results indicated that, with increasing corrosion time, the total length of the corrosion-induced cracks on the surface of the pier specimens increased, but the increasing rate of the total length decreased. The mass loss of TSLTS reinforcement joints increased linearly with the maximum width of longitudinal corrosion-induced cracks on the concrete cover of the self-compacting concrete (SCC) segment, and the critical mass loss of TSLTS reinforcement joints was approximately 4.0 % when longitudinal corrosion-induced cracks appeared. The probability distribution type of the width of longitudinal corrosion-induced cracks on the surface of pier specimens was mainly a lognormal distribution. When the mass loss of TSLTS reinforcement joints was less than 7.2 %, the damaged area of the pier specimens was mainly concentrated in the SCC segment, while when the mass loss of TSLTS reinforcement joints was higher than 8.8 %, the damaged area was located in the ordinary Portland concrete segment near the top of the pier specimens, and the corroded TSLTS reinforcement joints could still maintain their connection performance. With an increase in the corrosion degree of the steel bars, the axial capacity of the pier specimens decreased, and the equivalent stiffness also degraded. The degradation rate of the axial capacity of the pier specimens increased linearly with the mass loss of the TSLTS reinforcement joints, and the degradation of the axial capacity occurred only when the mass loss of the TSLTS reinforcement joints was greater than 4.6 %. The research results can provide a theoretical reference for the application of TSLTS reinforcement joints in PSB piers.