Experimental study of durable low-friction concrete contacts for precast segmental columns with resettable sliding joints

Abstract

Planar sliding joints have been introduced to precast segmental bridge columns to alleviate the detrimental effects of earthquakes. However, residual sliding movements may result from strong shaking. Resettable sliding joints comprising V-shaped or W-shaped interfaces of gentle inclinations have been proposed to achieve better resilience against seismic actions in regions of moderate to high seismicity. However, possible deterioration of the frictional performance at the concrete contact surfaces may affect the resetting performance of these joints. In this regard, the tribological features, performance and durability at the interface of resettable sliding joints in precast segmental bridge columns were investigated experimentally utilizing 3D printed moulds and computed tomography scanning technology. Various surface treatment and lubrication methods were evaluated monthly up to 360 days after casting based on a modified cyclic direct shear apparatus at high loading pressure. Results show that high-performance PTFE grease lubricant is useful in achieving and maintaining favourable coefficients of friction as low as 0.05.