High-Performance SMA–Based Self-Centring Precast Segmental Concrete Column: Design Concept, Test and Simulation

Abstract

This paper presents an experimental study of a novel high-performance self-centring (SC) precast segmental concrete column (PSCC) utilising shape memory alloy (SMA) bolts. The tested PSCC was constructed with four precast concrete segments and had a total height of 1555 mm. The whole column was assembled by connecting four segments through bolts solely, without using any complex anchorage for posttensioned components. Four 20-mm-diameter SMA bolts were used at the column base, whilst other segments were connected using high-strength steel bolts. Certain levels of prestrain were applied in the SMA and steel bolts when assembling, causing some minor initial cracks around the segment corners due to the casting imperfection and small gaps between the segments; however, no further crack development was observed after achieving stability. A series of cyclic and monotonic quasi-static tests were conducted to examine the working mechanism, structural behaviour, reusability, ductility and failure mode. Two cyclic horizontal loadings corresponding to a maximum drift ratio of 5% were applied consecutively, wherein the SMA bolts were retightened by hand in between. The SMA-SC-PSCC showed desirable flag-shaped behaviour under both loadings, with only some minor damages found on the concrete segments. Then, a monotonic loading was applied until the failure of the specimen, and the bottom segment fractured at a displacement of 86 mm (corresponding to 5.8% drift ratio). After the tests, a refined finite element model simulation was conducted as complementation. The satisfactory performance of the SC-PSCC showed that by using SMA bolts, the high-performance, low-damage and easy-construction design can be achieved simultaneously. The experimental and numerical results provided a promising design alternative in modern earthquake-resilient civil infrastructure.