Concentric Compressive Performance of Precast Concrete Filled Steel Tube with Intermediate Construction Connection Made of High-Performance Concretes

Abstract Precast concrete-filled steel tubular (CFST) circular columns assembled with connecting joints are commonly employed in building structures. However, there is a lack of research regarding the behavior of precast CFST columns that are connected with construction joints made of high-performance concrete (HPC), such as engineered cementitious composites (ECC) as well as high-strength fiber-reinforced concrete (HSFRC). This paper presents an experimental investigation of precast CFST circular columns subjected to axial loads, tubed with galvanized steel sheets (GSS) and connected with joints made of ECC, HSFRC and normal concrete (NC). Ten slender columns are tested until collapse. The primary studied parameters include the development length along with the connection concrete type. The experimental results reveal that an increase in the development length of the reinforcement, i.e., the length of the connecting concrete joint significantly enhances both the cracking and the load-bearing capacity of slender CFST precast columns that are connected with an intermediate concrete joint. Moreover, the combination of GSS tubes with ECC and HSFRC joints markedly enhances the ultimate load, demonstrating an impressive increase of 115% and 247%, respectively, over the precast NC control column. In addition, three-dimensional nonlinear finite element modeling is performed considering the initially existing imperfection within the precast CFST columns which is validated against the experimentally obtained data. These models are utilized to further investigate parameters, such as GSS thickness and longitudinal reinforcement ratio.