Experimental and numerical studies of circular precast concrete slender columns with intermediate connection filled with high-performance concrete

Precast concrete (PC) slender columns with intermediate connections are often used in building construction. However, no studies have been performed on the behavior of PC slender columns with intermediate connections filled with high-performance concrete namely engineering cementitious composites (ECC) and strain hardening cementitious composites (SHCC). This paper presents the testing and computer modeling of axially loaded PC slender columns with splices filled with ECC and SHCC. Experimental program and results are presented on nineteen PC slender columns under concentric compressive load up to collapse. The test parameters include the longitudinal reinforcement (µ) ratio, and embedded length of steel bars/infilled concrete connection (Le). Three different reinforcement ratios of 0.027, 0.031, and 0.036 are considered. The embedded length of steel bars/intermediate concrete connection varies from 15D, 22.5D, and 30D where D is the bar diameter. Experimental results indicate that the use of longer steel bars/intermediate concrete connection and a higher reinforcement ratio can significantly enhance both the cracking and ultimate loads of PC slender columns with an intermediate concrete connection. The elastic stiffness of the PC slender columns with ECC and SHCC connection is found to increase by 150% and 93%, respectively when compared to the control specimen. Similarly, filling the splice of the PC columns with ECC and SHCC improves the energy absorption capacity by 107% and 138%, respectively. Nonlinear three-dimensional finite element models (FEMs) are developed accounting for the initial imperfection of the slender columns and their accuracy is validated by experimental results. It is shown that the FEM can provide an accurate simulation of the performance of PC columns with splice connection.