Flexural performance of precast circular reinforced concrete members with intermediate connection filled with ultra-high-performance-concrete

Precast Reinforced concrete (RC) columns with circular sections are increasingly being utilized in the construction of RC structures. This paper reports investigations into the flexural behavior of precast circular RC members with an intermediate connection filled with Ultra-High-Performance-Concrete (UHPC). Experimental program and results are described of twelve RC circular members tested under four-point loads up to collapse. Of the twelve columns, three of them are solid ones without intermediate connection, while nine of them are precast Normal Concrete (NC) panels connected with UHPC. The studied parameters are the existence of an intermediate connection (with and without connection), the ratio of longitudinal reinforcement (µ) ratio and the length of steel bars embedded in the UHPC connection (Le). Three concrete types are used including Normal Concrete (NC), Strain Hardening Cementitious Composite (SHCC), and UHPC. Test results show that increasing the reinforcement ratio and the embedded length of the steel bars increases the strength and energy absorption of members. Finite element models (FEMs) developed using ABAQUS are presented for capturing the responses of RC columns incorporating different concrete types. The good agreement between computer simulation and experimental results suggests that the FEMs can be utilized to undertake further parametric studies with confidence.