Chen, Lai, Yan, Varma, Yu 2017
There is limited knowledge on concrete-filled steel tube-reinforced concrete composite members. CFT-RC members have advantages in having better lateral stability due to the RC plates’ flexural stiffness.
Experimental Study, Results & Discussion
There is limited knowledge on concrete-filled steel tube-reinforced concrete composite members. CFT-RC members have advantages in having better lateral stability due to the RC plates’ flexural stiffness. This paper explores the members’ fundamental behavior in axial load-displacement and creation of design equations estimating their axial compressive strength. Experimental results from 14 short column specimens-seven CFT-RC columns, four CFT columns, and three RC plates-are presented to fill knowledge gaps on these members. The specimens were a one-eighth scale of a prototype structure from the piers of the Ganhaizi Bridge in Sichuan, China. Parameters for the axial loading tests include the thickness of the steel tube wall and the RC plates. The steel rebars of the RC plates were welded to steel plates, then attached to the external face of the steel tube wall. Data from 104 CFT column tests were combined with the experimental results in a database to create behavior-based design equations. These equations assisted in approximating the axial compressive strength of the short column CFT-RC members. Experimental results report the failure mode of CFT-RC columns was the crushing of the RC plates at peak load, occurring at an axial strain of 0.002. The CFT columns sustain axial resistance after the RC plates fail. An increased steel tube and RC plate thickness culminated in an increased axial compressive strength in the CFT-RC columns. Observing the experimental results demonstrates the design equations ability to conservatively determine the axial compressive strength of the stub CFT-RC columns.
Analytical Study
Design equations were created from the cumulative database to estimate the strength of the CFT-RC column specimen. The calculated nominal axial strengths for all stub CFT-RC columns tested were compared with the measured experimental results.
Reference
Chen, B., Lai, Z., Yan Q., Varma, A. (2017): “Experimental Behavior and Design of CFT-RC Short Columns Subjected to Concentric Axial Loading” Journal of Structural Engineering Vol. 143 Issue 11 doi:10.1061/(ASCE)ST.1943- 541X.0001879.