A new composite DSTC system that uses two different grades of concrete is developed.
Performance of the system is investigated through tests of 28 circular and square column specimens.
The new system exhibits superior compressive behavior compared to those of the conventional NSC and HSC DSTCs.
Both circular and square composite columns exhibit extremely high axial load and deformation capacities.
Improved performance is attributable to the system’s ability to maximize the benefits offered by NSC and HSC.