Seismic performance of semi-precast high-strength recycled concrete columns with ultra-high-strength steel bar

Abstract

The purpose of this study is to promote the application of high-strength reinforcement and recycled aggregate concrete in post-earthquake repairable precast structures. Three large-scale recycled concrete columns with ultra-high-strength steel bar were designed and tested under quasi-static cyclic loads. The feasibility of semi-precast columns is verified, i.e., the concrete shell of the outer tube is precast first, and then the precast external shell is used as a formwork to cast concrete into the tube. The design parameters include axial load and the addition of steel fibers. The results indicate that all specimens exhibited a good deformation capacity with an ultimate drift ratio greater than 4%. Increasing axial load will increase the lateral load capacity of the specimen by 21%, while the deformability and repairability decrease. Adding steel fibers to the precast external shell can increase the lateral load capacity by 10%, as well as the deformability and repairability of the specimen. Due to the low bond strength of ultra-high-strength steel bar, it slips at the column footing in the tensile side. Eventually, the fiber-based model simplified flexural capacity calculation model considering the ultra-high-strength steel bar slippage in the tensile zone are established.

Keywords:

• Seismic performance
• semi-precast column
• recycled aggregate concrete
• ultra-high-strength steel bar
• reparability

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was supported by the National Natural Science Foundation of China (Grant No. 52178448).