Study on mechanical properties and bearing capacity calculation of eccentric compression of RC columns reinforced with prestressed lattice steel

Abstract

The external steel structure and RC column under eccentric compression have a reduced ability to work together, and using prestressing technology can significantly improve their ability to work together. Therefore, the paper proposes a new prestressed column reinforcement technology by adopting a space profile steel structure instead of angle steel and combining prestressing technology with the bolted connection. By conducting eccentric compression test studies on 11 specimens with different reinforcement methods, prestressing and eccentricity, load-displacement curves, stress distribution laws, ultimate bearing capacity, damage modes and prestressing influence rules were obtained. The main conclusions are as follows: prestressing can significantly improve the ability of external reinforcement steel structure and core column to work together and inhibit the development of concrete cracks. Compared with the traditional angle steel reinforcement, the bearing capacity is increased by 17.5 %, the stiffness is increased by 26.6 %, and the ductility is increased by 12.3 %. However, the reinforcement effect will be reduced if the prestressing is too large. It is recommended that the prestressing should be applied according to the size of 0.09 fc of the unilateral area of the core column. According to the prestressed lattice steel constraint mechanism, a mechanical analysis model of the reinforced member was established. Finally, based on the cross-section equilibrium method, a calculation method of eccentric compressive ultimate bearing capacity was proposed, and the research results can provide a basis for the engineering application of the new reinforcement method.