Interaction Diagrams of Short Rectangular RPC Columns Under Combined Axial Load Plus Uniaxial Bending

Abstract

Reactive Powder Concrete (RPC) represents one of the latest developments in concrete technology. The material and mechanical characteristics of RPC are significantly greater than the current ordinary concretes types classified as high-performance concrete. In this paper, the necessary equations are derived for the ultimate analysis of short rectangular RPC columns under combined axial load plus uniaxial bending. The derived equations are used to draw the required interaction diagrams which represent actual failure envelopes of eccentrically loaded RPC columns.To enable a close comparison with the corresponding interaction diagrams of ordinary reinforced concrete (ORC) columns, a 300X500 mm RPC column having concrete compressive strength f_c^,=110 MPa and steel yield stress f_y=400 MPa is analyzed twice (for steel ratio ρ=0.01 and ρ=0.03). The obtained interaction diagrams are compared with the corresponding interaction diagrams of ORC column having same cross section, same steel properties but different concrete compressive strength f_c^,=20.7 MPa. The comparison showed that failure envelopes of RPC columns, being influenced by the compression and tension capacities of concrete and yield stress of steel bars, are significantly larger than the corresponding failure envelopes of ORC columns which depend on the compression capacity of concrete only and the yield stress of steel bars.