Experimental tests on strain rate dependence of mechanical characteristics of stainless steel bars for seismic resistant reinforced concrete structures

Abstract

Ribbed austenitic stainless steel bars have been recently proposed for use in reinforced concrete structures and are now available, with same lengths and current diameters of conventional carbon steel bars. Reinforced concrete seismic resistant structures may derive profit by using stainless steel bars as reinforcement, for their higher ductility and toughness. These properties are particularly suitable for critical regions of r/c frames, as the capability of energy dissipation as well as the ductile elongation are greater than for conventional steel. In addition to these mechanical characteristics, the high corrosion resistance of stainless steel reinforcing bars must be underlined, as regards the durability of the structure, even at high temperatures. These may make them economically competitive compared to conventional steel bars. This paper deals with comparative experimental monotonic uniaxial tests which have been carried out on highly-ductile stainless steel (AISI316) and conventional carbon steel (FeB44k) bars with different strain rates, typically occurring in most reinforced concrete structures during seismic excitations, in order to reproduce the actual behaviour of steel reinforcing bars in r/c structures during earthquakes. Various mechanical characteristics have been correlated to the strain rate, revealing a significant dependence on the strain rate, more evident for highly-ductile stainless steel bars, than for conventional carbon steel bars.