Abstract
Ribbed reinforcing steel bars (rebars) are used for the reinforcement of concrete structures. In service, they are subjected to cyclic loading. Several studies addressing the relationship between rib geometry, stresses at the rebar surface induced by service loads and the rebar fatigue performance can be found in literature. However, the rebar’s fatigue performance is also influenced by residual stresses originating from the manufacturing process. In this contribution, a modeling approach is proposed to examine geometrically and thermo-mechanically induced stress concentrations in ribbed reinforcing bars made of the steel grade B500B. A linear-elastic load stress analysis and a thermo-mechanical analysis of the manufacturing process are conducted. The results are discussed and compared to literature results. In case of the load stress analysis, the results agree well with findings reported in literature and extend the current state of knowledge for B500B rebars with small diameters. In case of the thermo-mechanical analysis, compressive residual stresses at the rebar surface between two ribs and tensile residual stresses in the longitudinal direction at the tip of the ribs can be reported.
Highlights
Reinforcing bars are cylindrical steel bars used for the reinforcement of concrete structures [1]
Experimental approaches to determine residual stresses are restricted to single stress components or to the rebar surface [3,17,18,26,28]
The influence of rib spacing is significant only for small values. These results are in good agreement with numerous observations reported in literature [12–16,18–20,24] and extend the current state of knowledge for B500B rebars with small diameters. These results indicate that it is possible to predict the influence of single geometry parameters on the load stress distribution at least qualitatively with the model geometry used
Summary
Reinforcing bars are cylindrical steel bars used for the reinforcement of concrete structures [1]. A typical manufacturing route is the so called TempCoreTM process (Figure 1), within which the rebar is rapidly quenched from the austenitic state by water spray cooling in a first step after hot-rolling During this first step, the outer layer of the rebar transforms from austenite to martensite and possibly bainite up to a certain hardening depth, while the core stays austenitic. The rebar is cooled to room temperature in air During this second step, the remaining austenite transforms into ferrite and pearlite while the heat from the core reheats the outer martensitic layer, which becomes tempered (Figure 2). Experimental approaches to determine residual stresses are restricted to single stress components or to the rebar surface [3,17,18,26,28] To close this gap, numerical simulation plays an important role. The numerical predictions are discussed and compared to literature results
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call