The bond between concrete and steel under high slip rates is investigated in this paper. Beam-end specimens were used to investigate the bond properties. A modified split Hopkinson tension bar (SHTB) was used to induce the high strain rate loading. The slip between the rebar and the concrete was measured directly with the help of an optical extensometer measuring the displacement of the concrete and a digital image correlation measuring the movement of the rebar. The bond stress was derived indirectly from the strain measurements on the incident and transmission bar by utilizing the wave propagation theory. To fully understand the phenomenon, the experimental setup was modelled in LS-Dyna. In the simplified model, a contact algorithm was used to represent the bond zone between concrete and steel. This model served to validate the evaluation method of the experiments as the bond law was already implemented in the behaviour of the contact. In the detailed model, steel ribs were modelled explicitly and frictional contact between rebar and concrete was utilized to simulate the transfer of forces. Two material models were used to model the concrete behaviour, the Schwer and Murray and Concrete Surface Cap model. Bond stress-slip curves obtained from the experiments as well as from the numerical simulations are compared in the results section. The beam-end specimens are evaluated with respect to their suitability for high slip rate loading.
|Number of pages||8|
|Publication status||Published - 2022|
|Title||Bond in concrete - bond, anchorage, detailing: 5th International Conference|
|Duration||25 - 27 July 2022|
|Degree of recognition||International event|
|Location||University of Stuttgart|
- Beam-end test, Reinforcement's bond, Split Hopkinson bar, High rate loading