The aim of this research project is to investigate, experimentally and analytically, the effects of reinforcement corrosion on the flexural, shear and blast behaviours of reinforced concrete beams.
As part of the experimental study, twenty-four beams reinforced were tested under quasi-static and simulated blast loads using the University of Ottawa Shock tube. All beams had dimensions of 125 mm x 250 mm x 2400 mm and were tested under four-point bending. Tension reinforcement consisted of either 2 – 10M (ρ= 1%) or 2 – 15M bars (ρ= 1.6%) for the flexure dominant specimens, and 2 – 25 M bars (ρ= 4%) for the shear-dominant specimens. In all cases, transverse reinforcement consisted of 6 mm stirrups spaced at s = 100 mm (d/2) throughout the beam span. Eighteen of the specimens were subjected to an accelerated corrosion process to induce different amount of mass loss in the longitudinal and transverse steel reinforcement. The test variables included: the type of corrosion (i.e. on the longitudinal or transverse reinforcement), the amount of corrosion (i.e. % mass loss in the steel reinforcement) and the extent / location of corrosion on the tension steel reinforcement (i.e. over the full length, middle span or end spans).
The results from the experimental tests showed that corrosion of the tension and transverse steel reinforcement decreased the strength and ductility of the reinforced concrete beams under static loading, ultimately changing the failure mode. Similarly, the results from the blast tests showed that corrosion of the longitudinal and transverse reinforcement affected maximum displacements and support rotations, reduced blast capacity, increased damage and fragmentation, and ultimately changed the failure process from ductile to brittle. Results under both static and blast loads were sensitive to the amount and extent/location of the corrosion.
As part of the analytical study, the static results were predicted using 2D finite nonlinear element
(FE) modelling. The effects of corrosion were considered using several modeling features including: reduction in steel bar cross-sectional area, modification of the steel stress-strain response, and introducing corrosion-induced cracking using applied pre-strains. The predicted results from the FE simulations were to provide acceptable predictions in terms of load capacity and failure mode when compared to the experimental static test results.
The blast results were predicted using two approaches, including: 1) single-degree of freedom (SDOF) analysis (with the resistance functions developed using FE modelling); and 2) the blast analysis capabilities of FE software VecTor2. Overall both approaches led to acceptable predictions of maximum mid-span displacements when compared to the experiments.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/42927 |
| Date | 16 November 2021 |
| Creators | Njeem, Wesam Mustafa Jumaa |
| Contributors | Aoude, Hassan, Martin-Perez, Beatriz, Jrade, Ahmad |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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