Bond behavior of FRP-to-concrete under cyclic fatigue loading of RC structures strengthened with EB-FRP composites
Bibliographic record
Abstract
Reinforced concrete (RC) structures such as bridge girders are subjected, during their service life, to cyclic fatigue loading, mainly in the form of traffic loads. These structures are prone to progressive damage and may experience shear failure, which is often characterized by brittle rupture without any prior warning. Hence, retrofitting RC structures deficient in shear calls for the application of appropriate strengthening systems. The use of externally bonded (EB) fiber reinforced polymer (FRP) composites features numerous advantages and is a promising technology for shear strengthening of RC structures. However, the performance of EB-FRP retrofitted concrete structures can be highly influenced by the bond at FRP-to-concrete interface, as interfacial debonding can lead to the premature failure of the strengthening system. Limited investigations have been carried out on the FRP-to-concrete bond behavior of EB-FRP strengthened concrete structures under cyclic fatigue loading, and therefore, further related research will contribute to a better understanding of this complex research area. \n \nThe present research study aims to investigate the fatigue bond behavior at the FRP-to-concrete interface of EB-FRP strengthened RC structures. To this end, in the first phase of this study, a literature-review is conducted to identify the parameters affecting the fatigue bond mechanism at the FRP-to-concrete interface. Indeed, it is indicated that carbon FRPs (CFRPs) can provide better fatigue resistance than other FRP composites, such as glass and aramid FRPs. \n \nAn experimental investigation is conducted in the second phase of this study to fill existing gaps in the literature regarding the FRP-to-concrete bond behavior. A series of double-lap shear tests on CFRP-to-concrete bonded joints are designed to evaluate the interfacial behavior as a function of different variables, such as the FRP composite type (CFRP laminate vs. CFRP fabric sheet), the FRP-to-concrete width ratio (bonded FRP width to concrete width), and the FRP bond length under both monotonic and cyclic loading. The results of this experimental program demonstrate the superior performance of the CFRP composite bonding system using fabric sheet over the CFRP laminate in terms of bond ultimate resistance under monotonic loading and bond fatigue life under cyclic loading. Furthermore, increasing the CFRP-toconcrete width ratio was found to improve the bond behavior against the debonding failure mode under both loading conditions. As for the bond length, further discussions are presented to evaluate this parameter on the bond behavior, with emphasis on determining the effective bond length under both monotonic and cyclic loading conditions. \n \nBy incorporating the current experimental results and research data available in the literature, analytical studies are conducted to develop the following two models: 1) a bond stress-slip relationship under monotonic loading; and 2) a fatigue-life prediction model of CFRP-toconcrete bond under cyclic loading. Both models are shown to perform satisfactorily when validated against the selected database and can be an effective tool for predicting the bond behavior at the CFRP-to-concrete interface of concrete structures strengthened in shear with CFRP composites.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.004 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".