Experimental Study to Implement the Saw-Cut Technique in Post-tensioned Concrete Beams under Laboratory Conditions
Bibliographic record
Abstract
Post-tensioning is a common procedure used for prestressing a concrete member through reinforcement.The prestressing reinforcement is stressed after concrete casting, and the prestressing force is introduced by anchor heads at the member ends.Main codes provide specifications and requirements for design of post-tensioned concrete members (PCMs), so the designer set the initial prestressing force and must estimate the prestress losses along the service life of the member.Upon service loads.if prestress losses are underestimated in design, excessive deflections and unexpected cracking can occur, whereas inefficient designs are performed if prestress losses are overestimated.Therefore, an accurate determination of the residual prestressing force is essential within the context of the assessment of PCMs.However, conventional construction practice over the years has been carried out without the use of devices to track the evolution of prestress losses from casting, which, in turn, results in an unknown residual prestressing force.Therefore, it is necessary to implement suitable techniques and methods to determining the residual prestressing force in unmonitored PCMs.Hence, this contribution focuses on the development of an experimental study to implement the saw-cut technique to generate notches in post-tensioned concrete beams under laboratory conditions.The rationale of the testing procedure is described, together the main aspects to be considered from a metrological perspective from both electrical and non-electrical extensometry devices.The description of the experimental campaign and the variables considered to produce different stress-strain states, the steps to follow and track the sources of time-dependent prestress losses, and the main results obtained after testing a preliminary series of beams are presented.The advances achieved will serve as basis for a better understanding of the effects of notching by saw cutting and will facilitate further in-situ applications to determine the residual prestressing force in PCMs.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".