Bundling Effect on Bond and Development Length of Sand-Coated GFRP Bars
Bibliographic record
Abstract
One of the gaps in the new Building Code Requirements for Structural Concrete Reinforced with Glass Fiber–Reinforced Polymer (GFRP) Bars is design provisions for bundled GFRP bars. This study aims at establishing the bundling factor for the development length (Ld) of sand-coated GFRP bars embedded into normal strength concrete in bundles of two and three. A total of 12 notched beams were tested in flexure with spans ranging from 1 to 3 m, where the bars and surrounding concrete are under realistic tensile stress as opposed to pull-out tests. The embedment length (Le) of the bars varied from 17 to 87 times bar diameter (db), to establish a correlation with maximum tensile stress attained, thereby enabling calculating Ld. For each bundled arrangement, counterpart beams with spaced bars were also tested for comparison. It was found that bundling bars reduced the maximum attained longitudinal tensile stress at bond failure by 18%–30% for two bars and 20%–36% for three bars, within the studied Le range of 17–87db. At the full design tensile strength (ffu), Ld of bundles of two and three bars was 1.4 and 1.5 times larger, respectively, than spaced bars. As the tensile stress ratio (ff/ffu) reduced from 1.0 to 0.34 (as in compression-controlled failure), Ld of bundles increased up to 1.9 and 2.5 times the spaced bars, respectively. An expression for this variable bundling factor is proposed.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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; a candidate call from one teacher head, 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".