Assessing Compressive Properties of GFRP Bars: Novel Test Fixture and Statistical Analysis
Bibliographic record
Abstract
This study investigates the compressive behavior of thermoset glass fiber–reinforced polymer (GFRP) bars across different grades, sizes, and length-to-diameter (L/db) ratios using a novel testing fixture. A total of 61 specimens were subjected to testing, encompassing bars in three sizes, three grades, and three L/db ratios. The new testing fixture, informed by insights from previous methods and initial investigations, easily adaptable to different bar diameters, and eliminates the need for resin, grout, or permanent attachment, allowing for reuse. Using this testing method, consistent measurements of compressive strengths were obtained for L/db = 2, reaching approximately 0.86 of their average measured tensile strength. These measurements exhibited a low standard deviation (SD) of 0.047 and a low coefficient of variation (CoV) of 5.4%. Additionally, the elastic modulus in compression closely aligned with the tensile modulus, with a ratio of 0.97, and minimal variation in measurements (SD = 0.032 and CoV = 3.3%). Increasing the L/db ratio of bars from 2 to 6 escalated result variability and reduced the compressive to tensile strength ratio (ffc/fft) from 0.86 to 0.63, mainly due to increased susceptibility to buckling as observed in the experiments. However, the elastic modulus ratios (Efc/Eft) remained consistent around 1.0. The results of a comparative statistical analysis using data from studies over the last decade highlighted a decreasing trend in ffc/fft ratios with increasing L/db ratios, having an average of 0.7. However, Efc/Eft remains stable at around 1.0 across different L/db ratios.
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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".