Influence of Test Method on Direct Shear Behavior of Segmental Retaining Wall Units
Bibliographic record
Abstract
Abstract This paper reports the results of interface shear testing carried out to investigate the influence of test methodology on shear-displacement behavior of five different segmental (modular) masonry concrete block configurations. The tests were carried out in general conformance with existing ASTM and National Concrete Masonry Association test protocols. Three different normal load arrangements were investigated: (1) flexible airbag, (2) fixed vertical piston, and (3) an adjustable vertical piston. A video-extensometer camera device was used to record block deformations in the vertical plane during testing. The test results showed that the three load arrangements gave similar shear capacity failure envelopes for the frictional block system with flat concrete surfaces. For more typical block systems with concrete shear keys and trailing lips that exhibit dilatant interface shear behavior, or a system with shear pins, the most consistent test results were developed using the flexible airbag arrangement. The results of this paper can be used to guide the selection of the loading arrangement for conventional laboratory modular block shear testing.
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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 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".