Behaviour of undercut anchors subjected to high strain rate loading
Bibliographic record
Abstract
The increase in global terrorism has culminated in the protection of high profile buildings and monuments against the effects of blast loading – a high strain rate loading event. Depending on the design basis threat, the level of protection can range from façade and fenestration upgrade to retrofit of the structural systems. Post-event surveys after the Oklahoma City Bombing and other similar events indicated widespread window glass damage. Most of the injuries reported were attributed to the glass shards, especially in buildings proximate to the target building. Thus, the least protection recommended for buildings is to retrofit window glass against glass shard injury. When the window retrofit consists of anti-shattered film anchored to the window frames, blast loads are transferred to the window frames and ultimately to the structure of the façade through discrete window retention steel anchors. A lot of research has been conducted to investigate the response of upgraded windows however little research is available on the load transfer from the window frames to the façade structure through the window retention anchors. This paper presents results from a finite element analysis program to investigate the tensile behaviour of post-installed undercut anchors under high strain rates. Strain rates varying from 10-5 to 103 s-1 were applied to single undercut steel anchors embedded in concrete blocks. Anchor diameters of 12 mm, 16 mm and 20 mm with various embedment depths were selected for the analyses. The analyses results show increased tensile capacity of undercut anchors with increase in strain rate. The maximum dynamic increase factor for tension of undercut anchors at strain rate of 103 s-1 was about 1.60 for the anchors investigated.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 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 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".