1870s innovation in London Canada's Blackfriars Bridge
Bibliographic record
Abstract
Blackfriars Bridge in London, Canada, is a wrought-iron bowstring-arch-truss bridge fabricated by the Wrought Iron Bridge Company of Canton, Ohio and erected in 1875. Although typical of the 19 km of wrought-iron bowstrings constructed by the company in this period, the bridge is one of the first to feature a ‘double-panel’ web diagonal arrangement that was patented in the USA one year after the bridge was constructed. Considering the state of structural engineering knowledge in the 1870s, this paper investigates whether the structural response of the double-panel diagonal could have been correctly analysed by the original designers or whether the bridge may have been constructed as a prototype to validate this innovative feature. Design live loads are determined from values specified in the company's 1874 book of designs that depend on whether the bridge is located in the country, a town, a second-class city or a first-class city. The truss, statically indeterminate to the thirteenth degree, can be manually analysed neglecting slender web diagonals in compression if the participation of vertical members above the double-diagonals is ignored. The patent highlights the structural contribution of these members, however, and because their participation can only be accurately assessed using modern computer analyses, Blackfriars Bridge may have been built as a prototype to validate the double-panel design feature.
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.006 | 0.006 |
| Scholarly communication | 0.005 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.014 | 0.002 |
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".