Comprehensive Condition Assessment of ASR Affected Pier Cap and Pier Shaft from Montreal's Champlain Bridge
Bibliographic record
Abstract
Alkali-Silica Reaction (ASR) is amongst the most harmful damage mechanisms affecting concrete infrastructure in Canada and worldwide. Among ASR affected structures in Canada the Champlain Bridge (CB), a six-lane highway bridge which crossed the St. Lawrence River and St. Lawrence Seaway in the province of Quebec, is a prime example with deterioration leading to closure of the bridge in 2019 after only 57 years in service. During decommissioning of the CB, a number of sections from its structural members (i.e., pier shaft – PS, pier cap – PC) were stored for further coring and analysis. This work presents a comprehensive investigation of an ASR affected PC and PS from the CB including a thorough external appraisal (i.e., comprehensive visual inspection and non-destructive testing) accompanied by laboratory investigation of extracted concrete cores using a multi-level assessment protocol (i.e., microscopic and mechanical test procedures). Microscopic investigations were conducted primarily using the damage rating index and supplemental image analysis while mechanical assessment was conducted through resonant frequency, the stiffness-damage test and compressive testing. This assessment identified ASR as the primary damage mechanism with cores exhibiting high to very high levels of deterioration in both members. Image analysis identified distinct crack orientations in extracted cores corresponding to expected expansion occurring preferentially to the least restrained directions of both the PC and PS members. Finally, a strong correlation between microscopic damage features and mechanical performance of the affected core specimens was observed; induced deterioration was found to be strongly associated to direction, depth and environment of the specimens.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".