Visual and Non-Destructive Testing of ASR Affected Piers from Montreal’s Champlain Bridge
Bibliographic record
Abstract
Condition assessment of reinforced concrete structures presents a significant challenge worldwide as structures built in the post-war construction period (1950s–1970s) reach end of service life. The alkali-silica reaction (ASR) is one of several damage mechanisms which commonly affect infrastructure in Canada. Frequent freeze-thaw cycles and heavy use of de-icing salts in winter as well as high heat and humidity in summer are expected to have intensified ASR-induced damage. This work investigates five segments of a pier cap—PC, which had undergone encapsulation repair, and four segments of a pier shaft—PS, which represented dry and semi-submerged conditions, removed from a highway bridge constructed starting in 1957. Preliminary evaluation through visual inspection (conventional, qualitative and quantitative using the cracking index—CI) and non-destructive techniques (rebound hammer—RBH, ultrasonic pulse velocity—UPV and surface resistivity) was conducted on both internal (i.e., cut during decommissioning) and external (i.e., exposed while in service) surfaces of five PC segments and four PS segments. Differences in geometry, exposure conditions and repair history from the two members were found to have limited impact on the results of quantitative tests (i.e., CI, RBH and UPV results with average values of 1.6 mm/m, 37 MPa and 2.4 Km/s, respectively) while still exhibiting qualitative differences in visual determination (i.e., crack patterns, surface appearance and crack widths).
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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".