Physical modelling to support the rehabilitation and design optimization of the jetties at the mouth of the Columbia River
Bibliographic record
Abstract
Originally constructed between 1885-1939, the three jetties protecting the Mouth of the Columbia River (MCR), the North Jetty, the South Jetty, and Jetty A have been progressively damaged due to storm wave attack and the loss of the sand shoal material that comprise their foundation. The MCR jetties are an essential part of maintaining the Columbia/Snake River navigation system, a significant export gateway for the west coast. In late 2014 Moffatt and Nichol (M and N) and the National Research Council of Canada (NRC) were commissioned by the US Army Corps of Engineers (USACE) to conduct physical model studies to inform and guide the design of repair works for two of the jetties, the North Jetty and Jetty A. Due to the exposed Pacific North-west conditions, strict environmental constraints, and the historic evolution of the existing structures, most notably a substantial relic stone foundation, the proposed repair works were complex and unconventional. Two separate three-dimensional physical models were constructed and used to investigate the performance of the proposed repairs for the two unique physical and functional settings at each jetty. Alternatives included rock armour and concrete armour units, tested under a range of site-specific design conditions, including extreme water levels and harsh wave conditions. This paper summarizes the physical modelling studies, the unique challenges presented by the complex bathymetry, and the important role physical modelling had in verifying and optimizing the reconstruction proposed for the North Jetty and Jetty A. The physical modelling provided essential identification of the near-structure three-dimensional interactions and guided the quantification of damages leading to optimization of the final designs.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".