A Risk-Based Design Approach for Uncased Pipe Under Roads and Railways
Bibliographic record
Abstract
Abstract A risk-based pressure design approach has been developed for uncased pipe under roads and railways. Similar to the approach currently used in Canadian Standard Association’s Standard Z662, the approach uses a set of hoop stress factors to calculate the minimum wall thickness from the pipe’s pressure, diameter, and specified minimum yield strength. The hoop stress factors were calibrated to meet specified reliability targets considering the risk factors specific to roads and railways, which include elevated probabilities of mechanical damage due to higher construction activity rates, safety impact on road users, and potential costs of traffic interruption in case of a pipeline failure. The hoop stress factors are defined as a function of the safety class, which is determined according to the approach described in a companion IPC paper. This paper describes the development approach and provides a comparison between its results and the designs obtained from the current CSA Z662 approach. An analysis confirming adequacy of the resulting wall thicknesses to withstand normal traffic loads is also presented. The approach is being proposed as an alternative to the hoop stress factors currently used in CSA Z662.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".