Discussion of "Making use of brace overstrength to improve the seismic response of multistorey split-X concentrically braced steel frames"
Bibliographic record
Abstract
Redwood and Paultre 687 The authors have pointed out inconsistencies among the design and analysis assumptions used in Redwood et al. (1991). These inconsistencies originated from the collaboration among the first two authors of this reference, Redwood and Lu. In the paper under discussion, the first series of structures studied (the 2 to 12 storey L, R, and S buildings in Victoria and Quebec City) were designed without inclusion of P-delta effects that were included in the subsequent analyses. As pointed out in the paper, the lower base shear forces mandated by the 2005 National Building Code of Canada (NBCC) (NRCC 2005) compared with those in the 1990 NBCC (NRCC 1990) make P-delta effects more critical than earlier requirements. These forces are not insignificant. For example, the paper indicates that for the eight-storey L and R buildings in Victoria, the P-delta shear forces in the lowest storey would have increased the design shear forces by 20% and 30%, respectively. The enhanced storey ductility redistribution capacity (EDSRC) designed frames did have P-delta effects included; therefore, the improved performance of these buildings compared with the first series must be attributed to both the EDSRC approach and the impact of the P-delta forces included in these designs. The significant difference in design base shear forces as reported by the authors for the 8-storey split-X braced frame in Victoria (Vf/W is equal to 0.089 for NBCC 1990 (NRCC 1990) and 0.043 for NBCC 2005 (NRCC 2005)) can be partly explained by the difference in soil properties used in the two studies. Redwood et al. (1991) used a foundation factor of 1.0 corresponding to rock, dense and very dense coarse-grained soils, very stiff and hard fine-grained soils, etc., whereas the authors used accelerationand velocitybased site coefficients Fa = 1.0 and Fv = 0.78, and Fa = 0.836 and Fv = 0.640, corresponding to site class B for Victoria and Quebec City, respectively. However, site class C would appear to better represent the conditions used by Redwood et al. (1991). The difference is significant, as can be seen from the values of the design spectral acceleration function S(T) in the following table (NRCC 2005):
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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 | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 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".