Seismic Behavior of Low-Ductility Concentrically-Braced Frames
Bibliographic record
Abstract
Current codes allow engineers in moderate seismic regions to ignore seismic detailing as long as they design the structure using R = 3. However, recent research has raised questions regarding the reliability of such systems. When subjected to the maximum considered earthquake seismic hazard, the collapse of these systems becomes inherently dependent on their reserve lateral load-resisting capacity. Several sources of reserve capacity in these structures have been identified: connections in the gravity framing system, connections in the braced frame system, column continuity, base fixity, and brace re-engagement. In this paper, the results of several parametric OpenSees studies are presented in order to evaluate the effect of these sources of reserve capacity in traditional R = 3 systems, with focus on a three-story prototype chevron concentrically-braced frame. Nonlinear, inelastic, static analysis, as well as nonlinear, inelastic, incremental dynamic analysis for a suite of earthquake ground motions was performed. Various limit states for these structures were identified, and failure of the welded connection between the brace and gusset plate was identified as the prominent event affecting collapse performance.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".