TIME-HISTORY ANALYSIS OF REINFORCED CONCRETE FRAMES RETROFITTED WITH BRB INCORPORATING SE-SMA CORE
Bibliographic record
Abstract
The numerical response of reinforced concrete frames designed following building codes and design standards prior to the enactment of modern seismic provisions was investigated using the nonlinear finite element method. An unbraced control frame and two frames retrofitted with a Buckling Restrained Brace (BRB) incorporating a stainless-steel core bar were modelled. The modelled structure reflects the first floor of a typical pre-1970s six-storey reinforced concrete frame building. The nonlinear static reverse cyclic loading performance of the frames was assessed, including the lateral strength and displacement capacities, stiffness response, and residual displacement, to validate the numerical response through experimental results available in the literature. A modified BRB design that incorporates a Superelastic Shape-Memory Alloy (SE-SMA) core bar and mitigates deficiencies identified with the original BRBs and conventional steel core bars, including accumulation of permanent displacements and concentration of strains/stresses on the core bar within the BRB, was also assessed under the same loading conditions. The results illustrate the benefits of implementing a self-centering material (SE-SMA) as a retrofit strategy to control permanent displacements. Furthermore, nonlinear time-history analyses were conducted. The control and SE-SMA retrofitted frames were subjected to earthquake records selected from available databases and simulated Western seismic hazard in Canada. Notably, the BRB frame incorporating an SE-SMA core exhibited improved seismic performance compared to the bare concrete frame by mitigating the accumulation of permanent displacements, decreasing peak lateral drift, and reducing cracking in the beam-column joints. The seismic performance of the six-storey control and SE-SMA retrofitted frames was later assessed under the same earthquake records. The results illustrate an improvement in the seismic performance of the structure retrofitted with the BRB incorporating SE-SMA as a core by reducing the transient and permanent drifts relative to the control frame. The reduction in residual displacements highlights the main benefit of SE-SMA bars as the core of BRBs since it increases the seismic performance and reduces damage in structures located in moderate to high seismic zones.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| 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".