Effect of hoop spacing on the seismic response of coupling beams
Bibliographic record
Abstract
Coupled walls are among the most commonly used seismic force resisting systems within mid-to-high rise reinforced concrete structures in Canada.Coupling beams are a crucial component of the coupled wall system due to their effective energy dissipation capabilities and high ductility.In situations where coupling beams have a span-to-depth ratio greater than 4.0, conventional longitudinal reinforcement and transverse hoops are typically used to resist the applied moments and shear forces.The 2014 version of the CSA A23.3 Standard provides specific hoop spacing requirements which help ensure that flexural members subjected to seismic loading are designed to avoid brittle failure modes.However, these hoop spacing requirements are identical for both ductile and moderately ductile flexural members.As ductile and moderately ductile systems are meant to have significantly different energy dissipation capabilities and inelastic behaviour, a differentiation in hoop spacing between these two systems is proposed.Specifically, this differentiation would be accomplished by a relaxation in hoop spacing requirements for moderately ductile members as well as stricter hoop spacing requirements for ductile members.In order to investigate the validity of this proposal, four coupling beam specimens with varying ductility and hoop spacing were subjected to reversed cyclic loading.The performance of the coupling beams was based on the following metrics: predicted capacity and maximum load achieved, displacement ductility, cumulative energy dissipation, stiffness degradation, and load sustainability.In addition to the coupling beam specimens, reversed cyclic tests were carried out on "bare" 15M, 20M, and 25M reinforcing steel specimens.The results of the "bare" bar tests were used to provide insight on how the unbraced length of reinforcement affects buckling.The hysteretic response of the coupling beam specimens showed that a relaxation in hoop spacing requirements for moderately ductile members may be possible.In terms of the ductile specimens, the current hoop spacing requirements seem appropriate.It is suggested that further research be carried out in this area to confirm the validity of the results.
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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 | 0.000 | 0.000 |
| 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) | 0.002 | 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".