Plastic Hinge Model and Displacement-Based Seismic Design Parameter Quantifications for Reinforced Concrete Block Structural Walls
Bibliographic record
Abstract
A practical alternative to the traditional rectangular cross sections of reinforced masonry structural wall systems is to alter the wall ends to allow for smaller compression zone depths, and thus higher curvatures to develop under increased seismic lateral loads. Despite the significantly enhanced seismic performance of flanged and end-confined masonry structural walls compared with their rectangular counterparts, seismic design parameters related to the former two types of walls have not been widely investigated. In addition, prescriptive design requirements for rectangular walls are under continuous development to meet the ongoing research findings in this area. The focus of the current study is to extract specific seismic design parameters of these three types of masonry walls having different end configurations for different aspect ratios when tested under reversed cyclic loads. The parameters investigated include the equivalent plastic hinge lengths, lp, the hysteretic damping levels and the trend of period shift corresponding to stiffness reduction with increased top wall drift. Three approaches were considered to evaluate the equivalent plastic hinge lengths, lp. The analyses showed that, following a widely accepted approach, the lp values at ultimate loads using the theoretical curvatures and experimental displacement ductility levels were approximately 40, 15, and 20% of the wall length for the rectangular, flanged, and end-confined walls, respectively. A mechanics-based model, accounting for the variation in curvature profile following yielding, strain penetration inside concrete foundation and the effects of inclined flexure-shear cracking, to determine wall top displacements was proposed. At 1% lateral drift, the calculated hysteretic damping ratios were found to be approximately 20% for all walls. At a displacement ductility level of 5.0, corresponding to almost no strength degradation, the period increased by at least 70% compared to that at first yield.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".