The Influence of Isolator Hysteresis on Equipment Performance in Seismic Isolated Buildings
Bibliographic record
Abstract
The seismic isolation code which must be used for all seismic isolated buildings in the United States is conservative in many of its provisions. While seismic isolation is flourishing in other countries, it is underused in the United States. For static analysis and for the selection of time histories, the spectrum is constant‐velocity for periods of one second and longer, leading to large displacements for long period systems and forcing the designer to use added damping to reduce these displacements. The damping systems used are hysteretic with the characteristic that damping decreases with increasing displacement. To achieve the damping needed to reduce these large displacements, expected from very rare seismic input, means that at smaller displacements, caused by realistic levels of seismic input, the damping will be very much higher, and there may be stiffening of the isolation system, meaning that the building may not act as isolated and there may be an impact on sensitive internal equipment. This paper shows how highly damped isolation systems are counterproductive to isolation and suggests an alternative approach that will conform to code requirements but ensure that, at moderate earthquake inputs, the equipment remains protected, and the large code‐mandated displacements are kept to acceptable levels.
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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 | 0.004 |
| 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 | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".