Seismic Isolator Pullout Countermeasure Selection
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Solution Overview
Problem
Existing proposals do not effectively determine the location for providing a pullout countermeasure in plant support structures, where the vertical reactive force is unevenly balanced, making it difficult to identify where a pullout force becomes excessive.
Innovation Solution
A support structure with seismic isolators that are identified for a pullout countermeasure using a formula (NDn + NEQn > Ntn) to determine excessive pullout forces, allowing for targeted application of the countermeasure, reducing the number of locations needing it compared to uniform end-based application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pullout countermeasure is uniformly provided at ends of the structure, then the reliability against pullout is improved, but the device complexity and cost increase
Solution Approach 1:
The patent applies local quality by providing pullout countermeasures only at specific locations where they are actually needed, rather than uniformly across all ends. The method calculates pullout forces at each seismic isolator location and selectively applies countermeasures only where the calculated pullout force exceeds a threshold, thereby maintaining reliability where needed while reducing unnecessary complexity elsewhere.
Solution Approach 2:
The patent uses partial action by providing pullout countermeasures at only some locations rather than all locations. By calculating the pullout force at each seismic isolator and applying countermeasures only where NEQn > 0 (indicating excessive pullout force), the solution avoids excessive application of countermeasures at locations where they are not needed, optimizing both reliability and complexity.
2Reliability
If a pullout countermeasure is provided at all locations, then the reliability is improved, but the manufacturing cost and material usage increase
Solution Approach 1:
The patent determines the specific locations where pullout countermeasures are needed by calculating the pullout force at each seismic isolator position. Countermeasures are applied only where the calculated pullout force NEQn exceeds zero, ensuring that materials are used only where necessary for reliability, rather than being wasted at locations where they are not needed.
Solution Approach 2:
The patent avoids excessive application of countermeasures by using partial action - applying them only where the calculated pullout force indicates they are needed (NEQn > 0). This selective approach reduces material usage while maintaining the reliability required for seismic isolation performance.
3Measurement precision
If the vertical reactive force is evenly balanced, then the pullout force distribution is predictable, but the adaptability to plant support structures is reduced
Solution Approach 1:
The patent segments the structure into individual seismic isolator locations and calculates the pullout force at each location separately using the formula NEQn. This segmentation allows the method to handle unevenly balanced vertical reactive forces in plant support structures, as each location is evaluated independently based on its specific load conditions rather than assuming uniform distribution.
Solution Approach 2:
The patent changes the approach from assuming even load distribution to calculating actual pullout forces based on specific parameters at each location (vertical reactive force, overturning moment, horizontal force). By using these variable parameters rather than fixed assumptions, the method adapts to different structure types including plant support structures with uneven load distributions.
Data Source
AI summary
In a boiler support structure in which certain seismic isolators are provided with a pullout countermeasure, the seismic isolators to be provided with the pullout countermeasure are individually identified according to whether the seismic isolator satisfies Formula (1): NDn+NEQn>Ntn . . . Formula (1), where NDn (NDn<0) is a compressive load occurring on each of the seismic isolators and calculated on the basis of a permanent load imposed on the boiler support structure; NEQn (NEQn>0) is a pullout force occurring on each of the seismic isolators and calculated on the assumption that an earthquake has occurred; and Ntn (Ntn>0) is an allowable pullout force of each of the seismic isolators and calculated using an allowable pullout stress of each of the seismic isolators.