Seismic Bracing Yield Fuse With Ductile Necked-Down Bar
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Solution Overview
Problem
Existing seismic bracing systems for nonstructural items in buildings require high anchor forces due to the Omega factor of 2.0, leading to increased weight and complexity, which is not compatible with lightweight and compact requirements.
Innovation Solution
The development of a lightweight, compact seismic bracing system that incorporates a yield fuse, allowing for ductile yielding and reducing the required anchor forces by 200%, thus enabling the use of an Omega factor of 1.0.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid braces or cable braces with sufficient strength are used to resist seismic forces, then the strength and reliability of the bracing system is improved, but the weight and complexity of the system increases
Solution Approach 1:
The bracing system is segmented into two functional components: a rigid brace element for carrying normal loads and a separate yield fuse element for absorbing seismic energy. This segmentation allows each component to be optimized independently, reducing the overall weight while maintaining strength requirements.
Solution Approach 2:
A yield fuse is introduced as an intermediary element between the rigid brace and the anchor connection. This fuse acts as a mediator that undergoes controlled ductile yielding to absorb seismic forces, protecting the rigid brace and anchor from excessive loads while reducing the required strength (and weight) of the overall system.
2Reliability
If the Omega factor of 2.0 is applied to increase anchor force requirements, then the reliability of the anchor connection is improved, but the device complexity and number of anchors required increases
Solution Approach 1:
The yield fuse serves as an intermediary that provides the required ductile yielding behavior, allowing the anchor connection to be designed with a reduced Omega factor of 1.0 instead of 2.0. This maintains reliability through controlled deformation while significantly reducing the number of anchors and overall system complexity.
Solution Approach 2:
The introduction of the yield fuse changes the deformation and force distribution parameters in the bracing system. By providing a dedicated element for plastic deformation, the system can operate under different design parameters (Omega=1.0 vs Omega=2.0), reducing anchor force requirements and simplifying the overall design.
3Strength
If commercially available brace connections are designed to be strong and rigid, then the strength of the connection is improved, but the adaptability to ductile yielding requirements decreases
Solution Approach 1:
The connection system is divided into a rigid commercial brace component and a separate yield fuse component. This segmentation allows the rigid brace to maintain its strength and rigidity characteristics while the yield fuse provides the necessary ductile yielding capability, achieving both requirements simultaneously.
Solution Approach 2:
The yield fuse acts as an intermediary element that bridges the gap between rigid commercial brace connections and ductile yielding requirements. It provides the necessary plastic deformation capability while allowing the use of standard rigid brace components, enhancing adaptability without sacrificing connection strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The seismic bracing system with yield fuses achieves superior brace performance by allowing ductile yielding instead of sudden brittle failure, reducing the number of required braces and anchors, and enhancing the overall seismic performance of nonstructural items.
Implementation Method 1
The fuse member is configured to undergo ductile yielding in a length dimension upon application of a tensile or compressive force along the length dimension of the fuse member
Data Source
AI summary
Embodiments of the disclosure include a seismic bracing yield fuse for seismically bracing nonstructural equipment from a structural member of a building. The seismic bracing yield fuse includes a fuse member configured to undergo ductile yielding in a length dimension upon application of a tensile or compressive force along the length dimension of the fuse member. The fuse member includes two ends and a central bar positioned between the two ends. The central bar includes a neck down portion including a substantially constant cross section.