Link-Fuse Joint Seismic Resistance Design
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Solution Overview
Problem
Conventional link beam designs in structures subject to seismic activity often suffer from joint failure, leading to significant damage and potential loss of structural integrity during extreme seismic events, as they are designed to permanently deform and dissipate energy through plastic deformation.
Innovation Solution
The introduction of a 'link-fuse' joint that allows for slippage under extreme loads, altering the structure's dynamic characteristics by lengthening its fundamental period and enabling elastic behavior, thereby reducing the need for large shear walls or steel frames and dissipating energy through sliding, which maintains connectivity and reduces damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional link beams are designed with fully connected reinforcing bars to resist seismic loads, then the beams can withstand seismic events, but the beams permanently deform and concrete cracks or spalls, requiring significant repair or replacement
Solution Approach 1:
The link beam is segmented into an elastic segment (concrete beam with reinforcing bars) and a fuse segment (separate steel member), allowing the fuse segment to absorb seismic energy through controlled deformation while the elastic segment remains intact and functional
Solution Approach 2:
The energy-dissipating function is extracted from the concrete beam and placed into a separate fuse member, allowing the concrete beam to maintain its elastic properties and structural integrity while the fuse member undergoes controlled plastic deformation
2Loss of energy
If link beams are designed to plastically deform to dissipate energy, then energy dissipation occurs, but the beams act with ductility and permanently deform, compromising structural integrity
Solution Approach 1:
The energy dissipation function is extracted and assigned to a dedicated fuse member, separating the energy dissipation role from the structural beam, allowing the beam to maintain its composition and elastic behavior
Solution Approach 2:
The fuse member acts as an intermediary element between the elastic link beam and the supporting structure, absorbing seismic energy through controlled deformation and protecting the main structural components from damage
3Force
If fully connected reinforcing bars are used in link beams, then the beams can resist seismic loads, but the joints are unable to function elastically, leading to significant damage
Solution Approach 1:
The connection system is segmented into an elastic connection (allowing rotational movement) and a fuse member (absorbing shear forces), enabling the joint to function elastically while still resisting seismic loads
Solution Approach 2:
The joint is designed with dynamic characteristics that allow it to adapt during seismic events - the elastic segment permits rotational movement to accommodate ground motion, while the fuse member engages to resist excessive forces
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 link-fuse joint enables structures to withstand seismic events without significant beam or joint failure, maintaining structural integrity and reducing overall building costs by allowing elastic behavior and energy dissipation, while preventing plastic deformation and damage.
Implementation Method 1
The friction developed from the clamping force within the plate assembly with the brass shims against the steel surface prevents the joint from slipping under most service loading conditions
Data Source
Figure 1
Figure 2
Figure 2a
AI summary
A link-fuse joint resists bending moments and shears generated by seismic loading. A joint connection includes a first plate assembly having a first connection plate including a first diagonal slot formed therethrough. A second plate assembly has a second connection plate including a second diagonal slot formed therethrough. The second diagonal slot is diagonally opposed to the first diagonal slot. The second connection plate is position such that at least a portion of the second diagonal slot aligns with a portion of the first diagonal slot. A pin is positioned through the first diagonal slot and the second diagonal slot. The joint connection accommodates a slippage of at least one of the first and second plate assemblies relative to each other when the joint connection is subject to a seismic load and without significant loss of clamping force.