Discontinuous Elastic Zone Connections for Seismic Drift
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Solution Overview
Problem
Current structural framing systems rely on plastic ductile behavior of beams and connections, which can lead to significant damage and misalignment during seismic events, and require field welding with associated quality control issues and limitations, whereas they aim to achieve allowable drift without plastic deformation and enable self-realignment.
Innovation Solution
The implementation of discontinuous elastic zone connections in structural frames, which include faying surfaces and compression elements to regulate movement and enhance elastic behavior, allowing for increased elasticity and damping without relying on inelastic deformation, and utilizing bolted connections instead of field welding to reduce construction time and improve quality control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If plastic ductile behavior of beams and connections is used to achieve allowable drift, then drift capacity is improved, but structural damage and misalignment occur
Solution Approach 1:
The connection is segmented into distinct functional zones: a discontinuous elastic zone with compliance elements that allows controlled deformation, and continuous rigid zones that maintain structural integrity. This segmentation enables the connection to achieve drift capacity through localized elastic deformation rather than plastic deformation of the entire beam or connection, thereby avoiding structural damage.
Solution Approach 2:
The invention changes the mechanical parameters of the connection by introducing compliance elements (springs, elastomeric bearings, or hollow core rubber bearings) with specific stiffness characteristics. These elements provide a controlled elastic response that extends the elastic range of the connection, allowing it to accommodate drift demands through elastic deformation rather than plastic deformation, thus maintaining structural integrity.
2Strength
If field welding is used to connect beams to columns, then connection strength is improved, but construction complexity and quality control issues increase
Solution Approach 1:
The invention replaces the complex field welding process with a bolted connection system that incorporates compliance elements. Instead of requiring skilled welding operations in the field, the connection uses pre-fabricated compliance elements that are installed using bolted connections, significantly reducing construction complexity and improving quality control while maintaining adequate connection strength through the bolted assembly.
Solution Approach 2:
The compliance elements are pre-fabricated and pre-assembled in the shop with precise positioning and configuration, eliminating the need for complex field welding operations. This preliminary action in a controlled shop environment ensures high quality and reduces on-site construction complexity, as the pre-assembled units are simply installed and bolted into place.
3Stability of the object's composition
If rigid connections are used throughout the structure, then structural stiffness is improved, but drift capacity exceeds allowable limits
Solution Approach 1:
The invention applies local quality by introducing compliance elements only at specific connection locations where drift accommodation is needed, while the rest of the structure maintains rigid connections for overall stiffness. This localized approach allows the structure to achieve the required drift capacity through controlled deformation at the compliance elements, while the majority of the structure remains stiff and stable.
Solution Approach 2:
The invention introduces dynamic characteristics to the connection by incorporating compliance elements that can deform elastically in response to lateral loads. This dynamic capability allows the connection to adapt to drift demands by undergoing controlled elastic deformation, while the overall structure maintains its stiffness through the rigid portions of the framing system.
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
This approach extends the elastic range of structural framing elements, allowing for significant drift without plastic deformation, enabling self-realignment and reducing construction complexities, while improving the reliability and cost-effectiveness of seismic-resistant systems.
Implementation Method 1
a compression element positioned on each fastening device, with the compression element comprising a singular component or plurality of deformable components in a stacked arrangement. The compression element is configured to act in combination with a respective fastening device so as to regulate movement of the faying surfaces relative to each other
Implementation Method 2
discontinuities in the elastic behavior of the structural frame at the discontinuous elastic zones... configured to provide and allow for discontinuous elastic behavior of such system(s)... enhance the elastic characteristics of the structural frame and of its response to transient loads
Data Source
AI summary
A structural frame for a building includes first structural members and second structural members, with a discontinuous elastic zone at locations where the first and second structural members are coupled and through which a load passes therebetween. Discontinuous elastic zone connections couple the first and second structural members and are configured to provide elasticity in the structural frame and dampen the effects of transient loads on the structural frame. Each discontinuous elastic zone connection includes faying surfaces opposing each other, fastening devices configured to secure respective first and second structural members, and a compression element positioned on each fastening device configured to act in combination with a fastening device to regulate movement of the faying surfaces relative to each other, and thus regulate the behavior of the discontinuous elastic zone connection resulting from loads applied by first and second structural members on opposing sides of a respective discontinuous elastic zone.