Self-Centering Steel Frame Connection Design
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Solution Overview
Problem
Existing lateral resisting systems in self-centering steel frames face challenges in achieving strong horizontal load resistance, self-centering performance, energy dissipation capacity, and excellent ductility and fatigue resistance, particularly in managing seismic loads and minimizing residual deformations after earthquakes.
Innovation Solution
A connection design method for a self-centering steel frame system that incorporates a self-centering column base structure with embedded steel plates, disc springs, and C-type energy dissipation steel plates, along with high-strength anchor rods and pull rods, allowing for controlled deformation and energy dissipation during earthquakes, while maintaining structural integrity and facilitating rapid post-earthquake recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ductility design is used to protect life and avoid collapse under strong earthquakes, then structural safety is improved, but plastic deformation of main stressed members occurs causing economic loss and functional interruption
Solution Approach 1:
The lateral resisting system is segmented into independent functional components: self-centering braces for elastic recovery, energy dissipation devices for controlled plastic deformation, and damping devices for additional energy absorption. This segmentation allows each component to perform its specific function without compromising the overall structural safety while enabling rapid functional recovery.
Solution Approach 2:
Different parts of the bracing system are assigned different material properties and deformation characteristics. The self-centering braces use high-strength steel with elastic behavior, while energy dissipation devices use materials designed for controlled plastic deformation. This local differentiation of material quality optimizes both safety and functional recovery.
2Stability of the object's composition
If traditional lateral resisting systems are used to resist horizontal loads, then structural stability is improved, but residual deformation occurs after earthquakes requiring repair
Solution Approach 1:
The self-centering braces are pre-installed with initial tension to provide immediate elastic restoring force after earthquake displacement. This preliminary action enables the structure to automatically return to its original position without requiring post-earthquake repair, as the elastic deformation is fully recoverable.
Solution Approach 2:
The energy dissipation devices are designed to undergo controlled plastic deformation (discarding) to absorb earthquake energy, while the self-centering braces undergo elastic deformation that is fully recovered after the event. This selective discarding and recovering strategy protects the main structure while allowing easy replacement of sacrificial components.
3Productivity
If self-centering mechanisms are implemented to reduce residual deformation, then functional recovery is improved, but horizontal load resistance capability may be compromised
Solution Approach 1:
The system merges three distinct mechanisms into a unified bracing system: self-centering braces for elastic recovery, energy dissipation devices for plastic energy absorption, and damping devices for additional energy dissipation. This combination ensures that horizontal load resistance is maintained through multiple simultaneous mechanisms while functional recovery is achieved through the self-centering component.
Solution Approach 2:
The lateral resisting system uses composite construction with different material systems: high-strength elastic materials for self-centering, controlled-plasticity materials for energy dissipation, and viscous damping materials for additional energy absorption. This composite approach allows each material to contribute its optimal properties to both strength and functional recovery.
4Reliability
If multiple energy dissipation components are added to achieve strong earthquake resistance, then seismic performance is improved, but device complexity increases
Solution Approach 1:
The bracing system employs multi-functional components where each element serves multiple purposes: the self-centering braces provide both lateral load resistance and self-centering action, while energy dissipation devices simultaneously dissipate energy and maintain structural integrity. This multi-functionality reduces the need for separate dedicated components, simplifying the overall system despite its enhanced seismic performance.
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 system achieves strong self-centering ability, effective energy dissipation, and improved ductility, ensuring minimal damage and rapid functional recovery after earthquakes, with simplified calculation methods for accurate stress analysis and enhanced structural stability.
Implementation Method 1
the deformation of the second disc spring group on the plurality of groups of high strength pull rods connected with the beams and the columns is increased, so as to realize the rapid post-earthquake self-centering of the frame structure
Implementation Method 2
in an earthquake, when the cross beams swing, the earthquake energy can be dissipated in the earthquake by the C-type energy dissipation steel plates between the beams and the columns
Data Source
AI summary
The present invention discloses a connection design method for a lateral resisting system of a self-centering steel frame, comprising: determining basic sizes and performance parameters of a steel frame, a connection design load, the performance targets of connections and an inter-storey drift angle limit, calculating an inter-storey lateral drift limit, the rotational stiffness of a beam column connection and a column base connection and the angular drift limits of the beam column connection and the column base connection, designing the section size of an energy dissipation steel plate, calculating an allowable bending moment of a column bottom and an allowable bending moment of the beam column connection, an axial force of anchor rod and the axial force of a beam column and the local pressure of each flange when the column bottom reaches angular drift limits, conducting strength checking, stability checking and local pressure checking, and checking self-centering capability.