Beam-to-Column Joint with Yieldable Tongue Plates
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Solution Overview
Problem
Existing beam-to-column joint connections in steel frame buildings lack independent beam-to-beam structural continuity and torsion capacity, limiting their ability to resist gravity loads and severe impacts, such as those caused by explosions or earthquakes, and fail to effectively distribute strain during cyclic rotational movements.
Innovation Solution
A joint connection structure featuring elongate horizontal cover plates with yieldable tongue portions that distribute strain over a larger volume of the beam, allowing for progressive plastic deformation and enhanced energy absorption during extreme events, thereby maintaining building integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional beam-to-column joint connections are used, then the structure is simple and easy to manufacture, but the joint connection lacks independent beam-to-beam structural continuity and torsion capacity, limiting ability to resist gravity loads and severe impacts
Solution Approach 1:
The joint connection is segmented into distinct functional components: cover plates for beam-to-beam continuity, gusset plates for beam-to-column connection, and yieldable tongue portions for energy dissipation. Each segment performs a specific function, allowing the complex joint to be designed and manufactured modularly while achieving superior structural performance.
Solution Approach 2:
The joint connection structure employs nested plates where cover plates are positioned over beam ends and nested with gusset plates that connect to columns. This nested arrangement creates multiple layers of structural reinforcement within a compact joint volume, providing both continuity and torsion capacity without excessive external complexity.
2Reliability
If reduced beam section (dog bone) joint connection is used, then inelastic hinge formation relieves stress in welded joint connection, but the plastic moment capacity of the beam is significantly reduced
Solution Approach 1:
Instead of reducing the beam section globally near the joint, the invention introduces local yieldable tongue portions on the cover plates that concentrate plastic deformation in specific localized areas. This allows the main beam section to retain its full moment capacity while providing controlled stress relief through localized yielding in the tongue portions.
Solution Approach 2:
The yieldable tongue portions act as intermediary elements between the beam and the rigid joint connection. These tongues serve as sacrificial components that undergo plastic deformation to absorb energy and relieve stress, protecting the main beam and welded connections from failure while maintaining the beam's full structural capacity.
3Stress or pressure
If slots and holes are provided in the web of the beam, then stress and strain distribution is improved in the vicinity of welded joint connection, but the beam's structural integrity and torsion capacity are compromised
Solution Approach 1:
Instead of modifying the beam web by adding slots or holes that compromise integrity, the invention extracts the stress distribution function to the cover plates and gusset plates. These external plates are configured with geometric features that promote favorable stress and strain distribution in the joint region without introducing weaknesses into the beam itself.
4Productivity
If conventional joint connections are used, then the structure is easier to erect, but the joint connection provides limited post-blast residual gravity load-carrying capacity and cannot resist simultaneous moment and axial tension
Solution Approach 1:
The cover plates and gusset plates are pre-configured with alignment features and connection details that facilitate rapid erection. The yieldable tongue portions are pre-formed to ensure proper stress distribution from the beginning, allowing the joint to achieve both easy assembly and superior post-event performance without requiring complex field adjustments.
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 solution significantly increases the beam's rotational performance and energy absorption capacity, extending its fatigue life and ensuring structural stability and human safety during severe events like earthquakes or blasts.
Implementation Method 1
the at least one of said pair of cover plates is plastically deformed progressively within said distal portion thereof with successive cycles of rotational movement, and said beam is also plastically deformed progressively in said volume thereof
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A building framework includes plural column assemblies (26) supporting plural beams (24) supporting floors of the building, with the union of the column assemblies and beams forming beam- to - column (or beam- to - column - to -beam) joint connection assemblies (28) according to this invention. The joint connection assemblies inventively include novel features which remarkably and surprisingly improve the distribution of strain and plastic deformation in the joint connection structure when subjected to extreme load challenges to the building structure (as may occur during earthquake, explosion, progressive collapse load conditions, or massive impact.