Beam-Column Joint Panel Yielding for Seismic Energy Absorption

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Solution Overview

Problem

The existing beam-column joint structures in earthquake-resistant buildings face limitations in energy absorption performance and structural stability due to the reliance on plastic deformation of beams, which leads to local buckling and increased construction complexity with stiffeners and doubler plates, reducing productivity.

Innovation Solution

A beam-column joint structure design where the beam-panel strength ratio is set between 1.05 and 1.5, and the column-beam strength ratio is between 1.5 and 3.0, allowing the joint section panel to yield first and increase yield strength, with a backing bar having a bevel to mitigate strain concentration, and using high-toughness steel with enhanced Charpy absorbed energy to ensure ductile fracture properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the beam-column joint structure relies on plastic deformation of beams for energy absorption, then energy absorption capacity is improved, but local buckling occurs and construction complexity increases due to stiffeners and doubler plates

Engineering Contradiction:
Improveenergy absorption capacityVSAvoidconstruction complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The joint section is divided into multiple panels (first joint section panel and second joint section panel) with different configurations. The first panel uses a backing bar configuration while the second panel uses a no-backing-bar configuration, allowing different energy absorption mechanisms in different segments of the same joint structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the joint section are given different properties: the first joint section panel has enhanced toughness through backing bar support, while the second joint section panel relies on the inherent toughness of the joint section itself. This local differentiation allows optimized energy absorption without requiring complex reinforcement throughout the entire joint.

Inventive Principle:
Principle #3Local quality

2Reliability

If stiffeners and doubler plates are added to prevent failure, then structural stability is improved, but productivity decreases due to increased construction complexity

Engineering Contradiction:
Improvestructural stabilityVSAvoidproductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention changes the key parameter of joint section toughness by controlling the beam-panel strength ratio and using high-toughness steel materials. This parameter change allows the joint section itself to provide sufficient structural stability without requiring additional stiffeners and doubler plates, thereby maintaining productivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a simple backing bar configuration in the first joint section panel that can be easily installed and removed, rather than permanent complex reinforcement systems. This approach provides necessary structural stability during critical phases while keeping construction simple and productive.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Use of energy by moving object

If the beam-panel strength ratio is set between 1.05 and 1.5, then the joint section panel yields first and energy absorption is improved, but the column-beam strength ratio must be precisely controlled between 1.5 and 3.0

Engineering Contradiction:
Improveenergy absorption performanceVSAvoidstrength ratio control
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The invention establishes specific parameter ranges (beam-panel strength ratio of 1.05-1.5 and column-beam strength ratio of 1.5-3.0) that optimize energy absorption performance. These parameter changes create a controlled yielding sequence where the joint section panel yields first, absorbing energy through plastic deformation while maintaining overall structural integrity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4481142A1Beam-column joint structure
Publication Date: 2024.12.25 ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE (EPFL)
  • EP4481142A1 patent drawingFigure 1~2
  • EP4481142A1 patent drawingFigure 3A~4
  • EP4481142A1 patent drawingFigure 5~6

AI summary

A beam-column joint structure (1) including: a column (11) and an I-beam (212) with a pair of beam flanges (216) of the I-beam joined directly to joint plates (16) of the column main body via a welded section (218); wherein at the intersect position (P1), the ratio of the full plastic strength of the column relative to the full plastic strength of the beam is 1.5 or more and 3.0 or less, and the ratio of the full plastic strength of the beam relative to the full plastic strength of a portion (17a) of the column in the range of the height of the beam in the vertical direction is 1.05 or more and 1.5 or less.