Steel Column Base Anchor Yield Deformation Control
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Solution Overview
Problem
The existing column base structure has limited yield bending capacity due to excessive yield deformation in outermost anchor bolts, which restricts the overall structural performance under bending stress.
Innovation Solution
The proposed solution involves a column structure with a base member that incorporates first and second anchor members, where the second anchor member has smaller yield deformation and is positioned closer to the flange, allowing for differential yield deformation and increased bending capacity. The first anchor member is formed from a higher strength material or has a longer axial length, and both are strategically positioned to absorb bending stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple anchor bolts are provided to fix the base member to the foundation, then the base member can be securely fixed, but the yield bending capacity is limited by the outermost anchor bolts experiencing excessive yield deformation
Solution Approach 1:
The anchor bolts are segmented into two distinct groups: first anchor bolts positioned at the outer sides and second anchor bolts positioned at the inner side. This segmentation allows each group to serve different functions - the first anchor bolts provide outer anchoring while the second anchor bolts control yield deformation through their smaller yield deformation characteristic, thereby resolving the contradiction between secure fixing and yield bending capacity.
Solution Approach 2:
Different anchor bolts are assigned different local qualities - the first anchor bolts use standard materials for outer anchoring, while the second anchor bolts use materials with smaller yield deformation (such as higher strength steel or different cross-sectional dimensions). This local differentiation enables the inner anchor bolts to control yield deformation while outer anchor bolts provide secure fixing, improving overall yield bending capacity.
2Strength
If the base member thickness is increased to improve bending capacity, then yield bending capacity increases, but the device complexity and material usage increase
Solution Approach 1:
Instead of changing the geometric parameter of base member thickness, the invention changes the material parameters of the anchor bolts - specifically the yield deformation characteristic of the second anchor bolts. By selecting materials with smaller yield deformation for the inner anchor bolts, the system achieves improved yield bending capacity without increasing base member thickness or structural complexity.
3Ease of manufacture
If only standard anchor bolts are used for simplicity, then manufacturing is easier, but yield bending capacity cannot be optimized
Solution Approach 1:
The invention applies local quality by using standard anchor bolt materials and dimensions for the first anchor bolts (outer side) where simplicity is prioritized, while using specialized materials with smaller yield deformation for the second anchor bolts (inner side) where optimized performance is needed. This localized differentiation enables yield bending capacity optimization without requiring all anchor bolts to be complex custom designs.
Data Source
AI summary
In a column structure (10), a steel column (30) is joined to a base plate (16A). The steel column (30) is configured by a web (30A) and a pair of flanges (30B) provided at each of two width direction ends of the web (30A). A base plate (16A) is provided to first anchor bolts (24) and second anchor bolts (26) that are fixed to a foundation 12. The second anchor bolts (26) are provided further toward the web (30A) width direction inside than the first anchor bolts (24), and the yield deformation of the second anchor bolts (26) is set smaller than the yield deformation of the first anchor bolts (24).