Column-to-Beam Shear Connections for Selective Seismic Yielding
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Solution Overview
Problem
Steel moment-resisting frames are expensive due to inefficient use of materials and require costly connections, and beam yielding during earthquakes makes repair difficult.
Innovation Solution
A column-to-beam connection system with a shear component featuring a base plate and vertical web with openings to absorb loads, allowing selective yielding and facilitating repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If moment-resisting frames use stiff and strong connections between beams and columns to provide building stiffness and strength, then structural reliability is improved, but manufacturing cost increases
Solution Approach 1:
The connection system is segmented into distinct functional components: a base plate connected to the column, a beam flange connection element, and a shear component with controlled weak points. This segmentation allows each component to be optimized independently, with the shear component designed to yield at predetermined locations while other components maintain strength and stiffness, reducing overall material usage and cost.
Solution Approach 2:
The shear component incorporates local quality variations through predetermined weak points or reduced thickness sections at specific locations. These localized areas are designed to yield first under seismic loads, while the rest of the connection maintains full strength. This allows the structure to achieve the required reliability through localized ductility rather than requiring all components to be uniformly strong, reducing manufacturing costs.
2Reliability
If beam yielding is used to absorb earthquake energy, then structural reliability is improved, but ease of repair deteriorates
Solution Approach 1:
The yielding function is extracted from the primary structural members (beams and columns) and concentrated into a dedicated shear component designed for sacrificial yielding. This isolated yielding component can be easily removed and replaced after seismic events, while the main structural frame remains intact and reusable, significantly improving ease of repair compared to traditional beam yielding approaches.
Solution Approach 2:
The shear component is designed as a disposable element that yields and can be discarded after absorbing seismic energy. The predetermined weak points ensure controlled yielding that protects the permanent structural members. After an earthquake, the yielded shear component is removed and replaced with a new one, while the expensive beams and columns are recovered and reused, making the system economically viable for seismic zones.
Data Source
AI summary
Column-to-beam connection systems are disclosed herein, along with moment-resisting frames including the same and methods of repairing the same. An example column-to-beam connection system includes a shear component. The shear component includes a base plate that is connected to a column flange. The shear component also includes at least one vertical web extending from the base plate. The vertical web is connected to with a beam flange. The vertical web also defines one or more openings therein.