In regions of high seismicity, ensuring life safety in structures during and after a seismic event is an engineer's primary goal. Buildings must be designed for strength, providing enough resistance to avoid collapse.
Traditionally, steel building frames have utilized beam-to-column connections that are welded with the frame beams perpendicular to the columns. Beams connected to the face of columns rotate when subjected to racking of the building frame. These beams are designed to protect the column integrity and prevent collapse by plastically deforming during frame motion. This deformation, however, likely decreases post-earthquake building integrity in the process.
The Pin-Fuse Joint® allows building movement by maintaining structural elasticity. The joint introduces a circular-plated end connection for the steel beams framing into the columns within a moment-resisting frame. Slip-critical bolts connect the curved steel end plates. A steel pin or hollow steel pipe in the center provides a rotation point. Composed of standard structural steel building materials, the joint can be employed in buildings made of structural steel, reinforced concrete, or both.
Under conditions such as wind and moderate seismic events, the joint remains fixed. But when a severe earthquake strikes, the joints rotate through slotted bolted connections in the end plates without breaking or disconnecting. This allows the building to flex as the shock waves pass through it, dissipating the energy and reducing the potential damage to the structure. When the earthquake is over, the Pin-Fuse Joints® return to their usual positions, with the torque in the bolts intact.
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