In steel structure construction, a moment-resisting joint is a connection between structural members that allows them to transfer moments or rotational forces from one member to another. These joints are designed to resist bending moments and provide stability and strength to the overall structure.
There are several types of moment-resisting joints commonly used in steel structure construction. Let’s explore them in detail:
- Bolted Flange Plate Connection: This type of joint involves connecting two beams or a beam and a column with bolted flange plates. The flange plates are welded to the ends of the beams or columns and are bolted together. The bolts transfer the bending moment between the connected members, allowing them to act as a continuous beam.
- Extended End-Plate Connection: In this joint, an extended end plate is welded to the end of a beam and bolted to the supporting column. The extended end plate provides a larger contact area and more bolts, which enhances the moment transfer capacity. This type of joint is commonly used in multi-story steel frame structures.
- Seated Connection: A seated connection involves connecting a beam to a column with a seated angle or plate. The beam’s bottom flange rests on the seated angle or plate, and shear studs are usually provided to enhance the connection’s shear resistance. Seated connections are commonly used in steel structures with composite floors.
- Flush End-Plate Connection: This joint consists of a flat end plate welded to the end of a beam and bolted to a column. The end plate is flush with the column, providing a clean and aesthetically pleasing appearance. Flush end-plate connections are widely used in industrial buildings and bridges.
- Moment-End Plate Connection: In this joint, the beam’s end plate is extended beyond the column face, forming a moment connection. The beam flanges are welded to the extended end plate, allowing the moment to be transferred between the beam and the column. Moment-end plate connections are commonly used in portal frames and rigid frames.
- Partially Restrained (PR) Connection: A partially restrained connection allows limited rotation between the connected members. This joint provides some flexibility and allows redistribution of moments in the structure. PR connections are commonly used in buildings where some degree of movement or rotation is desirable, such as in earthquake-resistant design.
- Fully Restrained (FR) Connection: A fully restrained connection is designed to prevent any rotation between the connected members. The connection resists both the moment and shear forces, providing maximum rigidity and strength. FR connections are commonly used in structures that require high levels of stability, such as high-rise buildings and bridges.
It’s important to note that the selection of a specific moment-resisting joint depends on various factors, including the structural design requirements, load conditions, architectural considerations, and construction techniques. The design and detailing of these joints are governed by relevant codes, standards, and engineering principles to ensure the safety and performance of the steel structure.
