What is bolted Joints? Explain different types of Bolted Joints.
Bolted joints are a type of connection used in steel structures where steel members are joined together using bolts and nuts. This method involves creating holes in the members, aligning them, and then inserting bolts through the holes. Nuts are tightened onto the bolts to secure the connection. Bolted joints provide a strong and reliable connection and offer several advantages, including ease of installation, disassembly, and potential for future modifications or repairs.
There are different types of bolted joints commonly used in steel structures. Here are some of them:
- Lap Joint: In a lap joint, two members overlap, and bolts are inserted through the overlapping portion to create the connection. This type of joint is often used when joining plates or sections together, such as in the flange connections of beams or columns.
- Butt Joint: A butt joint is formed when the ends of two members are brought into contact, and bolts are inserted through aligned holes to connect them. This type of joint is commonly used in splices or connections between two members end-to-end.
- Tension Joint: Tension joints are used when the connected members are subjected to tensile forces. The bolts in a tension joint are tightened to a specified preload, ensuring that the joint can withstand the applied tension without failure.
- Shear Joint: Shear joints are designed to resist shear forces between the connected members. The bolts in a shear joint are tightened to transfer the applied shear loads effectively. This type of joint is commonly used in connections between beams and columns or between beams and bracing members.
- Bearing Joint: Bearing joints are designed to transfer compressive forces between the connected members. The bolts in a bearing joint are tightened to ensure that the bearing surfaces of the members can withstand the applied compressive loads without deformation or failure.
- Slip-Critical Joint: Slip-critical joints are used when the connected members are subjected to shear forces or loads that tend to slide the joint surfaces relative to each other. The bolts in a slip-critical joint are tightened to specific torque values to create enough friction between the surfaces, preventing slipping.
- High-Strength Friction Grip (HSFG) Joint: HSFG joints are similar to slip-critical joints and are designed to resist slip between the joint surfaces. In HSFG joints, high-strength bolts are used with hardened washers to create the necessary friction.
It’s important to note that the design and installation of bolted joints require careful consideration of factors such as bolt size, material, grade, torque specifications, and the use of washers or other components to ensure proper performance and load transfer. Following industry standards and guidelines is crucial for the successful design and execution of bolted joints in steel structures.