What is Partial Penetration Flange Plate Connection? Explain in details step by step procedure to make a Partial Penetration Flange Plate Connection with example and application.

A partial penetration flange plate connection is another type of structural connection used in steel construction. It involves welding a flange plate to the end of a steel beam or column using a partial penetration weld, which means the weld does not fully penetrate the thickness of the flange plate. This connection provides sufficient strength while minimizing welding time and material consumption.

Here is a step-by-step procedure to make a partial penetration flange plate connection:

Step 1: Design and Calculation

• Determine the loads and forces acting on the structure, including axial, shear, and bending forces.
• Determine the required size and thickness of the flange plates based on the applied loads and the material properties.
• Calculate the required number and size of bolts for the connection, considering the forces they will need to withstand.

Step 2: Preparation

• Gather the necessary materials, including the steel members (beams or columns) and the flange plates.
• Ensure that the surfaces to be welded are clean and free from rust, oil, paint, or any other contaminants.
• Prepare the welding equipment, such as welding machine, electrodes, and protective gear (e.g., welding helmet, gloves, etc.).

Step 3: Positioning and Alignment

• Position the steel members in their desired locations, ensuring proper alignment and orientation.
• Place the flange plate over the end of the steel member, ensuring it is centered and aligned with the beam or column edge.
• Use clamps or tack welds to temporarily hold the flange plate in place.

Step 4: Welding

• Start by tack welding the flange plate to the steel member. Tack welds are small, temporary welds that hold the plate in position.
• Determine the required length of the partial penetration weld based on the design specifications.
• Set up the welding equipment to achieve the desired welding parameters, such as current, voltage, and electrode size.
• Begin welding by creating a partial penetration weld along the length of the flange plate. The weld should only penetrate a portion of the plate’s thickness, typically 25% to 75%, depending on the design requirements.
• Ensure that the weld achieves good fusion with the steel member and provides sufficient strength for the applied loads.

Step 5: Quality Control

• Inspect the weld visually to ensure it is free from defects such as cracks, porosity, or incomplete fusion.
• Conduct non-destructive testing (NDT) techniques like ultrasonic testing or magnetic particle inspection to verify the integrity of the weld.
• Verify the dimensions, alignment, and overall quality of the connection according to the design specifications.

Example and Application: Let’s consider an example of a partial penetration flange plate connection in a steel bridge. Suppose you have a steel bridge girder that needs to be connected to a diagonal brace.

In this case, a flange plate will be welded to the end of the bridge girder using a partial penetration weld. The flange plate provides a larger bearing surface for distributing the load from the girder to the brace. The partial penetration weld ensures sufficient strength while reducing the amount of welding time and material.

Partial penetration flange plate connections are commonly used in steel structures where cost-effectiveness and speed of construction are important factors. This type of connection is suitable for applications such as bridges, industrial buildings, and infrastructure projects. It allows for efficient and economical fabrication while maintaining the required structural strength.

In summary, a partial penetration flange plate connection involves welding a flange plate to a steel member using a weld that does not fully penetrate the plate’s thickness. This type of connection provides sufficient strength while minimizing welding time and material consumption. It is commonly used in various steel structures where cost-effectiveness and speed of construction are crucial.