A bolted flange plate connection is a type of connection used to join steel members, typically beams or columns, to flange plates using bolts. This connection provides structural stability and load transfer between the members. The design criteria for a bolted flange plate connection involve determining the required bolt size, number of bolts, and plate thickness to safely transfer the applied loads. Here is a step-by-step procedure for designing a bolted flange plate connection:
Step 1: Identify the Member Configuration Determine the specific configuration of the members and their dimensions. This includes the type of members (e.g., beams, columns), their lengths, cross-sectional properties, and material properties.
Step 2: Determine Applied Loads Identify the loads that will be applied to the connection. This includes dead loads, live loads, wind loads, seismic loads, and any other relevant loads. Determine the magnitude, distribution, and direction of these loads.
Step 3: Analyze the Structure Perform a structural analysis of the entire structure to determine the forces and moments acting on the connection. Consider the loading conditions, support conditions, and member stiffness.
Step 4: Determine Required Bolt Size Based on the applied loads, calculate the required bolt size. The bolt size should be selected to provide sufficient strength to resist the applied forces. Consider factors such as the bolt material, grade, and allowable stresses.
Step 5: Determine Bolt Spacing Calculate the required spacing between bolts to ensure an even distribution of forces across the connection. This is typically determined based on the bolt size, plate thickness, and design code requirements.
Step 6: Determine Plate Thickness Calculate the required plate thickness based on the applied loads, bolt spacing, and design code requirements. The plate thickness should be selected to provide sufficient stiffness and strength to transfer the loads.
Step 7: Check Bolt Shear Strength Check the shear strength of the bolts to ensure they can safely resist the applied shear forces. Verify that the shear stress in the bolts is within the allowable limits specified by design codes or standards.
Step 8: Check Plate Tensile Strength Check the tensile strength of the flange plate to ensure it can safely resist the applied tensile forces. Verify that the tensile stress in the plate is within the allowable limits specified by design codes or standards.
Step 9: Check Bearing Strength Check the bearing strength between the bolt and the plate to ensure it can safely transfer the applied forces. Verify that the bearing stress is within the allowable limits specified by design codes or standards.
Step 10: Design Verification Perform a design verification to confirm that the bolted flange plate connection meets the desired safety and performance requirements. This may involve performing structural analysis or calculations to confirm the adequacy of the bolts, plate thickness, and their connections.
Example:
Let’s consider the design of a bolted flange plate connection between a steel beam and a flange plate. The beam has a maximum moment of 100 kNm, and the flange plate is made of steel with a specified yield strength of 250 MPa. We will use M20 bolts with a specified yield strength of 400 MPa.
Step 1: Identify the Member Configuration The member configuration consists of a steel beam and a flange plate, both with known dimensions and material properties.
Step 2: Determine Applied Loads The beam has a maximum moment of 100 kNm.
Step 3: Analyze the Structure Perform a structural analysis of the entire structure to determine the forces and moments acting on the connection.
Step 4: Determine Required Bolt Size Based on the applied loads, select a suitable bolt size. In this case, we will use M20 bolts.
Step 5: Determine Bolt Spacing Calculate the required bolt spacing based on the bolt size, plate thickness, and design code requirements.
Step 6: Determine Plate Thickness Calculate the required plate thickness based on the applied loads, bolt spacing, and design code requirements.
Step 7: Check Bolt Shear Strength Check the shear strength of the bolts to ensure they can safely resist the applied shear forces.
Step 8: Check Plate Tensile Strength Check the tensile strength of the flange plate to ensure it can safely resist the applied tensile forces.
Step 9: Check Bearing Strength Check the bearing strength between the bolt and the plate to ensure it can safely transfer the applied forces.
Step 10: Design Verification Perform a design verification to confirm that the bolted flange plate connection meets the desired safety and performance requirements.
Please note that the specific calculations and design criteria for a bolted flange plate connection may vary depending on the design codes or standards being used. It is recommended to consult the relevant design code or consult with a qualified structural engineer to ensure accurate and compliant connection design.
