Flush end-plate connections are commonly used in steel structures to connect beams to columns. The design criteria for a flush end-plate connection involve determining the required end-plate dimensions, bolt sizes and spacing, and verifying the adequacy of the connection to safely transfer the applied loads. Here is a step-by-step procedure for designing a flush end-plate connection:
Step 1: Identify the Member Configuration Determine the specific configuration of the members involved in the connection, including the beam and the column. Gather information about their dimensions, material properties, and the connection requirements.
Step 2: Determine Applied Loads Identify the loads that will be applied to the connection, such as dead loads, live loads, wind loads, or seismic loads. Determine the magnitude, direction, and distribution 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 End-Plate Dimensions Calculate the required dimensions of the end plate based on the applied loads, the desired connection capacity, and design code requirements. The end plate dimensions should be selected to provide sufficient bearing area and stability for the connection.
Step 5: Check End-Plate Shear Strength Check the shear strength of the end plate to ensure it can safely resist the applied shear forces. Verify that the shear stress is within the allowable limits specified by design codes or standards.
Step 6: Check End-Plate Tensile Strength Check the tensile strength of the end plate to ensure it can safely resist the applied tensile forces. Verify that the tensile stress is within the allowable limits specified by design codes or standards.
Step 7: Determine Bolt Size and Spacing Determine the required bolt size and spacing based on the applied loads and the desired connection capacity. Calculate the number of bolts needed to safely transfer the loads. Consider factors such as bolt shear strength, bearing strength, and spacing requirements.
Step 8: 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 is within the allowable limits specified by design codes or standards.
Step 9: Check Bolt Bearing Strength Check the bearing strength between the bolt and the end 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 flush end-plate connection meets the desired safety and performance requirements. This may involve performing structural analysis or calculations to confirm the adequacy of the end plate dimensions, bolt sizes, and the connection capacity.
Example: Let’s consider the design of a flush end-plate connection between a steel beam and a column. The beam has a maximum moment of 100 kNm, and the desired connection capacity is 120 kNm. The material properties are as follows: beam and column yield strength = 250 MPa, bolt grade = 8.8 (yield strength = 640 MPa).
Step 1: Identify the Member Configuration The member configuration consists of a steel beam and a column, 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 End-Plate Dimensions Calculate the required dimensions of the end plate based on the applied loads, the desired connection capacity, and design code requirements.
Step 5: Check End-Plate Shear Strength Check the shear strength of the end plate to ensure it can safely resist the applied shear forces.
Step 6: Check End-Plate Tensile Strength Check the tensile strength of the end plate to ensure it can safely resist the applied tensile forces.
Step 7: Determine Bolt Size and Spacing Determine the required bolt size and spacing based on the applied loads and the desired connection capacity.
Step 8: Check Bolt Shear Strength Check the shear strength of the bolts to ensure they can safely resist the applied shear forces.
Step 9: Check Bolt Bearing Strength Check the bearing strength between the bolt and the end plate to ensure it can safely transfer the applied forces.
Step 10: Design Verification Perform a design verification to confirm that the flush end-plate connection meets the desired safety and performance requirements.
The detailed calculations and formulas for each step can vary depending on the specific design code or standard being used. It is important to consult the relevant design code or consult with a qualified structural engineer to ensure accurate and compliant connection design.
