Composite Girder Design Based on AISC 360-05 / CBC 10 / IBC 09

Designing a composite girder based on the AISC 360-05, CBC 10 (California Building Code), and IBC 09 (International Building Code) involves several steps. Here is a general outline of the design process:

Determine the Design Loads:

Identify the live load, dead load, and any other applicable loads specified by the project requirements or codes.
Determine the load duration factors, such as short-term or long-term loads, as specified by the codes.
Select the Concrete Slab:

Determine the type and thickness of the concrete slab that will act compositely with the steel girder.
Consider factors such as the required fire resistance, durability, and construction constraints.
Design the Composite Girder:

Determine the effective flange width (beff) of the composite girder based on the interaction of the steel girder and the concrete slab.
Calculate the moment of inertia (Ieff) and section modulus (Seff) of the composite girder using the appropriate formulas provided in the AISC 360-05 code.
Determine the maximum allowable deflection based on the project requirements and applicable code limits.
Calculate the required section modulus (Sreq) of the composite girder based on the maximum allowable deflection.
Select a suitable steel section that satisfies the required section modulus.
Check Composite Action:

Verify that the composite action between the steel girder and concrete slab is achieved. This can be done by comparing the moment capacity of the composite girder (Mn) to the applied factored moments.
Check Shear Capacity:

Calculate the factored shear forces on the composite girder and verify that the shear capacity of the girder is sufficient to resist these loads.
Check Deflection:

Verify that the composite girder’s deflection under the factored loads is within the allowable limits specified by the codes.
Provide Detailing and Connection Requirements:

Design the connection details between the steel girder and concrete slab, ensuring adequate strength and stiffness.
Consider requirements for shear connectors, such as headed studs or shear studs, to achieve composite action between the steel girder and concrete slab.
Check Fire Resistance:

Evaluate the fire resistance of the composite girder based on the thickness and type of concrete slab, as well as any additional fire protection measures required by the codes.