Reduced-Order Modeling of Composite Floor Slabs in Fire. I: Heat-Transfer Analysis

Area of Science:

• Structural Engineering
• Fire Safety Engineering
• Computational Mechanics

Background:

• Composite floor slabs with profiled steel decking are common in construction.
• Accurate thermal analysis of these structures under fire conditions is crucial for safety.
• Existing detailed models can be computationally intensive.

Purpose of the Study:

• To develop a reduced-order numerical modeling approach for analyzing heat transfer in composite floor slabs exposed to fire.
• To simplify the complex geometry of profiled steel decking for thermal analysis.
• To validate the proposed model against experimental data.

Main Methods:

• Utilized a layered thick-shell formulation with alternating shell elements for thick and thin slab portions.
• Incorporated a linear density reduction in concrete within the rib to account for tapered profiles.
• Adjusted concrete specific heat in the rib to indirectly model heat input from the decking web.
• Determined an optimal ratio for modified concrete specific heat based on slab geometry.

Main Results:

• The reduced-order model effectively captures in-plane and through-thickness heat transfer.
• The approach successfully accounts for the geometric complexities of profiled steel decking.
• The model's predictions show good agreement with experimental results, validating its accuracy.

Conclusions:

• The developed reduced-order numerical modeling approach provides an efficient and accurate method for analyzing heat transfer in composite floor slabs under fire.
• This method simplifies complex geometries, reducing computational cost while maintaining predictive capability.
• The validated model can aid in the fire safety design and assessment of composite structures.