Abstract
This study presents an advanced structural analysis of a metal racking system subjected to real fire conditions using numerical simulation techniques. Computational Fluid Dynamics (CFD), thermal modeling, and structural analysis via the Finite Element Method (FEM) were integrated to evaluate the stability of a representative frame from a picking racking system exposed to a natural fire scenario. The results indicate that the structure maintains its integrity for at least 60 minutes without experiencing either partial or global collapse.
Introduction
The fire resistance of metal storage systems in industrial environments is a critical factor in ensuring structural safety during fire scenarios. In this context, a detailed study of an industrial racking system has been conducted using a numerical methodology based on Eurocodes and the finite element method to simulate its structural behavior under realistic thermal conditions.
Case Study
The subject of the study is a typical frame of a metal picking racking system, connected to a mezzanine located 3.5 meters high, with beams forming 2.7-meter-wide bays. The structure includes 12 distributed loading levels, supporting a total capacity of up to 7500 kg per frame.
Objectives of the Structural Analysis
- Evaluate the structural stability of the storage system under a representative natural fire scenario.
- Simulate the thermal evolution of the exposed structural elements without passive fire protection.
- Identify the most critical failure mechanisms under combined thermal and structural loading conditions.
- Verify compliance with fire stability requirements according to EN 1991-1-2.
Results
Fire Modeling and Simulation Conditions
The fire scenario was modeled using computational fluid dynamics with the FDS (Fire Dynamics Simulator) software, developed by NIST, in accordance with Annex D of EN 1991-1-2. The heat release rate (HRR) curve and its temporal evolution were defined to represent a localized fire.
The gas temperature does not exceed 400 °C during the simulated event. This limit, along with the high thermal conductivity of steel, the thin profile walls, and the high section factor of the members, validates the structure’s performance under fire exposures equivalent to 15 and 60 minutes.
Structural Modeling
A nonlinear static analysis was performed, incorporating both geometric nonlinearity (second-order effects) and material nonlinearity (elasto-plastic model) using finite elements.
Boundary conditions were defined as follows:
- Uprights were considered pinned at their base.
- Picking loads were applied with a 0.1 m eccentricity in the beam direction.
- The mezzanine load had a reduced eccentricity (0.05 m) due to the continuity of the upper deck, minimizing bending moment generation.
The results include total and principal directional displacement maps, as well as Von Mises stress distributions. No critical stress concentrations were observed that would compromise system stability.
Conclusions
The numerical analysis confirms that the frame of the metal picking rack, including the mezzanine, retains its load-bearing capacity for at least 60 minutes of exposure to the modeled fire scenario. The structure does not show signs of partial or global collapse within the critical period. The multidisciplinary approach—integrating CFD simulation, thermal analysis, and advanced structural calculation—enables highly accurate prediction of metal systems’ behavior under fire. This ensures regulatory compliance and safeguards both facility integrity and personnel safety.
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