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Deformation of Installation Mounting Rails in Case of Fire: Deviation between strains acc. EN 1993‐1‐2 and tested strains above 760°C
Author(s) -
Beiter Clemens,
Reichel Susanne
Publication year - 2019
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.1121
Subject(s) - modular design , creep , structural engineering , deformation (meteorology) , bending , flexibility (engineering) , stress (linguistics) , thermal , scale (ratio) , materials science , engineering , computer science , composite material , mathematics , physics , linguistics , statistics , philosophy , quantum mechanics , meteorology , operating system
Central components of modular installation systems are thin‐walled mounting rails from cold formed steel, guiding loads from attached installations via bending to supports. For temperatures of 760°C and above calculations with the stress‐strain relationships of EN 1993‐1‐2 provide deviant and unsafe deformation results compared to large scale fire bending tests following the standard temperature‐time curve acc. to EN 1363‐1. Therefore, deflections of these mounting rails in case of fire could be reliably determined in the past only with large scale fire tests. As an important attribute of modular installation systems is their flexibility in geometry and load supporting configurations, fire tests for the deformation evaluation of mounting rails are either required to a significant extent or conservative approximations via worst case scenarios are used, leading to over engineered solutions. This article describes the evolving discrepancy of the stress‐strain formulation specified in EN 1993‐1‐2 compared to results of unsteady thermal creep tests between 700°C and 800°C for S250GD and S280GD steel grades. In addition, it describes a new method how reliable statements about deformations of thin‐walled profiles in case of fire based on unsteady thermal creep tests, numerical simulations and large scale validation testing can be made in a flexible manner.