Fire Resistant Steel Structure

Abstract

A fire resistant steel structure (10) comprises a steel beam (14) for receiving a vertical load and a support structure for supporting the horizontal beam (14) at two horizontally spaced locations. At least one fire-resistant tension member (30) has its ends (32, 32′) anchored outside the steel beam (14) in the support structure. It is arranged relative to the steel beam (14) in such a way that when the steel beam (14) is overheated and yields under the vertical load in case of severe fire conditions, it rests on the at least one fire-resistant tension member (30) and is vertically supported by the latter.

Description

TECHNICAL FIELD[0001]The present invention generally relates to a fire resistant steel structure.BACKGROUND ART[0002]Unprotected structural steel members like columns, girders, beams etc. lose most of their load bearing capacity when they are exposed to temperatures above 400 C. For warranting the required fire resistance rating in multistorey steel structures, it is well known in the art to use a fireproof heat insulation slowing down temperature rise in load bearing structural steel components. Known heat insulation measures comprise e.g.: fireproof encasements with slab-type materials made e.g. from calcium silicate or gypsum; mineral fiber insulations; spray applied fireproofing materials and intumescent paints or coatings. These fireproof insulations must generally be applied in-situ to all load bearing structural steel components, which is a costly and time-consuming operation.[0003]It is also known to use composite profiles, i.e. steel profiles with a partial or full concrete...

AI Technical Summary

Benefits of technology

[0020]In an alternative embodiment, the emergency backup support system for the steel beam includes at least one fire-resistant tension member arranged transversally to the steel beam. When the overheated steel beam yields in this embodiment, it rests on the at least one transverse fire-resistant tension member, e.g. directly with its lower flange or by means of an intermediate support member. Such a solution with at least one fire-resistant tension member arranged transversally to the steel beam may be of particular advantage in combination with a cellular steel beam having apertures in its web. This is because a transverse fire-resistant tension member does not impede the passage of conduits through the apertures in its web of the cellular steel beam.

[0021]Preferably, the at least one fire-resistant tension member is only slightly pre-stressed when the steel beam is cold, so as to have a sufficient reserve for supporting the overheated steel beam. Under the maximum load of the cold beam, the prestress tension in the at least one fire-resistant tension member should preferably not exceed 25%, more preferabl

Problems solved by technology

These fireproof insulations must generally be applied in-situ to all load bearing structural steel components, which is a costly and time-consuming operation.

However, they are

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