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This paper reports on an investigation of the effects of fire on long span truss floor systems in a tall building environment. The effects of fire spread over multiple floors of a building are the focus of this research, especially where this may lead to progressive collapse. The results from an investigation of a two-dimensional model of a multistory office building analysis are presented. The model is representative of the type of construction used in the World Trade Center Towers 1 and 2. The local and global response of the model is described over the course of a concurrent fire on three floors reaching a peak compartment temperature of 800°C. The results of the analysis show that large displacements may occur in long span structural floor systems without failure, however, the interaction of the highly deflected floors with the exterior or perimeter columns can lead to structural collapse. Additional structural members, such as hat trusses, that allow redistribution of loads away from the exterior columns to the core columns have a significant beneficial impact on the robustness of the structure. [ABSTRACT FROM AUTHOR]

Abstract: Much research has been and is currently being done to try and accurately recreate the effects of fire on structures including the effects of redistribution within the structure and the associated changes in load carrying mechanisms. This work has mostly focussed upon the most common and simplest structural forms currently used. As such most of the research to date tends to involve Universal Beam and Universal Column sections in a grid formation with spans of 6–9 m. This paper reports on an investigation of the effects of heating on a long span truss floor system. The ABAQUS finite element package is used to model the structure including fully non-linear behaviour and thermal expansion effects. Different boundary conditions and heating regimes are investigated to understand the response of the truss members to fire. The effects of heating on the lateral restraint available from the slender floor systems to a column have also been studied. The results and analysis indicate that composite truss flooring systems may not fail suddenly. Individual member buckling seems to be a much more gradual occurrence linked to material failure and expansion based geometry change rather than sudden “failure”. [Copyright &y& Elsevier]

A great deal of work on the behavior of composite steel concrete structures in fire has been developed since the Cardington frame fire tests (UK) conducted in the 1990s. This has now been broadened so that the design of structures to resist fire has a real engineering basis and is not reliant on results from single element testing in the standard furnace. Several projects involving office buildings in the UK and abroad have highlighted the need for developing the understanding of whole frame behavior in fire. Since the collapse of the World Trade Center in New York City in 2001 (9/11), robust engineering solutions incorporating the response of a building to fire are in great demand. The basics of structural mechanics at high temperatures can be used in such designs to understand the fire response of many structures with the aid of computer modeling. This article provides a direct comparison between the structural response of an eleven-story office building in the city of London, when designed in a prescriptive manner with applied fire protection on all load bearing steelwork, and the response of the same structure designed using a performance-based approach leaving the majority of secondary steelwork unprotected. The intent is to demonstrate that structural stability during a fire can be maintained in specific cases without relying on passive fire protection. This study contributes to the field of structural fire engineering by extending the research work previously conducted by the author to a real design case and addresses the issues raised by approving authorities, insurers, and the client when a fire engineered approach is used to calculate structural response to fire. It also demonstrates the use of advanced analysis to understand beam-core connection response in a fire, as part of a series of global finite element analyses to ensure that the unprotected structure proposed provides structural stability and maintains compartmentation for the design fires agreed upon among the necessary stakeholders in this project.S [ABSTRACT FROM AUTHOR]

This paper is proposing an machine learning based expert system for preliminary prediction of the insulation fire resisting performance of shallow floor systems when subject to exposure to the ISO 834 Standard Fire Curve. The proposed system is a digital tool which incorporates a machine learning algorithm trained on the outcomes of pre-run two-dimensional finite element heat transfer analyses of shallow floor system details. The algorithm predicts the insulation performance of similar details with a measurable accuracy of 96% (i.e the insulation rating band was predicted correctly in 96% of the cases) without the requirement for an explicit deterministic analysis. The paper presents the challenges and prerequisites to build such an expert system and acts as a proof of concept for the use of machine learning for the assessment of the insulation performance of shallow floor system under the guidance of BS EN 1363-1:2012. A Support Vector Machine machine learning algorithm is adopted in this work. The required processes that were needed for the development of the expert system include the stages of data acquisition, exploratory data analysis, choice of machine learning algorithm, model training, tuning, and validation. This expert system is useful for practitioners to rapidly assess the feasibility of different construction details at early stages of the design process. [ABSTRACT FROM AUTHOR]