M Laasonen, M Heinisuo, J Outinen, E Lehtimäki, D Pada
Planning environments of structures in fire
Abstract: The design of structures in fire has usually been based on ISO standard fires. For higher quality design the real situation should be analysed more carefully. This would improve the safety level of the structures and in many cases help avoid redundant fire protections. The method discussed in this paper is the natural fire design documented by [DIFISEK, 2005] where the gas temperatures are based on simulations of realistic natural fires. Fire simulations in this study are done using the FDS program by NIST. The method follows the European standard [EN, 2005] but the design process is still complex. The same building parts should perform smoothly in four different tasks: product modeling, fire simulation, heat transfer from gas to structures, and structural analysis. The utilization of building information models as initial data of fire simulation has been described e.g. in [Dimyadi et al., 2007] and in [Heinisuo et al., 2009]. This paper discusses how different kinds of structural analysis programs can be integrated to the design process and what requirements those programs set for data transfer. The final goal of the research is practical structural design for entire buildings in fire. In this phase, especially fire simulations need computation time but, for example, accurate and continuum finite element models will not be used for the entire building because of the laborious generation and analysis of the model. The most suitable solutions found so far include structural analysis programs where the members can be modeled as one-dimensional elements, beam elements. The heat transfer from gas to members is solved in the analysis program by applying Eurocode rules. At present, no standard data transfer form used in building projects includes all the entity data needed in these tasks. Very different data are needed in the analysis than, for example, in using continuum models for members.
Keywords: BIM, natural fire design, steel structures
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