Lifetime Cost Optimization for the Structural Fire Resistance of Concrete Slabs

Contemporary societal concerns emphasize the importance of cost optimization and sustainable constructions. However, with respect to structural fire safety, the application of prescriptive design rules remains common practice and optimization procedures are generally limited to a few examples of performance based design. Both methods consider an explicit or implicit prescribed safety level which is based on societal and empirical considerations. A more rational approach is to take into account the characteristics of the structure and to determine the economic optimum fire safety design. This economic optimum is obtained by minimizing the total costs, explicitly taking into account e.g. the fire ignition frequency, the probability of successful fire suppression and the damage costs due to a fire-induced failure. Applying this methodology to the design of simply supported concrete slabs indicates that in specific situations additional investments beyond the legally required minima constitute a more cost-effective design. It is concluded that the cost optimization of structural fire safety is a powerful tool to assess the utility of additional safety investments beyond the legal requirements.