ABSTRACT
ABSTRACT This paper presents a case study concerning a probabilistic performance based structural fire engineering analysis which served to inform the fire resistance requirements for two adjacent high-rise residential concrete structures in Mumbai, India. The analyses sought to define the probability of structural element failure in the event fire. Fire resistance solutions, i.e. 60, 90, 120 and 240 minutes, were trialed with the intent of ensuring that the proposed fire resistance solution results in an appropriately low probability of failure. The acceptably low probability of failure, forming the acceptance criteria, was derived based upon a review of International structural reliability literature, including the Natural Fire Safety Concept Valorization Project, EN 1990, ISO 2394 and the Joint Committee on Structural Safety (JCSS). Based upon the recommendations therein, an appropriately low probability of structural element failure in the event of fire was adopted in consideration of the relevant Society's Capacity to Commit Resources (SCCR). Considering the numerous factors featuring uncertainty/variability, e.g. fire load density, ventilation conditions, sprinkler reliability, construction tolerance, material properties, etc., it was determined that a fire resistance period of 120 minutes was appropriate for the two towers. This was derived after a series of Latin Hypercube Sampling studies, which: (i) generated design fire conditions, (ii) undertook heat transfer analyses to a concrete slab element, and (iii) assessed the slab utilization throughout the full duration of the fire. Sensitivity studies were also undertaken considering the impact of variance in core inputs, such as fire ignition rate, number of fatalities, and sprinkler intervention rates.
