Reliability risk assessment in high rise buildings in case of fire

Abstract

The practice of structural fire safety engineering remains to be case-specific and the estimation of fire resistance of structures is mostly deterministic. Many researchers in structural fire engineering utilize the performancebased design method but these studies do not include the inherent uncertainties in both the demand and capacity. This paper investigates the structural fire reliability of tall buildings based on the framework used for earthquake hazard by the Pacific Earthquake Engineering Research (PEER) and Eurocode. The financial district of Istanbul in Turkey is taken as a case study for this research. Parameters such as building type and height, structural system, number of floors, floor area, number of elevators and stairs, the use of fire suppression systems, evacuation routes are provided by the municipalities in order to develop a probabilistic methodology to estimate the fire safety of these structures. The analysis is conducted by estimating the intensity or the hazard curve as described by PEER framework. The hazard domain includes random variables such as the fire load, the opening factor, the fire duration and the maximum fire temperature. The findings of this research will provide essential information on the fire safety risk of each tall building in a densely populated financial district. It will allow the municipalities and fire brigades to have a probabilistic risk assessment of these structures and develop evacuation and human rescue plans accordingly in case of a fire hazard. Further, this research will provide useful data to insurance companies to estimate fire hazard insurance premiums. KEYWORDSStructures in fire, structural fire safety and reliability, performance based design, probabilistic analysis.

State-of-the-art of probabilistic performance based structural fire engineering

“…Also, Eurocode 1 suggests a Gumbel distribution for fuel load in office buildings with an average value of 420 MJ/m 2 (CEN, 2002). This variation in average fuel load density value indicates significant uncertainty which instigates its use as a random variable in design calculations as observed by a number of researcher (Ribeiro et al, 2016;Selamet and Akcan, 2015;Khorasani et al, 2015;Devaney, 2014;Shi et al, 2013;Guo and Jeffers, 2015;Iqbal and Harichandran, 2010;Gernay et al, 2015;Moss et al, 2014;Shrivastava et al, 2016). The large uncertainty in defining an average fuel load density for an office building is due to variation in fuel loads.…”

“…Unlike fuel load, there is less data available on ventilation area, which varies widely between different occupancies. There is limited literature for which ventilation conditions have been considered as a stochastic variable in their probabilistic analysis (Shi et al, 2013;Devaney, 2014;Selamet and Akcan, 2015;Iqbal and Harichandran, 2010;Moss et al, 2014;Shrivastava et al, 2016). The Joint Committee on Structural Safety [JCSS] code (Vrouwenvelder, 1997) JSFE 10,2 suggests an equation (Equation (2)) to account for the variation of opening of ventilation during a fire.…”

“…Therefore, most researchers treat them as deterministic (Guo, 2015;Guo et al, 2013;Gernay et al, 2015). Surface lining is considered uncertain by Moss et al (2014), Iqbal and Harichandran (2010), Selamet and Akcan (2015) in their studies, whereas the variation in compartment geometry is considered random only by Selamet and Akcan (2015). All these four factors (fuel load, ventilation, room geometry and surface lining) vary significantly as per the building use, and its location.…”