Tornado fragility and risk assessment of an archetype masonry school building

Abstract

Tornadoes are a low-occurrence high-consequence hazard and not only threaten the life safety of building occupants but have recently resulted in billions of dollars in direct and indirect damages for single events. Design codes do not consider tornado loads for building and other structures (with the exception of nuclear facilities) because the occurrence rate has historically been considered too low. The advent of performance-based seismic design has revolutionized the engineering thought process and as a result building owners can consider performance objectives that enable a building to perform better in an extreme hazard than observed with current design code. In this paper, the performance of a masonry school building subjected to tornado wind loads is investigated using a fragility methodology. The tornado fragility assessment methodology is described along with proposed damage states for consideration in loss estimation. An array of masonry material types are considered based on the Masonry Standards Joint Committee (MSJC) code to enable applicability of the fragilities developed herein for a range of designs throughout the United States.

Risk assessment of low-rise educational buildings with wooden roof structures against severe wind loadings

“…These specifications were observed in school buildings over 30 years of age. Masoomi, 2016 [22] modeled the anchorage by the concrete breakout capacity of the anchor bolts in concrete masonry units. However, field observations show that the uplift of roof trusses are caused by the bending of a 100mm x 300 mm by 10mm thick ASTM A36 steel plate holding the trusses down rather than the concrete break out of the 16 mm anchors.…”

Understanding Community Resilience from a PRA Perspective Using Binary Decision Diagrams

“…It is customary to model component fragilities with lognormal distributions (Masoomi & van de Lindt, ). The conditional probability of being in, or exceeding, a particular damage state, ds , conditioned on a level of IM , is defined by: where is the median value of the IM at which the component reaches the threshold of ds ; Φ() is the standard normal cumulative distribution function; is the standard deviation of the natural logarithm of IM for ds , a measure of uncertainty that comprises three basic sources—uncertainties in the seismic demand on the structure, which include structural response, damage–state threshold of the structure, and uncertainty in modeling the building type of interest.…”

Multi-Scale Remote Sensing of Tornado Effects

“…The per-building level also forms a logical basis for automated assessments via computer algorithms as groups of contiguous pixels (representing individual structures) serve as the basis for numerous automated damage studies (e.g., Thomas et al, 2012Thomas et al, , 2014. For purposes of insurance risk and resiliency, damage functions (fragility curves) are also commonly constructed at the per-building level (Roueche and Prevatt, 2013;van de Lindt et al, 2013;Roueche et al, 2015;Kashani et al, 2016;Masoomi and van de Lindt, 2016;Kopp et al, 2017).…”

“…Haan et al (2014) emphasize the need for field investigations and preservation of data sets to provide validation and calibration for physical simulations of tornadoes. Comprehensive and accessible damage data are likewise beneficial for the validation of tornado risk models (Masoomi and van de Lindt, 2016;Peng et al, 2016; Standohar-Alfano and van de Lindt, 2016), load models (Thampi et al, 2011;Roueche et al, 2015;Koliou et al, 2017) and new building code wind provisions (Ramseyer et al, 2016). The study of tornado damage to buildings is of particular importance to the estimation of tornado intensity, as building structures constitute a majority of damage indicators (DIs) in the Enhanced Fujita Scale (currently 23 of 28 DIs are building structures).…”