Tornado-Induced Loads on a Low-Rise Building and the Simulation of Them

Abstract

Tornadoes are vortices of air, typically 100–300 m in diameter, which develop within severe thunderstorms. In addition to velocity pressures, a tornado also causes a rapid change in atmospheric pressure, which can, in cases of closed or partially vented structures, produce direct differential pressure loads. In this paper, based on the assumption of an isothermal process with the Boyle-Mariotte gas law as its foundation, the Equation that represents the internal pressure change in a partially vented structure due to external pressure changes during tornado has been built. Based on that, a computational program which simulates forces on a building during tornadoes, has been established. The program calculates differential pressures on walls and roof of a building of any geometry; with one or many compartments, or many floors; and any arrangement of openings. The inputs are tornado parameters, external pressure coefficients (C_p,e) and building geometry. The outputs are time–history of differential pressures on the walls and roof; total horizontal force and vertical (uplift) force on the building. In cases of closed structures, the results are verified by simulation of the United States laboratory. The program is a useful tool for investigating the most adverse loads on a building during tornadoes.