Evaluation of wind pressure on the low-rise buildings and surrounding terrain under the influence of tornadolike vortex induced aerodynamic loads

Wind loading on buildings caused by straight line boundary layer winds has been thoroughly investigated in the past. The effects of vortex loading on structural projections will induce crosswind loads and torsional loads on low rise building which has severe dynamic resonant effect not only on the structural projections but also on over all structural elements of a building. These structural projections can be in the form of cantilever balconies, canopies, sunshades, overhangs, aesthetically projected elements. The purpose of each of these projections is different and designed to suit the convenience of habitats. During the tornado, the damage of projections becomes flying debris due to the fatigue effect of fluctuating pressure. In the present study,a model of low-rise buildings is tested under the influence of tornado-induced vortexes. Models were tested for F3 - F4 tornado for the wind speed 60m/s to 90m/s. Tornadoes of vortex core diameter 0.46 m to 1.06 m in a smooth open terrain, simulations were carried out. A prototype of model of building in a scale of 1:400, actual dimensions of building is 20m x 20m x 10 m; the prototype model is prepared using flexi glass. An arrangement is made to study the effect of building on the ground terrain in surrounding region of building. Model was provided with pressure tapping to measure the surface pressure on all the walls and roof.