EFFECTS OF STEPS ON WIND LOADS ON TALL BUILDINGS

Abstract

The aim of present study is to carry out extensive wind tunnel test on rigid models of ta buildings with various steps configuration for evaluating force coefficients, pressure 10 coefficient on different faces of building model. To carry out research work five building models are used which are made of plywood for force measurements and two models are of perspex sheet which is used for pressure measurement. The building models are made in the geometrical model scale ratio of 1:100. The models are tested under the boundary layer flow in an open circuit wind tunnel with a cross-section of 2 m (width) x 2 m (height) and the length of the section as 15 in. Floor roughing devices namely vortex generators, barrier wall, cubical blocks of size ISO mm. 100 mm and 50 mm are used on the upstream end of the test sections to achieve the mean wind velocity profile corresponding to terrain category 2 as per Indian Standard on wind loads. Various instruments are also used along with the data acquisition system for the base force f measurement and the surface pressure measurement over entire building models in the wind tunnel. The area of research in this report is to study wind loads on steps in tall building. The research contains experiment analysis of the various tall building models with various pattern of steps while keeping the floor area same in Boundary Layer Wind Tunnel. 'I'his report describes various alterations in the elevation of building and the wind load effect on these changes. It is observed that both base shear and base moments developed due to wind loads are not only influenced by wind directions, but these are also highly affected by steps. The research work also help us to guide to choose for suitable changes in building elevation which should be incorporated in the design so it will economize in terms of wind loads giving architects a better design opportunity.