Wind-induced dynamics and loads in a prismatic slender building: A modal approach based on unsteady pressure measurements

This paper presents a detailed numerical and experimental procedure for investigating the dynamic behavior of tall buildings subjected to multidirectional wind loads. The main objective of the procedure is to provide a framework for the calculation of the dynamic response and internal loads based on the combination of wind tunnel test results and modal information, so as to gain a deeper understanding of wind effects on tall buildings. The proposed procedure is applied by considering a very slender tall building excited by multidirectional wind loads. The building has the shape of a rectangular prism with section aspect ratio B/D=2.6B/D=2.6 and a height aspect ratio H/D=9H/D=9. Wind tunnel tests were performed on a 1:100 scale rigid model to provide the surface pressure data essential for the procedure proposed in this paper. A numerical modal approach is then used to evaluate the full-scale dynamics of the building and the corresponding internal loads due to wind action. The analysis carried out highlights the ability of the proposed procedure to consider the torsional mode and the higher modes in evaluating peak accelerations as well as the internal loads in the structure. The study also shows the effect of turbulence and the wind angle of attack as key parameters significantly affecting structural dynamic responses.

► A procedure for the dynamic response prediction in tall buildings is presented.
► The analysis highlights the importance of the torsional modes.
► The internal loads for each floor (shear, bending moments and torques) are obtained.
► The internal loads are expressed as the sum of the inertial and the external loads.
► The worst load conditions to which the building is subjected are evaluated.