Dynamic response estimation of tall buildings with 3D modes: A probabilistic approach to the high frequency force balance method

The estimation of the wind-induced response of tall buildings is often carried out through the use of high frequency force balance (HFFB) tests. This technique is characterized by its versatility and rapidity of use, especially in comparison to other experimental methods. Nevertheless, the estimates of the structural response that can be obtained from its application are affected by uncertainties due to the lack of knowledge on the pressure field over the building surface. The importance of this is particularly relevant in the case of modern tall buildings with their complex geometric shapes and 3D and non-linear modes.This paper presents a novel approach for dealing with this possible source of error in the response estimation. In particular the uncertain spectral structure of the floor loads is modeled through a limited number of probabilistic parameters. This allows the definition of a local level fragility model that includes both the uncertainties inherent to the HFFB technique and the aleatory nature of the aerodynamic loads. The proposed model is applied to a case study building presenting non-linear 3D modes.

► The uncertainties in the floor loads when using the HFFB method are considered.
► A method is proposed to take them into account within a reliability framework.
► The proposed methodology is general as it is based on the physics of the problem.
► The effectiveness of the method is demonstrated for a representative case study.