Evaluation and minimization of moment coefficient of tall buildings with trilateral cross-section via a surrogate model

Wind load is commonly regarded as the dominant lateral load in designing tall buildings. Thus, it is of necessity to investigate the parameters affecting wind-induced loads. One of these parameters is the exterior shape of tall building, which using its aerodynamic shape modifications, wind loads, can be decreased. In this research, the exterior shape of different tall buildings with trilateral cross-section is constructed via the polynomial parameterization method. The advantage of the proposed method in producing the building geometry is that it is able to apply all aerodynamic modifications to triangular buildings. Then, the effect of each geometrical parameter on the moment coefficient along the drag is investigated as the aerodynamic response of tall buildings. Using geometric parameters screening, it was found that two geometrical parameters (T, b1) have the maximum impact on the aerodynamic response of the tall buildings which apply twist and curved sides modifications, respectively. Then, using the polynomial regression method, explicit relation of the mean moment coefficient in terms of these two geometrical parameters is illustrated using a third-order polynomial, which can be used as a surrogate model to evaluate the moment coefficient instead of computational fluid dynamic analysis. The surrogate model can significantly reduce the computational cost, and operate as an appropriate guide for building designers to investigate the effect of building geometrical variables on aerodynamic performance. Finally, the minimum point of the proposed model is determined as the optimal shape of the tall building. In addition, a comparative analysis of the aerodynamic responses of the optimal model with the basic triangle model shows that the moment coefficient is reduced by 56%. This demonstrates the considerable effect of these two geometrical parameters in improving the aerodynamic performance.