Influence of Wind Angle Incidence and Architectural Elements on the External Pressure Coefficient of Hyperbolic Paraboloid Roofs

Abstract

In the study of wind loads in buildings, the aerodynamics of roofs with parabolic shapes, which cause complex pressure distributions due to their sensitivity to wind, are often omitted and neglected by several codes and norms. In this way, computer simulations are a viable and reliable alternative. Here, wind action was considered in an innovative project composed of parabolic and circumferential generatrices: the Church of Saint Francis of Assisi. Designed by Brazilian architect Oscar Niemeyer in Belo Horizonte, Brazil, two paraboloid vaults and three circular arches of reinforced concrete composed its structure. This work generated great international recognition for the architect after 1943, as the design of the roofs did not require walls. For geometry modeling, Autodesk AutoCAD software was adopted, and the models were considered in a control volume. The simulations were performed using Ansys Workbench software and the RNG K-Epsilon turbulence model. The wind speed at different heights was calculated using the Power-law approximation. A basic wind speed of 30 m/s was adopted, and the mesh used was composed of tetrahedrons. To validate the methodology, different models with hyperbolic-paraboloid roofs from the literature were considered. In addition, the visualization of the flow around the geometry from the streamlines, the wind profile, and the analysis of the isobaric lines of the external pressure coefficients for different directions of incidence and architectural elements that make up the building were presented.