STUDY OF THE INFLUENCE OF SECOND ORDER EFFECTS ON THE EXAMPLE OF THE STEEL FRAME OF THE AIRPORT

Abstract

With the help of modern licensed BIM-information systems of PC Dlubal RSTAB and PC Dlubal RFEM, simulation of stress-strain state and cross-section selection of complex spatial steel structures of the airport, located in Frankfurt am Main (Germany), based on theories 1st and 2nd order effects according to standard DIN EN 1993-1-1-2010 were performed. Spatial steel structures of the airport located in Frankfurt am Main, have been adopted as the object of study. The prototype is the Chennai Airport (India), an architectural concept developed by the American company Frederic Schwartz Architects. The main bearing structures are adopted in the form of spatial steel trusses of complex shape. To determine the cross-sectional dimensions and spacing of the spatial trusses, preliminary calculations were performed. Finally, the step of the spacious trusses was 9 m. The collection of self-weight and imposed loads is carried out in accordance with DIN EN 1991-1-1. The collection of wind loads acting on a complex geometric shape was performed using a virtual wind tunnel and accelerograms, using a CFD analysis of the Dlubal RWIND Simulation PC. To perform CFD analysis, the Dlubal RSTAB PC model was exported to the Dlubal RFEM PC, which made it possible to take into account the presence of external enclosures, overlapping elements and cover, modeled using zero plates, when modeling wind flows. After setting the basic calculation parameters, the model was generated and exported to the Dlubal RWIND Simulation PC. Wind flow simulation in Dlubal RWIND Simulation PC, performed for eight wind directions, of which four most unfavorable were transferred to Dlubal RSTAB PC as separate downloads for further calculation. According to the results of the comparison of the coefficients of the cross-sectional area, it is found that taking into account the effects of the second order, depending on the type of design considered, may lead to the need to increase the estimated cross-sectional area in the range from 22 to 42%. Thus, for complex spatial steel structures, the provisions of the Eurocode standards are confirmed, according to which the consideration of 2nd order effects is obligatory for consideration.