Workshop on Aerodynamics Basic Research in the Videoconference Format of Central Aerohydrodynamic Institute (TsAGI), Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, SPbPU, Lomonosov Moscow State University, Institute of Mechanics

Topic: Aerodynamic Research into Typical Cross-sections of Bridge Superstructures

Author: Yuri Anatolyevich Gosteev (NSTU) gosteev@corp.nstu.ru

The problem of aeroelastic oscillations of large-span bridges (span length Lz > 100 m) is still essential. One has only to think about a recent incident with bridge oscillations in Volgograd (May, 2010, Lz = 155m). The literature review devoted to the given problem shows the lack of an insufficient level of data systematization concerning aerodynamic characteristics (ADF) of bridge constructions. The existing sources provide mainly the information about wire and cable bridges. Even in the most detailed sources (in particular, in Eurocode) they neglect the influence of the form of cross-sections of bridge superstructures on ADF, the turbulence level of a wind current.

The given paper shows how to complete outlined gaps by means of the database creation of ADF of typical cross-sections of girder bridge superstructures (more than 30 configurations). This database keeps the coefficients of average aerodynamic force component and moment, their derivatives with respect to the angle of attack, Strouhal number, galloping parameters of typical cross-sections when changing the modification of conditions in an approach flow – a turbulence level (0.5…8%) and the angle of attack (-5°…5°).

The set of computational experiments was accompanied with wind tunnel simulation and it allowed recognizing flow phenomena of investigated bodies, classifying them according to flow breakdown. The results of physical and computational modelling demonstrate the formation of investigated cross-sections of a stable vortex path in aerodynamic trail and it points at the possibility of vortex excitation of oscillations. It has been found that typical cross-sections with the width ratio no more than 4 are exposed to galloping.

There has been established a significant influence of a cross-section shape on the drag coefficient of a multiple beam span construction that is not taken into the consideration by current regulatory sources. Error analysis of Eurocode data usage while determining bridge ADF is also provided.

Research results are included into the Industry Road Guidance Document IRGD 218.2.040–2014 «Guidelines for the Evaluation of Aerodynamic Characteristics of Cross-sections in Bridge Superstructures» Federal Road Agency of the Ministry of Transport of the Russian Federation.