Aerodynamic Interference And Wind Environment Of Parallel Bridges

Recent years the advancement of bridges has been witnessed due to the increasing of economy. Consequently, the bridges with double-deck and multi-deck have been built. The wide constructing of this bridge type and the problems faced in the practical engineering have drawn much attention regarding the aerodynamic interference of the decks. There is a wide gap between single deck bridges and double or multi decks bridges concerning the static wind loads, vortex induced vibration, flutter, and buffeting because of the short distance of the bridge decks. With the increasing of bridge span, the above aerodynamic interference have been key issues in the wind resistance design and should not be ignored. The paper is based on Fenghuajiang arch steel bridge with parallel decks. By adopting Fluent software, numerical simulation is conducted pertaining the aerodynamic interference of the old and new bridges. The details are as following:(1) The construction situation of bridges with double-deck and multi-deck is presented and the study of aerodynamic interference of series connecting structures, high construction group, and bridges with double-deck and multi-deck is discussed.(2) The theory of calculating fluent dynamics, the processing procedure and parameter setting of the adopted commercial software Gambit and Fluent are introduced. Based on these, a two dimensional cross section of the arch bridge with a scale of1:50is selected in order to conduct the numerical simulation. The understanding of Fluent processing methods and numerical simulation are deepened.(3) The aerodynamic interference of the newly built Fenghuajiang arch bridge to the nearly old bridge wind environment are analyzed in detail. The wind speed at the deck level is captured by installed measuring points in the vehicle center with a certain height. Wind multitude factors are introduced in order to reflect the wind field profile of the bridge deck directly. The aerodynamic disturbing circumstance is studied by analyzing the wind multitude factors and their isoline chart and thus the wind environment of the old bridge decks are checked and accessed. Also the wind environment of new bridge is analyzed.(4) The three force coefficients of the single deck bridge girder are obtained by Fluent numerical simulation and wind tunnel testing. The reliability of the numerical simulation is testified by the comparison. Then the changing law of three force coefficients of girders and arch ribs of different D/B (the ratio of net distance and single deck width) for the new bridge is obtained by Fluent numerical simulation. This is benefit to the selection of the most secure scheme.(5) Conclusions and outlook are made on the basis of the paper study fruits and the shortcomings are pointed in order to make some suggestion for the future research.