Full Aeroelastic Model Testing for Examining Wind-Induced Vibration of a 5,000 m Spanned Suspension Bridge

Abstract

This paper presents an experimental investigation on wind-induced vibrations of a suspension bridge with ultimate main span length, including flutter and buffeting. Since the upper limit of a suspension bridge's main span can reach more than 5,000 m based on strength and weight of steel main cables, a feasible prototype with a span arrangement of 2,000 + 5,000 + 2,000 m has been proposed. In order to improve flutter stability, a twin box girder has been designed with a 40 m slot in center and two 20 m wide decks suspended by four main cables. Its full aeroelastic model was designed and manufactured with the geometrical scale of 1:620, and the wind tunnel testing was carried out under smooth flows and turbulent flows for different angles of attack. A big difference in critical flutter speed was found between the proposed slotted girder and corresponding slot-sealed girder, which verifies the necessity of a widely-slotted (WS) twin box girder for a super-long suspension bridge. Among three angles of attack, the critical flutter speed under smooth flow has the maximum value of 80.9 m/s at −3 • and the minimum value of 51.4 m/s at 3 • . On-coming turbulence will not only cause buffeting responses but also influence the critical flutter speed in an unfavorable way.

Three-dimensional FSI Simulation by Using a Novel Hybrid Scaling – Application to the Tacoma Narrows Bridge

“…Later on, with the strong need to capture the complex three-dimensional mutual interaction of the structural oscillation and the airflow around it, more sophisticated full aero-elastic wind tunnel models were applied. In the case of a number of large span bridges, these advanced tests were used [4][5][6][7]. Both the section and full aero-elastic models have their advantages and disadvantages.…”

Span-wise coherence of fluctuating forces on twin bridge decks and the turbulence effect

“…A pressure integration cannot reckon surface friction in, which may affect the accuracy of drag but has limited influence on lift and moment. Meanwhile, the full aeroelastic testing (Ge et al, 2018) indicated the role of buffeting was highlighted along vertical and torsional directions while the stochastic buffeting accounted for less than 20% of total lateral response. The static lateral deformation is more important in super-long cases.…”

“…The outlines of twin decks are in the background of an ultimate-long suspension bridge. In Ge et al (2018), a full aeroelastic model testing was carried out with a total length of 2000+5000 + 2000 m (Figure 1(a)). For this super-long span, a widely slotted TBG provides better aerodynamic stability than a single girder.…”

“…A central-slotted deck with better aerodynamic stability becomes feasible when the bridge is super long, for example, a cross-strait project where the common angle of attack is 0°. The symmetrical section in Figure 1 made the additional incidence angle small if mean wind was horizontal (Ge et al, 2018). To keep pace with the full aeroelastic model testing, the data at 0° is to be discussed.…”

Wind tunnel testing and frequency domain buffeting analysis of a 5000 m suspension bridge

“…By comparison, the RMS responses are the direct results of turbulence intensities. In the cases of I = 10% and 11% where intensities are close, the integral sales have a 25% difference because of the spire locations in the wind tunnel (details in Ge et al, 2018). However, the dynamic responses keep close to each other.…”