Effects of Secondary Elements on Vortex-Induced Vibration of a Streamlined Box Girder
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pISSN 1226-7988, eISSN 1976-3808 www.springer.com/12205
DOI 10.1007/s12205-020-0035-0
Structural Engineering
Effects of Secondary Elements on Vortex-Induced Vibration of a Streamlined Box Girder Xingyu Chen
a,b
, Fang Qiua, Haojun Tang
a
, Yongle Li
a
, and Xinyu Xu
a,b
aDept. of Bridge Engineering, Southwest Jiaotong University, Chengdu 610031, China bChina Railway Eryuan Engineering Group Co., Ltd, Chengdu 610031, China
ARTICLE HISTORY
ABSTRACT
Received 7 January 2020 Revised 7 July 2020 Accepted 19 August 2020 Published Online 9 November 2020
Box girders are aerodynamically favorable, and the paper presents a study on the vortexinduced vibration (VIV) of this girder type at large angles of attack. Taking a box girder as an example, the form of the guardrails and the position of the maintenance tracks were improved to increase the VIV performance. The aerodynamic mechanism was further investigated according to the change in flow field around the girder. Results showed that the VIV performance of the box girder at positive angles of attack is worse. Improving secondary elements is an effective way to increase the VIV performance. Adding four rectangle bars above the original guardrails could achieve the target by preventing the generation of the vortex and blocking its movement. Moving the maintenance tracks inwards with a reasonable distance could also achieve the target as the flow passes through the girder more smoothly. With the combination of the optimal form of the guardrails and the optimal position of the maintenance tracks, the VIV performance of the bridge is higher. The countermeasures provide reference for the inhibition of the VIV of box girders.
KEYWORDS Aerodynamic mechanism Flow field Angles of attack Secondary elements Box girder Vortex- induced vibration
1. Introduction Box girders with streamlined shapes are widely used in cablestayed bridges and suspension bridges because of the good aerodynamic performance. For instance, the Sutong Bridge with a center span of 1,088 m, the Great Belt Bridge of 1,624 m, and the Tatara Bridge of 890 m are composed of a single box girder. The Stonecutters Bridge with a center span of 1,018 m, the Yi Sun-sin Bridge of 1,545 m, and the Xihoumen Bridge of 1,650 m are composed of two separated box girders connected by cross beams. With the continuous increase in bridge span, how to reduce or avoid the aerodynamic response of long-span bridges, such as vortex-induced vibration (VIV), flutter instability, and buffeting, is still a difficult issue, which should be taken into account in the structural design process. Generally, flutter instability of long-span bridges occurs at higher wind velocities, while VIV could occur at moderate wind velocities. VIV is commonly excited by a pair of vortices shed from a cross-section periodically and alternately. Many scholars focus on the flow field characteristics and study the vortexshedding behavior. Wind tunnel tests, especially for particle CORRESPONDENCE Haojun Tang
[email protected]
ⓒ 2020 Korean Society of
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