The nose-up effect on twin-box bridge deck flutter

Maja Rønne*, Allan Larsen, Jens Honore Walther

*Corresponding author for this work

Research output: Contribution to conferencePaperResearchpeer-review


For the past three decades a significant amount of research has been conducted on bridge flutter. Wind tunnel tests for a 2000 m class twin-box suspension bridge have revealed that a twin-box deck carrying 4 m tall 50% open area ratio wind screens at the deck edges achieved higher critical wind speeds for onset of flutter than a similar deck without wind screens. A result at odds with the well-known behavior for the mono-box deck. The wind tunnel tests also revealed that the critical flutter wind speed increased if the bridge deck assumed a nose-up twist relative to horizontal when exposed to high wind speeds – a phenomenon termed the "nose-up" effect. Static wind tunnel tests of this twin-box cross section revealed a positive moment coefficient at 0⁰ angle of attack as well as a positive moment slope, ensuring the that the elastically supported deck would always meet the wind at ever increasing angles of attack for increasing wind speeds. The aerodynamic action of the wind screens on the twin-box bridge girder is believed to create the observed nose-up aerodynamic moment at 0⁰ angle of attack. The present paper reviews the findings of the wind tunnel tests with a view to gain physical insight into the "nose-up" effect and to carry out flutter predictions from numerical simulation of the wind flow about the twin-box bridge girder.
Original languageEnglish
Publication date2020
Number of pages19
Publication statusPublished - 2020
Event2020 World Congress on Advances in Civil, Environmental, and Materials Research (ACEM20) & 2020 Structures Congress (Structures20) - Seoul, Korea, Republic of
Duration: 25 Aug 202029 Aug 2020


Conference2020 World Congress on Advances in Civil, Environmental, and Materials Research (ACEM20) & 2020 Structures Congress (Structures20)
Country/TerritoryKorea, Republic of


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