Kajian Interaksi Turbulensi Angin Dengan Getaran Induksi Vortex Dek Jembatan Bentang Panjang

Fariduzzaman Fariduzzaman

Abstract

Wind over earth’s surface is naturally turbulent, where the contour of it  has direct influence to this flow structure of earth surface. During their life,long span bridges structure will experience various turbulence level of wind flow. It depends on location, whether in urban, suburban, seashore or bypass a strait.

An experiment of a bridge model inLMWT (LAGG Mini Wind Tunnel) has been carried out, to study the effect of wind turbulence on a shape of deck that frequentlyused in Indonesia. The turbulence intensity (Iu) applied was coming from a turbulence generator.

The experimental results has shown that the wind turbulence will cause an irregular (random) oscillation on the deck. At low turbulence, that is Iu less than 13%, Vortex Induced Vibration (VIV) clearly observed. However as Turbulence Intensity was increased the VIVoccurrence  isalso gradually disappear, covered by those random oscillation of the deck.

 

Keywords:long span bridge, vortex induced vibration, wind turbulence, wind tunnel, deck oscillation

 

Abstrak

Aliran angin di atas permukaan bumi adalah aliran yang selalu tubulen, dimana kontur permukaan bumi sangat berpengaruh langsung pada aliran permukaan bumi ini.Suatu struktur jembatan bentang panjang akan dilalui angin dengan tingkat turbulensi yang bervariasi, tergantung pada lokasi jembatan apakah di perkotaan, pedesaan, tepi pantai atau melintasi selat.

Suatu eksperimen menggunakan terowongan angin LMWT (LAGG Mini Wind Tunnel), telah dilakukan untuk mengkaji efek turbulensi angin pada bentuk dek yang paling sering digunakan di Indonesia. Tingkat turbulensi (Iu)aliran pada dasarnya dipengaruhi oleh generator turbulen.

Hasil eksperimen menunjukkan bahwa turbulensi angin mengakibatkan osilasi dek yang tak teratur (random). Pada Iu rendah, Getaran Induksi Vortex (GIV) jelas terlihat, namun semakin tinggi Iu semakin hilang tanda adanya GIV, tertutupi oleh osilasi dek yang random.

 

Katakunci: jembatan bentang panjang, getaran induksi vortex, turbulen angin, terowongan angin, osilasi dek

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References

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