Lokal oyulmayı azaltmak amacıyla iki köprü ayağı tipi için geometrik iyileştirme

Öz

Köprü ayakları çevresinde oluşan lokal oyulma, köprü çökmelerinde ve köprülerde meydana gelen ağır hasarlarda kritik bir rol oynamaktadır. Birçok araştırmacı lokal oyulma sorununu incelemiştir. Ancak, çalışmaların çoğunluğu sadece karmaşık akım davranışının incelenmesine odaklanmış, herhangi bir yapısal kısıta bağlı olmayan ve inşa zorluklarını göz ardı eden yeni köprü ayağı tasarımları önerilmiştir. Bu çalışmada, sıklıkla kullanılan konvansiyonel köprü ayağı tiplerine uygulanan geometrik iyileştirmelerin, nehir yatağında oyulmaya neden olan akım parametreleri üzerindeki etkilerinin incelenmesi amaçlanmıştır. Referans geometrilerin etrafını dolaşan, herhangi bir taşıyıcı özelliği olmayan dik üçgen biçimindeki eklentiler uygulanmıştır. Söz konusu dik üçgen biçimindeki eklentiler uzunlukları cinsinden parametrize edilmiş ve uygulanan farklı modifikasyonlar arasından en iyi seçeneğin ortaya çıkarılması için ardışık nümerik çözümler gerçekleştirilmiştir.
Değişiklik yapılan geometrilerin performansı, oyulmayı tetikleyen ve gelişiminden sorumlu olan iki önemli akım parametresi olan nehir yatağına etkiyen basınç ve kayma gerilmesi değerleri üzerinden değerlendirilmiştir. Sonuçlar, küçük yükseklik ve büyük genişlik değerine sahip konik eklentilerin, nehir yatağına etkiyen maksimum basınç ve kayma gerilmelerini düşürmesi bakımından daha etkili olduğunu göstermiştir

Anahtar Kelimeler

• HAD
• köprü ayağı
• oyulma
• modelleme

Geometric improvement for two bridge pier types to reduce local scour

Öz

Local scour around the bridge piers play a critical role in collapse and heavy damages on bridges. Many researchers have studied local scour problem. However, majority of the studies only focused on examination of the complex flow structure and offering new pier geometry designs without any structural restrictions, which ignore construction difficulties. This study attempts to investigate the effect of geometric enhancements on commonly used conventional pier types to reduce scour related flow parameters acting on riverbed. A right triangular implementation that wraps the reference shapes were accordingly applied as non-load bearing curtain walls. Triangular implementation has been parametrized by its leg lengths and successive numerical analyses were conducted to reveal the better option among different modifications.
Performance of the modified piers were compared in terms of pressure and the bed shear stresses acting on riverbed representing the two important flow forces that are responsible for triggering and developing scour. The results show that low height values with high width values of conical implementations perform better in terms of reducing maximum pressure and shear stress acting on riverbed.

Anahtar Kelimeler

• CFD
• bridge pier
• scour
• modeling

Kaynakça

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