Experimental Investigation of Final Scour Depths Around Circular Bridge Piers Under Clear-Water Conditions

Abstract

In this experimental study, final scour depths around circular bridge piers under clear-water conditions were investigated within the scope of the project TÜBİTAK 109M637. Circular bridge piers with 4 different diameters and uniform bed material having median diameter of 3.47 mm were used during the experiments. The scour depths measured by means of ultrasonic velocity profilers were compared with the scour depths obtained from the present equations in the literature and the effect of some parameters related to scour depth was investigated. As a result of various regression analyses, an equation was proposed to predict the final scour depth and statistically significant parameters were obtained. The highest scour depth was observed in the upstream side of the pier. It has been found that the scour depth increases with increasing flow intensity, densimetric particle Froude Number and pier diameter.

Keywords

• Bridge pier,local scour,clear water scour,steady flow

Temiz Su Koşulları Altında Dairesel Köprü Ayaklarının Etrafındaki Nihai Oyulma Derinliklerinin Deneysel Araştırılması

Öz

Bu deneysel çalışmada, TÜBİTAK 109M637 projesi kapsamında inşa edilen hareketli tabanlı doğrusal kanalda kararlı akım şartlarında dairesel kesitli köprü ayakları etrafındaki nihai temiz su oyulması incelenmiştir. Deneysel çalışmada 4 farklı boyutlu dairesel köprü ayağı ve 3,47 mm ortalama tane çapına sahip üniform taban malzemesi kullanılmıştır. Ultrasonik hız profilleyicisi yardımıyla ölçülen oyulma derinlikleri, literatürdeki mevcut bağıntılardan elde edilen oyulma derinlikleri ile karşılaştırılmış ve oyulma derinliği ile ilişkili bazı parametrelerin oyulma derinliğine olan etkisi incelenmiştir. Çeşitli regresyon analizleri sonucu nihai temiz su oyulma derinliğini tahmin eden bir bağıntı önerilmiş ve istatistiksel olarak anlamlı parametreler elde edilmiştir. En yüksek oyulma derinliğinin ayağın memba bölgesinde meydana geldiği gözlenmiştir. Akım şiddeti, yoğunluk farkı esaslı dane Froude sayısı ve köprü ayak çapı arttıkça oyulma derinliğinin arttığı tespit edilmiştir.

Anahtar Kelimeler

• Köprü ayağı,yerel oyulma,temiz su oyulması,kararlı akım

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