ÇELİK KİRİŞLİ KÖPRÜLERDE YÜKE BAĞLI YORULMA ETKİSİNİN İNCELENMESİ

Yorulma, yapının güvenliğine etki eden önemli bir tasarım durumudur. Araç yükünün döngüsel etkisinden dolayı çelik kirişlerin bağlantı detaylarında yorulma kaynaklı yapısal çatlaklar oluşmakta, bu çatlaklara karşı gerekli tedbirler alınmazsa çatlaklar büyümekte ve sonuçta yapısal elemanlar iç kuvvetleri taşıyamayan kararsız bir duruma gelip fonksiyonunu yitirmektedir. AASHTO Köprü Tasarım Şartnamesi çelik kirişli köprülerde yorulmayı yüke bağlı ve distorsiyona bağlı olarak sınıflandırmış, yorulma güvenliğini sağlamak için yapısal elemanlarda çatlak oluşumunu önlemeyi ya da en aza indirmeyi hedeflemiştir. Yüke bağlı yorulma incelemesinde; yorulma çatlaklarının oluşmasını önlemek için yapısal elemanlarda yük ve gerilme sınırları dikkate alınmakta, uygun bağlantı detay kategorisi için yorulma güvenliği kontrol edilmektedir. Bu çalışmada üç açıklıklı çelik kirişli bir köprü CSiBridge paket programıyla yorulma yükleri altında analiz edilmiştir, analizde AASHTO Şartnamesinde yorulma tasarım özellikleri kullanılmıştır. Analiz sonuçlarına göre yapıda uygun yorulma kategorisi dikkate alınarak yapının yorulma yönünden güvenli olduğu ispat edilmiştir.

Anahtar Kelimeler:

çelik köprü, kompozit kiriş, yorulma, yorulma analizi

THE INVESTIGATION OF FATIGUE EFFECT OF LOAD-INDUCED IN STEEL GIRDER BRIDGES

Fatigue is an important design state affecting the safety of the structure. Due to the cyclical effect of vehicle load, fatigue-induced structural cracks occur in the connection details of steel girders. If the necessary measures are not taken against these cracks; the cracks grow and as a result the structural elements become unstable, it can not carry the internal forces and lose their function. The AASHTO Bridge Design Specification classifies fatigue as load- dependent and distortion-dependent in steel girder bridges and in order to ensure fatigue safety, it is aimed to prevent or minimize the formation of cracks in structural elements. In load-induced fatigue investigation; load and stress limits are taken into account in structural elements to prevent fatigue cracks and fatigue safety is checked for the appropriate connection detail category. In this study, a three-span steel girder bridge was analyzed under fatigue loads with CSiBridge package program. In the analysis, fatigue design properties of AASHTO Specification were used. According to the results of the analysis, it has been proved that the structure is safe from fatigue considering the appropriate fatigue category.

Keywords:

steel bridge, composite girder, fatigue, fatigue analysis,

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