Catwalk Design and Erection of the 1915 Çanakkale Bridge

The 1915 Çanakkale Bridge has the longest main span of 2,023m in the world, and the total span length between anchorages reaches 4,163m. The bridge is located at the North-eastern end of the Çanakkale Strait in Türkiye which is one of navigation channels with the most heavy traffic and windy condition. The planning, design and erection of catwalk system as an aerial workspace for main cable erection raised various technical challenges against extreme loadings such as strong winds and earthquake. The specific behaviour of catwalk under lateral loads was taken in account to FE analysis model development and wind tunnel test supported to investigate the aerodynamic stability of catwalk system. Catwalk has the width of 4.5m, which supported by 12 spiral strand ropes with a diameter of 50mm and MBL of 2,100kN. Catwalk was divided at each tower top and storm system was not included. During construction of catwalk, suspender system ensured the minimum clearance of 70m from the sea level for marine traffic. After the completion of catwalk floor erection, to balance the horizontal forces on tower top during PPWS erection, the tower top had to be offset from their final position. The steel tower’s flexibility was quite sufficient to the required pull back amount of approx. 1.7m in European tower and 2.6m in Asian tower