Evolution of Incrementally Launched Bridge Decks in Turkey

Incremental Launching Method (ILM) has been seen as an efficient alternative by Contractors and Local Authorities considering many aspects like construction time, cost, and environmental effects. In last decade, Turkey had started several important highway projects including Northern Marmara Motorway, İzmir-İstanbul Highway and recent 1915 Çanakkale Bridge and Motorway Project around Marmara Sea. After a long hiatus, the application of the ILM method restarted in 2014, in the first phase of The Northern Marmara Motorway (NMM). Three viaducts were constructed according to ILM. After the success of this technique, in the second phase of NMM project two more viaducts were constructed according to ILM with some improvements in construction cycles and span lengths. In the recent Çanakkale Motorway project, four viaducts were constructed using the ILM method. In the motorway section, in order to reduce the seismic mass and provide an aesthetic appearance deck was designed as single cell box section with precast struts. This paper summarizes the evolution of post-tensioned concrete deck designs for ILM viaducts over the past ten years in Turkey.