Incremental launching method for bridges of Northern Marmara Motorway, Turkey

This paper presents the challenge of the incremental launching of three viaducts of the Northern Marmara Motorway project in Istanbul Turkey. The incremental launching method (ILM) was pushed at its own limit to be adapted to this Viaduct. The deck, with 55 meter long spans, was moved by sliding on piers up to 82 meter high through a complex vertical and horizontal alignment.

This paper gives an overview of this construction methods, and the specificity of these viaducts. In particular, specific procedures were implemented to control the behaviour of the piers during launching operations, due to their slenderness and their non-conventional anti-seismic design. Specific geometric checks were also necessary to follow the launching curve. Temporary structure associate to ILM will also be described in the paper: prefabrication yard, design and construction of the launching nose, choice and design of launching devices.