Design and Construction of Bridges on Morava Corridor

Morava Corridor Motorway Project is a 112 km dual-carriageway motorway currently under construction in Serbia, with a design speed of 130 km/h, from Pojate and the A1 (the North-South motorway in central Serbia) through Kruševac and up into Preljina in the north of Čačak. The project runs east/west in the West Morava River valley and is seen as a key enabler of the economic corridor to the industrial city of Kruševac and its ultimate international connections to Bosnia, Montenegro and Macedonia. It consists of 78 bridges, 26 overpasses, and 11 underpasses. With the length of the motorway and the number of structures currently under construction, this is one of the largest construction projects currently in Serbia. In this paper, experiences during design and construction of these bridges has been presented. First, design approaches (such as strut-and-tie method for design of pile caps and pier caps) has been discussed, and construction aspects of the project have been reviewed. The motorway is located in seismically active region, with peak ground acceleration up to 0.2g. Precast construction was used for the majority of structures, which enable fast and efficient construction. Pretensioning of the concrete beams has been applied on almost all bridges, which is the type of the prestressing extremely rare in Serbia, where posttensioning is always used in bridge construction. By pretensioning, large number of beams were produced in timely manner and in controlled environment. Also, the eight longest bridges, with a total length of more than 3.3 km, are seismically isolated, which is one of the first uses of seismic isolation in Serbia. These bridge are the first bridges in Serbia which are in the same time seismically isolated and pretensioned. Seismic isolation provided large savings for the substructure reinforcement demand, while limiting the expansion segment length to about 200m.