Troja Bridge has officially opened and become fully operational in the Czech Republic. Mott MacDonald prepared the preliminary tender and detailed design for the new bridge, which spans the Vltava River in Prague.
The bridge is made up of two stand-alone structures, separated by an expansion joint, on the Troja side of the river and forms part of the new Prague Ring Road transportation link. Stretching 200m long and 34m wide, it will carry trams, four lanes of road traffic, pedestrians and cyclists.
Mott MacDonald’s design consists of a steel tied arch featuring a network arrangement of suspender rods. The prestressed concrete bridge deck is suspended from the arch using two inclined planes of network hangers, which connect the arch to the two composite steel-concrete arch ties. This hangar arrangement provides four times the stiffness of a comparable tied arch using vertical suspender rods. The elegance of the bridge mainly results from both the ratio of the rise to the span of the arch, accounting for its slenderness of 1:10 and the 1:180 ratio of the overall height of the arch to its span. The dense network of hangers has made it possible to achieve these ratios by improving the strength and rigidity of the structure.
Radko Bucek, Mott MacDonald’s managing director for the Czech Republic, said: “Troja Bridge represents a major step forward in structural efficiency. By reconfiguring the hangers of the classic bowstring arch from a conventional vertical arrangement to a diagonal one, we have dramatically improved the bridge’s performance.”