engleski

Construction of Prestressed Structure Above Kupa and Dobra Rivers on the Zagreb-Rijeka Motorway

On the Zagreb &#8211 ; ; Rijeka Motorway it was necessary to construct several bigger bridges two of which cross rivers. The Viaduct Drežnik (2485 m long) over the Kupa river and the Dobra bridge (550 m long) are made mostly of spans that are 35 m long. At river crossings it was necessary to insert spans of double length (70 m), and that imposed partially modified construction method. Except this river crossings, there are no obstacles that required markedly bigger span length and special construction methods, it seamed reasonable to envisage deck structures made of precast girders with deck slabs cast-in-situ. Full continuity of deck structure was envisaged and by nonprestressed reinforcement above all supports. except those beside the biggest span length which was prestressed. Road level above the ground is such that the highest piers are not more that 20 m high, so span lengths of about 30 m (and even less) would meet aesthetic requirements. However, the soil is such that deep foundation is necessary, and therefore the span length was chosen somewhat bigger. Other obstacles as railway and local roads, impose some restraint on span lengths or on their layout. The span length is, otherwise, determined by precast girders selfweight.

precast girders; 70 m span; river crossing; full continuity; construction sequence

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