engleski

Twin Rječina bridges - Diferent design codes

A new southern bridge has been completed parallel to the existing northern Rječina Bridge of the Rijeka city beltway, built in 1984. This bridge carries two-lane eastbound traffic, while its existing north twin will maintain the two-lane westbound traffic. Both north and south bridges were designed already in the 1970’s. Recently the growing congestion on the Rijeka beltway called for the construction of the new bridge, parallel to the existing crossing to upgrade the single- carriageway road to motorway standards. The 30- years old original design of the south Rječina Bridge defined its general layout and proportions. However, the design had to be adjusted to currently valid code (Eurocode) provisions and requirements. The new Rječina Bridge is a prestressed concrete rigid strut frame structure with the box type superstructure. The superstructure is continuous over three spans, with the main span of 108.5 m and with two identical side spans of 50 m each. Its new design exemplifies more stringent requirements on bridge structures, incorporated in current structural standards in comparison to standards valid about thirty years ago, which is discussed in this paper. It should be noted that the northern old bridge is still in a rather good condition with some visible damage confined to bridge equipment only and uplift preventing tendons at abutments, which must be replaced.

Strut frame bridge; twin bridges; bridge design; design standards development

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