New Croatian Bridges

A short overview on larger Croatian bridges is presented. Some of them have been recently finished, and some are currently under construction. All bridges to be presented are designed at the Structural Department of Civil Engineering Faculty in Zagreb, Croatia. In the conclusion of the article, some aspects of conceptual design problems shalI be highlighted. The Maslenica Highway Bridge, completed in 1997., is a concrete arch of 200 meters span. The arch cross ii section is box type, double ceH with depth to width ratio of 4.0/9.0 metres. The arch was constructed by free cantilevering on travelling formwork carriages in 5.26 m long segments. The superstructure comprises eight simple-span precast prestressed girders made continuous over intermediate supports and interconnected by concrete deck slab cast in situ. The bridge was designed taking into the account the severity of the marine environment, and the experience from inspections of other arch bridges. Bridge similar to Maslenica is to be built on the new Adriatic highway crossing the canyon of the Krka river. Several preliminary designs have been reviewed for this crossing, and finally a concrete arch of 210 m span chosen for construction. The Bridge across the Rijeka dubrovacka is currently under construction. It comprises two technologically completely different superstructures, prestressed concrete box of the approach bridge and main composite Cable stayed bridge. Box girder, 60 m long and constructed by free cantilevering is connected to a Cable stayed bridge 244 m long, making a clear span of 304 m. The bridge is to be completed by the end of 200 1. The bridge over the Drava river at BeliAE#263 ; e consists of two - span continuous main composite bridge and prestressed concrete approach viaducts. The superstructure of the composite bridge comprises two steel plate girders with variable height and reinforced concrete deck plate. The constraints of river traffic dictated the layout of main bridge with spans of 95.5 m and one pier in the river bed. The bridge over the Sava river at Martinska Ves is a 145 m span suspension pedestrian bridge, 4 m wide. Bridge layout was chosen according to the restraints of river traffic. Curently under construction, it shalI be finished by the spring 2002. The Dobra Vrbovsko bridge crosses 65 m deep valley. The prestressed concrete box type superstructure is continuous over 5 spans, with maximum length of 50 m. The incrementallaunching construction method of the superstructure is selected. For the first time in Croatia external prestressing with tendons inside the box girder was adopted for additionalload and live loads. Construction works started in the October 200 1. The Kamacnik bridge crosses the river valley, 60 m deep, in protected environment. The prestressed concrete box type superstructure has three spans, 71 + 127 + 24 m. Cantilever construction procedure is to be executed, utilizing counterweight on the end of the shortest span and one auxilliary piero