engleski

DESIGN AND CONSTRUCTION OF KRKA RIVER ARCH BRIDGE

A new concrete arch bridge with 204.0 m span was constructed across the Krka River canyon on the section Skradin-Šibenik of the Adriatic highway. The bridge site lies in an environmentally protected area very close to the Krka national park. The superstructure is continuous with spans L=3x32.0+3x28.0+3x32.0+28.0+24.0=360.0 m comprising two main steel box-type beams spaced at 7.6 m, strong steel cross beams and a concrete deck plate in composite action with both main and cross beams. The application of the composite superstructure, made possible significant reduction of the dead weight and enhanced the bridge appearance in comparison to other Croatian concrete arch bridges. Because of the importance of the Krka River bridge and aggressive environment monitoring system was installed for measurements of deformations, local temperature values, movements in service at critical points and corrosion rate. The construction of the bridge across the Krka River canyon commenced in the year 2003 and was successfully completed in two years in 2005. The whole arch cross section was constructed by free cantilevering, on traveling formwork carriages, in segments 5.25 meters long, starting symmetrically from arch abutments. Piers at the arch abutments had to be extended by auxiliary steel staying pylons to facilitate successive cantilevering. The arch was supported during construction by stays equilibrated by anchor stays, connected to rock anchors. The steel superstructure grillage was erected by longitudinal launching in three phases. The concrete deck plate consists of from full depth precast slabs interconnected by on site concreting of longitudinal and transversal joints above shear connectors.

Arch; bridge; bridge design; composite superstructure

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