At the foot of the Grossglockner, a new steel bridge spans the Salzach river near Kaprun, Austria. Its single span streamlined design offers a new blueprint for similar projects. Prefabrication, efficient material use and fast construction were important considerations of the final design solution.
The bridge, with a composite concrete deck, accommodates a 3.25 m wide carriageway as well as a pedestrian and cycle path.
The composite girder construction method for the design of the bridge represents a pioneering solution that can serve as a blueprint for similar projects.
It was designed as a single span 50 m structure by Lang Hugger Rampp Architects and engineered by SSF Ingenieure.
The 2.5 m high stringers of the bridge consist of a hollow steel box girder with inclined upper chords, which are used to provide a protected environment for utility services. The upper chords are divided into two inclined surfaces, which provide design clarity and a streamlined effect. The carriageway consists of a combination of a 20 cm thick precast section and 20 – 33 cm thick in-situ concrete sections.
The precast sections form 19 double-web beam cross-sections, so-called π-slabs, which were reinforced as composite elements with external reinforcement in the lower tension areas. They span over 8.2 m between the longitudinal girders and made it possible to dispense with formwork. This efficient and innovative construction method also eliminated the need for enclosures to protect the Salzach river from pollution during construction.
The external reinforcement elements consist of composite dowel bars, which are beams cut in half along the web in a puzzle-like clothoid shape. This form of composite construction is characterised by economical use of steel and can be used where a very slender design is required due to low construction heights. The bridge abutments are also kept to a minimal design enhancing the streamline design of the structure. The external reinforcement elements were designed to be galvanized to provide lifelong protection of the steel components against corrosion.
Due to a high degree of prefabrication, efficient and fast construction times were achieved for the completion of the bridge and the composite girder construction method represents a pioneering solution that can serve as a blueprint for similar projects.
Composite dowel beams were galvanized to provide life long protection to the steel bridge components
Engineers | SSF Ingenieure