Railroad Overbridge Over Dunajska Street in Ljubljana (Slovenia)
The overbridge has three spans: 9.245 + 26.260 + 9.245 m, and is wide enough to accommodate four tracks. In addition, it is situated obliquely vis-a-vis Dunajska street.
This relatively small structure in terms of dimensions greatly differs from designs applied in the world for this type of structure until that time. Given the fact that the overbridge is in the downtown Ljubljana, aesthetic and town planning criteria were a priority.
On the basis of experiments with composite structures, an original solution was proposed, with the concrete slab (as an element of the composite structure) placed in the lower zone, contrary to general practice according to which composite structure slabs are placed in the upper zone of the main girder. This resulted in the prestressing of the structure in the span, instead of, as is usually the case, above the supports.
The overbridge involves different statical systems during construction, from a continuous pure steel girder, up to a frame system which also includes a part of the supporting wall on which the structure rests.
The bridge was completed and opened for traffic in 1964.