Railroad Cable-Stayed Bridge Across the River Sava in Belgrade
The railroad bridge across the River Sava between the "Novi Beograd" and "Prokop" stations is 1928 m long in all. It consists of a crossing over the river and approaches on the left and right banks. This was practically the first railroad bridge employing a cable-stayed girder system in the world. The prevalent view until that time was that bridges employing this system were, similarly to suspension bridges, too flexible for railroad traffic.
The approaches on the left bank section are 791.36 m long, the central section above the River Sava and the Winter Harbor is 557.94 m and the approach on the right bank section 578.76 m long. The approach structures of the left bank are prestressed concrete continous girders, with a spans of about 45 m, except for two 61 m spans above a wide city street. On the right bank there are prestressed structures with spans 63.03 + 75.5 + 63.03 m onto which reinforced concrete structures are conected with spans of 35.0 + 2 x 38.5 +35 m.
The main bridge structure – its central section – is a continous girder (stiffening beam) with spans of 52.74 + 85.00 +254.00 + 50.00 + 64.20 = 555.94 m, with cable stays in the central spans. The stiffening beam consists of two box girders of a constant height of 4.45 m mutually interlinked by an orthotropic deck, which carries the ballast and tracks. On both sides of the main span there is a pair of vertical pylons anchored in the bridge stiffening girder. The cable stays are distributed in two vertical planes supporting the stiffening girder at approximately every fifth of the 254 m span. All the cables are anchored above the supports of 50 m long lateral spans. Adopting BBR system parallel wire cables with high fatigue resistant Hi-Am anchors, along with measures to increase the bridge mass, optimum stress level, excellent cable tension for dead loads and an insignificant influence of cable sag on vertical displacement of the structure,was acheived.
We should mention that this is the first time that this type of cables were used in Europe. Since that time, up to date, this type of cable has been the dominant form used for cable-stayed bridges in the world.
The piers under the pylons are founded on caissons, while the other piers are founded on bored HW system piles, 1.50 m in diameter.
The superstructure of the bridge has been executed as in an open railroad, i.e. applying a classical crushed stone ballast. This has significantly reduced the noise level (essential for a bridge in an urban environment), yielding the same exploitation conditions on the entire section, and with improved damping of oscillations caused by live load.
The bridge was completed and opened for traffic in 1979.