The necessity of a new cross over the Mtkvari River, in the Tbilisi city center, has been growing rapidly for the last few years. The Municipal Development Fund of Georgia required a comprehensive study, including socioeconomics, traffic management, environmental and structural aspects, amongst others.
Due to the complex constraints of such a project in a urban environment, more than 20 alternatives were developed and analysed, varying the location of the crossing, the road arrangement and the type of bridge. After a multi-criteria selection process, the location and type of bridge was decided.
The bridge crosses the Mtkvari River and two riverside avenues, and connects an elevated roundabout on Marshal Gelovani Av. with a new intersection on Samtredia St., on the left bank. It is a cable-stayed bridge, with one centered plan of stays in the main span and two ruled surfaces for the backstays, creating a very exciting visual effect. The deck is divided into two different branches as part of the roundabout.
The bridge presents a layout of 185+450+85 ft (56+137+26 m), where the first spans are the double-branch round about spans, and the 450 ft (137 m) is the main cablestayed span. The bridge was pre-designed as a composite steel-concrete deck, with a multi-cell steel box girder with upper concrete slab. The slab’s overhangs are supported by a 3D triangular bracket system.
The highlight of the bridge is a 150 ft (45.7 m) high concrete pylon that, along with the stays, creates the strong visual appeal of the structure. The back stays anchorage is located inside the roundabout.
The preliminary design was performed with a tridimensional finite element model, representing all the bridge elements.