**REFERENCE: **Ring Road Viaducts

**Preparation of a preliminary design project for the construction part of the project from km 52 + 363.42 to km 53 + 692.42 and from km 54 + 360 to km 54 + 560 of the Sofia ring road from Ralevitsa Str. to Lyulin motorway; Sofia city**

*Improving Sofia infrastructure demand the creation of bypass of the ring road. As part of the project two flyover viaducts are considered in a dense populated area of the existing ring road. Due to the existing infrastructure and surrounding the new viaducts are under heavy restriction.*

*The project concerns the design of two road bridges.*

**Bridge of km 52+363,42 to km 53+692,42**

Total length of the bridge 1329.00 m with a width of 27.50 m (2 lanes 10.50 m + dividing strip 3.00 m + 2 pavements 1.75 m).

Total length of the ramps 153.50 m with a width of 8.50 m (1 lane 6.00 m + dividing strip 0.75 m m + pavement 1.75 m).

The structure of the bridge consists of 57 spans of different lengths, divided into 13 separate sections:

- Reinforced concrete construction has 10 sections (section lengths from 70 m to 110 m, total length – 858 m and the spans are between 15 m and 30 m).
- The steel top structure has 3 sections (section lengths from 135 m to 168 m, total length – 471 m and the spans are between 29 m and 55 m).
- The ramps are two and have a reinforced concrete superstructure (with lengths of 96.50 m and 57.00 m respectively).

**Bridge of km 54+350 to km 54+570**

Total length of the bridge 200.00 m with a width of 27.50 m (2 lanes 10.50 m + dividing strip 3.00 m + 2 pavements 1.75 m).

The construction of the bridge consists two separate facilities, one for each direction of the road. It is divided into 4 sections with reinforced concrete superstructure with a length of 100 m, two for each direction. Each of the sections has 3 spans (2 end spans of 30.00 m and the middle span of 40 m).

**Total length of developed road bridges 1682.50 m and their total area is 43 352.25 square meters.**