Construction of the Struma Motorway – Lot 3.2.2 Detour – Kresna

Contracting Authority

Location

Town of Kresna, from km 396+137 to km 400+340

Period of implementation

Glavbolgarstroy’s role in the project

Nature of works

The Struma Motorway is a key infrastructure project in Bulgaria of strategic importance for the management of national and international transport flows. It forms part of the Trans-European Transport Network (TEN-T) corridor “Baltic Sea – Black Sea – Aegean Sea”, connecting 11 European countries, including two non-EU states.

The project section is divided into two sub-sections and includes the construction of major motorway infrastructure, tunnels, viaducts, bridges, and environmental protection facilities.

The project includes the construction of: 10 viaducts with a total approximate length of 2,925.6 m; 3 single-tube tunnels for bidirectional traffic with a total approximate length of 812 m; 1 double-tube tunnel with a total approximate length of 2,621.2 m; 7 agricultural underpasses; Noise protection and drainage structures; Wildlife protection and fragmentation fencing systems, as well as bird protection measures along the entire alignment.

Technical characteristics

Subsection 1: Kresna Detour (Right Carriageway)

The new alignment crosses the Struma River at two locations, passes adjacent to the Tisata Nature Reserve, over the I-1 primary road, the Sofia–Kulata railway line, and over the Vlahinska River.

This subsection includes five major structures: two tunnels and three bridges - Kresna Tunnel 1 – length 359 m; Kresna Tunnel 2 – length 231 m; Two bridges over the Struma River – lengths 298 m and 296 m; Bridge over the Vlahinska River – length 203 m

At the end of the section, a rest area with a staged connection to the I-1 Sofia–Kulata primary road will be constructed.

Crossings with agricultural roads are provided via four underpasses, and the project includes 22 culverts, which also function as wildlife passages for reptiles.

Subsection 2: Struma Motorway Lot 3.2.2 – Kroupnik–Kresna Section (Left Carriageway)

The project alignment passes through a highly complex mountainous terrain, with significant portions of the roadway constructed on high embankments.

The section includes a series of major engineering structures, including viaducts and tunnels - Viaduct at km 389+200; Viaduct No. 16 at km 390+993; Viaduct No. 17 at km 391+592; Viaduct No. 18 at km 392+602; Viaduct No. 19 at km 394+450; Viaduct at km 397+900; Viaduct at km 401+100 (for both carriageways)

Additional agricultural underpasses are located at km 398+655 and km 398+912, as well as a road underpass at km 400+504. Kresna Tunnel 1: between km 398+342 and km 398+701, length 359 m; Kresna Tunnel 2: between km 398+860 and km 399+091, length 231 m

Due to their proximity, both tunnels are constructed simultaneously from four working faces. Both are single-tube tunnels with two traffic lanes and one-way traffic operation. Tisata Tunnel - located between km 393+100 and km 393+322, length 222 m. Construction will commence following relocation of the transit gas pipeline within the alignment area. The tunnel is designed as a single-tube structure with three traffic lanes and one-way traffic flow. St. Nedelya Tunnel: a double-tube tunnel structure - Western tube: 1,297.26 m; Eastern tube: 1,323.94 m

The two tubes will be constructed in parallel and connected via ventilation and emergency evacuation galleries spaced at intervals of up to 280 m. Each tube provides two traffic lanes with one-way traffic flow in the direction Kulata–Sofia.

The section terminates with a connection to the Kresna bypass road and the local road network.