site.btaKresna Town Bypass on Struma Motorway Takes Shape with Bridges and Tunnels

Three major bridges and two tunnels will be built on the 4.2 km long Kresna town bypass on the last section of the Struma Motorway that remains to be constructed, the Road Infrastructure Agency (RIA) said in a press release on Wednesday.

The town bypass will be part of the eastern carriageway of the Krupnik–Kresna section of the Struma Motorway. The design splits the section into an eastern carriageway and a western carriageway with some distance between them. The option was chosen after a long saga during which environmentalists challenged the project for its likely impact on natural habitats in the area. The Kresna Gorge and the mountains on both sides of it are known for their rich biodiversity.

Currently, more than 60 heavy-duty machines and 170 construction workers are operating on site. In addition to the heavy machinery, specialized drilling equipment is being used for the installation of piles, the RIA said. The construction area is being cleared of bushes and trees, and the topsoil is being removed. Work is underway on all underpasses for agricultural crossings and on parts of the reconstruction of power lines and irrigation channels.

Preparatory work has begun for one of the planned tunnels, with excavations being reinforced at the pre-portal sites. For the bridges, pile foundations with a diameter of 1.2 metres are being installed, with a total length of approximately 650 metres.

Construction of the Kresna town bypass began on November 27, 2025. The section will be nearly 4.2 km long and is part of Lot 3.2.2 of the Struma Motorway. Once completed, the route, which will pass east of the town of Kresna, will divert transit traffic out of the populated area and improve road safety. The estimated completion time for the construction works is around two years.

According to the RIA, the bypass will have a G 10.50 cross-section, equivalent to two traffic lanes. The first 200 metres coincide with road I-1, after which the route follows a new alignment. The section will cross the Struma River in two places, pass near the Tisata Reserve, over road I-1 and the Sofia–Kulata railway line, and over the Vlahinska River. Five major structures will be built on the site – two tunnels and three bridges. The Kresna 1 and Kresna 2 tunnels will be 359 m and 231 m long, respectively. The two bridges over the Struma River will measure 298 m and 296 m, while the third bridge over the Vlahinska River will be 203 m. At the end of the section, there will be a rest area, followed by a stage connection to the I-1 Sofia–Kulata road. The rest area will accommodate commercial units, 50 parking spaces for trucks and buses, and 49 spaces for passenger cars, five of which will be reserved for people with disabilities.

Agricultural road crossings will be carried out on two levels through four underpasses, ensuring farmers in the region have safe and convenient access to their land. To protect biodiversity, 22 small structures (culverts) will be built to function as “reptile passages.” The project also includes the construction of retaining walls in two sections measuring 37 m and 71 m, and one pocket retaining wall of 119 m.

The construction of the Kresna town bypass is part of the design and build project for Lot 3.2.2 of the Struma Motorway, covering the Krupnik–Kresna section – left (western) carriageway from km 389+100 to km 399+500, and the Kresna bypass – part of the right (eastern) carriageway from km 396+137 (according to I-1 /E79/ road kilometre) to km 401+691.90 ≡ 397+000 of Lot 3.3 of the Struma Motorway, including road connections.

The design and construction contractor is a joint venture named Struma 3.2.2, comprising GBS Infrastructure Construction AD, Glavbolgarstroy International EAD, and EPOS – Empresa Portuguesa de Obras Subterráneas AD, Portugal. The contract value for Lot 3.2.2 is BGN 570,239,136.32 (EUR 291,558,640.74). Construction supervision is carried out by the joint venture Struma 2019-PPI-SVS, which includes Patinvest Engineering AD and SWS Engineering Spa, Trento, Italy. The supervision contract value is BGN 9,413,253.89 (EUR 4,883,860.05). The construction period for Lot 3.2.2 under the contract is 1,286 calendar days (about three and a half years), starting from the signing of Protocol 2a, the RIA said.

In 2023, the Kresna road junction, another stage of Lot 3.2.2, was completed. The junction was supplemented with three new road connections, necessary to ensure safe and conflict-free links between road I-1/E-79 Sofia–Kulata and the Kresna–Sandanski section of the Struma Motorway.