The great challenge of the A1 Sibiu – Pitesti Highway. The mountain section with 50 passages and a 1.7 kilometer tunnel

The most difficult section of the Sibiu-Pitesti Highway has entered an important stage. On the Cornetu-Tigveni mountain sector, work is progressing on the foundations and on the ecoduct on Valea Oltului, while the construction site is preparing for the drilling of the Poiana Tunnel, the longest of the highway.

The construction site of the A1 highway, on the Corbetu – Tigveni section. Photo: Daniel Guță. TRUTH

More than 40 kilometers of the 122 kilometers of the A1 Sibiu – Pitesti Highway have been opened to road traffic in recent years, and the most difficult section, approximately 80 kilometers between the towns of Boita and Curtea de Argeș, is under construction, with an estimated completion date of 2027-2028.

The mountain highway crosses the Olt Valley and Băiașului Valley, through Sibiu, Vâlcea and Argeș counties, and its route will include nine tunnels, with a total length of 8.5 kilometers, and over 100 passages.

The most complex section of the future highway was designed between the towns of Cornetu (Vâlcea county), on the Oltului Valley, and Tigveni (Argeș county), located near Curtea de Argeș.

Mobilization on the mountain highway construction site

Section 3 of the Sibiu – Pitesti Highway is 37.5 kilometers long and will include over 50 bridges, passages and viaducts, as well as the Poiana Tunnel, located on the border of Vâlcea and Argeș counties, with a length of 1.7 kilometers. Hundreds of workers have been mobilized since the beginning of the year on the route of the future highway at the foot of the Coziai Mountains.

The works started at the beginning of 2025, and so far the Romanian state has issued the necessary construction permits for approximately 25 kilometers of the highway route. For the rest of the segments, it is necessary to review the environmental agreement and carry out additional expropriations.

On the segments in the construction site, work is being done on the foundations of several viaducts, drilling for deep bored piles, technological platforms are being set up and reinforcements and formwork are being installed for the future piers of the viaducts.

Near the Cornetu Monastery, on the Oltului Valley, the place where Section 3 of the Sibiu – Pitesti Highway begins, work has begun on the Călinești Ecoduct. It will have a minimum width of 100 meters and a length of over 300 meters and will cross the DN7, the CF201 railway and the Olt river, between kilometers 45+300 and 45+750, north of the town of Călinești.

Technological roads and working platforms have been set up, and work is being done on the banks of the Olt river to stabilize the slopes and future foundations. The Călinești Ecoduct, the second one designed on the Sibiu-Pitesti Highway, next to the one in Lazaret, has the role of ensuring the continuity of natural habitats and allowing the safe crossing of wildlife over the transport infrastructure.

Preparations for digging the longest tunnel

Also, the ground was prepared for the start of drilling the longest tunnel on the Sibiu – Pitesti Highway. At the beginning of January, the TBM (Tunnel Boring Machine), used for digging long tunnels, was brought to Constanța Port, and its components were transported to Călărași, for pre-assembly.

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Sibiu Pitesti Highway Oltului Valley, Cornetu Tigveni Section Photo Daniel Guță THE TRUTH (1) jpg

“After the preliminary assembly of some elements, the segments of this “technological giant” will be transported, with oversized vehicles, to the construction site of Section 3 (Cornetu – Tigveni) of the Sibiu – Pitesti (A1) Highway. This machine stands out for several notable features: the diameter of 12.49 meters (as much as a four-story building), the length of 100 meters (the equivalent of a football field) and the weight of 3,300 tons. The Poiana tunnel (1.7 kilometers) will be the first road tunnel in Romania drilled with TBM technology, an absolute national first”recently informed Cristian Pistol, director of CNAIR.

The Poiana tunnel, with two galleries and two lanes per direction, was planned to cross the Frasinet Hill, between Vâlcea and Argeș counties, being necessary to avoid the area with active landslides on the Poieni Valley.

Section 3 Cornetu – Tigveni is being built by the association Astaldi/WeBuild – Tancrad. The contract, signed in 2022, has an estimated value of 5.32 billion lei (without VAT), and the completion of the works is expected around 2028, depending on the duration of the review of the environmental agreement and the obtaining of building permits for the rest of the route. According to CNAIR, the stage of execution has reached about 11%.

With the completion of the three sections of the Sibiu – Pitesti Highway under construction, it will make possible the connection of the historic regions of Muntenia and Transylvania by highway. The mountain highway is part of the A1 Nădlac – Bucharest highway, with a length of almost 580 kilometers, of which a segment of approximately 10 kilometers, between the towns of Holdea and Margina, remains in the construction site. After its completion, A1 will completely connect the western border of Romania, at Nădlac, with the Capital.

The legendary place crossed by the future highway

Unlike other highway segments, the Cornetu – Tigveni section mostly crosses an almost wild area, which follows the Băiașului Valley (Alb River), with several picturesque villages, but difficult to access due to the relief and unmodernized roads.

The statue of Basarab I. Photo: Daniel Guță. TRUTH

On one side of the Băiașului Valley rise the sharp ridges of the Cozia Mountains, declared a nature reserve since 1966. The future highway will bypass the Cozia National Park in the north, in Vâlcea county, with an area of ​​over 17,000 hectares, crossing the valley where several picturesque villages are lined up. In the north of the route, travelers encounter other villages scattered on the hills in the submontane area of ​​the Făgăraș Mountains.

Băiașului Valley would have been the site of the legendary battle of 1330, where the mountain voivode Basarab I defeated the army of King Carol Robert of Anjou, a moment that marks the beginning of the independence of Wallachia. The event was later known as the “Battle of Posada”, although this name is not mentioned in medieval chronicles, and its exact location has not been precisely identified. Some historians claimed that the fight was in the clearing at the crossroads between the neighboring villages of Perișani, Pripoare and Băiașu.

The statue of Basarab I was erected here, to remember the place of the famous battle mentioned in the medieval chronicles. Other historians show, however, that the battle between the armies of the Kingdom of Hungary and those of Wallachia would have been fought a few kilometers downstream, near Cornetu, where the waters of Băiaș flow into Olt.

A prominent rock, called Doancă's Tower, erected in the vicinity of the Ioan Iacob Hozevitul Monastery, would have marked the place where the mountain armies crushed, in an ambush, those of the king of Hungary.

Over time, the hypotheses launched by historians regarding the place of the battle in 1330 also targeted the Olt Gorge, the Mehadia area, the Prahova Valley or the Rucăr-Bran Corridor.