NGHE AN - The overpasses over mountains and dams on the Dien Chau - Bai Vot expressway, including Xuan Duong 1, 2; Than Vu 1, 2 and O O, are being urgently completed and are expected to open to traffic on April 30.
Dien Chau - Bai Vot Expressway started construction in May 2021 with a total investment of more than 11,150 billion VND. The starting point of the route is in Dien Cat commune, Dien Chau district, Nghe An province, connecting Nghi Son - Dien Chau expressway. The end point is in Thanh Binh Thinh commune, Duc Tho district, Ha Tinh province, at the Bai Vot - Ham Nghi expressway intersection. The section through Nghe An is 44.4 km long, Ha Tinh is 4.9 km long.
From north to south, the entire route has 5 viaducts crossing mountains and dams running through Dien Chau and Nghi Loc districts, Nghe An province, including Xuan Duong 1, 2; Than Vu 1, 2 and O O. To build the bridges, in some locations, the contractor had to level the entire hillside and place pillars tens of meters high under the dam.
According to the design, these bridges are 17.5 m wide with 4 lanes, with a hard median strip in the middle. The total construction cost is about 1,000 billion VND.
In the photo is Than Vu 2 Bridge in Nghi Dong Commune, Nghi Loc District at present and when the pillars were poured in October 2023. The project is 1,280 m long, with 32 Super T girder spans, and is the longest off-road overpass on the route.
Xuan Duong 1 Bridge is 880 m long with 22 Super T girder spans winding around two small mountains, in Dien Phu commune, Dien Chau district.
Engineer Thai Ba Luc, Commander of Hoa Hiep Company Limited, said that this area is mainly a valley, so the feasible solution is to build a viaduct over the mountain and a dam. If we build a road, we will encounter many difficulties because the materials to fill the land are very large, and it will also affect the surrounding landscape.
Connected to Than Vu tunnel - the most complex geological structure on the North-South expressway - is Xuan Duong 2 bridge, 808 m long, 19 pillars, 2 abutments with 20 Super T girder spans. The lowest pillar height is 8 m, the highest is over 52 m. This is the overpass with the highest pillar on the entire Dien Chau - Bai Vot route.
According to engineer Luc, Xuan Duong 2 crosses Xuan Duong dam so the geology is quite weak, while the original design was short bored piles, fearing that the quality would not be guaranteed. The unit then adjusted the design, drilling the bored piles deeper, with a negative point of 40 m, so the limitation was overcome.
On April 11, Hoa Hiep Company mobilized machinery and workers to spread asphalt concrete on Xuan Duong 2 bridge surface, the northern gate of Than Vu tunnel.
On the same day, contractors simultaneously began work on the remaining four bridges. The five overpasses are expected to be completed on April 18, in time for the opening ceremony to take place nearly two weeks later.
Than Vu 2 Bridge connects Than Vu 1, consists of 31 pillars, the highest pillar is nearly 50 m, construction started in early 2022. At first, due to unfavorable weather, continuous rain and the contractor supporting people to cut down pine trees to clear the land, the start was slower than other projects on the route.
Than Vu 2 is located in a rugged mountainous area. The construction process has increased the cost of raw materials and fuel, causing many difficulties for the contractor. According to the original plan, the construction of Than Vu 2 bridge will be carried out from the middle to both ends of the bridge, with one gantry in each direction.
To shorten the time, the engineer changed the construction solution, making a girder casting yard on the top of a high hill, then launching the girders longitudinally in both directions, combined with a horizontal spearhead. Thanks to that, at peak times, the unit could launch 5 spans in a month, and on average it was 3 spans.
In addition to the five mountain and dam viaducts, the Dien Chau - Bai Vot expressway also has 26 other bridges (18 along the route and 8 across), many of which have been put into operation. In the photo, workers are constructing an overpass along the route through Hung Tay commune, Hung Nguyen district in early April.
Previously on March 16, Hung Duc Bridge, nearly 4.1 km long, spanning Lam and La Giang rivers connecting Nghe An and Ha Tinh provinces, is the longest river-crossing bridge on the entire North-South expressway, was completed and is expected to be completed in early May.
5 viaducts are the highlight of the Dien Chau - Bai Vot highway, vehicles will pass through mountains, forests, lakes and dams.
The contractor said that if a check-in point for taking photos and selling coffee could be arranged in the south of Than Vu tunnel, it would help the locality attract tourists.
In the photo is the O O bridge over O O lake in the late afternoon, which is also a place that often attracts young people to come and take souvenir photos.
Route 5 of the mountain-crossing viaduct and dam lake on the Dien Chau - Bai Vot expressway. Graphics: Hieu Nguyen
According to the Ministry of Transport, the Dien Chau - Bai Vot project aims to open 30 km of the route from the beginning of the route, at the intersection of National Highway 7 in Dien Cat commune, Dien Chau district, to the intersection of National Highway 46B, in Hung Tay commune, Hung Nguyen district (Nghe An province) before April 30. The remaining 19 km section has weak soil and needs time to wait for loading, so it will be completed later.
Mr. Truong Duc Lien, Deputy General Director of Phuc Thanh Hung Investment Joint Stock Company (project enterprise), said that the bidding packages of the entire project have reached 82% of the contract volume. The contractor is using maximum machinery, mobilizing nearly 2,000 workers with more than 100 construction teams to keep up with the schedule.
"With 30 km expected to be open on April 30, the output has now reached over 90%. If the weather is favorable, the plan will be guaranteed," said Mr. Lien.
Vnexpress.net
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