Revealing the cost of building a highway viaduct in the Mekong Delta region

The 50 km long Ho Chi Minh City - Trung Luong Expressway is built with a prestressed reinforced concrete viaduct system.

This is the information reported by the Institute of Economics - Ministry of Construction to the leaders of the Ministry of Construction on the results of research on the effectiveness of investment in building overpasses for expressways in the Mekong Delta region.

Mr. Nguyen Tan Vinh, Director of the Institute of Economics, said that in early April 2025, the Ministry of Construction announced the set of construction investment capital rates and construction prices of structural components of works.

Accordingly, the investment capital for the construction of highways and viaducts has been announced in a basic and complete list of types of highways and viaducts that are commonly invested in and constructed nationwide today.

Comparing initial investment costs shows that the investment cost to build an overpass is on average 2.6 times higher than that of a highway (with the same width and number of lanes).

However, the investment capital announced above does not include compensation, support and resettlement costs; loan interest during construction; environmental impact assessment; weak ground treatment and some other related cost items of the project (specifically, expressway projects in the Mekong Delta often require relatively heavy weak ground treatment).

Therefore, using the investment rate index as announced by the Ministry of Construction to analyze and compare the investment cost of building a highway using sand-filled foundation and the reinforced concrete viaduct option is not really suitable and complete.

According to the Institute of Economics - Ministry of Construction, the comparison and evaluation of the effectiveness between the investment plan for building expressways and viaducts is determined by the initial construction investment capital and maintenance and repair costs calculated for the design life of the project (choosing a design life of 100 years).

Specifically, taking into account the entire project life cycle, the total investment cost for building the overpass is 459,289 billion VND/km, 2.01% higher than the average cost of building a highway.

“If evaluated purely on the basis of comparing initial investment costs, the viaduct option has no economic advantage, but if calculated over the entire project life cycle (the design life of the project), the cost of building an viaduct is not much higher than that of a highway. In fact, some difficulties in the current stage regarding the supply of materials as well as the impact of economic, social and environmental issues require a broader assessment when choosing an option,” said the leader of the Institute of Economics - Ministry of Construction.

Firstly, the option of using sand-filled roadbeds is affected by a number of unfavorable factors such as the need for large-scale site clearance; the lack of sand supply; difficulties in controlling sand prices during project implementation; impacts on local traffic; and the impact of subsidence and landslides during management and exploitation...

Meanwhile, base sand accounts for a large proportion of the investment capital for building 1 km of highway (about 15-16%), equivalent to about 210,981 m3/1 km.

Second, the option of using reinforced concrete overpasses has outstanding advantages in terms of construction progress. Because the construction progress can be controlled due to not having to bear much impact on site clearance, and the construction time of the embankment depends on many factors such as weather, terrain, and construction geology.

In fact, all highway projects running through weak ground areas must be treated before filling the foundation. If treated by wicking and loading, it can take more than 12 months, affecting the project progress.

In addition, the option of using reinforced concrete overpasses also helps reduce the area of ​​land clearance, save land funds, especially in places where it is not possible to expand the land, helping to save costs related to land acquisition; at the same time, ensuring the sustainability of the environment and community in the project area because it is not divided.

The leader of the Institute of Economics - Ministry of Construction said that for investment projects to build expressways in the Mekong Delta region, it is possible to consider the option of combining the use of sand-filled roadbeds with the use of viaducts in certain sections to overcome shortcomings in the management, exploitation, supply, and transportation of embankment materials, and in geological areas when having to calculate and use many solutions to handle subsidence.

“It is necessary to encourage research on the application of new technologies, new environmentally friendly materials and the application of research results on reinforced concrete overpasses in the construction of traffic works to reduce operating costs, improve quality, and reduce construction time (large-span U-shaped beams using high-strength concrete HPC and ultra-high-strength concrete UHPC)”, the leader of the Institute of Economics - Ministry of Construction proposed.

Source: https://baodautu.vn/he-lo-chi-phi-xay-dung-cau-can-cao-toc-tai-khu-vuc-dong-bang-song-cuu-long-d279392.html