We can be Heroes

Paraguay’s Puente Héroes del Chaco will provide a vital transport link for the country once it is complete, Mauro Nogarin and Mike Woof report
January 11, 2023
By Mauro Nogarin and Mike Woof
© Iakov Filimonov | Dreamstime.com
© Iakov Filimonov | Dreamstime.com

In Paraguay, the project to construct the Puente Héroes del Chaco project is delivering transport infrastructure that guarantees the economic future of the country. This project has the objective of uniting two large productive regions of Paraguay as well as promoting the demographic and economic development of the cities of José Falcón, Villa Hayes and Nanawa. There has been steady population growth in and around Paraguay’s capital over a number of years and developing the transport infrastructure in the area is important to ensure that can continue. In addition, the bridge will help decongest traffic on existing routes in the area by handling around 10,000 vehicles/day. Drivers in and surrounding the city will benefit from shorter journey times also, while the bridge will provide an important route for heavy trucks carrying goods.

Concrete has been poured for the two towers supporting the bridge structure © MOPC Paraguay
Concrete has been poured for the two towers supporting the bridge structure © MOPC Paraguay

Construction of the new bridge constitutes a key infrastructure project for Paraguay’s road connections with Argentina and Brazil, linking Puerto Falcón to the Botanical Road Corridor, Ñu Guasu Highway, Luque – San Bernardino Route and Route 2.

The work forms part of the Paraguay 2030 National Development Plan, with the section located in the area between Asunción and Chaco’í, (Villa district Hayes). The project is providing a new crossing over the Paraguay River as well as a new connection with the existing road network in Asunción and the Route to Puerto Falcón.

In general terms, this project consists of the construction of a highway with a total length of 7km, two lateral accesses of approximately 1.5km each, and a 450m bridge over the Paraguay River. The bridge is a key link in the chain and will have two lanes in each direction. Vulnerable road users have not been overlooked though and the bridge will also feature a bike lane and a pedestrian path. With its four vehicle lanes, dividers and lanes for vulnerable road users, the total deck width for the bridge is 28.44m.

Viaduct sessions on either side of the River Paraguay are being built to connect to the central section of the bridge © MOPC Paraguay
Viaduct sessions on either side of the River Paraguay are being built to connect to the central section of the bridge © MOPC Paraguay

Construction work commenced in early 2021 and the bridge was initially expected to take 36 months to be completed, according to the work schedule. The structure is due for delivery at the end of 2023 and is currently more than 70% complete.

This important infrastructure project was awarded to the Union Consortium, which is comprised of the contractors CDD Construcciones and Constructora Heisecke. The consortium had a budget of US$180 million for the project.

Construction of the bridge has faced a number of technical challenges though. Extensive studies were carried out to determine the geology in the area and ensure that building a bridge would be viable. According to the geotechnical studies carried out by the Japanese Government International Cooperation Agency (JICA), most of the soils around where the bridge is being built are of alluvial origin. These soils are composed mainly of sediments deposited by the numerous rivers and streams present in the area. The data also confirmed that fine silty sands of medium to dense substance were found below 8m depth in some cases, down to a depth of 20m. The design of the structure accounted for this, with sufficient piling being used to ensure the bridge would cope with the anticipated loads given the local geology.

Meanwhile, for the design of the 7km of highway, the parameters were based on the recommendations of the Paraguayan Highway Manual and the AASHTO Geometric Design Standards for Highways. And the new highway section is being constructed with a design speed of 80km/h.

The deck for the viaduct sections sits on precast beams raised into position
The deck for the viaduct sections sits on precast beams raised into position © MOPC Paraguay

The design for the Héroes del Chaco bridge that has been adopted is for a cable-stayed structure featuring two viaduct sections. The viaduct on the right bank will connect with the Falcón-Remanso route while the viaduct on the left bank will connect with the Costanera Norte route. To support this enormous bridge and viaduct infrastructure, a total of 371 piles have been driven, 311 on land and 60 in the riverbed. The two approach viaducts are approximately 1,500m long on each side and have similar characteristics in terms of their structural design.

Progress on the project is being achieved, despite a number of challenges both expected and unexpected. The installation of the viaduct beams on the Costanera Norte side was completed in the first week of July 2022, while on the Asunción side this was completed in the first week of August 2022. This phase of the project began at the end of June 2021 with the use of a beam launching machine, which also allowed the original work schedule to be maintained. Telescopic cranes were used for part of the work also but only for certain stages of the viaduct construction works.

The manufacture of all the prestressed beams was carried out in the same Consorcio Unión facility in Chaco'i. Each of these beams weighs 40tonnes and a total of 590 beams is being used for the construction of both viaducts.

A special structure has been used to raise most of the beams on which the deck rests
A special structure has been used to raise most of the beams on which the deck rests © MOPC Paraguay

Being constructed on top of these viaducts is the 28.5m-wide deck, which is made up of a deck of 11 double T beams. There is a 0.25m-thick compression slab that in turn rests on precast slabs, which have been prefabricated and are laid on the top of the beams.

In July 2022, the assembly work for the construction of the central section of the bridge commenced. The middle section of the bridge consists of a cable-stayed deck that is 450m-long and has a main span measuring 260m in length, with 95m-long sections on either side. The bridge is supported by two diamond-shaped towers while its minimum deck depth is 2.45m.

Also in July 2022, the concreting of the tower on the Chaco'i side of the Paraguay River was completed. This is 108m-high and sits on foundations made up of 30 piles, each of which is 2m in diameter and 45m-deep.

In this phase of the work, steel structures are being used that have been manufactured especially for the bridge project. These structures are 32m-wide by 6m-long and weigh around 200tonnes.

According to information from the Union Consortium, an average advance rate of 6m/week of deck is being achieved.

To complete the construction of each tower, 1,900m3 of concrete were needed. The deck has been designed to sit on a crossbar at a height of 35m. The design and structure of the towers are very similar on both sides of the bridge, carrying the cables that support the entire deck.

Design issues

The completion date has now been set for the important Héroes del Chaco bridge project in Paraguay. This is a significant development in light of a series of issues with the project.

The Ministry of Public Works and Communications (MOPC) in Paraguay said that the bridge will now be ready for traffic in April 2023. However, the bridge project is now expected to cost considerably more than was originally anticipated.

This is an important project for Paraguay and the country’s government took steps to ensure that the work would be carried out as intended. The bridge is being built by the consortium Consorcio Union, which comprises CDD Construcciones and Constructora Heisecke, with much of the funding also being supplied by the Inter-American Development Bank (IADB).

Once the bridge is open to traffic, it will relieve congestion on an existing bridge around 8km to the north. The bridge will provide a new connection between Paraguay’s capital, Asunción, and the town of Chaco'i.

Originally the 450m bridge was expected to cost $115 million. But, there were concerns over a number of issues with the project, including the design, which led to an investigation being carried out.

Local shipping firms said that the proposed bridge, with its 22m clearance height, would not be sufficient to allow large vessels to pass underneath and would adversely affect ship traffic as a result, impacting on economic activity along the river. The local shipbuilding organisation, Cafym, called for a new bridge design with a clearance height of 29m.

The issue of river traffic is an important one for Paraguay. The country is landlocked but the River Paraguay is navigable by comparatively large vessels and is a tributary of the Parana River, which merges downstream with the Uruguay River. The Paraguay River is vital for Paraguay’s international transport and commercial trade, so the issue of the deck height was crucial. Redesign work had to be carried out as a result, and the redesign and construction delays caused a number of issues with the project. The MOPC ran short of the necessary funds to complete the work. As a result, more funding had to be secured from banks to allow the completion of the project.

The work is now back on track and with a completion date announced, this will come as some relief for the city’s drivers who currently have to contend with traffic delays at peak periods. Once the bridge is complete it will help boost transport for Paraguay, linking the country to Argentina and also providing through access to Brazil. In addition to the bridge and its access roads, improvement work is also being carried out for the PY12 route linking Chaco'i with General Bruguez. This road runs parallel with a stretch of Paraguay’s border with northern Argentina. The upgraded road will provide a better connection for the Héroes del Chaco bridge and Paraguay’s capital Asunción, as well as improving overall transport links between Paraguay and Argentina.

Centra stage

Traffic in Paraguay’s busy and congested capital, Asuncion, will benefit from the new bridge
Traffic in Paraguay’s busy and congested capital, Asuncion, will benefit from the new bridge © Iakov Filimonov | Dreamstime.com

Asunción is one of South America’s oldest cities, having been a centre of human habitation over many centuries. As Paraguay’s capital,it is also the country’s largest city with over 500,000 inhabitants and a metropolitan population in excess of two million. Of note too is that the city is also the landlocked nation’s major port, sitting on the navigable Paraguay River.

As economic growth has been steady in the city, the population has also grown and this has resulted in increasing vehicle numbers using the city’s network.

Traffic congestion has worsened in recent years, resulting in a need for an expansion of its road capacity as well as investment in public transport and further development of bus lanes.