Customer case

Trapezoidal sections improve economy of the long span bridge superstructure

August 19, 2021 6 min read

18 m long open profiles on a truck

Case details

Country Hungary
Company WKS Duna Polska SP. Z O.O. and SAM Shipbuilding & Machinery
Industry Building structures and infrastructure

SSAB has been involved in the development and implementation of steel bridge structures for many years. Our solutions for both superstructure and substructure steel bridge components make us competitive in this construction sector. SSAB plates, pipes, sections and profiles open the way for sustainable and cost-effective bridge construction, which means savings in overall life cycle costs. The two bridge projects in Hungary are a perfect example of how to implement VU sections into a steel bridge superstructure.

Roll-forming a profile

VU production in Toijala mill

Toijala Works can produce elements up to 21 meters if required. Choosing roll-formed trapezoidal sections for a project brings certain advantages, especially if long decks are needed. Additional welding can be avoided and components can be manufactured faster at the customer’s premises.

Hannu Koukkari, Account Manager, SSAB Finland

Komarno Bridge

Komarno bridge on Hungarian-Slovak boarder (photo courtesy Pont-Terv engineering, Source: https://www.worldhighways.com/)

On 17th of September 2020, a new Danube road bridge was inaugurated, opening up a new route for heavy trucks between two countries – Hungary and Slovakia. The impressive 600 m long construction with inclined asymmetric cable tower was a great success for all parties. SSAB supplied more than 1000 tons of rolled formed and press bent trapezoidal sections to production facilities in Poland and Slovakia where orthotropic decks were manufactured. After welding, the orthotropic deck parts were transported to the bridge construction site in Komarno on the Slovak-Hungarian border.

A few weeks later, SSAB received a new material specification for the next Danube bridge in Kalocsa-Paks, Hungary. The bridge is part of a larger infrastructure project. There is total of three bridges, two of which are reinforced with concrete frames and one with steel frames. In addition to these, the project will include new roads and roundabouts, cycle paths and service roads. The steel bridge is designed as 2-lane bridge with a length of 946 m and 10 supports and double-sided floodplain. The main purpose of this M6 motorway investment is to reduce travel time between local cities and to boost economy in the region. The bridge will be completed by mid-2024.

Paks bridge

Paks bridge in Hungary (photo courtesy WKS Duna Polska)

Looking at the steel structure specification, we knew it would be very demanding in production in Toijala Works. Material list was very comprehensive and contained a lot of technical requirements. There were several cross-sections, various steel grades and great number of lengths.

Aleksandra Burska, Regional Sales Manager, SSAB Poland

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Production site of SAM Shipbuilding and Machinery

The material must be delivered in batches according to the production schedule presented by subcontractors. This is a challenging task for production, but also for the logistic department. Thanks to the cooperation between SSAB Finland and SSAB Services’ Polish sales department, it was possible to manufacture all of the steel parts specified by the customer.

Toijala Works has manufactured the first part of the specification - 500 tons of VU sections. There were five different cross-sections in two steel grades and more than fifteen different lengths. The longest of them were up to 18 meters.

Sections are used as stiffeners in orthotropic decks and they support a steel plate structure forming a long-lasting and firm component. Trapezoidal sections have very good torsion and fatigue resistance. Closed ribs are easy in surface treatment, which means lower production and life cycle costs. The elements have a high straightness and dimension accuracy.

SSAB Steel Service Center in Oborniki Wielkopolskie produces sections from the second part of the material specification. The project includes elements at the end of the bridge and elements for the foundation of barriers made of 10 mm thick S355J2C + N material. These plasma cut and press bent profiles are 12 meters long. The project consists of about 220 tons of bent elements.

In the next phase of the project, SSAB will be responsible for the production of bridge webs made of 12-20 mm thick S355J2C + N plates. The elements are plasma cut and bent on a press brake. This part of the project consists of about 530 tons of bent elements.

Production will continue at both SSAB’s production units in Finland and Poland. The total volume of all sections exceeds 1 200 tons. More than 200 tonnes have already been delivered to a subcontractor, WKS Duna Polska. After summer holidays, SSAB will continue with deliveries.

Press-bending in Oborniki

Ursviken bending machine in SSAB Steel Service Center Oborniki

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