M49: construction of the Kraszna bridge progresses in twenty-metre sections

The Kraszna Bridge is being pushed into place as part of the M49 expressway project being built under the Építési és Közlekedési Minisztérium investment, according to magyarepitok.hu. As we have reported on several occasions, the 28.15-kilometre section of the expressway between the M3 motorway and Ököritófülpös is being constructed by Duna Aszfalt Építő Zrt.. This project, together with the later construction of the Ököritófülpös-Csenger section, will create an expressway connection between the M3 motorway and the national border, opening up the road to the Satu Mare region.

We last reported on the progress of road construction between Mátészalka and Ököritófülpös in August last reported in August. This time, with the help of the relevant experts, we provide detailed information about the structures under construction, including the work on the Kraszna Bridge.

He also pointed out that preparatory works have already started on the other parts of the almost 30-kilometre-long Mátészalka-Ököritófülpös section. "The consolidation of the subsoil on the rearmost section is planned to start this year," he said. "The same is true for the two structures in the first half of the section that have not yet been worked on due to traffic diversions or other organisational reasons."

Looking ahead, he said: this year, foundation works are planned to be completed on 3-4 more structures and the construction of the reinforced concrete substructure can start. "At the same time, the finishing works on the bridges that have already been started will also begin," Mr Dezső concluded.

Nearly 1000 tonnes of steel make up the main support structure of the Krasnodar Bridge

The most significant of the works to be built is the bridge over the Krasna, which will cross the river on the M49 at the western border of Kocsord. According to the project manager in charge of the steel structures for this section, the Kraszna bridge, which will be built with two 184.5 m reinforced concrete deck slabs, will span the Kraszna flood protection embankment and the river with four openings (35, 50, 61 and 37.5 m spans). Szabolcs Parragi also said that the main supporting structure of the two tracks on the bridge is made up of 965 tonnes of steel structure, the largest of which exceeds 26 tonnes in weight for each of the transport units.

He also pointed out that in preparation for the works, nearly 60 percent of the bridge's steel structure per span was put in place, which means a total of 6 pairs of bridge elements out of 11. "The longitudinal and transverse splicing of these elements was carried out on site, after which the steel structure, which had been certified as satisfactory, could be put on its way after the material tests in accordance with the specifications," he added.

These tools have been proven on several major bridges

The bridge construction, which started on 17 June and is scheduled to be completed in the first third of next year, involves moving the steel structure of the bridge, which is being preassembled on the assembly area. "The reinforced concrete deck will be laid after the bridge is in place," added Szabolcs Parragi.

According to him, the pushing technique has already been used on a number of bridges. "The main moving structures were first used on the Deák Ferenc bridge (Danube bridge on the southern M0) and most recently on the Szapáry bridge (Tisza bridge on the M4). The additional lifting structures were used for the loading on the Sajó bridge (B2) of the 260 bypass."

Shifts are made every 20 metres

In response to a question, the expert also said that the bridge decks will be put in place with a longitudinal movement of 217 metres each. "The shifts will be carried out in stages every 20 metres or so. The purpose of this is to ensure that a new bridge section to be painted is always placed in the corrosion protection tent set up in the installation area."

He concluded by pointing out that the vertical load capacity of the moving structures is many times that of the structures being pushed, so their utilisation is barely more than 10 percent. "The biggest challenge is therefore to ensure adequate friction during longitudinal movement, which is essential for the bridge itself to move. To ensure that the friction force is adequate, the heights of the individual supports must be constantly varied, thereby constantly varying their reaction forces."