The largest railway bridge of the Budapest-Kelebia railway line is completed

A successful static load test was conducted at the beginning of autumn on the new railway bridge between Dunaharaszti and Taksony on the Danube-Tisza Canal, which was constructed by Colas Út Zrt.

Sergei on the bridge

The load test is carried out in two phases: static and dynamic loads, Huba Melkovics told our portal. The chief engineer of Colas added that the bridge was opened to construction traffic after the static test. During this test, the 116-tonne locomotive of MÁV M62, nicknamed Sergey, and three wagons loaded with crushed stone, each weighing 70 tonnes, were placed on the bridge. During the test load, the structural and air temperatures were measured, as well as the natural frequency of the bridge.

The expert added:

"In total, we loaded 326 tonnes onto the structure, which, as is traditional, is also loaded by the engineer. The loads were placed in three positions on the bridge, while four parameters were measured: the deflection of the structure, the elongation (stress) at the characteristic points of the main bridge girders, the displacement of the spars and the subsidence of the two bridge spans. In all cases, the measured deflections were less than or equal to those calculated with the high accuracy model."

Continuity of construction traffic was ensured during the construction

The construction of the largest opening railway bridge on the Hungarian section of the Budapest-Belgrade (BuBe) railway line by Colas Út Zrt. started in April 2023. The double-span, single-arch bridge was built on united spans but with two separate structures. The right-hand side was the first to be completed in just seven months and was opened to construction traffic in December 2023 after load tests. The construction of the left structure could then begin and was completed by August.

The bridge has been built with two separate structures to ensure that the railway line can continue to carry construction traffic during the works.

Nearly 1050 tonnes of weight over water

The structure has a traditional symmetrical lattice girder structure with two bridge piers. The total length of the superstructure is 54.4 metres.
Gábor Borbély, the construction manager of Colas, said that the bridge has an orthotropic deck structure, i.e. the flat steel plate is supported by densely spaced welded longitudinal and transverse ribs. The railway track structure is carried on this deck with ballast transfer.

The self-weight of the two bridge structures is 520 tonnes, and the self-weight of the ballast and rails is similar.

Colas's experts carried out the project in five phases in just 14 months, with a maximum of 30 people working on the site at any one time. Approximately 3,500 cubic metres of earth had to be moved to clear the two bridge structures and their surroundings.

The two bridge structures are almost identical. Gábor Borbély said:

"The construction of the first bridge structure went well, so only minor changes were made to the left lane."

The police also helped the project

During the construction of the left bridge deck, 1500 fm of piles were used for the foundation of the substructure. The elements of the structure were delivered to the site in oversized consignments, in a total of eight phases.

The delivery vehicles with their special loads arrived at the work site at night, under police escort, with partial road closures in some sections.

This was necessary because the steel structures, each weighing between 31 and 33 tonnes, are 5.8 metres wide and would have shifted from one lane to the other during transport.

Rotating bench and sliding table for the assembly of bridge elements

"We used a 250-tonne crane to lift the bridge elements on site. We followed the same phases as for the first bridge structure for the left deck. We set up an assembly area on the site, where we installed a rotating bench. The bridge elements were lifted off the transport vehicles and aligned in the installation position using the latter structure. The assembly bench, where the crane lifted the steel structures weighing more than 30 tonnes, was continued by a sliding platform, which we used to push the bridge pieces into position for assembly," said Csaba Ruzsik, the bridge foreman, describing one of the most spectacular phases of the work.

The bridge structure was assembled from four pieces

After the construction of the right bridge deck elements was completed, the auxiliary structure to support the pushing and fitting of the steel structure was pulled over by means of a cross-tracking track constructed between the tracks, so that it could be used for the left deck works. In this way, significant time and cost savings were achieved by speeding up the transition between the two bridge structures.

The longitudinal alignment of each bridge element created a cross-section of 13-16 metres.

The entire structure, consisting of four articulated bridge sections, was assembled with three cross-joints. A cable tunnel was also built on the new bridge to allow the passage of utilities.

They have also finished landscaping the area around the bridge

During the construction of the right-hand track bridge, a provisor bridge on the left-hand track ensured the smooth passage of construction traffic. Once the first bridge structure was completed, the temporary bridge on the other side was demolished to build the left bridge structure. The substructure of the old Danube-Tisza Canal Bridge was then demolished. In the final phase of the project, the sheathing walls were completed, the thermal stone pavement was laid and the inspection steps were installed. After removing the reed slabs, the landscaping work was carried out. The new bridge is now open to construction traffic.

Together or apart?

The construction manager of Colas said that the advantage of building the new Danube-Tisza canal structure with separate bridge spans was that construction traffic could be maintained with fewer interruptions. The main challenges were the work alongside the railway traffic and the need to build the workspace in several phases, which slowed down the construction work. Gábor Borbély added that after the left bridge structure was completed, the substructures of the old bridge and the auxiliary structures used to build the bridge were dismantled, which was a complicated process and required considerable concentration.

The 150 railway line will also link freight traffic in Western Europe and the Balkans

After the modernisation of the Budapest-Kelebia railway, it will be one of the busiest lines between Western Europe and the Balkans. The BuBe will connect to the Salzburg - Belgrade - Thessaloniki rail corridor, which serves the southern Carpathian Basin and the northern Balkans, and will provide a direct link to Western and Northern Europe via Budapest.