Northern Railway Bridge

Location and name of the bridge
Name of the bridge: "Újpest" railway bridge
Distance: 1654+500 km
Country: Hungary
City/town: Budapest
Railway: Budapest - Esztergom line
Year of building - completion: 1894 - 1896.
Year of rebuilding - completion: 1952 - 1955.
Span lengths: 7 * 92.0 + 21.60 m
Designer: ÁMTI, UVATERV, Dénes Bots
Main contractor: Bridge Construction Company, Ganz-MÁVAG
Reconstruction cost: 70 million HUF
Owner of the bridge: MÁV (Hungarian Railways)

Traffic function of the bridge
railway bridge, carrying one track

Antecedents; the history of the bridge
In 1892 a new railway line was designed between the Hungarian capital and the city of Esztergom in order to have a more efficient connection from the industrial points of view between these two places. As the owner of this line, the Italian Fratelli Marsiglia et Co. Company was interested in extending this connection to the left side of the river, the construction of a one-track, new railway bridge was decided on the north part of Budapest. After having the permission of the Hungarian authorities, they commissioned the Italian company, Societa Nazionale delle Ufficine di Savigliane, to make the design and the construction.
For 1894 the plans were ready and in spring the erection of the bridge was started. The original bridge over the river was a seven-span, simple supported, trough-type truss of parabolic arches of chords. In 1928-1929 some strengthening of the structure seemed necessary. In 1932-1933 the floor system had to be replaced.
During World War II this bridge was a target of bombardments, the first span, which was destroyed, was the side one on Buda, which collapsed into the river. Later in several steps the complete construction was destroyed.
In February 1945 a military highway pontoon bridge was built near to this bridge by Soviet corps. Later a provisory bridge was constructed by MÁV for pedestrians and for the public utilities. Final reconstruction started in 1952.

The technical data of the bridge

Structural system, span lengths, widths
The reconstruction started rather late because of the engagement of bridge manufacturing factories and the shortage of the necessary rolled material. As a consequence, two spans of the bridge were assembled from the elements of the so-called "K" military bridge manufactured in the 30's. Further elements for the other spans were manufactured in Diósgyőr and Ózd. The structure contains individual single span trusses, which were connected to each other for the period of erection.
The whole complex contains other bridges over the banks and the island in the river.

Foundation, substructure
After removing the collapsed remains, the upper parts of all piers were renewed and new structural beams were built. The core of the piers was made from concrete B70, its surface was covered with limestone blocks.

Quantities of applied materials
Weight of the steel structure: 3990 t

Method of construction/erection; joints
A complete scaffold was built in the middle span of the bridge. The floor structure of the span and the bottom one third of the mains was lifted to the scaffold by gantry cranes. The upper part of the mains was put their place with Derrick cranes moving along the floor girders. The further parts of the bridge were built by incremental launching, using a Derrick crane, moving on the upper chord of the built structure, and applying provisional connections above the piers between the neighbouring spans.

Test loading(s); periodical assessment of serviceability
More parts of the complex are over the age of 40 years and because of the non-regular repair some of them are in rather damaged condition.
In all steel parts of the complex, corrosion caused damages. Characteristically these are concentrated to those areas, where the main girders and the elements of the sidewalks and bicycle lanes cross one another. Corrosion damages are also general in the reinforced concrete elements of the above structures.
There are a lot of cracks in the upper flanges of the plated girder in Buda, where the track was directly connected to the extended upper flange plate. The seven river spans are seven simply supported 1 1/2 K trusses and they were designed and constructed as a non-permanent structure. Mainly the bolted connections of the stringers are in bad condition.
Four steel parts of the complex construction (two-span plated girder on Buda, seven river spans of K truss, 3 span truss on the side flow on Pest side, single span truss on the quay in Pest) were tested in 1995 by distinct methods.
In all cases, calculations have been carried out to make an estimate for the remaining life of the elements of the floor system and for the mains. As we had no measured data for the traffic intensity of the bridges, an estimated load spectrum has been used.
There were no problems for the mains, but in case for stringers by this method the required safety could not be shown.
On all steel bridges load tests have been made using a loading train one to four M62 type diesel engines. In all spans the characteristic deflections were measured and the check of the vertical alignment of the structures was also carried out.
As a conclusion of this process, it was stated, that in the near future a general reconstruction of the all complex is necessary to ensure the requirements of safe traffic conditions.

Literature
Nemeskéri-Kiss, G.: Alépitményi munkák az ujpesti vasuti Duna-hid ujjáépitésénél, Mélyépitéstudományi Szemle, 1956. No. 6
Nemeskéri-Kiss, G.: Vasszerkezet szerelési munkák az ujpesti vasuti Duna-hid ujjáépitésénél, Mélyépitéstudományi Szemle, 1956. No. 7. and No. 8.