Budapest's busiest road bridge renovated at night

At the Árpád Bridge ramp leading to Margaret Island, specialists from Colas Közlekedésépítő Zrt., commissioned by Budapest Közút Zrt., replaced one of the four expansion joints at Pillar IX during the summer, between 10 p.m. and 5 a.m., replacing one of the four expansion systems at pier IX while ensuring traffic flow across the bridge.

The rubber lamellas of the 14.153 m structure, which was installed in the 1980s, have aged and lost their water tightness, causing corrosion damage to the steel end cross member and the concrete structures of the pillar.
The condition of the dilatation system is a key issue for the crossings, as it is the structure that absorbs the movements in the bridge deck caused by expansion and contraction due to temperature changes and other external forces. If it does not function properly it can cause deformation and damage to the bridge.

Prepared down to the smallest detail

According to the information received from Colas, the start of construction was preceded by a laser scanner survey and the preparation of the BIM model.

The experts obtained a precise and comprehensive picture of the condition and dimensions of the structure from the point cloud of the dilatation and its surroundings.

Careful preparation of the works was also ensured by the fact that before taking over the worksite, the contractor, the client's Budapest Közút Zrt. staff and the project's technical inspector held several rounds of meetings to discuss the organisational and traffic engineering plans, the type of dilatation system and the materials to be used during the works. These were finally finalised in the technological instructions and the execution plans.

The Colas's own proprietary provizorium ensured smooth passage of vehicles

To ensure continuous traffic flow, the work was carried out at night, with drivers always free to use at least one of the three lanes. The passage of cars over the work area was made possible by the Colas's proprietary provisioning system. The structure proved its worth once again, with its simplified opening/closing and lashing solutions being used effectively during continuous diversions.

It was a challenge to organise traffic and coordinate the work

The traffic diversion was carried out in two phases:

either the outer or the inner lane was used for traffic, alternating several times a night if necessary.

The biggest challenge for the organisation was to coordinate night work and strict traffic requirements, especially when coordinating subcontractor tasks.

The new dilatation structure was erected in two parts

 During the replacement of the support VIII of the Margaret Island monument on the Buda side, the demolition works were carried out on the concrete side with hand chisels and a demolition head mounted on a rotary excavator, while on the steel side the old structure was cut with a flame cutter and a secator.
The new expansion was erected in two sections due to traffic constraints and then welded together on site.
On the steel side, the structure was placed on the existing reinforcing ribs,
adjusted in height during manufacture, on the basis of a laser scanner survey, while on the concrete side, the expansion was temporarily fixed to the drilled/glued-in mounting studs at the point of installation. The mounting frames holding the dilatation in place during transport were then released.
The installed structure is a Mageba manufactured Tensa Modular LR2 Hybrid dilatation compatible with the previous system, with 240 and 160 mm of movement.

Bridge elements cleaned and surface protected

The steel surfaces exposed during the demolition were cleaned by sandblasting and then coated with a multi-layer corrosion protection coating of the same colour as the dilatation.
The waterproofing around the dilatation was done with a lubricated RMA system, while the track surface was restored with a new asphalt pavement in a 40-40 cm wide strip in both directions after the replacement was completed. The pavement overlay on the section affected by the work was also resurfaced using the same technology.

Only one battery left to replace

It took 40 days to complete. This was the third of the four dilatations at the Margaret Island exit to be replaced in recent years, leaving only one original multi-lamella structure from the 1980s to be replaced. The new, state-of-the-art structure is expected to have a lifespan of several decades if properly maintained.
The project is a good example of how the use of advanced engineering survey technologies (laser scanning, BIM) and efficient traffic engineering solutions can be used to upgrade key elements of busy road bridges while maintaining smooth urban traffic flow.