Demolition of the Mainzer Hochstraße

The Mainzer Hochstraße is dilapidated and will be demolished.

Information on

The Mainz elevated road is dilapidated and will be demolished. The city administration of Mainz is currently preparing a tender in the competitive dialogue procurement process. In contrast to conventional construction contracts, competitive dialogue involves functional tendering. This gives applicants the opportunity to propose a special solution based on their own expertise, while the city of Mainz retains planning influence over the project.

Until the time of demolition, the structure will continue to be closely inspected and maintained in accordance with German DIN standards and taking into account its condition.

Prestressing steel

The Mainz elevated road is a prestressed steel bridge. The prestressed steel is pressed into the concrete inside sheath tubes. In this type of bridge, the tensile forces are largely transferred via the steel strands, which are prestressed during construction. The prestressed steel strands or wires are enclosed in mortar in a sheath tube and together form a "tension member" (see Figure 1). There are many such tension members in the Mainz elevated road.

The environment

The structure spans approximately 1.3 kilometers of the urban area between Rheinallee and Mombacher Straße. There are scattered trees and bushes in the immediate vicinity. To the west of the structure, at Mombacher Straße, the structure borders the trees towards Hartenbergpark.

Various industrial, commercial, and residential properties, including a clinic and an animal shelter, are located in the immediate vicinity. Contact has been established with the affected individuals and businesses, and the basic framework conditions are in place.

In addition, the structure crosses the following three DB lines:

Line No. 3510 Bingen (Rh) Central Station – Mainz Central Station
Section Mainz-Mombach – Mainz Central Station
Infrastructure operator DB Netz AG
Double track, electrified

Line No. 3523 Alzey – Mainz Central Station
Section Mainz Waggonfabrik – Mainz Central Station
Infrastructure operator DB Netz AG
Single track, not electrified

Route No. 3525 Mainz-Mombach – Mainz-Bischofsheim
Section Mainz-Mombach – Mainz Kaiserbrücke
Infrastructure operator DB Netz AG
Double track, electrified

In addition, various roads, bus routes, and a tram line are crossed by the structure.

The dismantling

The tender for the demolition will be conducted in a competitive dialogue with a preliminary market research procedure, which will be supervised by the procurement lawyers Professor Trautner (Heussen Rechtsanwaltsgesellschaft) and Mr. Nickel (Nickel Rechtsanwälte). In the competitive dialogue procurement procedure, the planning and execution will be awarded to a bidder or a consortium of bidders. The planning will be discussed and adjusted in dialogue rounds with the bidding parties on the basis of the draft plans until a final result is achieved. This gives the city administration the opportunity to influence the planning and to take the various needs of all parties into account in the best possible way.
The tender was issued in July 2024.

The city administration closely monitors the structure due to its condition and age. Additional annual structural inspections are carried out. In addition, regular visual inspections and renovations are carried out to maintain the condition of the structure as best as possible until it is demolished. For safety reasons, nets have been stretched across some areas to prevent concrete from crumbling. In addition, the city administration is preparing all issues relevant to demolition, such as nature and species conservation compensation areas. The framework conditions for demolition are also being determined.

The contact protection plates on the bridge over the railway tracks are currently being dismantled. This demolition measure has been brought forward for safety reasons.

FAQ

Why is the Mainzer Hochstraße fully closed?

Traffic has a significant impact on the load on a bridge and, as a result, on its deterioration. However, to prevent further deterioration and because the bridge is dilapidated, it has been closed to traffic in order to ensure long-term safety in the traffic area.

Why is the Mainzer Hochstraße being demolished - it looks quite good?

The Mainz elevated road was built in the 1960s. Over time, due to weather conditions and increased traffic volume, the bridge has reached the end of its service life. Now, the only option is to slow down the deterioration, which will be carried out by the city administration until the bridge is demolished. Unlike steel bridges, for example, damage to reinforced concrete bridges is not always visible to the naked eye. In the case of the Mainz elevated road, samples of the concrete and steel from inside the concrete, in conjunction with complex static calculations, are necessary to determine the condition with reasonable accuracy.

There is no economically viable renovation option in this case because a bridge would have to be built underneath the bridge as a supporting structure. Therefore, demolition is the only option, both technically and economically.

Can the elevated road not be used for other purposes, such as for solar installations or as a cycle and pedestrian bridge or parking area?

In many cities such as New York, Stockholm, and Seoul, old bridges are being repurposed as pedestrian bridges. Steel bridges are sometimes well suited for this purpose—defects can be identified and repaired relatively easily—but this is not the case with the Mainz elevated highway due to its construction. For safety reasons, it cannot be used as a parking area, bike path, or photovoltaic farm.

Due to its design, deterioration is inevitable. To ensure long-term safety in the urban area, demolition of the bridge is necessary. Short- and medium-term conversion is also not possible for safety reasons.

Are the plans for the demolition available?

The demolition of the elevated road will be put out to tender in a competitive dialogue. Planning and execution will be awarded to a single company or consortium of bidders. The draft plans will be discussed and adjusted during the tendering process in dialogue between the bidders and the city administration. Consequently, plans will only be available after the contract has been awarded. Further information sessions and updates on the project progress will follow.

Is there a construction schedule?

A construction schedule does not yet exist, as the planning will only be determined in 2024 as part of the competitive dialogue award procedure.

Will there be traffic closures?

Due to the complex infrastructure situation around the elevated road, traffic disruptions will unfortunately be unavoidable. The goal is to minimize traffic disruptions. Further information on traffic planning will follow. The city administration asks all those affected for their understanding and patience.

Are preparations underway for the demolition?

Yes, all preparations for demolition are currently being made. The Europe-wide tender in competitive dialogue will be published in the first quarter of 2024. Planning and execution will be put out to tender together in the award procedure. In addition, the plans can be discussed and adjusted between the contractor and the city administration.

Will a new bridge be built?

Since the closure, traffic has been successfully diverted via the four newly constructed junctions. Accordingly, there are no plans to build a new bridge. The demolition is expected to bring many urban development benefits. At present, there are no concrete plans for the period after the demolition.

Who is involved in the costs?

As this is a demolition project and not a new build, the project is not subsidized at federal level. The costs are being covered by the city of Mainz.