Maximum complexity

A recently completed project to supply and install replacement expansion joints for a refurbishment project in the centre of Zurich required an extraordinary amount of detailing and planning.

Anybody who assumes the use of single-gap expansion joints should always be straightforward never worked on a project like this! Although single-gap joints such as TENSA®GRIP Type RS are generally easier to design, fabricate and install than various other types of expansion joint, every project presents its own challenges – as demonstrated by this renovation project in Switzerland’s biggest city.

The Zollbrücke, or Customs Bridge, is located in the heart of Zurich, right next to the city’s main train station, where it carries a road, twin tram tracks, cycle lanes and pedestrian walkways across the river that flows under the train station. In the course of planning a recent project to renew the tram tracks in that area, the city authorities decided to use the opportunity to also replace the single-gap expansion joints (each over 35 m long) at both ends of the bridge. Although this was sensible and beneficial considering such factors as traffic disruption, traffic management measures, site mobilisation effort and economies of scale, the substantial challenges relating to the expansion joints’ design, manufacture and installation remained. These included, in particular:

  • designing and detailing the more modern expansion joints to precisely suit the complex geometry of the existing joints and their connecting structures, with suitable connections at all points;

  • allowing for the passage of the tram tracks and various service pipes/cables through the expansion joint, while still maintaining watertightness;

  • installation of each expansion joint in six stages to suit traffic management, with short sections of joint welded to previously installed sections and subsequent insertion of the continuous rubber sealing profiles;

  • dealing with the challenges of working next to live tram and street traffic or on temporarily closed tram tracks, with all the associated safety implications;

  • ensuring absolute adherence to a tight overall schedule and very limited track and road closures (sometimes at night);

  • and even replacing one section of joint underneath a wall.

These challenges are somewhat illustrated by the attached photographs, but not in a way that could ever do justice to the special efforts and capabilities required by a project like this. But that is what mageba is there for, always happy to play a small role in helping the communities we serve function more efficiently, more reliably, better.

Contractor: Tiefbauamt Stadt Zürich / Verkehrsbetriebe Zürich
Owner: Tiefbauamt Stadt Zürich

The Zollbrücke in the heart of Zurich carries a pair of tram tracks as well as road, cycle and pedestrian traffic along the side of the city’s central train station

The bridge effectively forms an extension to a longer structure that allows the Sihl river to flow right under Zurich’s main train station and all its above-ground platforms

The existing expansion joints at each end of the bridge (one shown here) were replaced during a major tram track renewal project

Lifting of one section of one expansion joint (a “TENSA®GRIP RB-A80 Special with tram track detailing” joint) into position

A section of joint in position at one end of the cleared bridge structure, with openings for tram track rails and cables to pass through

Much of the work had to be carried out at night to minimise impacts on traffic and to accelerate the construction program

With each joint installed in six sections for traffic management purposes, the sections required to be welded together on site with subsequent insertion of the continuous rubber seals

View of one section of one joint after lifting into position, with the existing track structure fully removed on the bridge

Precise coordination of the construction detailing and installation needs of tram infrastructure passing through an expansion joint can be particularly demanding

Each joint had to be installed in six stages – one section at a time – depending on traffic management and constructional details

Each expansion joint required to be precisely designed to suit the geometry of the existing situation, e.g. with horizontal and vertical bends as shown here

Carefully detailed sliding cover plates were required in pedestrian and cycle areas – designed to accommodate the same movements as the joint underneath

One expansion joint required to be installed to replace an existing joint where it passed underneath a wall, with cover plates provided to cover the movement gap beneath the wall

Each expansion joint required to be connected at one end to the longitudinal joint between the bridge and the adjacent structure that supports the train station (here after passing under a wall)