The TENSA®POLYFLEX®ADVANCED polyurethane-based flexible plug expansion joint is vastly superior to the traditional asphaltic-type flexible plug joint, as has been shown by extensive laboratory testing and years of experience under traffic on numerous bridges. The many advantages offered by the PU-based version, as described in detail in this product brochure, include its great strength and elasticity (with the material allowing 650% elongation before failure), its resistance to both very low and very high temperatures, and the special advantages it offers when used to replace old small-movement joints on existing structures. These advantages relating to installation on existing structures have now been enhanced by a recent prefabrication innovation that makes installation even quicker and easier, further reducing the impact on traffic and making it less dependent on the weather.

Longdong Avenue, one of Shanghai’s most important expressways with a length of almost 14 km, has recently been renovated and enhanced with a new viaduct. The project required the installation of 250 m of small-movement expansion joints, the design of which had to take into account the urban environment and the nearby vibration-sensitive production facilities of China’s largest microchip manufacturer. The use of low-noise, plug-type expansion joints was specified, and the TENSA®POLYFLEX®Advanced (type PU) joint was selected. Although the use of this joint type typically avoids the need to break out concrete or steel when replacing an existing expansion joint, and consequently can generally be installed quicker on existing structures with much less impact on traffic than other types of joint, the work can still require affected traffic lanes to be closed for up to 24 hours – or longer if delayed by wet weather. To accelerate the installation process, and make it virtually independent of the weather (a significant consideration since the work would be carried out in Shanghai’s rainy season), mageba’s local engineers proposed a major innovation in how the joints could be installed. Slab elements of the reinforced PU material were prefabricated in mageba’s Shanghai factory, to be joined together in situ using fresh PU material and secured to the bridge structure using quick-curing polymer concrete, thereby drastically reducing the work needing to be done on site. This new method enables the length of lane closures to be substantially shortened, to just 5 to 8 hours.

This project exemplifies what mageba is all about: Innovative, best-in-class products that are continually being improved, and highly competent staff that are always ready to go the extra mile to better meet their clients’ needs. Many thanks to our Shanghai team for the effort, passion and ingenuity they showed on this project!