Dual use: pedestrian bridge becomes event space whenever required

Integrating abandoned industrial sites into the fabric of a city is a common element of many city renewal and placemaking actions today. In Germany, the city of Bocholt launched a major urban regeneration project to convert the former industrial quarter into a new district that will offer residential and work space as well as cultural and educational facilities.

Launched in 2016, the ‘Kulturquartier Bocholt Aa und Industriestraße’ initiative - KuBAaI for short - adopts the river Aa as a key element in the renovation and ecological recultivation of the 25 hectare site. As the key axis of this site intervention, the river has been renaturalised and its banks widened and newly planted. For the future crossing of the river, our colleagues in Amsterdam were commissioned to design a number of structures. These include the Podiumbrücke (or podium bridge), Quartiersbrücke, Eisenbahnbrücke, Webereibrücke and underpasses. In close cooperation with SeARCH Architects and B+B Landscape Architects, they also planned an ecological zone and an open staircase.

Our bridge engineering team in Düsseldorf was responsible for the detailed design of the Podiumbrücke. The bridge has a special function here: it is also to be used as a public square and a venue for events such as concerts. With a width of 14 metres and a length of 50 metres, this pedestrian crossing offers sufficient space for this purpose.

Sustainable bridge design: steel and fiberglass

The requirements for the bridge were relatively high: it had to be extremely resilient, durable and low-maintenance, as well as easy to access - while also meeting very exacting aesthetic standards.

Weathering steel girder construction: A weatherproof steel was used for the girder construction, which is both resilient and particularly low-maintenance. Compared to normal construction steel, weathering steel has a much higher resistance to atmospheric corrosion. The steel develops its characteristic-rust coloured protection layer after exposure to weather conditions, which confers the material with long-lasting durability. In this context, the material’s quality also seamlessly echoes and blends in with the industrial aesthetics of the local environment.

Durable fibreglass bridge deck: Since concrete is too heavy for a bridge of this size, our designers decided to use a lightweight composite material for the bridge deck – glass-fibre reinforced plastic (GFRP). The fibreglass-reinforced plastic slabs are not only much lighter in weight, they also appear slimmer overall. In addition, fibreglass is extremely durable and low-maintenance.

Since the deck will double-up as a social space, our designers decided to install vibration dampers to minimize vibrations during events.