Lanlugang Bridge, Shanghai Metro Line 17, Shanghai

A Wave Band of Playful Lightness

Lanlugang Bridge sits in western Shanghai, where the city meets waterways and open fields. As part of Shanghai Metro Line 17, it is built primarily for daily commuting—linking suburban Qingpu toward Hongqiao and on into the wider network of the city.

The bridge spans the landscape with a quiet presence. 380 metres in length and a main span of 180 metres, the concrete superstructure nonetheless appears surprisingly light. The key lies in a clear articulation of the surface: a smooth, understated plane above, and below it a band of playful wave patterning.

The upper zone remains restrained as fair-faced concrete. Along the lower outer edge of the box girder runs a sequence of large, circular waves. With an outer diameter of 2.2 metres, the motif is deliberately oversized so it remains legible from a distance. Up close, a fine surface granulation becomes apparent, sharpening the contrast to the smooth upper zone.

The texture was created using structure formliner 2/102 Parana, a plaster-like pattern with granulation of up to 4 mm. The wave design required a specific approach: the hollow wave-shaped formliner is not a complete mold, but instead consists of hollow ring mold units produced using special processes. These units are precisely joint and adhere onto the steel formwork one by one with the aid of positioning technology.

From a technical standpoint, the challenge lay in accurately bonding and positioning the rings on the steel formwork, as well as in carefully sealing the transitions. RECKLI Stop Off Paste PUR was used to ensure clean edges, and Stripping Wax TL-SO was applied for a clean demoulding process.

In total, around 200 m² of structure formliners were used, producing approximately 3,500 m² of textured concrete surface.