Pretty spiral bridge gets cyclists and pedestrians over ugly harbor
Bicycle bridges aren't only in the Netherlands, although they seem to have a lot of them; Here's a really interesting one in Raunheim on the River Main. It is very close to an oil terminal and tank farm, not the prettiest or safest part of town. Architects Schneider + Schumacher explain in Architizer:
The location of the bridge so close to the harbour's storage tanks was of particular concern at the design stage. The oil depot is used for the transfer and storage of highly flammable substances. For this reason, the bridge had to be designed to prevent people on the bridge gaining access to the passing tankers, or at least to make it difficult.
So on the pretty river side, there is a low handrail and one can see out, and on the secure oil harbour side, there is a 9 foot high wall for safety and security.
The construction, with a total length of approximately 170m, consists of a continuous five-part girder, which allows some 70m to be spanned at the harbour entrance. Viewed from above, the bridge appears as a lightly undulating S-shape, which, at its north end, culminates in a circular access ramp: a 14-metre spiral, constructed of white concrete.
More images in Architizer