This type of civil engineering work, intended to provide safe routes for pedestrians or cyclists, offers the opportunity to design very lightweight structures that reach top performance. The narrowness of the bridge deck forces the designers to look for finesse in the structure which, to avoid being unsightly, must be sufficiently slender. The budget available is generally limited for this type of structure, which nevertheless requires very advanced design studies. The guarantees that need to be provided in terms of loading is as important as for a road bridge, because the extreme situation of a crowd using the bridge must be taken into consideration. To free as much of the already narrow bridge deck as much as possible, off-centre structures are sometimes required, and this specific issue is added to questions of transverse stability, which arise once a certain span is reached. As walkways are often situated in a dense and specific urban context, they require a more elaborate integration approach. The density of pedestrians or cyclists using them implies a perception at their speed, and requires that their appearance incorporates this human dimension to create a pleasing impression.

Greisch office has designed many structures of this kind, particularly when converting former railway track beds for use by pedestrians and cyclists in Wallonia. This work gave rise to structures of modest size but with impeccable functional efficiency as well as tremendous elegance.