The new Lent-Tabor footway and bicycle bridge cannot compete with Maribor's Stari Most, the city's Old Bridge. It must bow to its formidable presence. We propose a structure that in a way is a complement to the Old Bridge.
The bridge's deck is calculated to the limit in order to make it as slender as possible. The structure is clad in wood endowing the new footbridge with both an archaic and contemporary character at the same time.
Its visual iconographic strength lies in the concealment of structure, which renders it equally abstract and expressive. It becomes one more piece of the Stari Most structure.
Visually it is as transparent as possible. Without intricate or ostentatious structural feats, it is natural and simple: two supports and maximum slenderness.
Economically it is rational: it possesses a simple but elegant structure, calculated to the limit and without requiring sophisticated construction techniques; at the same time portraying a memorable image, singular and easily identifiable.
The structure consists in a classical system of two longitudinal steel beams located on both sides of the deck, but modified to configure an attractive transversal section. This structural section improves the views of the river from the footbridge and houses comfortably the pedestrians and the cyclists, while assuring an efficient response to the structural requirements. In this sense, the thickness of the deck is forced to a minimum, in order to favor the desired intentions of elegance and slenderness of the footbridge. To achieve this minimum thickness of the deck, that remains constant through all its length, a system of Tuned Mass Dampers is set up in the lateral spans, in order to prevent and control any possible vibration effect, assuring the comfort of both pedestrians and cyclists.
The deck is directly supported on the abutments at both banks of the river, and in two intermediate piers. For these intermediate piers a very delicate and transparent solution is required, emerging naturally from the river and respecting the continuity of the deck. A set of steel columns with different inclination is proposed for each pier, giving the impression of an aleatory distribution of ancher posts. This aleatory distribution of the columns derives however from a structural logic: a set of four columns with small inclination is placed at both sides of the deck, allowing a direct transfer of the vertical loads from the longitudinal beams, while three additional inclined columns are placed in the central area of the section, assuring the required lateral stability of the footbridge.
According to this structural system a very simple and fast construction process is proposed, by considering the elevation of the intermediate areas of the deck on each span, that arrive floating in the river, from cantilevering deck arms on both lateral abutments and interior piers.
Finally, it is also interesting to remark that very low maintenance is required for the footbridge. Only specific and simple interventions are needed, and they can be done easily considering both the accessibility from the deck and the proximity of the water level.