The conceptual design of this drawbridge has been awarded and selected among many other proposals. The bridge is a movable structure to allow the passing of existing maritime traffic coming from a nearby shipyard and passenger ships. Additionaly, the minimum bridge clearance must be 5 m to let small recreational vessels pass under it.
It is planned to use a hybrid structure of duplex stainless steel and composite material of glass fiber reinforced polymer (GFRP) to obtain a lighter structure that is simpler to maintain in an aggressive and corrosive environment. The structure comprises a span of 75 m with two leaves. The structural layout is a continuous tapered beam, elastically fixed in both abutments and articulated at middle span to allow vertical rotation of the deck.
To increase the stiffness of the deck and guarantee its adequate dynamic behavior (it is a very slim structure), the deck has a width that changes parabolically between 3 m at middle span and 5.5 m at the supports (where internal efforts are higher).
The bridge is fundamental to the City of Zumaia’s development plans for its marine area, providing links from the city center to the docks across a busy channel. The bridge is a gateway for ships.
The design concept is based on three basic ideas: the use of light-weight materials, the use of materials free of maintenance such as stainless-steel and GFRP and a minimalist approach (sober and elegant forms and clean lines, creating a bridge with a clear identity, but not dominating the beautiful port environment).