DFA: Butterfly bridge

The link across Christianshavns Kanal and Trangraven is designed as three linear bridge spans that meet above the water’s surface in a star shape.

Two of the spans can be opened independently of each other. When the moving spans are up they serve as barriers which means that the bridge always functions to and from Plads Islands.

The main structure of the steel bridge consists of a singleweb, continuous T-beam. The beam web, which extends over the entire bridge, is built of a trapezoidal hollow section, hermetically welded to protect it from corrosion. The bridge deck is composed of an orthogonal anisotropic plate construction.

The moveable superstructure is formed of two individual bridge flaps. A counterweight to support the process of motion is not provided. Towards the flap tip the construction height decreases again to pass to the standard cross-section.

The anchor point of the hydraulic cylinder is about 5 m from the axis of rotation. The axis of rotation and its support are part of the central pedestal. The hydraulic cylinders are stored on the pile cap of the center landing. When closed, the flap tip rests on the opposite shore-side bridge.

The bridge is supported by elastomeric bearings and is brought into the correct position by a centering element in the middle in the process of movement. When closing the bridge two Oleo buffers are provided in addition to the elastomeric bearings. The entire onshore connection is realized as a very light and removable design, so that in the event of a general overhaul of the existing shore walls and an envisaged widening of the road on the embankment beside the north abutment, the onshore ramp can be easily removed and modified.

Butterfly bridge over Christianshavns Kanal and Trangraven, Copenhagen
Program: bridge
Architects: Dietmar Feichtinger Architectes
Engineerign: Wtm Engineers
Areodynamic studies: Schippke
Cost: 4.7 M€
Lenght: 63 m
Completion: 2015