Effects of butterfly web design on bridge construction

A new type of bridge called „Butterfly Web Bridge” has been constructed in Japan. In a butterfly web bridge, the panels used as the web are cut so as to appear pinched in the centre, giving a butterfly-wing shape. 80 MPa steel fibre reinforced concrete is used for the butterfly shaped web made of precast panels with a thickness of 150 mm. After the shear tests of butterfly webs, the design method was proposed. In this paper, four projects of expressway bridges using this new technology will be shown. By a simplified construction process, construction time can be reduced. Then, future development will be proposed in the last part of this paper. It is a 500-m-span extradosed bridge. The butterfly web technology will greatly affect bridge design and construction in the near future.