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 center, giving a butterfly‐wing shape. For the butterfly‐shaped web made of precast panels with a thickness of 150 mm, 80 MPa steel fiber‐reinforced concrete is used. The design method was proposed after the shear tests of butterfly webs. In this paper, four projects of expressway bridges using this new technology will be shown. It has been shown that by a simplified construction process, construction time can be reduced. Then, future development is proposed in the last part of this paper by considering a 500‐m‐span extradosed bridge. The butterfly web technology will greatly affect bridge design and construction in the near future.