A new type of bridge called the Butterfly Web Bridge is being built in Japan, the Takubo Kawabashi Bridge. The bridge is a highway bridge with a total span of 10, of which the largest span is 87.5m. The butterfly web structure is a butterfly shaped prefabricated plate with a thickness of 150mm at the box girder web. The web is composed of concrete with a strength of 80MPa, and the tensile stress area is reinforced by a single prestressed bar. In addition, the 150mm thick web is reinforced with steel fibers instead of steel bars. The bridge was constructed using the free cantilever method. The butterfly web is prefabricated in the concrete plant and weighs 3.3t. This makes the construction weight of the main girder lighter than that of ordinary concrete web box girder. As a result, the cantilever construction is about 50% faster than the traditional pouring in situ method.