The phononic crystal (PC) concept is introduced to the floating bridge, in order to reduce the flexural vibrations. Four kinds of PC floating bridge models, including the identically hinged and two-component rigid connected, section-hinged, cell-hinged cases are defined. The corresponding structures with the actual available bridge section size are constructed. And the frequency dispersion relations and amplitude frequency responses of these structures are calculated and analyzed. The study shows that, the four kinds of PC floating bridges all have good band gap (BG) properties. Due to the restraints of foundation, the PC floating bridges have the first BGs from 0Hz to the corresponding pivotal frequencies. For the identically hinged and two-component cell-hinged cases, the pivotal frequencies are submerged in the adjacent BGs, so they have wide BGs start from 0Hz. Moreover, compared with the rigid connected case, the existence of hinges helps to obtain wider BGs with stronger attenuation. Finally, we design a combined floating bridge from hinged connecting the identically hinged and two-component cell-hinged cells and realize extended wide BGs.