Feasibility study of a hybrid FRP-steel cable-stayed pedestrian swing bridge

The paper illustrates the feasibility study of a cable-stayed, pedestrian, swing bridge crossing the Navicelli Canal in Pisa, Italy. The static scheme of the bridge is asymmetric with one tower and three pairs of stays. The maximum span length is 21.26 m and the useful width is 2.50 m. According to the proposed design, the bridge deck will be made of glass fibre-reinforced polymer pultruded profiles; the tower and stays will be of ordinary steel; stainless steel bolts and plates will be used for the connections. A finite element model of the bridge was developed to analyse its structural behaviour during construction, service life, and maintenance operations. Construction stages – with particular attention to the cable stringing procedure – were carefully studied to help reduce the overall deformability of the bridge. Structural verifications were carried out according to the EuroComp Design Code, Italian CNR instructions, and German DIBt specifications. The calculated total weight of the bridge deck is about 11 t, including non-structural elements. Thanks to the low self-weight of the deck, a 3 kW electric motor will be sufficient for movement, with savings in both installation and operational costs with respect to a full steel bridge.