SEISMIC DESIGN OF THE METSOVITIKOS SUSPENSION BRIDGE, PINDOS MOUNTAINS, GREECE

This spectacular landmark suspension bridge has been designed to span the Metsovitikos River in the Pindos Mountains of Western Greece, an area of significant seismic activity. The rock anchored suspension bridge spans 550 m (1800 ft) across a steep sided valley between tunnel portals at each end of the bridge. The steel deck is supported on suspension cables spanning 800 m (2640 ft) to rock anchorages in the mountainside above the abutments. This unique structure has presented a number of seismic engineering challenges whose solutions have required state-of-the-art computational techniques. The performance based seismic design basis has adopted the principles of ATC-32. A number of innovative ground assessment methodologies have been developed during the design. The stability of the anchorages on the mountainside has been demonstrated using a combination of two-dimensional and three-dimensional explicit nonlinear, finite element analyses. The rock matrix has been modeled using a ubiquitous joint failure model. The cable form adopted provides an excellent concept for seismic resistant design. The long period structure is naturally isolated during the design earthquakes and the P-delta effects present are stabilizing because the anchorages are located well above the bridge center of mass. Even in this region of significant seismic activity, the earthquake loads do not govern the design of the primary structural elements.