Osmangazi South Approach ViaductOverview
The Osmangazi Bridge near Istanbul, currently under construction with a main span of 1,550 m, will carry six lanes of highway across the bay, greatly improving road connectivity between Istanbul and south-western Turkey. The bridge is in an area of high seismic activity, with the Anatolian fault running perpendicular to the bridge alignment. It is predicted that this fault will rupture during the next seismic event, causing severe ground movements. The design of the bridge and its approach viaducts to resist and survive such seismic events is thus of critical importance.
The seismic protection system selected for the south approach viaduct consists of 22 isolation units, each comprising two LASTO-LRB lead rubber bearings (with capacity up to 42 MN each) placed side by side, together with 108 RESTON-SA shock absorbers (with stroke of up to 1,175 mm) working in both the longitudinal and transverse directions.
RESTON-SPHERICAL bearings and specially designed uplift resisting devices are also required at each end of the structure. The bearings are each designed to carry loads of 20 MN and to allow longitudinal sliding movements of +/- 1,470 mm.
LASTO-LRB seismic isolators, RESTON-SA shock absorbers, RESTON-SPHERICAL bearings, uplift devices