<p>Expansion joints and bridge bearings are ideal devices for Smart Structural Health Monitoring.</p><p>Expansion joints are suitable for the determination of actual vehicle loads, as they are installed in all large span bridges and are directly loaded by overrolling traffic. Knowing the precise traffic loading is crucial for e.g. determination of the remaining bridge service life for the numerous bridges in need of rehabilitation measures.</p><p>Bridge bearings enable a pooled load transfer and movements and rotations with small restraining effects. The majority of changes in the state of the bridge have a direct effect on the loading and the rotation and displacement of bearings. E.g. a change of stiffness will lead to a change of the bearing load and the bearing rotation resp. displacement. Monitoring the reactions and loading of bridge bearing is a cost-effective monitoring measure for the primary structural system. If the bearing system is completely replaced by smart monitoring bearings it is feasible to determine the exact dead load which allows a reduction of the partial safety factor G [4].</p><p>This paper describes a smart monitoring expansion joint and two smart monitoring spherical bearings, which are installed in a real bridge, i.e. the German pilot project “Smart Bridge in the Digital Motorway Test Bed”. The devices have been extensively tested in laboratory tests and on a test bed, but it is the first application of both smart monitoring devices in a real bridge with normal traffic.</p>
<p>A seismic isolator shall be capable to transmit vertical loads, to decouple the prevailing mass from ground motions, to provide sufficient restoring force, energy dissipation and adequate functionality under service loads and movements. In case of curved surface sliders the friction between the main sliding surfaces is crucial for most of the fundamental requirements listed above. The quasi static coefficient of friction is the significant parameter for the determination of restoring forces due to movements under service conditions. The dynamic coefficient of friction is decisive for energy dissipation and restoring capability during a seismic event. Both these coefficients have to be determined in separate test procedures given in standards EN 1337-2 and EN 15129. This paper gives an overview of the state of the art comparing the European and American design rules.</p>
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