Experimental Study of Bridge Elastomeric and Other Isolation and Energy211 Dissipation Systems with Emphasis on Uplift Prevention and High Velocity Near-211 Source Seismic Excitation

摘要

This report provides an assessment of the benefits offered by damping systems in211u001enear-source earthquakes and of the accuracy of currently available tools for 211u001eanalytical prediction of their seimsic response. A two-span continuous deck 211u001ebridge configuration was used in the test program. First an isolator testing 211u001emachine was designed and constructed that was capable of testing small bearings 211u001eunder controlled conditions. Next, three vastly different bearings (flat sliding, 211u001efriction pendulum, and elastomeric) were tested prestressed in the developed 211u001etesting machine. Test results provided strong evidence for the capability of 211u001eprestressing to prevent uplift or tension in isolation bearing. Finally, an 211u001eexperimental study of bridge elastomeric isolation systems with emphasis on near-211u001esource high velocity seismic excitation was performed. The addition of the 211u001edamping devices caused a substantial reduction in displacement, provided relief 211u001eto the vulnerable pier, caused a reduction in the total shear force transmitted 211u001eto the bridge substructure, and provided for redistribution of the reduced 211u001einterita forces from the vulnerable pier to the presumed strong abutments.