LATERAL-LOAD RESPONSE OF A REINFORCED-CONCRETE BRIDGE

Cyclic, transverse loads were applied to the bents of a three-span rei nforced concrete bridge. At a load equal to 45% of the bridge's weight , the bent drift ratio was 0.5%. The bridge's high stiffness was attri buted to its continuous superstructure and stiff abutments, which resi sted approximately 80% of the applied load. After the soil surrounding the abutments had been excavated, the bridge's stiffness was 15% of t he initial stiffness. After the researchers had isolated the bridge su perstructure from the abutments, the stiffness was 9% of the initial s tiffness. Despite the bents' poor details, damage was limited to yield ing of the wingwalls and column cracking; similar bridges should resis t likely transverse seismic motions with little damage. The tests prov ided estimates of the abutment and bent resistances that can be used t o evaluate modeling procedures. Following existing modeling procedures , the researchers assembled a model that reflected the measured nonlin ear properties of the concrete, steel, soil, bearing pads and polystyr ene. The model reproduced the measured response well.