Behavior of Reinforced Wall System During the 1999 Kocaeli (Izmit), Turkey, Earthquake

A four-span bridge together with a 10 m-high and 100 m-long bridge approach fill was one of the highway facilities damaged due to surface faulting along the Trans-European Motorway during 1999 Kocaeli Earthquake (Mw 7.4). The fault rupture crossed beneath an overpass bridge within a few meters away from the bridge abutment while damaging the approach fill which was reinforced with a double-faced mechanically stabilized earth wall (MSEW) system. The faulting-induced excessive tectonic ground deformations including near-field seismic shakings were the main sources of damage in the walls. Such effects, along with the others, caused cracks and panel separations in wall faces as a result of a liquefaction-induced differential settlement in the cross section. The performance of the reinforced walls was satisfactory that there was no significant structural damage despite the total collapse of the bridge decks. The wall system provided a unique case history under extreme loading conditions, while proving that they are flexible and can withstand large ground deformations. This paper discusses how the walls performed based on post-earthquake reconnaissance studies. The faulting activity, geology of the site, strong ground motions and damage states in the reinforced wall are discussed in details