INSPECTION OF BRIDGES AFTER RECENT ARMENIAN EARTHQUAKE

Abstract

This brief article discusses the effects of the Armenian earthquake of 7 December 1988 upon the bridges in the region. The magnitude of the main shock of the earthquake was 7.0 on the MSK scale, with a focal depth of 14 km. The intensity of the epicentre was 9-10 points on the MSK-64 scale. The earthquake was accompanied by landslides and rockfalls along the river banks on steep mountain slopes and in the vicinity of tectonic fractures. Many of the smaller railway bridges had reinforced concrete superstructures. In larger bridges metal trusses were used. Bridge piers were constructed of stones and concrete. Most of these smaller bridges were severely damaged, with at least one abutment being destroyed and others damaged. The bridges having metal superstructures only suffered light damage. Modern railway bridges which are made from reinforced concrete prestressed beams, with massive piers containing a reinforced concrete core, were undamaged. Highway bridges have composite reinforced concrete superstructures, with piers constructed either of conventional or prestressed precast concrete. Those bridges located near the epicentre were severely damaged. The damage indicated that the girder bearings were torn away from the piers. In the earthquake zone, pier damage was observed. The stone and concrete piers of older bridges suffered moderate to heavy damage. Prestressed reinforced concrete piers were undamaged. The results indicate that large and medium span bridges located at likely epicentres should have the lightest possible superstructures furnished with antiseismic devices to prevent movement along the subgirder plates. Pier foundations should be based on the hardest possible ground, and be constructed of prestressed reinforced concrete. The French title for this article is: Examen des ponts apres le tremblement de terre en Armenie. The German title for this article is: Die Untersuchung der Bruecken nach dem Erdbeben in Armenien. For the covering abstract of the conference see IRRD 851274.