Differential Settlement Problem of Buildings on the Rock and Filling

Adapazarı region, in Turkey, is hit by moderate magnitude earthquakes of 6.5 - 7.5 every 10 - 30 years. The great loss of life and damage resulted by the massive earthquake that occurred in the region in 1999 was the biggest reason of creating new residents at the north of the city where the bedrock are encountered in shallow depths as in Camili, Karaman and Korucuk. Construction of new buildings in these areas continues rapidly in the current status. These regions seem to have the advantage of having no problem related to soil bearing capacity failure and liquefaction during the earthquakes. However, observations of diagonal cracks at a large number of buildings a few months/years after their construction in these areas have revealed the fact that there are some other problems. Due to the sloping topography in these regions, some portion of the foundations of some buildings was seated over a filling instead of excavating the whole soil under the building and seating the foundation completely on the bedrock. In these cases, the reason of the damage of the buildings is clear to be differential settlement of the building. In this study, the soil properties and the reasons of the damages that happen to a building, which was built by following this method, are examined.