Calculated and Observed Settlements of Multistory Building Founded on Loess

ln the Paper are presented the results of laboratory and field tests which were carried out on loess soil in Belgrade In order to determine the type of the foundation for the 13-storey building a preliminary investigation was made. In this phase of investigation exploratory borings and sampling were performed in a standard way. On the basis of the available laboratory and field test results it was concluded that the soil was made of macro porous land loess 14-20 m in thickness. lt was found that the loess on this location had the dry density varying between the limits γd = 15.5 - 15.8 kN/m3. Considering that the subsoil has high values of dry density, the designer adopted the shallow foundations. At the end of the period of three years one part of the building settled considerably and the differential settlements reached very high values. Due to the significant values of the angular distortion the building was seriously damaged. By additional investigation the undisturbed loess samples were cut from blocks and the laboratory results have shown much lower values of the deformation parameters than those obtained in the preliminary investigations. Using the deformation parameters and the coefficients of subsidence for the undisturbed samples cut from blocks, a very good agreement between the calculated and observed settlement was obtained