Study on the Parameters Affecting Rectifying Asymmetric Settlement of Concrete Building Foundations by Jacking Method

Tabriz, one of the metropolises of Iran, has a particular geotechnical condition. Recently, it has been reported that some of the new structures are tilted in Freshteh town located in the northwest of Tabriz. Different thicknesses of the first subsurface layer, the high level of ground water, and the presence of sand layers between the clay layers are the main reasons for uneven consolidation settlement of buildings in the mentioned area. Residents usually do not feel safe to live in these tilted buildings. However, demolishing and reconstructing tilted structures is a waste of money, unless there is no other solution. Moreover, the demolishing of valuable historical buildings is out of choice. Thus, restoration processes for tilted structures should be considered and developed. Various methods are used to rectify the tilted structures including compaction grouting, underpinning of the foundation, chemical grouting, jacking, soil extraction technique, etc. Among different methods for rectifying uneven settlement of structures, in this study, because of some advantages, the jacking technique has been chosen to rectify the Tilted Reinforced Concrete (RC) buildings. This method can be used in dense urban areas and the residents can stay in their apartment or office in much of the rectifying process. Geotechnical finite element software of Midas GTS NX was used for numerical modeling and analysis of this direct soil-structure interaction rectifying project. The results were verified based on the data reported by Ma et al. (2008). The force applied by the jacks to rectify the uneven settlement should continue until the two sides of the foundation would reach the equal value of vertical displacement, or the uneven settlement of the foundation is reduced to the minimum possible amount. Also, the structural elements of the building should be able to withstand the force applied by the jack and do not crack or collapse during the rectification stages.