Tilting of a Large Apartment Building in Bogota, Colombia, Due to Foundation Failure and the Recuperation of Its Verticality

Bogotá is located on a high plain (2600m asl) with a soft, highly compressible, plastic clay 250 m thick or more. It is surrounded by 300 m high hills, or higher, and at the foothills the soil profile has soft clay layers of varying thickness. This is a complex type of soil profile, and more often than desired it has resulted on foundation problems for buildings from 2 to 25 stories high. This paper describes the foundation failure due to excessive differential settlements or tilt towards the east, in this case the thicker lacustrine deposit, of a 17 stories high, very rigid concrete wall structure, part of an apartment complex, and the solution. The building is founded on the large piles some of which did not reach the sound clay stone foundation. Once the problem was detected, the structure was underpinned, using micro-piles or root piles to the deeper, sounder soils to support the walls on the eastern area, then an excavation under the footings at the western side was performed to discover the upper 3 m of the foundation piles, which were cut, while the structure was supported on hydraulic jacks and steel bar-pipes, Then the foundation above the piles was lowered 20 cm to its proper horizontal planes. The process is described in detail. Including sophisticated structural and geotechnical instrumentation and very detailed computer finite elements model used. The structure was successfully recuperated and the horizontal plane obtained as predicted by engineers participating.