The Impact of Spatial Variability on Deep Foundation Design for Tall Buildings

This paper discusses the vertical and horizontal spatial variation of geotechnical design parameters in weak carbonate rock formations, such as those typically found in the Middle East region. Improper consideration of such spatial variation, especially for design of deep foundations of heavy structures, can have a significant impact on the design foundation depth. Spatial variation of foundation design parameters from some of the world's tallest towers is discussed in this paper, and using data from one of the super tall residential towers, which is more than 300m tall, the potential risk of such large variation in design parameters is demonstrated. Use of geophysical data to reduce such risk, and the benefits of using design parameters derived from such geophysics data to validate other in -situ and lab test data, are also discussed with an example from the results of three load tests from a supertall tower project.

Keywords: foundations, spatial variation, geophysics, tall towers, carbonate rocks, risk.