Like the Burj Dubai (Poulos & Bunce 2008), the foundation system for each of the towers in the Emirates Twin Towers complex buildings consists of a piled raft, founded on deep deposits of calcareous soils and rocks (Poulos & Davids 2005). Based on what was determined to be relatively good conditions near the ground surface, a piled raft system was identified as being most suitable for the foundation of each tower based on the series of analyses conducted by the foundation project engineers (Poulos & Davids 2005). In each case, project engineers evaluated 18 different load combinations to assess loading as follows:

1. One loading set for the ultimate dead and live loading only;

2. Four groups of 4 loading sets for various combinations of dead, live, and wind loading for the ultimate limit state; and,

3. One loading set for the long-term serviceability limit state (dead plus live loading) (Poulos & Davids 2005).

In addition, project engineers employed conventional pile capacity analyses to evaluate the eventual geotechnical capacity of the raft and piles as follows:

1. For the piles, this capacity was taken as the sum of the shaft and base capacities; and,

2. For the raft, account was taken of the layering of the geotechnical profile and the large size of the foundation, and a value of 2.0 MPa was adopted for the ultimate bearing capacity.

Beyond the foregoing conventional analyses, the project engineers also conducted analyses of the foundation system using the computer program geotechnical analysis of raft with piles (Poulos & Davids 2005) as depicted in Figure 2 below.

Figure 2. Computed final settlement contours for the hotel tower.

Contour interval: 5 mm.

Source: Poulos & Davids 2005,...

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Taken together, the exhaustive analyses conducted on the project site allowed the twin tower foundation project engineers to characterize the site more completely compared to most other projects, particularly given the wide range of on site and computer-generated modeling permutations that were completed (Poulos & Davids 2005). According to the project engineers for the twin towers, "The substantial design effort was complemented by a comprehensive program of pile load testing, including static compression tests, static and cyclic tension tests, and lateral load tests. The compression tests were among the largest carried out in the Middle East and involved loads up to 30 MN" (Poulos & Davids 2005, p. 722). The project engineers also credit close collaboration with the geotechnical engineers for the project in formulating effective foundation solutions (Poulos & Davids 2005).