Tower Construction

[image courtesy of skyscraperpage.com]

Just browsing some info on the construction of the Burj Dubai, by SOM, I found this on a forum for skyscraperpage.com, which was really interesting: "To ensure the structural stability of the Burj Dubai during construction, the tower’s vertical and lateral movements are tracked with the help of a satellite-based global positioning system. During construction, any change in load distribution of the building is closely monitored in real time through the use of more than 700 sensors embedded in its structure."
Sounds a little overkill, but this process has been used quite commonly in recent times, and in earlier years, used aircraft bombsights for the same quality control.

[image courtesy of skyscraperpage.com]

Another interesting fact about the tower is its foundation. "The 800-meter (1,827 feet) Burj Dubai will need the mother of all foundations to support a super-structure that is expected to weigh 500,000 tons. The tower will rest on a 3.7m-thick triangular frame foundation supported by 192 rounded steel piles or support cylinders measuring 1.5m in diameter and extending 50m (164 ft.) below the ground."
It's hard to measure up foundations with other buildings because it all depends on the depth of bedrock. With Dubai, I'm not sure of the bedrock depth, but if so many skyscrapers are popping up so plentifully in the past decade, then it can't be at too much of an inconvenient depth. In comparison, the glorious Petronas Towers has an extremely deep foundation which may or may not still be the deepest. Composed of "barrettes" (like a bored pile or a drilled shaft, rectangular instead of circular), these structural members go as far as 130m deep! With the Petronas Towers, they had to improve of the karstic limestone below ground by filling all voids in the rock with grout for additional strength. The actual depth of the barrette foundation there is about 120m!