huangyhg

cracked drilled shaft
3 leg lattice communications tower, 450 feet tall supported on (3)- 6' to 8' diameter drilled shafts. each leg is supported on a base plate that is grouted with 4 anchor rods. the base plate is centered on the foundation. the drilled shaft appears to extend above grade approximately 12" to 18". one of the 3 shafts has cracked. the first crack is about 1" wide and is roughly a straight line that crosses the outside corner of the baseplate and is perpendicular to the diagonal of the baseplate. it extends from face to face of the shaft. the second crack is approx. 1/2" wide and is perpendicular to the first crack and starts at the outside corner of the baseplate and extends to outer face of the shaft. all i have are pictures right now, so i can't tell if the crack continues from top of foundation down past top of grade. i do see where concrete seeped out from under the formwork where the concrete was formed above grade. don't know much about this yet but wanted to see if anyone has seen this happen before. don't know the depth or cage size. do have pictures of a cage but can't confirm it was installed or even set at the right elevation.
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three each ties, (#4), required in the top five inches of foundation surrounding anchor bolts. when present, no cracks as described in my experience.

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