Boy, I wish I never said "a simple poking stick does better than both." I have used a manual static cone since 1984 in Florida and the Midwest very successfully and I swear by it. Geo Durham makes it.
Mayne's paper indicates that due to the small Poisson's ratio, the difference between the two is so small that it can practically be neglected. Clyde Baker was a forensic investigator on the project addressed in Mayne's paper and said during a talk up here in Chicago that the original engineers...
When would one be used rather than the other? Say the depth to rock is 100 ft (H) and the footing is 25 ft wide (B), I would use the Young's Modulus. If B=100 ft and H=25 ft, I would use the constrained modulus. Does anyone have any references or guidance when to choose between the two when...
JAE,
The geology of the Chicago area is very well mapped and based on the shallow borings and a geologic review, we will recommned a site class but always recommend a deep boring be drilled from a CYA standpoint.
No to your question JackTrades. Be careful about driving them to "refusal." Overdriving can damage them via "brooming." With a 15000 ft-lb hammmer, generally 3 blows on the last inch will get you a 40-50 ultimate capacity pile and there is no need to drive it harder.
We found the opposite is true. In downtown Chicago, it is better to quickly drive a larger vibro for a shorter duration than a smaller vibro for a longer duration when it comes to the human perception issue (got less complaints).
