lei - Questions

Design of poured concrete on the shear wall:

• When the final f’c extrapolated from a break of 3 days then an additional break of 5 days (it is usually 3, 7 & 28 days), it is directly indicated that the first cylinder itself was defective.

• When the f’c of 5000psi was one of the 28th day (i.e. final) result, then it clearly indicates that it’s necessary to return the design engineer who is specified f’c 7000.

• It is really possible that he or she can review their previous calculations and determine lower compression that will still satisfy their own design.

• If it is not so then it will clearly requirement of other physical attributes like load, span, etc. it will have to be adjusted.

• Practically on a job, I was inspecting probably 3-day break spec, 5-day break, confirmed below fake spec.

• Usually, the contractor decided to tear the wall out and repour, but later on, it was determined to be a mechanical failure at the batch plant where only half the cement was batched.

• In case of another multi-storey hotel, it wasn’t the compression, it was the lack of adequate reconsolidation including vibration.

• When the forms where is stripped from a large, significance and poured in place shear wall, there were a large number of voids -some the size of a basketball.

• It was ultimately referred to the engineer, who specified filling a large number of voids with a simple compound.

• I personally didn’t feel particularly warm and fuzzy about the fix, but the engineer seemed more satisfied.

• One example of which I know is that a cantilevered deck at an officer’s club, on a military base.

But after all, the testing fell short of the design, the general contractor, and batch plant manager approach to the officer in charge (Airforce colonel which is assigned to oversee the project) to propose one of the serious field testings to demonstrate that the cantilever would work.

Finally, he decided to redo it.