Freeport NIP(2.8)-CS040508May 8, 2004
Mr. Larry Davis
City of Coppell
255 Parkway Blvd.
Coppell, TX 75019
'"Hanson
Hanson Pipe & Products, Inc..
1000 MacAr~hur Blvd.
Grand Prairie
TX 75050
Tel 9?2 263-218~
Fax 9?2-260-3604
www.hanson pipeand products.eom
Re: Steel Placement in 6'x8' Vault Extensions
Dear Mr. Davis:
It has been brought to our attention there are concerns that the City of Coppell has about the steel
placement in a 6'x8' vault dser or extension that was produced for a particular project in your area.
During our investigation, I noticed that in a particular spot located on the sidewall of the riser that the
steel appeared to have shifted dudng the placement of the concrete. Because of this, the chairs or
spacers that were used became separated or disassembled from the reinforcing cage which initially
caused the problem.
As you requested, three (3) cores were taken from separate areas of the riser to determine both the
actual steel placement and compressive strength of the structure in question. After reviewing the
results our findings were:
1. The concrete cover over the steel represented in the (3) cores is consistent at 2 inches.
2. The average compressive strength of the (3) test specimens is 4,081 lbs/in2. It should be
noted that the design concrete strength is 5,000 lbs/in2.
Hanson Pipe & Products is committed to providing it's customers with the best quality product
possible, while at the same time meeting or exceeding the needs of our customers. In order to help
us achieve these goals, Hanson has its own QC/QA program that meets or exceeds state and local
requirements. The present instance is an unfortunate example of our inspection program having
missed a fabrication problem.
In conclusion, we have determined that in order to solve the problem and to keep it from happening
again, a different type of spacer or chair will be used in this and similar products. Furthermore,
please be assured that all possible measures will be taken in correcting this problem and our
intentions are to prevent this from occurring again in the future.
Please do not hesitate to contact me at 972-260-3507 with any question that you may have.
Sincerely,
Ken D. Cambron - QC/QA Manager
Hanson Pipe & Products, Inc.