HomeMy WebLinkAboutSpecial Inspection Field Test & Inspection Report 2003-4-15
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Engineering. Consulting. Testing
FINAL SUMMARY REPORT
April 15,2003
Report No.: 722-10212-214
Mr. Ron Wilson
Eugene Water & Electric Board
P.O. Box 10148
Eugene, OR 97440
Re: EWEB Hayden Bridge Reservoir Project
3957 Hayden Bridge Road
Springfield, Oregon
D.P.: 01-00399-01
,Dear Mr. Wilson:
Professional Service Industries, Inc. is pleased to submit a final summary letter for the above listed
project. Between July 12,2001 and December 19,2002, our firm obtained ,concrete test cylinders during
concrete placement; performed in-place nuclear density testing on crushed aggregate backfill;
constructed masonry prisms and grout samples, and performed structural welding inspections. The
compaction tests met or exceeded the minimum strength compaction requirements of 95% and the
concrete', .prisms and grout test specimens exceed design strengths (except as per attached letter dated
November 21,2002).
Note: For specific details regarding our inspection and testing services, please reference our previously
submitted reports.
Respectfully submitted,
l:~~~KVA~
Department Manager
C: City of Springfield
Slayden Construction
OBEC Consulting Engineers
Attachment: Letter dated November 21,2002
Professional Service Industries, Inc.. 1040A Shelley St.. Springfield, OR 97477. Phone 541/746-9649. Fax 541/746-7163
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OBEC CONSULTING ENGINEERS
PROJECT DISCUSSION MEMO
Project No: 30-31
Date: 11/21/02
Designer: Pete Slocum
Project: EWEB
15 MG Reservoir, Pump Station & Electrical Upgrade
Low Concrete Strength in two (2) reservoir columns
The following is an updated technical memo to EWEB regarding the low strength concrete in two
reservoir columns located at B-3 and C-3 (Slayden's grid scheme),
Introduction
Two (2) reservoir columns were given twice the air, 13% (air entrainment admixture had been added at
both the batch and the site by Morse Brothers).
Description
After determining this condition, Gordon Drake (OBEC) directed Slayden Construction to stop the
colunm pours using that load of concrete.
On June 20, I received a call from the field (Ron Wilson (EWEB), Gordon Drake and Slayden's
superintendent Scott) to discuss the allowable strength and measures to resolve this issue as Slayden was
ready to pour the beams on top of the low strength columns. The COIUIIlllS have about 20 feet of low
strength concrete in the bottom, and the rest of the 40-foot columns were poured with spec. concrete:.
The 7-day cylinder break was approx 2350 psi, well below the anticipated 3500 psi for that concrete mix
at that age.
The resolutions and actions agreed upon were the following:
1) Proceed with pouring the beams on the columns. The low strength columns (2350 psi) can carry
the beam self-weight and forming.
2) Prior to placing any of the roof (hollow core panels and topping slab), break another cylinder.
The cylinder break strength was acceptable and the roof construction continued,
After 5 months the last cylinder for that pour was broken and the strength was 3531 psi which is below
the specified 28 day strength for column concrete (4000 psi per the plans and specifications).
Low strength concrete is usually allowed by ODOT to 85% of specified (with compensation) which
would be 3400 psi in this case. The 5 month break of 3531 meets the 85% , so is normally accepted, The
required strength to support all design loads is 2600 psi, It is the determination of the responsible
Engineer (Pete Slocum) that 3531 psi concrete provides the necessary strength for all loading conditions it
will be subjected to,
Conclusion
We recommend that the material be accepted and no further action is required. It is hoped this memo
provides EWEB with the information needed at this time. Please feel free to call OBEC at any time
concerning this memo, .
Copies: Gordon Drake, OBEC field
Gary Rayor, OBEC project manager
Guy Hakanson, OBEC assistant project manager
Ron Wilson, EWEB
Original: Correspondence file
NOTE: Initial and date after last word message.