HomeMy WebLinkAboutAddendum to Geotechnical Investigation March 15 2005Beneath the proposed buildings we recommend that all undocumented fill and the upper 3 feet
of previously placed fill be removed to a depth of 3 feet below existing grade or finished grade
(whichever is deeper) and be replaced as a compacted fill densified to at least 95 percent of the
soil's maximum dry density (per ASTM D-1557). This remedial grading should extend laterally
at least 5 feet beyond the building perimeters.
Section 6.1.3: Remedial grading will be required only beneath the proposed buildings (as
recommended above) and in the area of undocumented fill encountered elsewhere on-site. All
areas to receive fill or surface improvements should be scarified, moisture conditioned and
compacted as noted within our previous report.
Section 6.2.4: Initial water-soluble sulfate testing indicated that the on-site soils possess a
negligible sulfate rating per the Uniform Building Code (UBC). Additional soluble testing will
be performed at completion of grading to determine the as -grade sulfate rating for the building
areas.
Section 6.2.5: Corrosion testing should be performed by a qualified corrosion engineer. We
request that the owner directly hire an independent corrosion engineer.
Section 6.3.4/6.3.5: All fill placed beneath and within 5 feet laterally of the buildings should be
compacted to at least 95 percent of the soil's maximum dry density (per ASTM D-1557). Fill
placed outside of the building areas should be compacted to at least 90 percent relative
compaction.
Section 6.7.1: R -value testing should be performed upon completion of site grading to determine
the R -value of the as -graded pavement areas. Based on that R -value test(s), revisions to the
preliminary pavement section recommendations may be warranted.
Section 6.9: We have received and reviewed the site plan provided to us by Megaland Engineers.
Our previous borings and limits of recommended remedial grading have been plotted onto this
map (attached as Figure 1). We have also reviewed the Rough Grading Plan, issued by Megaland
Engineers (undated). This plan appears to have been prepared in accordance with the
recommendations provided in our previous report. Due to the location of the westerly wall
footing for Parcel 5 (also referenced as Major 1) relative to the top of the proposed fill slope, we
recommend that the westerly wall footing for this building be deepened such that the horizontal
distance to daylight from the outside edge of the wall footing will be at least 7 feet.
Based on these revised grading recommendations, it is our opinion that the allowable soil bearing
pressure recommended in our 2003 report can be increased to 3,000 psf. This increase in the
recommended soil bearing pressure is based, in part, on the increased degree of recommended
soil compaction beneath the proposed building. The remaining foundation recommendations
presented in our 2003 report remain applicable, except as amended in this letter.
Project No. T2137-12-01 .2. March 15, 2005
Should you have any questions after reviewing this addendum, please contact the undersigned at
your convenience.
Very truly yours
GEOCON INLAND EMPIRE, INC.
(,rF
2042
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Attachments: Figure I
Centre Builders, Inc., Letter
(2) Addressee
(4) Centre Builders, Inc.
Attention: Ron Miller
Project No. T2137-12-01 .3-
Centre Builders, Inc.
uFebruary 28, 2005
Mr. Robert R. Russell
Geocon Inland Empire, Inc.
41571 Corning Place #101
Murrieta, California 92562-7605
RE: Butterfield Station — Temecula, California
Dear Mr. Russell:
In order to obtain bids to accomplish the rough grading on the Butterfield Ranch
project we will need an amended letter to the supplemental investigation report
dated 05-21-04. We respectfully suggest you readdress the following items from the
05-21-04 report.
3.3 Correct this statement if later information regarding the previously placed fill
has supporting documentation
6.1.3 Verify if this statement will apply if later information regarding the previously
placed fill has supporting documentation
6.2.4 Indicate a Water -Sulfate Test will be performed after the rough grading is
completed and the finding published
6.2.5 Soils Engineer will need to hire an engineer to evaluate the corrosiveness of
the soil after grading so we may obtain the correct concrete mix.
6.3.4 State in this paragraph the parking lot compaction to be 90% at completion of
rough grading and the pads to be 95%
6.7.1 It will be important the Soils Engineer note in his report that he will test for
"R" Value after Rough Grading is complete. I have attached the section of the Soils
Report at our project on Apis Road. This may result in a Cost Savings.
6.9 Soils Engineer should be reviewing the latest Joe Reyes plan. The plan we are
using does not have an issue date. Also he needs to indicate the amount of over -
excavation at each building pad, as well as the limit of pad over build.
Fig. 2 Issue the Geologic map based on the latest information
Robert Russell - GeoconInla�pire •
Page 2
We do not have retaining walls, but will, our loading dock walls need special
consideration.
Please provide the on Civil Engineer's plan a line indicating the over -build at each
building pad, as well as the depth of over -excavation from finish grade.
Should you have any questions, please do not hesitate to give us a call. I believe it
would be best if you issued this information in the form of a draft so we may make
any final comments prior to issue. It is my understanding Joe Reyes will need this
information for the City.
Sincerely,
RI Her
Vice President
RM: per
Attachment
Cc: Jerry D. Swanger
Joe Reyes