Willow Park-CS1103112011) Rhonda Adloo - Willow Park Page 1
From: Michael Garza
To: jason @jrrosedevelopment.com
CC: Larry Davis; Rhonda Adloo
Date: 3/11/20119:16 AM
Subject: Willow Park
Attachments: IMG_2195.JPG; IMG_2209.jpg; IMG_2211.jpg; geotech.gif; geotech2.gif
Jason,
The following pictures are of the sewer line backfill that is not suitable material. About 80% of this site is not suitable material.
Densities should be taken for the backfill material. My understanding is that there have been no geotech labs out there to take
densities. We will not accept this and it will need to be removed and replaced. It was my understanding from the pre -con that you
were going to cut down the unsuitable material and dispose of it, then in turn, bring in suitable fill material. I have attached a
portion of your Geotech's report regarding the unsuitable material. It would be to your advantage to remove this material and
replace it with suitable fill material.
If you have any questions please contact me at your convenience.
thanks,
Mike
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A mo istu re- barrier should be used bene a Ih the, slab foundation in areas whe re f I oo r coverin gs wil I be
utilized (such as, but not limited to, wood flooring, tile, linoleurn, and carpeting).
Subgrade Preparation
Uncontrolled fill was encountered across the site ranging in depth fforn 4 to 6 feet from the existing
ground surface. In order to utilize ground supported foundation systems it will be necessary to
remove and replace the uncontrolled till with engineering control a0cillows. The fill rnatenal should
be excavated and deleterious materials greater than 4 inches in size, or any organics should be
removed from the fill. The fill to be replaced should consist of material with at least 60 percent
passing the No. 4 sieve- The excavated soils may then be placed in loose lifts not exceeding 10
inches arid cc rnpacted to at least 95 percent of the materials maximum dry density per the standard
Proctor test (ASTNI D698) at moisture content of optimum to +4 percent above optimum.
Pavemunt Design Recommendations
The following pavement sections are a minimi-rim recommended for this project based on a 20-year
Fife design. They are based on our engineering judgment and experience with environmental
factors, including temperature, humidity, rainfall and swell characteristics of the soils,
We recommend a 6-inch section for streets in residential communities. A m in im U m 7-inch section is
recommended in areas receiving frequent heavy trucks and clumpsters, Concrete with a minimum
H-day compressive strength of 3,500 pounds per square inch is recommended,
All topsoil, existing pavernent and structures, vegetation, and any unsuitable materials should be
removed. The pavement subgrade should be proafrolled with a fully loaded tandem axle dump truck
or similar prieumatic-dre equipment to locate are:j; luo5e subgrade.. In areas to be cut, the
proofroll should be Performed after the final grade is established. In areas to be filled, the proofroll
should be perfornned prior to placement of engineered fill and after the pavement subgrade is
established- Areas of loose -or s. subgrad:e encountered in the proolrall should be removed and
replaced with engineered fill, of moisture r-o n ditioried (dried or wetted. as needed) and compacted in
Place.
The clay soils are plastic and can undergo some volume change when subjected ta, moisture
variations, If the moisture contents of these up
I P ripper sails reduce, they may shrink. and Cracks may
develop- If the rnoisture content of these materials increase, they could swell and lose strength,
Shrinkage, swelling, or strength lo5s could be detrimental to the proper function of the pavement.
VTQ Hu. 09-15503 P;19Q 5
AM concrete, trees, stumps, brush, abandoned structurea, roots, vegetation, rubbish and any other
undesirable matter should be removed and disposed of properly, All vegetation should be removed
and ft exposed surface should be scarified to an additional depth of at least 5 inches. It is the
intent of these recommendations to provide a loose surface with no features that would tend to
prevent uniform compaction by the equipment to be used.
All areas to be filled should be d isced or bladed until u n ifo rm and free from large c lods, b rO Ug ht to a
moisture content between oplimum and 4 per points above the optimum moisture value, and
cornpacled to between 95 and 1.00 percent of optimum density in, accordance with ASTM D698.
Fill Materials
Materials to be used for general site frill should consist of on-site material approved by the Soils
Engineer. Imported general site fill should have a liquid limit less than 60 and should be approved by
the Soils Engineer. There should be no roots, vegetation or any other undesirable matter in the soil,
and no rocks 1;3rgur than 4 inches in diameter.
The fill material should be placed in level., uni I aryers. vwh ich, when Compacted, :sh Oki Id have a
moisture content and density conforming to the stipulations called for herein.. Each layer should be
thoroughly mixed during spreading to provide uniformity of the layer The fill thickness should not
exceed 10-inch loose lifts.
Prior to and in conjunction with the compacting operation, each layer should be brought to the
proper moisture content as determined byAST10' 0698. We recommend the clay soils be moisture
conditi on ed to a moisture content that is between optimum a n d 4 percentage p o ints above opbmum.
After each layer has been properly placed, mixed acid spread, it should be thoroughly compacted to
between 95 and 100 percent of Standard Proctor Density as determined by ASTNI D698.
Density Tests
Field Density tests shOUld boa made by the Soils Engineer or his representative. Density tests should
be taken in eooh [avei of IN.- compacted material below ire disturbed surface, If the materials fait to
I
rneet the density spin. tied, the course should be rV - -. w, - ked as necessary to obtain the specified
compaction.
ProjW No, 09-15003 Page r,