Arbor Manors 4R2-CS120720 Rhonda Adloo
From: Michael Garza
Sent: Friday, July 20, 2012 4:14 PM
To: Rhonda Adloo
Subject: FW: Fire Lane Arbor Manors-Alternative Subgrade
Attachments: nps7A64 MH 7.20.12.pdf
Can you add this correspondence to the Arbor Manors retail file.
Thanks,
Michael Garza, P.E.
Civil Engineer
City of Coppell
972-304-7019
From: Michael Herrera j mailto:michael @hermansenlanddevelopment.comj
Sent: Friday, July 20, 2012 11:10 AM
To: Michael Garza
Cc: Robb James (robb @mlgraypartnership.com); Kyle Hogue (Kyle @gacon.com); Lance Rose (lance @ncapartners.com);
kirk hermansen
Subject: Fire Lane Arbor Manors -Alternative Subgrade
Michael,
Per my voicemail, I would like to submit for review an alternative subgrade, which is supported by our Geotechnical
Report, for your consideration.
I have highlighted the relevant items in regards to the subgrade.
4.6.1 Pavement Subgrade Preparation
Where rigid concrete pavement is used, lime stabilization of the subgrade soils will not be necessary and the pavement
can be places on properly compacted subgrade.
Please review and let me know if we can remove the lime stabilization due to the result of the Geotechnical Report.
Thank you for your consideration.
Michael Herrera
Hermansen Land Development
5944 Luther Lane,Suite 725
Dallas,Texas 75225
Ph: 214-373-4202 x23
Cell: 972-951-5261
Fx: 214-373-0737
Em: michael@hermansenlanddevelopment.com
Website: www.hermansenlanddevelopment.com
1
9. Trees in general, should not be planted closer to a structure than the mature height of the
tree. A tree planted closer to a structure than the recommended distance may extend its
roots beneath the structure, allowing removal of subgrade moisture and/or causing
structural distress.
10. Utilities which project through slab -on -grade floors, particularly where expansive soils or
soils subject to settlement are present, should be designed with some degree of flexibility
and/or with a sleeve to reduce the potential for damage to the utilities should movement
occur.
4.6 Pavement Recommendations
4.6.1 Pavement Subgrade Preparation
The near surface soils at this site consist of sandy clay. Where rigid concrete pavement is used,
iinie slabihzaliouu of the stibgrade soils wffl riot I)e uur.,ccssary and the pavement can be placed on
properly compacted subgrade. It is our understanding that flexible (Asphalt) pavement sections
are not planned.
Initially, all topsoil including any deleterious materials must be removed from the areas proposed
for pavement construction. After stripping and excavating to the proposed pavement subgrade level,
and prior to placing fill, the exposed pavement subgrade should be proof -rolled with a tandem axle
dump truck or similar rubber tired vehicle. Soils, which are observed to rut or deflect excessively
under the moving load, should be undercut and replaced with properly compacted fill. The
proof - rolling and undercutting activities should be witnessed by a representative of the geotechnical
engineer and should be performed during a period of dry weather. The p venieuut suui)grade sofls
should their be scare fled acid re conuiracled to ad least 95 pe cc rit of the standard IProcdor niax_inuuunu
duy deull:idy AS "I "M IC69, iull the noisduuu °e u °anllge of oirdituuutu doer. abov�:e , oirdnnuuutu, for a depth of at
least 6 iruches I)e1ow the suu:rface,
After subgrade preparation and observation have been completed, fill placement if required may
begin. The fill soils may consist of on -site or similar soils. The first layer of fill material should be
placed in a relatively uniform horizontal lift and be adequately keyed into the stripped and scarified
subgrade soils. Fill materials should be free of organic or other deleterious materials and have a
maximum particle size less than 3 inches. Fill should be compacted to at least 95 percent of standard
Proctor maximum dry density as determined by ASTM Designation D 698. Fill should be placed in
maximum lifts of 8 inches of loose material and should be compacted within the range of optimum
to 4 percentage points above the optimum moisture content value. The pavement subgrade at final
elevation should be tested within 72 hours prior to placement of paving concrete.
GTC Project No: 12G102
Page 9 of 11
4.6.2 Pavement Design
The design thickness of a pavement will depend on the magnitude of axle loads and the number
of load repetitions. Parking and drive areas will be constructed at locations around the building.
Based on information provided, we understand that the parking areas will be subjected to normal
daily traffic consisting of passenger automobiles only with occasional delivery and trash pick -up
trucks limited heavy duty drive areas. Based on 20 year design life and computation based on
AASHTO design methods the following pavement sections are recommended. Light Duty
pavement sections are recommended for passenger vehicle parking areas and the Heavy Duty
pavement sections are recommended for fire lanes, truck parking and drive areas.
RIGID PAVEMENT DESIGN THICKNESS
The concrete should have a minimum compressive strength of 3,500 psi at 28 days. The
concrete should also be designed with 5 ± 1 percent entrained air to improve workability and
durability. Proper finishing of concrete pavements requires the use of appropriate construction
joints to reduce the potential for cracking. Construction joints should be designed in accordance
with current Portland Cement Association guidelines. Joints should be sealed to reduce the
potential for water infiltration into pavement joints and subsequent infiltration into the
supporting soils. The design of steel reinforcement should be in accordance with accepted codes,
Minimum reinforcement consisting of #3 bars placed at 18" centers is recommended.
Large front loading trash dump trucks frequently impose concentrated front -wheel loads on
pavements during loading. This type of loading typically results in rutting of the pavement and
ultimately, pavement failures. Therefore, we recommend that the pavement in trash pickup areas
and loading dock areas should consist of a minimum 7 -inch thick, reinforced concrete slab.
5.0 CONSTRUCTION CONSIDERATIONS
It is recommended that GTC be retained to provide observation and testing of construction activities
involved in the foundations and pavements, earthwork, and related activities of this project. GTC
cannot accept any responsibility for any conditions, which deviated from those, described in this
report, nor for the performance of the foundations and pavements if not engaged to also provide
construction observation and testing for this project.
The upper fine - grained soils encountered at this site may be sensitive to disturbances caused by
construction traffic and changes in moisture content. During wet weather periods, increases in the
moisture content of the soil can cause significant reduction in the soil strength and support
capabilities. In addition, soils, which become wet may be slow to dry and thus significantly retard
GTC Project No: 12G102
Page 10 of 11
Light Duty
Heavy Duty
Portland Cement Concrete
5.0 inches
6.0 inches
(3500 psi)
Subgrade or Subbase
As Discussed Previously`
The concrete should have a minimum compressive strength of 3,500 psi at 28 days. The
concrete should also be designed with 5 ± 1 percent entrained air to improve workability and
durability. Proper finishing of concrete pavements requires the use of appropriate construction
joints to reduce the potential for cracking. Construction joints should be designed in accordance
with current Portland Cement Association guidelines. Joints should be sealed to reduce the
potential for water infiltration into pavement joints and subsequent infiltration into the
supporting soils. The design of steel reinforcement should be in accordance with accepted codes,
Minimum reinforcement consisting of #3 bars placed at 18" centers is recommended.
Large front loading trash dump trucks frequently impose concentrated front -wheel loads on
pavements during loading. This type of loading typically results in rutting of the pavement and
ultimately, pavement failures. Therefore, we recommend that the pavement in trash pickup areas
and loading dock areas should consist of a minimum 7 -inch thick, reinforced concrete slab.
5.0 CONSTRUCTION CONSIDERATIONS
It is recommended that GTC be retained to provide observation and testing of construction activities
involved in the foundations and pavements, earthwork, and related activities of this project. GTC
cannot accept any responsibility for any conditions, which deviated from those, described in this
report, nor for the performance of the foundations and pavements if not engaged to also provide
construction observation and testing for this project.
The upper fine - grained soils encountered at this site may be sensitive to disturbances caused by
construction traffic and changes in moisture content. During wet weather periods, increases in the
moisture content of the soil can cause significant reduction in the soil strength and support
capabilities. In addition, soils, which become wet may be slow to dry and thus significantly retard
GTC Project No: 12G102
Page 10 of 11
301., 303.
2290
CITY OF COPPELL DALLAS COUNTY, TEXAS