RTI Geotech Report Vol 1.pdf

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GEOTECHNICAL/DRILLING/TESTING/ENVIRONMENTAL/SURVEY

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GEOTECHNICAL Engineering Services

Report of Geotechnical Exploration Proposed Ohio Army National Guard Regional Training Institute (RTI) Building Project

East Broad Street Columbus, Ohio

TesTech File No: 25531

Prepared for

PBS&J

Aviation Services 7300 Turfway Road, Suite 400 Florence, KY 41042

June 6, 2008 website: www.testechinc.com

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622 Fax: 317-353-2054

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537 Fax: 614-863-4547

June 6, 2008

PBS&J

Aviation Services 7300 Turfway Road, Suite 400 Florence, Kentucky 41042

Attention: Mr. Jeffrey W. Bonecutter, P.E.

Project Manager

Re: Report of Geotechnical Exploration for the Proposed Ohio Army National Guard Regional Training Institute (RTI) Building Project East Broad Street Columbus, Ohio.

TesTech File Number 25531

Dear Mr. Bonecutter:

TesTech is pleased to submit the findings of the geotechnical exploration program conducted for the proposed Ohio Army National Guard Regional Training Institute (RTI) Building Project and the associated site development on East Broad Street in Columbus, Ohio. We are pleased to transmit herewith two (2) copies of our report.

The scope of the investigations included site reconnaissance, site exploration, field and laboratory testing and an engineering evaluation of the materials and conditions encountered at the site. Assessment of site environmental conditions, including the detection of pollutants in the soil or groundwater, and delineation of jurisdictional wetlands were beyond the scope of this exploration.

Recommendations with respect to the foundation design and construction, pavement design parameters, site classification for seismic design, suitability of fill stockpile as fill material on project during construction, material compaction requirements, groundwater conditions and dewatering methods, and general earthwork activities are presented in this report.

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- 2 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622

Fax: 317-353-2054

Design Considerations:

Based on the information provided by PBS&J, the proposed structure is a three-story building and will occupy a footprint of 123,000 ft2. The building will be permanent masonry type construction with split face block façade and standing seam metal roof. The proposed new building will include administration space, educational space, dining area, bunks and associated electrical, communications, and HVAC support facilities. The associated site development will include parking and driveway areas. A detention pond is also included in the associated site development. The proposed parking area will be about 3 acres to be capable of accommodating approximately two hundred vehicles and associated roadways and entrance drives. The concept plan showing the proposed building and the associated development provided by PBS&J is attached to this report.

The maximum anticipated column load for the proposed conventional steel frame building with concentrically braced frames is 300 kips and the maximum anticipated wall load is 4.5 kips per lineal foot. It is our opinion that estimated loads of up to 100 pounds per square foot for slab distributed loads are within acceptable engineering practice principles for such types of construction.

Site Description:

The proposed project site is one of 4 quadrants of a total of 70-acre site. The site is bounded by 4 roadways within the property limits of the Defense Supply Center in Columbus, Ohio. The project site is bounded on the north by Pershing Avenue, on the south by Roosevelt Lane, on the east by 8TH Boulevard, and on the west by Foyle Avenue. The site which is approximately 17 acres has turf vegetative cover approximately over the entire project site. The site was previously developed as a warehouse facility with rail lines however; all the structures have been demolished. There exists a large soil stockpile approximately 5 feet thick of uncompacted fill material over an area of approximately 100’ by 200’.

Generally, the upper approximately 3 to 10 feet of soils of the project site appear to consist of fill. There seems to be continuing dumping of fill soils, construction debris and garden waste on the project site from the observations made during the field investigations. Based on recent construction activities and the dumping in the area of the project site, it may appear reasonable to infer that the fill soils may be deeper and laterally extensive than the above given depths in some areas of the site and as shown in the borings. Topographically, the site is relatively flat but appears to drain to the west.

The change in elevation at the boring locations is approximately 3 feet ranging from EL. 792.00 feet to EL. 795.30 feet.

Regional Bedrock Geology:

Bedrock was not encountered during our geotechnical exploration at the project site. Based on the information obtained from the General Soils Map of Franklin County, Ohio by the United States Department of Agriculture, Soil Conservation Service in cooperation with Ohio

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- 3 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622

Fax: 317-353-2054

Department of Natural Resources, Division of Lands and Soil, and Ohio Agricultural Research and Development Center, Franklin County is within the glaciated till plain of Central Ohio.

Franklin County was glaciated by at least two different glacial periods. Evidence of Illinoisan glaciation has been found in the form of fine, well-sorted sands in buried valleys beneath the more recent Wisconsin age glacial till. The Wisconsin glacier removed or buried most of the Illinoisan deposits.

The bedrock underlying the glacial deposits, and exposed in places by erosion or construction, is sedimentary. Ages range from lower Devonian in the west to lower Mississippian in the east.

Lithologies consist of dolomitic limestone, shale and sandstone. The oldest member of the Devonian system in the county is the Rasin River Formation, dolomitic limestone exposed in places in the valleys of Big and Little Darby Creeks on the west side of the county. The formations within the Devonian System to the east are younger and situated above the Rasin River. They include the Columbus and Delaware Limestones and the Ohio and Olentangy Shales. The limestone is along the Scioto River Valley and the shale is along the northern Oletangy River Valley. The Mississippian System is exposed in the valleys of Big Walnut and Rocky Fork Creeks. The formations include, from oldest to youngest, Bedford Shale, Berea Sandstone, Sunbury Shale, and Cuyahoga Sandstone. These formations occur as alternating beds of shale and sandstone.

Based on the Web Soil Survey from USDA Natural Resources Conservation Service, the soils found across the subject property are primarily composed of the Bennington-Urban Land Complex, 0 to 2 percent slopes (BfA) and Urban Land-Bennington Complex, 2 to 6 percent slopes (Uu).

The soils in most areas of the site have been disturbed or buried by filling and other earthmoving operations.

Field Investigations:

The geotechnical field exploration was conducted by TesTech, Inc. from May 15 to May 21, 2008. The purpose of this investigation was to explore the existing site soil conditions and evaluate the subsurface conditions in supporting the proposed construction.

The fieldwork consisted of the drilling of thirty (30) soil borings at the project site. Fifteen (15) soil borings were drilled within the proposed building footprint and fifteen (15) soil borings were performed for the proposed parking and roadway areas including the detention pond. The building borings were advanced to a depth of 20 feet and the borings for all the remaining structures were advanced to a depth of 10 feet below the existing ground surface. The borings were advanced utilizing hollow stem augers powered by an All Terrain Vehicle (ATV) drill rig

(CME 55X).

The soil borings were advanced utilizing split spoon sampling techniques per ASTM D 1586 and Shelby Tube sampling per ASTM D 1587.

Standard Penetration Testing (SPT) was conducted at 2.5-foot intervals to a depth of 10 feet and at 5-foot intervals thereafter utilizing a split spoon sampler. The results of the SPT tests are given on the attached boring logs.

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- 4 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622

Fax: 317-353-2054

Pocket penetrometer testing was performed on the cohesive split spoon samples to estimate the undrained shear strength of the site cohesive soils. The results are shown on the attached boring logs. The groundwater conditions were monitored during sampling and upon completion of the drilling operations and removal of augers. The boring locations are shown on the attached Boring Location Plan provided by PBS&J.

Per discussions with the Client, a maximum of four (4) bulk samples were to be taken from the 5 feet thick stockpile of uncompacted fill material on the project site to determine the suitability of the material as engineered fill on the project during construction. The four (4) bulk samples were obtained during the field investigations. However, due to layering and compositions of the soils in the stockpile, none of the four (4) bulk samples taken were tested in the laboratory per further discussions with the Client. No engineering recommendations are therefore provided on the suitability of the stockpiled soils as engineered fill in the report.

The following lists the major findings and conclusions of this exploration:

Subsurface Conditions:

The subsurface conditions encountered at the boring locations revealed approximately 7 to 12 inches thick layer of topsoil or 12 inches of asphalt and aggregate base materials overlying clay fills and natural clay, silt, sand, and gravel soils.

Clay fill was predominantly encountered below the topsoil and pavement layers to depths approximately between 3.0 and 12.0 feet below the existing ground surface in all the borings with the exception of five (5) borings (B-12, B-15, P-1, P-4, and P-10) where natural clay soils were encountered below the topsoil and pavement layers. SPT blow counts (N values) in the clay fill ranged from 4 to 18 blows per foot (bpf) indicating a soft to very stiff consistency.

Unconfined compressive strength estimates based on pocket penetrometer testing ranged from

1.0 to 3.0 tons per square foot (tsf). Moisture content in the clay fill varied from 14.2 to 31.3 percent. The clay fills were classified as CL under the Unified Soil Classification System

(USCS).

Below the topsoil, pavement layers and clay fills, native clay soils were encountered in all the borings to the maximum termination depth of 20 feet below the existing grade. The natural clay was soft to hard in consistency with SPT N values ranging from 4 to 76 bpf. Unconfined compressive strength estimates based on pocket penetrometer testing ranged from 1.0 to 4.5 tsf. Moisture content in the natural clay varied from 10.0 to 28.1 percent. The natural clay was classified as CL and CL-ML under USCS.

Natural stiff silt with SPT N values of 10 and 14 bpf were encountered in Borings B-2 and B-3 between approximate depths of 13.0 and 20.0 feet below the existing ground surface.

Unconfined compressive strength estimate based on pocket penetrometer testing was 1.75 tsf.

Moisture content in the natural silt varied from 20.5 to 23.6 percent. The natural silt was classified as ML under USCS.

Medium dense natural sand and gravel soils of varying thicknesses were also encountered in Borings B-2, B-4, B-10, B-11, and P-1 at depths ranging approximately from 6 to 20 feet below the existing grade. SPT N values in the natural sand and gravel soils ranged from 11 to 23 bpf

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- 5 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622

Fax: 317-353-2054 with moisture contents varying from 13.6 to 27.7 percent. The natural sand and gravel soils were classified as SM and SP under USCS.

Generalized descriptions of the subsurface conditions encountered at the project site are given above. More detailed descriptions are given in the attached boring logs. It should be noted that the stratification lines shown on the soil boring logs do not represent exact geological planes but approximate transitions between soil types. In-situ stratum changes could occur gradually or at slightly different depths.

Groundwater was measured in all the borings approximately between the depths of 2.0 and

10.7 feet below the existing ground surface during drilling and upon completion of the soil boring operations and removal of augers. The groundwater appears to be under pressure and will flow into excavations when encountered during construction. The groundwater conditions observed reflect the conditions at the time of our exploration only. Fluctuations of the groundwater table should be expected to occur both seasonally and annually due to variations in rainfall, evaporation, transpiration, construction activities, and other site-specific factors. The contractor should be prepared to control surface and groundwater during construction with a sump and pump system.

According to Uniform Building Code (UBC) Chapter 16, Figure 16-2, the proposed site is located in seismic zone 1. Based on our previous experiences within the proximity of the project area, the soil profile type for the project site is assigned as SD per the Uniform Building Code or as Site Class D per Ohio Building Code 2007.

Laboratory Investigations:

Ninety-one (91) soil moisture content tests per ASTM D 2216, four (4) sieve analysis tests per ASTM D 422 and D 1140, and seven (7) Atterberg Limits tests per ASTM D 4318 were conducted for selected representative cohesionless and cohesive split spoon and bulk samples.

Tables 1 and 2 below list the Atterberg Limits and sieve analysis test results. The test results are provided in the attachments.

Table 1 – Atterberg Limits Test Results

Boring No. Depth (ft) Liquid Limit (%) Plastic Limit (%) Plasticity Index (%)

B-7 3.5-5.0 34 18 16

B-7 18.0-20.0 21 15 6

B-12 3.5-5.0 24 16 8

P-2 1.0-2.5 32 18 14

P-9 3.5-5.0 50 22 28

P-1, P-9 (Bulk) 2.0-5.0 38 19 19

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- 6 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622

P-14, D-1 (Bulk) 2.0-5.0 39 19 20

Table 2 – Sieve Analysis Test Results

Boring No. Depth (ft) % Gravel

Sand

Silt & Clay USCS

B-2 18.5-20.0 3.5 58.7 37.8 SM

B-7 18.5-20.0 9.0 33.5 57.5 CL-ML

B-11 8.5-15.0 11.3 48.7 40 SM

P-14, D-1 (Bulk) 2.0-5.0 9.9 23.8 66.3 CL

Two (2) composite bag samples of subgrade materials were obtained from surface and near surface soils in the areas of Borings P-1, P-9, P-14, and D-1. The composite samples were tested for Modified Proctor values. Soaked California Bearing Ratio (CBR) tests were also conducted on the composite bulk samples. The test results are provided in the attachments.

Table 3 below summarizes the test results for the Modified Proctor and CBR Tests.

It should be noted that the CBR values listed in Table 3 are the interpolated values at 95 percent compaction of the maximum dry density per the Modified Proctor test (ASTM D-1557). It is imperative that the on-site construction follows the compaction criteria required in this report in order for the pavement subgrade to achieve enough strength and support for heavy-traffic loading.

Table 3 Modified Proctor and CBR Test Results for Composite Bulk Samples

Sample No. Depth (ft)

Maximum Dry Density

(pcf)

Optimum Moisture Content

CBR

Natural Moisture Content (%)

P-1, P-9 2.0-5.0 120.8 11.4 4.3 18.0

P-14, D-1 2.0-5.0 121.2 10.0 4.8 19.7

One (1) Shelby Tube sample was obtained from Boring B-10 for unconfined compressive strength of the site clay fills/soils. However, the sample was non-testable due to the presence of voids and debris.

One (1) bag sample of topsoil, approximately 10 pounds in weight was obtained from different locations of the site. A representative sample of the topsoil was tested for organic content. The test results are provided in Table 4 on the next page.

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- 7 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622

Table 4 Loss on Ignition Test Results

Sample Description As Received Moisture Content (%) L.O.I (%)

Brown Topsoil 18.7 6.6

The composite bulk and selective split spoon samples were tested for pH and Resistivity in order to determine the corrosion potential for pipes and the reactivity potential for concrete structures below grade. Figure 1 illustrates the pH related to the strength of base and acid properties of soils. Table 5 lists the relationship between resistivity and corrosivity.

The test for pH was conducted with the aid of a calibrated pH meter. For the Resistivity test, the soil sample was compacted in a test device and resistivity measured at relatively moist condition. Then additional trials were performed at increasing moisture contents. The resistivity decreases with increasing moisture and eventually reaches a minimum value. These minimum values are reported in Table 5.

Figure 1 pH and soil properties

Table 5 Corrosivity of Soils on Steel based on Soil Resistivity

Soil Resistivity Range (ohm-cm) Corrosivity

0 to 2000 Severe 2000 to 10,000 Moderate to Severe

10,000 to 30,000 Mild Above 30,000 Not Likely

Table 6 pH and Resistivity Test Results

Boring No. Sample Depth (ft) pH Resistivity (Ω-cm)

At natural moisture content

B-5, B-9, B-11, P-9 1.0-2.5 8.2 2250

P-14, D-1 (Bulk) 2.0-5.0 8.2 2200

Engineering Recommendations:

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- 8 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622

Based on the information provided by PBS&J, it is our opinion that the subject site is suitable for the proposed construction.

Based on the interpretation of the standard penetration resistance tests, pocket penetrometer test results, the available information provided by PBS&J, our engineering evaluation of the subsurface conditions, and our experiences with similar projects, the proposed building can be supported by conventional spread and continuous wall footing foundation systems bearing on the in-situ soils and/or compacted engineered fill.

In case of building loads allowing for a smaller footing size, it is recommended that continuous wall and column footings still be designed with minimum widths of 18 inches and 24 inches, respectively. These minimum widths are recommended to provide a margin of safety against a local shear or punching shear failure

Exterior footings should be embedded at a minimum depth of 32 inches or the local frost depth, whichever is deeper, below finished grade to reduce the potential for frost heave.

Provided the recommendations presented herein are incorporated into the design and construction of the foundations, a net allowable bearing pressure of 2,000 pounds per square foot (psf) can be used in designing continuous wall and conventional spread footings bearing on the in-situ soils and/or compacted engineered fill.

Total and differential settlements are expected to be on the order of less than 1-in. and ½-inch, respectively, if the recommended site preparation and foundation systems are used.

The slab-on-grade of the proposed building should be supported on the in-situ soils and/or compacted engineered fill. The slab-on-grade should be constructed on a 6-inch mat of free-draining granular material such as ASTM No. 57 crushed limestone aggregate for uniform support and lateral drainage. A subgrade modulus of 100 pounds per cubic inch (pci) is recommended for the structural design. Adequate construction joints should be provided to accommodate minimal differential movement.

Laboratory pH and resistivity test results of the site clay soils show a low corrosivity potential to concrete and a moderate to severe risk of steel corrosion. A Type-I cement per ACI Building Code 318-02 for footings and slab is recommended. A minimum of 3” concrete protection to steel bar in the footings and 2” cover to steel bar in the slab is required per ACI Building Code 318-02.

Metal pipes used on the project site should be coated. All the mechanical joints, valves, fasteners etc. should be stainless steel or brass to prevent corrosion. Cathodic protection should be designed for the metal pipes.

Based on our engineering evaluation, interpretation of the standard penetration resistance tests, analysis of the laboratory results, and our experiences with similar projects, we recommend an average CBR value of 4.6 at 95% of the maximum dry density per the Modified Proctor test (ASTM D-1557) and a modulus of subgrade reaction “k” value of 150 pci for pavement design.

If earthwork activities take place during wet weather, drying of the site soils may be required to

Page - 9 - of 12

- 9 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622

Fax: 317-353-2054 get the moistures to the recommended range of the optimum moisture content (OMC).

Additionally, chemical modification using lime may be required during wet weather to dry out the site soils.

Any fat clay encountered during construction should be removed and replaced with compacted engineered fill or lime modified/stabilized.

It should be noted that the properties of the site clay soils would be severely influenced by moisture. We thus recommend that perimeter drains be employed around the building foundation perimeter. A diagram provided in the attachments shows a typical foundation perimeter drain.

Based on the subsurface conditions encountered at the location of the proposed detention pond, the subsoils are suitable for the construction of the detention pond.

It is recommended that the Geotechnical Engineer is retained to observe the site preparation process and document the foundation excavations as well as check compaction of the foundation subgrade and backfill. Significant deviations from the specified or anticipated conditions should be reported to the owner’s representative and to the foundation designer.

Earthwork Recommendations:

Typically, late spring to early fall is the time frame when weather conditions are most favorable for earthwork in the project area. Earthwork activities undertaken during the wetter portions of the year typically encounter substantial difficulties associated with snow and rain.

In the proposed building area, once the topsoil and unsuitable soils (soft soils and soils containing deleterious materials) are removed, the exposed subgrade should then be scarified to a minimum depth of 12 inches and re-compacted due to the non-uniformity in strength of the upper 3 feet of fills and natural soils and proof-rolled. Proof-rolling should be done to determine if any soft zones or unsuitable soils are present and to ensure a suitable base for the placement of possible additional fill. The proof-rolling should be performed after a suitable period of dry weather to avoid degrading an otherwise acceptable subgrade. The proof-roll test should be conducted with a fully loaded tandem-axle dump truck of at least 40-ton weight with a tire inflation pressure of 120 pounds per square inch (psi) passing over the subgrade area.

Soft and wet soils should be removed (undercut), modified, and re-compacted or replaced with compacted engineered fill. Modification may include scarifying the subgrade to aerate the soft or wet soils or may include addition of lime and cement. Field conditions will dictate the method used in stabilizing soft and wet subgrade soils. The depth of any undercut should be determined in the field by the Geotechnical Engineer during proof-rolling operations.

Positive surface drainage should be maintained to prevent the accumulation of water at all times. The stripping and excavation operations should be performed in a manner consistent with good erosion and sediment control practice. If the exposed subgrade becomes excessively wet or frozen, or if conditions encountered during construction differ from those described previously in this report, the Geotechnical Engineer should be contacted.

Page - 10 - of 12

- 10 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239

In the proposed area of building construction, the exposed soils should be compared with those encountered in the soil borings. The soils beneath the foundation excavation should be tested with a Dynamic Cone Penetrometer (DCP), hand auger and pocket penetrometer to a minimum depth of three (3) feet. This test is necessary to discover if compressible soils are present underneath the foundation elevation. All soft and wet soils must be removed (undercut) from the foundation areas and replaced with compacted engineered fill, approved granular materials or lean concrete with 500 psi design strength at 28 days. The depth of any undercut should be determined in the field by the Geotechnical Engineer. The foundation bearing area should be nearly level with a maximum slope of less than 10 degrees. Foundation concrete should be placed the same day or as soon as practicable after excavation, compaction and inspection.

The Geotechnical Engineer should be consulted for the detailed recommendations pertaining to the site conditions.

All engineered fills should be compacted to at least 95% of the maximum dry density determined by Modified Proctor Test per ASTM D 1557. The moisture content of the fill materials should be controlled within ±3% percent of the optimum moisture content per the Modified Proctor Test. The fill materials should be placed in no more than 8 inches horizontal loose lifts.

The building site should be stripped and cleared of all topsoil. Any unsuitable fills (fills containing deleterious materials and organic matter) encountered during excavation operations should be removed and replaced with compacted engineered fill. Any unsuitable fill material encountered below footing excavations should be excavated to a minimum depth of 24 inches and replaced with compacted engineered fill. The limits of the surface preparation should be the footprint of the building plus no less than 10 feet beyond the edges of the footprint. Material from the clearing operations should be removed from the site and disposed of at a legal dumpsite. The topsoil can be stockpiled and re-used in landscaped areas.

Generally, it is desirable to remove all structures, utilities, leachate facilities, etc., from the proposed pavement areas. It is especially important that no old foundations, utility lines, or any deleterious materials should be left down to a depth of 3 feet below the pavement subgrade.

Once undesirable materials are removed, the resulting excavations should be replaced with compacted engineered fill.

The pavement subgrade should be suitably compacted to at least 95% of ASTM D-1557 (Modified Proctor). Soft and deleterious materials should be undercut and replaced with compacted engineered fill.

All pavements and parking areas should be sloped adequately and away from the building to prevent ponding of water. For pavement drainage, a transverse slope of 1.5% for the pavement surface should be applied each way from the centerline. Surface drainage should be established to prevent drainage towards the existing structures. The stripping and excavation operations should be performed in a manner consistent with good erosion and sediment control practice. If the exposed subgrade becomes excessively wet or frozen, or if conditions are encountered different from those described previously in this report, the Geotechnical Engineer should be contacted.

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- 11 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239

It should be emphasized that suitable drainage is critical to maintaining good foundation and pavement conditions. Catch basins with finger drains are recommended for the new pavement areas in addition to edge drains and/or subdrains.

All excavated areas should be sloped away from the existing structures to prevent ponding of water. The site drainage should be such that the run-off onto adjacent property is controlled properly. In addition, surface runoff from adjacent areas should not be allowed to enter the construction site.

It is also recommended that the compaction processes be directed by the Geotechnical Engineer in the field. The compaction of the pavement areas should be checked with a nuclear density gauge to ensure conformance with the recommended in-place density and moisture contents.

It is imperative that qualified inspection personnel be assigned to the construction of this project to perform material sampling, laboratory and field testing to insure compliance with the specifications.

Groundwater may likely pose some construction problems for deep utilities if required. The groundwater at the project site appears to be under pressure and will flow into excavations when encountered during construction. It is the contractor’s responsibility to dewater the site for foundations and any other deep excavations involved during construction. A sump and pump system is recommended to be used in case of dewatering groundwater for site preparation and shallow foundation excavations. Dewatering should be performed in a manner that will not disturb or loosen the subgrade soils. Sumping should not be conducted in foundation subgrade areas. Runoff water entering the excavation should be intercepted outside of the subgrade area.

If water intrusion or exposure softens the bearing soils, the softened soils must be removed from the foundation excavation bottom immediately prior to placement of the concrete.

The sides of excavations deeper than 4 feet should be sloped back for safety, or sheeting and bracing system should be used. OSHA and other applicable agency requirements pertaining to worker safety should be met. In addition, all excavations should comply with the requirements of OSHA 29 CFR, Part 1926 Sub Part P, “Excavations and Trenches”. This document states that safety is the responsibility of the contractor. Reference to these OSHA requirements should be included in the project specifications.

Limitations of Liability:

Conclusions and recommendations presented in this report are based upon the available soil information, currently accepted engineering principles, and available information provided by PBS&J. TesTech should be notified of any revisions to the scope of this project so that these revisions may be evaluated against the subsurface conditions. Should it be necessary to revise the recommendations outlined in this report, TesTech will submit a written report to address any necessary changes to the foundation and earthwork recommendations. No other warranties, expressed or implied, are made.

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- 12 -website: www.testechinc.com

8534 Yankee Street Dayton, Ohio 45458 Phone: 937-435-3200 Fax: 937-291-6549

8164 Executive Court Lansing, MI 48917

Phone: 517-622-3000 Fax: 517-622-3009

810 Morrison Road Columbus, Ohio 43230 Phone: 614-863-4537

Fax: 614-863-4547

1428 Sadlier Circle East Drive Indianapolis, IN 46239 Phone: 317-353-1622

Fax: 317-353-2054

The soils encountered in the borings varied between boring locations. Other discontinuities in soil type and geology may exist, including abrupt strata changes and soil strength variations.

The extent of these variations may not be fully determined from the borings or site reconnaissance. Additional variations may not become apparent until mass excavation commences. It is recommended that the owner retains the services of TesTech to observe the construction of foundations and verify the bearing capacity of the soils and/or bedrock encountered during foundation and pavement construction, as well as monitor the placement of fills and backfill. If not retained to perform these services, TesTech Inc. cannot be held responsible for the impact that any differing conditions may have on the performance of the project.

We appreciate the opportunity to offer these services. If you have any questions regarding this report or if we may be of further assistance to you, please contact our office at 937-435-3200.

Respectfully yours, TesTech, Inc.

Paul K. Oduroh, Ph.D., P.E. Larry J. King, P.E., P.S.

Director - Geotechnical Engineering Vice President

Attachments:

Site Location Map Boring Location Plan provided by PBS&J Logs of Test Borings Laboratory Test Results Unified Soil Classification System Diagram of a Typical Perimeter Drain Soil Report