PROJECT NO JUNE, 2016

Transcription

1 PROJECT NO JUNE, 2016 GEOTECHNICAL INVESTIGATION NORTH CREEK APARTMENTS CARL STERN DRIVE AND F.M. 685 HUTTO, TEXAS Presented To: CMC COMMERCIAL REALTY GROUP, INC. DALLAS, TEXAS

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3 TABLE OF CONTENTS PAGE INTRODUCTION... 1 Project Description... 1 Authorization... 2 Purpose and Scope... 2 FIELD AND LABORATORY INVESTIGATIONS... 2 General... 2 Field Investigation... 3 Laboratory Testing... 3 GENERAL SITE CONDITIONS... 4 Physiography... 4 Geology and Stratigraphy... 4 Ground Water... 6 Texas Health and Safety Code and TCEQ Comment... 7 Seismic Site Classification... 7 ANALYSIS AND RECOMMENDATIONS... 7 Potential Vertical Movements... 7 Foundations - General... 8 Subgrade Modification... 9 Foundation Design, Monolithic Slabs-on-Grade Flat Slabs Retaining Walls Pool Earthwork Pavement Construction Observation and Testing Frequency i -

4 TABLE OF CONTENTS (Continued) ILLUSTRATIONS PLATE PLAN OF BORINGS... 1 BORING LOGS KEYS TO TERMS AND SYMBOLS USED... 21&22 LABORATORY TEST RESULTS SPECIFICATIONS PAGE WATER INJECTION W/POLYETHYLENE SHEET AND ON-SITE SOIL CAP ii -

5 INTRODUCTION Project Description This report presents the results of a geotechnical investigation performed for the North Creek apartment complex to be located at Carl Stern Drive and F.M. 685 in Hutto, Texas. The general orientation of the apartment complex is shown on the Plan of Borings, Plate 1 of the report Illustrations. The site plan indicates that the complex will consist of 12 multi-family residential buildings and a clubhouse building. The apartment buildings are anticipated to be three-story structures, whereas, the clubhouse building will be a single-story structure. Ground-supported, monolithic slab-on-grade foundations are anticipated. Project development will also include a pool and site paving for parking and drives. Based on the updated site plan provided on June 30, 2016, there are 12 apartment buildings as opposed to the original 11 buildings. In addition, the layout has changed and there are three buildings that do not have borings within or near the footprint. It is recommended that additional borings be performed in these three buildings prior to construction. The locations of these three buildings, and the proposed additional borings, can be seen on the Plan of Borings, Plate 1 of the report Illustrations. Recommendations in this report are based on existing site grades. If cut and fill in excess of two feet is required to achieve finished floor elevations, this office should be provided with grading when it becomes available for additional analysis and recommendations. Project No June 30, 2016

6 Authorization This investigation was authorized by Mr. Steve Huff by signature of our Proposal No. 5-39G on May 25, Purpose and Scope The purpose of this investigation has been to evaluate the general subsurface conditions and provide recommendations for: design of the foundation systems; below-grade and retaining walls; pavement subgrade; and site preparation and earthwork compaction criteria. The investigation has included drilling sample borings, performing laboratory testing, analyzing engineering and geologic data and developing geotechnical recommendations. The following sections present the methodology used in this investigation. Recommendations provided herein are site-specific and were developed for the project discussed in the report Introduction. Persons using this report for other than the intended purpose do so at their own risk. FIELD AND LABORATORY INVESTIGATIONS General The field and laboratory investigations have been conducted in accordance with applicable standards and procedures set forth in the 2016 Annual Book of ASTM Standards, Volumes and 04.09, "Soil and Rock." These volumes should be consulted for information on specific test procedures. Project No June 30, 2016

7 Field Investigation Subsurface conditions were evaluated with 19 soil sample borings drilled to depths of 15 to 20 feet below existing surface grades in June The locations of the borings are shown on Plate 1 of the report Illustrations. Borings were advanced between sampling intervals by means of a truck-mounted drilling rig equipped with continuous flight augers. Samples of cohesive soils were obtained with 3-inch diameter Shelby tubes (ASTM D 1587). Cohesionless soils (sands and gravels) were sampled in conjunction with the Standard Penetration test (SPT) ASTM D Weathered limestone was evaluated in-situ using the Texas Department of Transportation (TxDOT) cone penetrometer test. Delayed water level observations were made in the open boreholes to evaluate ground water conditions. Borings were backfilled at completion of field operations. Sample depth, description of materials, field tests, water conditions and soil classification [Unified Soil Classification System (USCS), ASTM D 2488] are presented on the Boring Logs, Plates 2 through 20. Keys to terms and symbols used on the logs are included as Plates 21 and 22. Laboratory Testing All samples were returned to the laboratory and visually logged in accordance with the USCS. The consistency of cohesive soils was evaluated by means of a pocket penetrometer. Results of the pocket penetrometer readings are presented on the boring logs. Project No June 30, 2016

8 Laboratory tests were performed to evaluate index properties and confirm visual classification of selected samples. Tests and ASTM designations are provided in Table 1. TABLE 1. TESTS CONDUCTED AND ASTM DESIGNATIONS Type of Test ASTM Designation Atterberg Limits D 4318 Moisture Content D 2216 Soil Suction D 5298 The results of these tests are summarized on Plates 23 through 26. GENERAL SITE CONDITIONS Physiography The site is located southwest of Carl Stern Drive and F.M At the time of the field investigation (June 2016), the site was a relatively flat with only a few feet of elevation change. The majority of the surface of the site was an undeveloped open tract of land covered with grass, with the southern portion of the site having numerous trees and some dilapidated structures. Geology and Stratigraphy The site is located within alluvial soils overlying the Cretaceous Pecan Gap Chalk Formation. Subsurface conditions encountered in the borings consisted of alluvial soils over limestone. One boring encountered 1-1/2 feet of fill at the surface consisting of tan limestone fragments. Below the fill, and at the surface in the remaining borings, the alluvial soils consisted of dark Project No June 30, 2016

9 brown to brown to light brown, high to moderate plasticity (CH to CL) clay, sandy clay, and gravelly clay. There were varying amounts of sand and gravel encountered in the alluvial soils. The soils were stiff to hard at the time of the investigation. Tan, hard to very hard (rock classification), weathered limestone was present in all 19 borings at depths of 8 to 17 feet. Some borings had some gray seams within the tan, weathered limestone. All 19 borings were terminated within the tan, weathered limestone. The moisture contents within the upper 10 to 15 feet of the subsurface soils varied across the site. Generally, where there were no trees, the soils were relatively moist throughout the depths explored. The suction profiles for six selected borings (three in the trees and three in the grassed areas) are provided in the following graph. Project No June 30, 2016

10 Ground Water Ground water seepage was encountered at depths of 6 to 14 feet in 18 of the 19 borings during drilling. During post-drilling water level observations made one day subsequent to completion of drilling, ground water was encountered in all 19 borings at depths of 4-1/2 to 9-1/2 feet. The depth to, and amount of ground water, will fluctuate with variations in seasonal and yearly rainfall. Project No June 30, 2016

11 Texas Health and Safety Code and TCEQ Comment Pursuant to the Texas Health and Safety Code, Chapter 361, and 30 Texas Administrative Code 330, , Reed Engineering Group, Ltd. has performed appropriate soil tests as required by these regulations to demonstrate that the subject property does not overlie a closed municipal solid waste landfill. The site observations and subsurface data do not indicate the presence of buried municipal solid waste at this site. Based on these data, development of this site will not require a Development Permit, as described in and , Subchapter T. Seismic Site Classification The site has been classified with respect to seismic design criteria contained in the 2012 International Building Code (IBC), Section 1613, and ASCE/SEI 7, Chapter 20. The criteria require characterization of the upper 100 feet of subsurface materials. Based on the ASCE/SEI 7-10 criteria, the site is classified as Site Class C in accordance with Table ANALYSIS AND RECOMMENDATIONS Potential Vertical Movements Potential Vertical Movements (PVM) were evaluated using an empirical procedure developed by McDowell 1 and modified by the Texas Department of Transportation, TxDOT Test Method 124-E 2 in conjunction with the soil suction tests. Based on the PVM calculations and past experience, potential movements are estimated to be on the order of three to four inches, dependent upon location. Movements will be associated with seasonal changes in soil moisture. 1 McDowell, C. "The Relation of Laboratory Testing to Design for Pavements and Structures on Expansive Soils." Quarterly of the Colorado School of Mines, Volume 54, No. 4, "Method for Determining the Potential Vertical Rise, PVR." (1978). Texas Department of Transportation, Test Method Tex-124-E. Project No June 30, 2016

12 Ground-supported improvements (i.e., sidewalks and paving) will move in response to changes in soil moisture. The movement will be observed as heave if the soils are dry at the time the pavement or sidewalk is constructed. The movement will be observed as settlement if the soils are moist at the time of construction. Generally, settlement will be limited to the outer perimeter (outer four to five feet) of larger slabs. Prudent watering during extended dry climatic periods can control settlement. Some movement of site paving and sidewalks should be anticipated. The estimated PVM is based on existing site grades. If cut and fill in excess of two feet is required to achieve finished floor elevations, this office should be provided with grading when it becomes available for additional analysis and recommendations. Foundations General Potential movements associated with heave from a dry condition to a moist condition are estimated to be on the order of three to four inches, dependent upon location. Additional movement is possible if the clays become saturated, such as can happen from utility leaks and excessive ponding adjacent to the foundations. It is recommended that the magnitude of potential movement be reduced as outlined in the Subgrade Modification section below prior to construction of slab-on-grade foundations. The estimated movements, as well as the recommendations in the following sections, are based on the existing grades. It is recommended that the following recommendations be reviewed by this office when grading plans become available. Project No June 30, 2016

13 Subgrade Modification It is recommended that the magnitude of potential movement be reduced prior to construction of slab-on-grade foundations. Reducing the potential for movement prior to construction of the foundation can be accomplished by either: mechanically excavating the upper expansive soils, mixing the soils with water, then recompacting the excavated soils at an elevated moisture in controlled lifts (mechanical preswelling); or preswelling via multiple passes of water pressure injection. Both options are presented in the following sections. At completion of either the injection or excavation and recompaction process, a surface moisture barrier may be required to maintain the desired moisture within the modified soil. The need for a moisture barrier cap will depend upon the construction schedule. If construction of the foundations can be coordinated to occur within three weeks following completion of injection or excavation and recompaction operations, then construction of the moisture barrier cap will not be necessary. However, if the construction of foundations cannot occur within approximately three weeks following completion of injection or excavation and recompaction operations, the building pads should be capped with a moisture barrier to prevent the modified subgrade from excessive drying. The moisture barrier cap may consist of a six-mil polyethylene sheet covered with at least six inches of on-site soils to hold it in-place. The moisture barrier cap should be placed within seven working days following completion of injection or excavation and recompaction operations. Specific recommendations for pre-swelling are presented in the following paragraphs. Project No June 30, 2016

14 Pressure Injection Option - This option consists of performing cut and fill balance followed by injection, then providing a surface seal. The performance of an injected subgrade is dependent upon the quality of the workmanship. Therefore, water pressure injection is not recommended unless a representative of this office is present full-time to observe all injection operations. Procedures consist of the following. 1. Strip vegetation and dispose of the organic cuttings in accordance with project specifications. 2. Cut and fill balance with on-site soils to required finished subgrade elevation. Place and compact soils in accordance with recommendations in the Earthwork section. 3. Preswell the upper clays via pressure injection with water to a depth of seven feet below respective finished subgrade elevations. Extend the injection footprint a minimum of five feet beyond general building lines. Guideline specifications for performance of the injection process are included in the report Specifications. 4. If foundation construction will not commence within approximately three weeks of completion of injection operations, place and compact the surface moisture barrier, consisting of six-mil polyethylene covered with a minimum of six inches of on-site or similar soil. The actual number of injection passes required will be dependent upon the soil moisture conditions at the time of construction. For estimating purposes, a minimum of three injection passes should be anticipated. The injection footprint should be extended a minimum of five feet beyond the general building lines. Potential movements considering properly preswelled subgrade as described above are estimated to be approximately one inch. Project No June 30, 2016

15 Excavation and Recompaction Option - An alternative method of pre-wetting the upper soils to reduce the potential for post-construction swell consists of excavation of the upper soil, mechanically mixing the soil with water, then recompaction of the excavated soil in controlled lifts. This method of pre-wetting the soils is not effective unless the water is uniformly blended with the soil. Simply wetting the surface of the soil will not achieve the required result. General procedures are as follows. 1. Strip vegetation and dispose of the organic materials in accordance with the project specifications. 2. Excavate to a depth of six feet below existing grade or finished floor, whichever is greater. Extend the footprint of the excavated area a minimum of five feet beyond the general building lines. 3. Scarify the exposed subgrade to a depth of six inches, water as necessary and recompact to the density and moisture recommended in the Earthwork section. 4. Compact site-excavated soils in lifts as outlined in the Earthwork section to the subgrade required for the desired moisture cap. Place and compact soils in accordance with recommendations in the Earthwork section. Note: If insufficient on-site fill exists to achieve the proposed subgrade, all imported fill for use below the building should consist of "select" fill or approved common fill. Balance on-site soils to provide a uniform thickness of the imported fill. 5. If foundation construction will not commence within approximately three weeks of completion of excavation and recompaction operations, place and compact the surface moisture barrier, consisting of six-mil polyethylene covered with a minimum of six inches of on-site or similar soil. Consideration should be given to benching the perimeter of the excavation, from the bottom up, at one horizontal to one vertical (1H:1V) to create a transition zone between reworked soils and non-reworked soils. This will decrease the potential for concentrated differential movement between treated and untreated areas. Project No June 30, 2016

16 Other Considerations - Careful consideration should be given to the actual area treated to reduce movement. The potential for post-construction heave will be reduced in the treated areas; however, areas left untreated will result in differential movement. In general, it is recommended the treated area extend a minimum of five feet beyond the general building lines to reduce the potential for differential movement between the buildings, the sidewalk and entrance pavement or in areas where site paving is relatively flat because of drainage or ADA considerations. The moisture barrier caps should be placed within approximately seven working days following completion of the water injection or excavation and recompaction operations to limit moisture loss within the preswelled soils. Positive drainage of water away from the structures must be provided and maintained after construction. Foundation Design, Monolithic Slabs-on-Grade The foundations may be designed as conventionally reinforced or post-tensioned slabs-ongrade. The foundations should be designed to resist differential "center" and "edge" lift movements. Design parameters based on 3 rd Edition of the Post-Tensioned Institute (PTI) design procedure are provided. The recommended design values in Table 2 are applicable considering properly preswelled subgrade to corresponding depths as described in the preceding Subgrade Modification section. Project No June 30, 2016

17 TABLE 2. PTI DESIGN STIFFNESS VALUES (PTI 3 RD EDITION) APPLICABLE CONSIDERING SUBGRADE MODIFICATION SECTION Movement Mode Edge Moisture Variation Distance (e m ) (feet) Differential Soil Movement (y m ) (inches) Center Lift Edge Lift All designs should conform to the deflection tolerances contained in Table 6.2 of the PTI Manual. The recommended criteria (L/C ) in Table 6.2 are reproduced below. Material Center Lift, C Edge Lift, C Wood Frame Stucco or Plaster Brick Veneer Concrete Masonry Units Prefab Roof Trusses* * Trusses that clearspan the full length or width of the foundation from edge to edge. Project No June 30, 2016

18 The optimum performance of any ground-supported structure constructed on an expansive soil requires that: the foundation be provided with a reasonable degree of stiffness to resist future differential ground movements; proper grading and construction details are used to minimize future differential foundation movement and the resulting distress; and the owner is aware of proper landscaping and maintenance procedures. The minimum design values above are based on the context that all additional fill placed in the pad consists of on-site soils or select fill, and that it is placed in accordance with the Earthwork section of this report. This should be confirmed by field density testing as outlined in the Earthwork and Construction Observation sections. Grade beams should be designed for a maximum bearing pressure of 2.5 kips per square foot (ksf) and should be founded a minimum depth of 6 inches into undisturbed natural soils or compacted and tested fill. All beams, including reinforcing, should be continuous, should not vary in cross-section and should be provided with sufficient steel reinforcement for positive and negative moment resistance. It may be possible to allow slightly greater deflection for center lift design if vertical control joints are provided at key locations along exterior masonry walls to allow for differential wall movement. The structural engineer should work with the builder to determine deflection tolerances, joint spacing and various methods available for providing vertical control joints in the exterior walls. Brick arches spanning above two separate perimeter beams should be avoided if possible. Project No June 30, 2016

19 Elements of the foundations that form cantilevers (such as bay windows or other protrusions) are vulnerable to differential movement relative to the larger areas of the foundation. As a result, these areas are vulnerable to structural damage. The structural engineer should account for the increased potential for both positive and negative bending moments at these points when performing the design. A minimum 10-mil thick polyethylene sheet is recommended below the foundations to limit migration of moisture through the slabs from the underlying clays. This is of particular importance below sections of the foundations covered with carpeting, paint or tile. Penetrations and lapped joints should be sealed with a waterproof tape. Because of anticipated damage during construction, polyethylene sheets used for capping the preswelled pads should not be reused as a moisture barrier below the foundations. The ground surface should be sloped to provide positive and rapid drainage of surface water away from the structures. Positive drainage away from the structures should be maintained throughout the life of the project. If bedding soils are required adjacent to the buildings, the fill/bedding soil interface should be sloped to drain away from the foundations. Flat Slabs Perimeter slabs and other ground-supported features will move as the underlying soils undergo initial heave. The slabs should be free to move upwards without stressing the foundation systems. Maintenance of positive drainage of surface water away from flat slabs will reduce the probability of the site undergoing the full potential heave. Project No June 30, 2016

20 Retaining Walls Lateral earth pressures against retaining walls will be a function of the backfill within the "active zone" of earth pressure. The "active zone" can be estimated as an included angle of 38 from the vertical, extended upward from the base of the wall. Considering backfill using site-excavated materials, lateral earth pressures can be estimated based on an equivalent fluid pressure of 60 pounds per cubic foot (pcf) for active conditions, or 80 pcf for at-rest conditions. Rotation, or lateral movement on the top of the wall, equal to 0.02 times the height of the wall will be necessary for on-site soil backfill for the active condition. Alternatively, imported "select" fill may be used as backfill in the active zone. Considering "select" fill, lateral earth pressures can be estimated based on an equivalent fluid pressure of 35 pcf, active conditions, or 50 pcf at-rest conditions. Lateral movement of the top of the wall equal to times the height of the wall will be necessary for the "active" pressure condition for "select" fill backfill. The lateral earth pressures are applicable for horizontal surface grades and non-surcharged, drained conditions. A drainage system should be installed behind the base of the retaining walls to limit development of excess hydrostatic pressures. The drainage system should consist, as a minimum, of 12-inch by 12-inch pocket drains spaced 15 feet on-center, installed near the base of the wall. Project No June 30, 2016

21 Fill in the pocket drains should consist of durable crushed stone such as ASTM C 33, Size 67 or coarser, wrapped in filter fabric (Mirafi 140N or equivalent). Backfill around the gravel drain should consist of site-excavated soils or "select fill. A compacted clay cap is recommended within the upper two feet of the surface to limit surface-water infiltration behind the walls. Retaining walls may be founded on spread or continuous footings placed a minimum of 18 inches into undisturbed, on-site soils or compacted and tested fill. Footings should be proportioned for a maximum bearing pressure of 3,000 pounds per square foot (psf). Movement of the footings and walls should be anticipated. Flexible walls are recommended. Solid concrete walls should be battered into the soil to limit outward rotational movement caused by differential footing movement. Passive resistance to lateral movement can be estimated based on an equivalent fluid pressure of 450 pcf for on-site materials. This value is applicable for footings founded on undisturbed, on-site soils or compacted and tested fill. In addition to passive resistance, a coefficient of friction between the base of the footing and the underlying soil equal to 0.35 may be used. The lateral earth pressure values do not incorporate specific factors of safety. If applicable, factors of safety should be integrated into the structural design of the wall. Project No June 30, 2016

22 Earth slopes greater than eight feet in height should be evaluated for global stability. This also applies to slopes combined with retaining walls that have a combined height in excess of eight feet. Global stability analysis was not within the scope of the present investigation. This office can assist in the analysis if desired. All constructed slopes should be vegetated as soon as possible. Use of erosion control fabric is recommended during vegetation of the slopes. The recommendations above are applicable for retaining walls that are not subject to inundation by water. Modification of the recommendations may be necessary for wet applications (such as detention ponds, water features and along creek beds). This office should be provided with grading plans and wall layouts to review for any necessary modifications to the recommendations for wet applications. Pool It is recommended the subgrade soils within the pool area, including the pool deck, be modified as per the Subgrade Modification section to reduce the potential movements. Depth of modification below the pool should be measured from the finished pool deck. Lateral earth pressures against pool walls will be a function of the backfill within the "active zone" of earth pressure. The "active zone" can be estimated as an included angle of 38 from the vertical, extended upward from the base of the wall. Project No June 30, 2016

23 Considering backfill using site-excavated materials, lateral earth pressures can be estimated based on an equivalent fluid pressure of 60 pcf for active conditions, or 80 pcf for at-rest conditions. Alternatively, imported "select" fill may be used as backfill in the active zone. Considering "select" fill, lateral earth pressures can be estimated based on an equivalent fluid pressure of 35 pcf, active conditions, or 50 pcf at-rest conditions. The lateral earth pressures are applicable for horizontal surface grades and non-surcharged, drained conditions. The lateral earth pressure values do not incorporate specific factors of safety. If applicable, factors of safety should be integrated into the structural design of the wall. Earthwork All vegetation, construction debris, and topsoil containing organic material should be cleared and grubbed at the beginning of earthwork construction. Soils exposed at the surface, which will underlie fill, should be scarified to a depth of 6 inches and recompacted to a dry density of between 92 and 98 percent of the maximum density as determined by ASTM D 698 "Standard Proctor." The moisture content should range from +1 to +5 percentage points above optimum. General fill utilizing site-excavated soils should be placed in maximum eight-inch loose lifts (loose measurement) and compacted to the moisture and density requirements outlined above. The final 6 inches of subgrade below pavement should be compacted to a minimum of 95 percent of Standard Proctor, at or above optimum moisture. Project No June 30, 2016

24 Tree stumps existing within the building pads should be excavated to a minimum depth of five feet and removed from the site. Roots larger than two inches in diameter should be excavated and removed from the site. The excavated areas should be backfilled with on-site soils compacted in accordance with the recommendations outlined above. Proper backfilling around the foundations will reduce the potential for water seepage beneath the structures. Fill against the outside of perimeter grade beams should consist of siteexcavated clays or approved equal soils. The fill should be placed and compacted in accordance with the recommendations outlined above for general fill. "Select" fill is defined as uniformly blended clayey sand with a Plasticity Index (PI) of between 4 and 15. Select fill should be placed in maximum 8-inch loose lifts and compacted to at least 95 percent of the Standard Proctor density, at a moisture content between -2 to +3 percentage points of optimum moisture. Pavement Concrete pavement is anticipated for both car and light truck parking and for drives and service areas. In general, stabilization of the subgrade is not cost-effective when using rigid pavement and does not significantly increase the load-carrying capacity of the pavement. However, stabilization does provide a construction or working pad and may be advantageous from this perspective, especially if construction occurs during the wetter portions of the year. Stabilization is recommended if traffic speeds will exceed 30 miles per hour (mph). Project No June 30, 2016

25 The specific pavement sections will be dependent upon the type and frequency of traffic. For drives and parking subject to cars and light trucks, a 5-inch thick, 3,000 pounds per square inch (psi) compressive strength pavement section constructed over a subgrade which has been scarified and recompacted as outlined in the Earthwork section, should provide for unlimited repetitions over a 20-year life. For drives and service areas subject to the equivalent of 5 or less loaded semi-trucks per day and within fire lanes, a minimum 6-inch thick, 3,000-psi compressive strength pavement section is recommended. The pavement should be constructed over a subgrade that has been scarified and recompacted as outlined in the Earthwork section. Pavements should be lightly reinforced to control shrinkage cracks. Reinforcing should consist of the approximate equivalent of #3 bars (metric #10) at 18 inches on-center. The specific amount of steel should be determined based on spacing of expansion, construction and contraction (saw) joints. Pavement sections should be saw-cut at an approximate spacing in feet of 2.5 to 3 times the pavement thickness expressed in inches, not to exceed a maximum spacing of 20 feet. (For example, a 5-inch pavement should be saw-cut in approximate to 15-foot squares.) The actual joint pattern should be carefully designed to avoid irregular shapes. Recommended jointing techniques are discussed in detail in "Guide for Design and Construction of Concrete Parking Lots," published by the American Concrete Institute 3. 3 "Guide for Design and Construction of Concrete Parking Lots" (1987). American Concrete Institute, Publication MSP 34, Silver Spring, MD. Project No June 30, 2016

26 The above sections are based on the stated analysis and traffic conditions. If traffic conditions will exceed those stated, this office should be contacted for additional analysis and recommendations. Additional thickness or subgrade stabilization may be required to meet the City of Hutto development code. Construction Observation and Testing Frequency It is recommended the following items (as a minimum) be observed and tested by a representative of this office during construction. Observation: Fill placement and compaction. Pressure-injection operations. Foundation construction and concrete placement. Testing: Earthwork One test per 5,000 square feet per lift within fills below the buildings. One test per 10,000 square feet per lift within fills in the paving area. One test per 150 linear feet per lift in utility and grade beam backfill. Post-injection borings, one boring per 10,000 square feet of injected area, or a minimum of two per building pad, whichever is greater. The purpose of the recommended observation and testing is to confirm the proper foundation bearing stratum and the earthwork and building pad construction procedures. Project No June 30, 2016

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28 Depth (ft) Project Number : Date Completed : 6/14/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, brown, very stiff, w/trace of calcareous concretions (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff, w/some calcareous concretions, trace of ironstone seams & fine sand (CL) CLAY, light brown, very stiff to hard, w/trace of fine sand, calcareous concretions & iron-stained seams (CL) Water level on 6/15/ Seepage during drilling 15 LIMESTONE, tan, hard to very hard, weathered 100 Blows = 1 inch Blows = 1-1/2 inches Total Depth = 20 feet Seepage 14' during drilling. 9' after 5 minutes. 8' & end of day. 8' & 11' on 6/15/2016. BORING LOG B-01 PLATE 2 GEOTECHNICAL CONSULTANTS -

29 Depth (ft) Project Number : Date Completed : 6/14/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, stiff to very, w/trace of calcareous nodules (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft w/some gravel 5 CLAY, brown & light brown, very stiff, w/some calcareous concretions & iron-stained seams (CH) Water level on 6/15/2016 LIMESTONE, tan, hard to very hard, w/some silty clay seams, weathered Seepage during drilling Blows = 1/2 inch Blows = 1/2 inch Total Depth = 15 feet Seepage 8' during drilling. 7-1/2' after 10 minutes. 5-1/2' & end of day. 6' & 11' on 6/15/ BORING LOG B-02 PLATE 3 GEOTECHNICAL CONSULTANTS -

30 Depth (ft) Project Number : Date Completed : 6/14/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, very stiff to stiff, w/trace of calcareous concretions (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff, w/gravel & some medium sand (CL) Water level on 6/15/2016 Seepage during drilling 10 -w/large gravel from 11' to 12.5' LIMESTONE, tan, hard to very hard, weathered Blows = 1/2 inch 20 Total Depth = 20 feet Seepage 9' during drilling. 9' after 10 minutes. 8' & end of day. 8' & 11' on 6/15/2016. BORING LOG B-03 PLATE 4 GEOTECHNICAL CONSULTANTS -

31 Depth (ft) Project Number : Date Completed : 6/14/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, stiff to very stiff, w/trace of calcareous concretions (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff to hard, w/some fine sand & trace of calcareous concretions (CH) Water level on 6/15/ LIMESTONE, tan, hard to very hard, weathered 100 Blows = 1/2 inch 15 LIMESTONE, tan & gray, very hard, weathered 100 Blows = 1/2 inch Total Depth = 16 feet Dry after 5 minutes. 12-1/2' & end of day. 5' & 9' on 6/15/ BORING LOG B-04 PLATE 5 GEOTECHNICAL CONSULTANTS -

32 Depth (ft) Project Number : Date Completed : 6/14/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, very stiff, w/trace of calcareous concretions (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff, w/trace of medium sand & calcareous concretions (CH - CL) Water level on 6/15/ LIMESTONE, tan, moderately hard to very hard, weathered Seepage during drilling 100 Blows = 1 inch Blows = 1/2 inch Total Depth = 16 feet Seepage 11' during drilling. 14' after 3 minutes. 7-1/2' & end of day. 8' & 10' on 6/15/ BORING LOG B-05 PLATE 6 GEOTECHNICAL CONSULTANTS -

33 Depth (ft) Project Number : Date Completed : 6/14/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, stiff to very stiff, w/trace of calcareous concretions (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff, w/trace of gravel & calcareous concretions (CL) Water level on 6/16/2016 CLAY, light brown & reddish--brown, w/gravel, medium sand & trace of iron-stained seams (CL - GC) 10 Seepage during drilling 15 LIMESTONE, tan & gray, hard to very hard, weathered Blows = 1 inch Total Depth = 20 feet Seepage 12' during drilling. 9' after 3 minutes. 9' & end of day. 7-1/2' & 11' on 6/15/2016. BORING LOG B-06 PLATE 7 GEOTECHNICAL CONSULTANTS -

34 Depth (ft) Project Number : Date Completed : 6/15/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, stiff, very stiff, w/trace of calcareous concretions & gravel (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff, w/trace of calcareous nodules, gravel & iron-stained seams (CH) CLAY, light brown, very stiff, w/fine sand, trace of nodules & iron-stained seams (CH - CL) Water level on 6/16/ GRAVELLY CLAY, light brown (GC) Seepage during drilling LIMESTONE, tan, hard to very hard, weathered 50 Blows = 3 inches Blows = 1/2 inch Total Depth = 20 feet Seepage 11' during drilling. 8-1/2' after 3 minutes. 7-1/2' & end of day. 8-1/2' & 12' on 6/16/2016. BORING LOG B-07 PLATE 8 GEOTECHNICAL CONSULTANTS -

35 Depth (ft) Project Number : Date Completed : 6/15/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, stiff to very stiff, w/trace of calcareous nodules & gravel (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff, w/some gravel, medium sand, trace of calcareous nodules & iron-stained seams (CH - CL) 5 GRAVELLY CLAY, light brown, hard, w/iron-stained seams (GC) Water level on 6/16/2016 Seepage during drilling 10 LIMESTONE, tan, hard to very hard, weathered 100 Blows = 1/2 inch Blows = 1 inch Total Depth = 17 feet 20 Seepage 9' during drilling. 11' after 5 minutes. 8' & end of day. 8' & 10' on 6/16/2016. BORING LOG B-08 PLATE 9 GEOTECHNICAL CONSULTANTS -

36 Depth (ft) Project Number : Date Completed : 6/15/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, very stiff, w/trace of medium sand, gravel & calcareous nodules (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, hard, w/trace of fine sand, calcareous nodules & gravel (CL) 5 Water level on 6/16/2016 Seepage during drilling 10 SANDY CLAY, w/some gravel (GC) 50 Blows = 3 inches 15 LIMESTONE, tan, hard to very hard, weathered 20 LIMESTONE, tan & gray, very hard, weathered 100 Blows = 1 inch Total Depth = 20 feet Seepage 9' during drilling. 9' after 3 minutes. 8' & end of day. 7-1/2' & 13-1/2' on 6/16/2016. BORING LOG B-09 PLATE 10 GEOTECHNICAL CONSULTANTS -

37 Depth (ft) Project Number : Date Completed : 6/15/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, stiff to very stiff, w/trace of calcareous nodules (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff, w/calcareous concretions & trace of fine sand (CH - CL) Water level on 6/16/2016 CLAY, light brown & brown, hard, w/some gravel & trace of fine sand (CH - CL) 10 Seepage during drilling LIMESTONE, tan, hard to very hard, weathered Blows = 1/2 inch 100 Blows = 1/2 inch Total Depth = 18 feet 20 Seepage 10' during drilling. 14-1/2' after 3 minutes. 7' & end of day. 7-1/2' & 13' on 6/16/2016. BORING LOG B-10 PLATE 11 GEOTECHNICAL CONSULTANTS -

38 Depth (ft) Project Number : Date Completed : 6/15/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, very stiff, w/trace of calcareous concretions & gravel (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff, w/trace of fine sand, calcareous concretions & gravel (CH - CL) -w/gravel below 7' Seepage during drilling Water level on 6/16/ LIMESTONE, tan, hard to very hard, weathered Blows = 1/2 inch 100 Blows = 1 inch Total Depth = 18 feet 20 Seepage 7' during drilling. 9' after 3 minutes. 8-1/2' & end of day. 8-1/2' & 13' on 6/16/2016. BORING LOG B-11 PLATE 12 GEOTECHNICAL CONSULTANTS -

39 Depth (ft) Project Number : Date Completed : 6/16/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, very stiff, w/trace of calcareous nodules, iron-stained seams & gravel (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, brown, very stiff, w/trace of calcareous nodules (CH) CLAY, light brown, stiff, w/trace of fine sand & calcareous nodules (CH) Seepage during drilling Water level on 6/16/ LIMESTONE, tan, hard to very hard, w/silty clay, weathered 15 LIMESTONE, tan, hard to very hard, weathered Blows = 1 inch Total Depth = 20 feet Seepage 9' during drilling. 9-1/2' after 3 minutes. 9-1/2' & end of day. 9-1/2' & 13' on 6/16/2016. BORING LOG B-12 PLATE 13 GEOTECHNICAL CONSULTANTS -

40 Depth (ft) Project Number : Date Completed : 6/16/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, very stiff, w/trace of calcareous nodules & gravel (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft w/gravel below 4.2' GRAVELLY CLAY, light brown, w/some medium sand & trace of calcareous nodules (GC) Water level on 6/16/2016 GRAVELLY CLAY, light gray & yellowish-brown, w/some medium sand & trace of calcareous nodules (GC) Seepage during drilling 10 LIMESTONE, tan, hard to very hard, weathered 100 Blows = 1 inch Blows = 1/2 inch Total Depth = 17 feet 20 Seepage 9' during drilling. 7' after 3 minutes. 7' & end of day. 6' & 12' on 6/16/2016. BORING LOG B-13 PLATE 14 GEOTECHNICAL CONSULTANTS -

41 Depth (ft) Project Number : Date Completed : 6/15/2016 Sample rec % (rqd %) Graphic Log LIMESTONE FRAGMENTS, tan (GP) North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, dark brown, hard, w/trace of calcareous nodules, fine sand, iron-stained seams & gravel (CH) 5 CLAY, light brown, hard, w/trace of fine sand & calcareous nodules (CH) Water level on 6/16/ Seepage during drilling LIMESTONE, tan, hard to very hard, weathered LIMESTONE, tan & gray, very hard, weathered 100 Blows = 1/2 inch Total Depth = 20 feet Seepage 12' during drilling. 10' after 3 minutes. 10' & end of day. 9' & 13' on 6/16/2016. BORING LOG B-14 PLATE 15 GEOTECHNICAL CONSULTANTS -

42 Depth (ft) Project Number : Date Completed : 6/15/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown & light brown, very stiff to hard, w/trace of calcareous concretions & gravel (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff, w/some silt & trace of calcareous concretions (CL) Water level on 6/16/2016 Seepage during drilling 10 LIMESTONE, tan & gray, very hard, weathered 100 Blows = 1/2 inch Blows = 1/2 inch Total Depth = 17 feet 20 Seepage 9' during drilling. 8' after 3 minutes. 6' & end of day. 8' & 11-1/2' on 6/16/2016. BORING LOG B-15 PLATE 16 GEOTECHNICAL CONSULTANTS -

43 Depth (ft) Project Number : Date Completed : 6/15/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, very stiff, w/trace of fine sand, gravel & calcareous nodules (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, stiff to very stiff, w/trace of calcareous concretions, medium sand, gravel & iron-stained seams (CH - CL) Seepage during drilling Water level on 6/16/ w/gravel LIMESTONE, tan & gray, very hard, weathered 50 Blows = 3 inches Blows = 1/2 inch Total Depth = 18 feet 20 Seepage 7' during drilling. 9' after 3 minutes. 9' & end of day. 9-1/2' & 13' on 6/16/2016. BORING LOG B-16 PLATE 17 GEOTECHNICAL CONSULTANTS -

44 Depth (ft) Project Number : Date Completed : 6/16/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, very stiff, w/trace of calcareous nodules (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, stiff, hard, w/trace of some calcareous nodules, medium sand & gravel (CH) Water level on 6/16/2016 Seepage during drilling 50 Blows = 4 inches 10 LIMESTONE, tan, hard to very hard, weathered Blows = 1/2 inch Total Depth = 15 feet Seepage 6' during drilling. 4-1/2' after 3 minutes. 4-1/2' & end of day. 4-1/2' & 8' on 6/16/ BORING LOG B-17 PLATE 18 GEOTECHNICAL CONSULTANTS -

45 Depth (ft) Project Number : Date Completed : 6/15/2016 Sample rec % (rqd %) Graphic Log North Creek PApartments Carl Stern Drive locand F.M. 685 Hutto, loc2 Texas DESCRIPTION OF STRATA CLAY, dark brown, very stiff, w/trace of calcareous concretions (CH) REED ENGINEERING GROUP Location: See Plate 1 Standard Penetration Tests Blows per Foot Elev. Pocket Penetrometer Readings (ft) Tons Per Sq. Ft CLAY, light brown, very stiff to hard, w/some gravel & trace of calcareous concretions (CL) Water level on 6/16/2016 CLAY, light brown, hard, w/some fine sand & trace of gravel (CH) Seepage during drilling 10 LIMESTONE, tan, hard to very hard, weathered 100 Blows = 2 inches Blows = 1 inch Total Depth = 17 feet 20 Seepage 9' during drilling. 8' after 3 minutes. 8' & end of day. 8' & 10-1/2' on 6/16/2016. BORING LOG B-18 PLATE 19 GEOTECHNICAL CONSULTANTS -