Report of Geotechnical Exploration PROPOSED SANITARY SEWER AND FORCE MAIN REPLACEMENT

Transcription

1 Report of Geotechnical Exploration PROPOSED SANITARY SEWER AND FORCE MAIN REPLACEMENT Collier County Project Number Vanderbilt Drive and Finger Streets From Vanderbilt Beach Road to 111th Avenue Collier County, Florida Forge Engineering Project Number May 2015

2 May 19, 2015 COLLIER COUNTY UTILITIES PLANNING AND PROJECT MANAGEMENT Ms. Corrine Trtan 3339 Tamiami Trail East, Suite 303 Naples, Florida Office: (239) Subject: Report of Geotechnical Exploration PROPOSED SANITARY SEWER AND FORCE MAIN REPLACEMENT Collier County Project Number Vanderbilt Drive and Finger Streets From Vanderbilt Beach Road to 111 th Avenue Collier County, Florida Forge Engineering Project Number Forge Engineering Inc. (FORGE) is pleased to present this report of our geotechnical exploration completed for the proposed sanitary sewer and force main replacement cited above. We have completed in general the services outlined in our re-revised proposal PRR dated December 11, 2014, and authorized by your Notice-to-Proceed dated January 6, This report presents the project information provided to us, the results of our field and laboratory testing, together with our evaluation regarding the impact of the encountered materials on the proposed construction. Purpose The purpose of this geotechnical exploration was to explore the general soil conditions along the proposed sanitary sewer and force main replacement alignment and to provide an evaluation of the existing soil conditions and their potential impact on the proposed construction. Environmental assessments or other studies were beyond the scope of our services.

3 Report of Geotechnical Exploration FORGE Project No Collier County Project No , Vanderbilt and Finger Streets May 19, 2015 This report has been prepared for the exclusive use of Collier County Utilities Planning and Project Management and their consultants for specific application to the proposed improvements specified in this report. FORGE has endeavored to comply with generally accepted geotechnical engineering practice common to the local area. FORGE makes no other warrant, express, or implied. Project Information Our understanding of your needs for this project is based on information provided by you, CDM-Smith, and our prior experience on similar projects. We understand this phase of the project consists of replacing aging sanitary sewers and force mains along Vanderbilt Drive between Vanderbilt Beach Road and Bluebill Avenue/Immokalee Road along with 14 perpendicular streets (Finger Streets). The scope of requested services was compiled by your consultant CDM-Smith. The request identifies number, depth, and general locations of the requested borings, roadway cores, along with specific soil data to be included in this report. Figure 1 in the Appendix depicts the location of subject area. Site Conditions The proposed pipeline improvements that are the subject of this report can generally be divided into two distinct areas, Vanderbilt Drive (borings 1 through 19), and all the Finger Streets (borings 20 through 39). The Vanderbilt Drive section of the project can be described as a narrow rural-style two-lane undivided roadway with minimal shoulder width, a west side concrete sidewalk, and varying drainage swales. The Finger Streets section of the subject project has marginal shoulders and grassed swales on both sides of the road. There are no sidewalks along the Finger Streets portion of the project. Field Explorations The subsurface soil and groundwater conditions along the proposed pipeline alignments were explored with 39 Standard Penetration Test (SPT) borings. The SPT borings were extended to depths of 20-to 25-feet below the existing ground surface spaced at approximately 500-foot intervals along Vanderbilt Drive. The SPT borings were conducted in the northbound lanes along Vanderbilt Drive and were alternated along the Finger Streets between the westbound and eastbound sides. Page 2 of 8

4 Report of Geotechnical Exploration FORGE Project No Collier County Project No , Vanderbilt and Finger Streets May 19, 2015 FORGE also completed fourteen (14) asphalt pavement cores utilizing a 4-inch diameter bit to core the pavement. The cores were returned to our laboratory and measured for thickness. Seven of the cores were taken evenly spaced along Vanderbilt Drive. The remaining seven (7) cores were completed near the center of every other Finger Street. All borings and asphalt cores along Vanderbilt Drive where offset approximately 8 to 10 feet from the centerline of the roadway. The borings and asphalt cores along the Finger Streets where offset approximately 8 feet from the centerline of the roadway. Sheet 1 in the Appendix provides a generalized location for each of the soil borings and pavement cores. It should be noted that a strong odor of fuel (kerosene/diesel) was detected in boring B-4 in the 2 to 4 foot depth range and in boring B-5 from the surface to about 20 feet below the ground surface. No testing was completed on samples from these borings. Laboratory Testing To aid in identification and classification, laboratory testing was conducted on representative soil samples retained from the borings. Specifically, in house testing consisted of visual classification, grain size analyses, -200 sieve, moisture content, Atterberg limits, and organic content tests. Outside laboratory testing services, consisting of corrosion series testing (ph, resistivity, chloride, and sulfate) were also completed. The table below provides a summary of the laboratory test results. LABORATORY TEST RESULTS Stratum Number Moisture Content (%) Fine Content (%) Organic Content (%) Atterberg Limits ph Resistivity (ohms-cm) Chloride Content (ppm) Sulfate Content (ppm) NP NP < NP N/A N/A N/A N/A NP N/A N/A N/A N/A Page 3 of 8

5 Report of Geotechnical Exploration FORGE Project No Collier County Project No , Vanderbilt and Finger Streets May 19, 2015 Results Summary Underlying the asphaltic pavement section, the borings generally encountered various combinations of granular soils (Stratum 1 and 2) to the termination depth. In roughly half the boring locations, a highly weathered LIMESTONE (Stratum 3, a sand, silt, and gravel matrix) was encountered at depths ranging from 15 to 20 feet below the ground surface and extending to the termination of the borings. One boring, B-26 (along a Finger Street) encountered an Organic SAND to PEAT material extending from near surface to about 12 feet below the ground surface. The results from the corrosion series testing indicate that the site soils are classified as Moderate to Extremely Aggressive for concrete. Below we have tabulated a summary of the strata encountered along the proposed alignments. Sheet 2 in the Appendix provides specific soil data for each of the borings completed. SOIL DESCRIPTIONS Stratum Number Soil Description USC (1) 1 Tan to brown SAND, occasional Shell SP 2 Dark brown SAND, occasional Roots SP 3 Gray weathered to highly weathered LIMESTONE NA 4 Black Organic Silty SAND PT (1) UNIFIED SOIL CLASSIFICATION The groundwater level recorded at the time of drilling ranged from 4 to 6 feet below the existing grades. It should be anticipated the groundwater level would fluctuate due to seasonal rainfall variations, surface water runoff patterns, tidal fluctuation in the nearby Vanderbilt Channel, construction operations, and other interrelated factors. We estimate the seasonal high groundwater level to be approximately 2 feet below the existing ground surface. Page 4 of 8

6 Report of Geotechnical Exploration FORGE Project No Collier County Project No , Vanderbilt and Finger Streets May 19, 2015 The roadway pavement cores varied in thickness from 1¾ to 8½ inches. Beneath the asphaltic concrete, a limerock base was present at all locations except B-1 and B-2, which were taken off the roadway. The flexible pavement section (asphalt and limerock) was typically about 1 foot thick. Table 1 in the Appendix provides a summary of the asphaltic pavement thickness. Evaluation and Recommendations Our evaluation is based on the project information provided to us, the findings of our field exploration program, and our experience in the area. The subsurface conditions will vary between the boring locations. Should new information become available during design or the conditions encountered during construction be substantially different from the information presented in this report, FORGE should be engaged to review the information and evaluate the impact on our submitted recommendations. The following table provides requested soil parameters that may be assigned to the strata encountered during our exploration. Stratum Number Dry Unit Wt. (pcf) SOIL PARAMETERS Friction Angle ᶲ Cohesion (psf) Poisson Ratio, (ʋ) Modulus of Elasticity, (psf) 1 & , ,500, NA NA Stratum Number Modulus Of Subgrade Reaction (psi/in) SOIL PARAMETERS (continued) Saturated Soil Unit Wt. (pcf) Buoyant Soil Unit Weight (pcf) Passive Earth Pressure Coefficient (Kp) Allowable Bearing Capacity (psf) 1 & , ,000 4 NA NA NA Page 5 of 8

7 Report of Geotechnical Exploration FORGE Project No Collier County Project No , Vanderbilt and Finger Streets May 19, 2015 The soils along the proposed alignment generally are considered select materials with a few exceptions. Soils along the terminus of Conners Avenue (B-26) encountered an organic SAND/Peat layer that will not be suitable for backfilling. This material should be anticipated to be present for a length of about 500 feet. The other area of concern is along Vanderbilt Drive between 107 th Avenue and 109 th Avenue. A distinct fuel (diesel/kerosene) odor was detected in the soil samples and may require removal or some other type of mitigation. The encountered soils will be easily excavated but will offer little sidewall stability. The high water table and lack of cohesion will require shoring to stabilize the sidewalls. FORGE recommends that all excavations be done in accordance with OSHA 1926 Subpart P Excavations Regulations. With the water table encountered at depths of 4 to 6 feet below existing grade within the vicinity of the proposed sanitary sewer and force main replacement with manholes, dewatering heights of approximately 6 to 8 feet may be required. Water levels should be maintained at least two feet below the bottom of all excavations. Depending on the size of the excavation and length of time required for construction, various dewatering techniques could be employed. Dewatering methods such as sumps may be suitable for small and quick excavation work while larger and longer excavations will likely require well points. The upper strata of SANDS encountered are generally clean fine sands that will be suitable for backfilling. However where roots are encountered, we recommend screening of these soils be completed to remove the roots prior to placement. If any additional fill material is required for backfilling, we recommend a relatively clean fine SAND material with less than 12-percent fines be imported. All soil backfill shall be sand with a Unified Soil Classification of SP, SP-SM, SP-SC, or SW. Fill shall have a maximum of 12% fine content and be moisture conditioned to achieve proper compaction. The proposed jack and bore entry/exit pits on the north and south side of 111 th will be located at a ground surface elevation close to the existing roadway. Both of the entry/exit pits will be located in a stratum of medium dense relatively clean SAND. The Page 6 of 8

8 Report of Geotechnical Exploration FORGE Project No Collier County Project No , Vanderbilt and Finger Streets May 19, 2015 SAND will be easily excavated but will require shoring to stabilize the sidewalls for excavation depths greater than three or four feet. Additionally, depending on the dewatering system employed we suggest that the contractor consider the use of a mud slab (low strength concrete) to provide a stable working platform. Well points should be anticipated for excavations below the water table. Jack and bore construction should be conducted in general accordance with the handbook titled, Construction Standards Handbook for Work within the Public Right-of- Way Collier County, Florida. Outlined in this document are requirements for permitting and construction requirements. If overcutting during the boring process occurs, the voids should be remedied by pressure grouting the entire length of the installation. The remainder of this report presents our recommendations for site preparation. We recommend your earthwork specifications include site preparation sections similar to those presented below: 1. All excavation and placement work shall be completed in general accordance with Section 125, of the current issue of FDOT Standard Specifications for Road and Bridge Construction. 2. Soil shall be moisture conditioned to +3% of the materials optimum moisture content defined by the maximum dry density. 3. Soil bedding and backfill shall be select sand with a Unified Soil Classification of SP or SP-SM, SP-SC, or SW. 4. Where backfilling under wet conditions procedures for section shall be followed. 5. All soil backfill shall be placed in lifts not exceeding 12-inches in thickness. Lift height shall be reduced to 6-inches or less for material compacted with walk behind rollers or plate compactors. Each lift shall be compacted until a density of at least 95 percent of the modified Proctor maximum dry density is uniformly obtained. 6. Field density tests shall be made after compaction of the existing grade, at the bottom of all excavations, and in all backfill or fill to verify the specified degree of compaction is obtained. 7. The test frequency should be a minimum of one test per lift, per 100 linear feet. Page 7 of 8

9 Report of Geotechnical Exploration Collier County Project No , Vanderbilt and Finger Streets FORGE Project No May 19, 2015 Additional Services FORGE should be engaged to review the project foundation plans and earthwork specifications. We would then suggest changes in the specifications so our recommendations are properly interpreted and implemented. FORGE should also be employed to complete the construction materials testing on this project and visit the project during construction to observe the site conditions encountered and the construction techniques used. Our observations would then be compared with the parameters used in our evaluation. Soil samples obtained during this exploration will be available for contractor review for a period of 120 days following the bid date. Closing We appreciate working with you as your geotechnical consultant and look forward to PI~~>Bll~Of119t working with you on the remainder of this and future projects. us when LUND ''' we may be of further assistance, or if you have any questions~-~r8_tn~ Y ns.~~~~..,,,,,.. '?'"«': (; ~ 'N s ~... ' "'- v...~c)': :: rr NO A2 t>aa -'ra Sincerely,.Q,...~ 1c 0:, =... 1c~ '. ~ Forge Engineering, Inc.... E. ~...,.,, ';(::..'f.~ ~ -1/--!1~( ~. - ~~. Mc6in~ W: ~~ Distribution: 1 -Addressee (via ) 1 -File Appendix: Figure 1, Site Location Map Sheet 1, Boring/Coring Location Plan Sheet 2, Summary of Standard Penetration Test Borings Table 1, Coring Summary.Richard P. Lundberg, P.E cn=richard P. Lundberg, P.E., o=forge Engineering, Inc., ou=licensed Professional Engineer, =rlundberg@forg eeng.com, c=us 11:50: '00'04Page 8of 8 PO Box Naples, FL Fax ~$ ~~.... ~-~~C.,,,..B. I.E.,,, 8"g'j'(Y R chard P. LUfftib!ff Principal Engineer Registered Florida Project Engineer -...

10 APPENDIX

11 Page 1 of 1 These drawings and design are the exclusive property of Forge Engineering, Inc. No use or reproduction is authorized without the express written authorization from Forge Engineering, Inc. SHEET 1: BORING/CORING LOCATION PLAN PROPOSED SANITARY SEWER AND FORCE MAIN REPLACEMENT COLLIER COUNTY PROJECT NO VANDERBILT DRIVE AND FINGER STREETS FROM VANDERBILT BEACH ROAD TO 111 TH AVENUE NAPLES, COLLIER COUNTY, FLORIDA FORGE PROJECT NO FORGE ENGINEERING INNOVATIVE ENGINEERING SOLUTIONS P.O. BOX , P F B-1 B-3 B-4 B-5 B-6 B-7 B-8 B-9 B-10 B-11 B-12 B-13 B-14 B-15 B-16 B-17 B-18 B-19 B-2 C-1 C-2 C-3 C-4 C-5 C-6 C-7 B-30 B-32 B-39 B-23 B-28 B-36 B-34 B-37 B-31 C-13 B-29 B-25 C-11 B-35 B-21 C-10 C-9 B-38 NAPLES, FLORIDA CERT. AUTH.: INC Drawn By: RJM Date 3/19/2015 Revised: B-22 B-27 B-33 C-12 C-14 B-20 C-8 B-24 B-26 B-1 Number and Approximate Soil Boring Location B-1/C-1 Number and Approximate Soil Boring & Core Location

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14 TABLE 1, CORING SUMMARY PROPOSED SANITARY SEWER AND FORCE MAIN REPLACEMENT COLLIER COUNTY PROJECT NO VANDERBILT DRIVE AND FINGER STREETS From Vanderbilt Beach Road to 111th Avenue Collier County Project No Forge Engineering Project Number NUMBER APPROXIMATE LOCATION THICKNESS (IN.) 1 Road Offset Lane Direction Asphalt VANDERBILT DRIVE C-1 Flamingo Avenue NB 7 ¼ C-2 Conners Avenue NB 5 ¼ C-3 Germain Avenue NB 8 ½ C-4 Tradewinds Avenue NB 7 C-5 Pine Avenue NB 8 C-6 Palm Court NB 6 ½ C-7 91 st Avenue N. NB 4 ½ FINGER STREETS C-8 Flamingo Avenue WB 4 ½ C-9 Egret Avenue WB 3 ¼ C-10 Seabee Avenue WB 2 C-11 Seagull Avenue WB 2 ¼ C-12 Tradewinds Avenue WB 1 ¾ C-13 Bayside Avenue WB 2 ¾ C-14 Oak Avenue WB 2 ½ 1 All cores were completed in outside wheel path approximately 8 feet from centerline. SB=Southbound Lane, NB=Northbound Lane, EB=Eastbound Lane, WB=Westbound Lane