Senior Geotechnical Engineer SC License No.: 21288

Transcription

1 9 Pilgrim Road Greenville, SC Phone (864) Fax (864) November 30, 2017 Greystone Cottages HOA Board of Directors c/o Mr. Bill McCall 101 Ashler Drive Greer, South Carolina Reference: Asphalt Roadway Evaluation Greystone Cottages Greer, South Carolina EAS Project No.: EAS Dear Board of Directors: As requested, Engineering and Surveying Professionals, Inc. (EAS) has performed asphalt coring and curb inspections at the above referenced project. The coring and inspections were performed by personnel under the supervision of an engineer licensed in the state of South Carolina. These inspections were performed in accordance with generally accepted engineering practices. EAS appreciates the opportunity to work with you on this project. If there are any questions you have concerning this report, please do not hesitate to contact us. Respectfully Submitted, EAS PROFESSIONALS, INC Matthew C. Christie, P.E. CMT Manager Douglas R. Dunko, P.E Senior Geotechnical Engineer SC License No.: Attachments: Test Location Plan Dynamic/Static Cone Penetrometer Log Asphalt Core Photographs Design Detail Geotechnical, Environmental, Construction Materials and Forensic Engineering Construction Materials Testing Laboratory Testing Land Surveying Specialty Inspections

2 INTRODUCTION Greystone Cottages located in Greer, South Carolina consists of a single-family, residential neighborhood that was constructed in 4 phases with private roadways throughout the neighborhood. Phase 1 was constructed approximately 7 years ago with Phase 2 constructed thereafter. Phase 4 was constructed approximately 1 year ago with Phase 3 constructed just prior. Engineering and Surveying Professionals, Inc. (EAS) was asked to perform an evaluation of the existing general condition of the residential roads that consisted of asphalt coring and subgrade testing to verify if the pavement sections examined meet the provided design criteria and to determine if the soil subgrade has correlated soil support values needed to support the applied residential vehicle loads. EAS was also asked to inspect curbing, gutters, and sidewalks for conformance to project specifications. EXPLORATION Based on information provided to EAS, the asphalt roadways were specified to have a 2-inch thick Type C Asphalt layer with a 6-inch think Compacted Macadam Aggregate Base Course (CABC) (see the attached provided plan details) underlain by properly compacted structural fill soils or stable residual soils. The rolled curbing, gutters, and sidewalks were specified to be constructed using a 3,000 pound per square inch (psi) cast-in-place Portland Cement Concrete (PCC). Curb and gutters were designed to have a 3/4-inch pre-molded joint filled expansion joint placed at the point of all curves, edges, and center of driveways, and at uniform 40-foot intervals. The pavement and curbing design is typical of residential roads that do not see daily, heavy truck traffic except for the occasional moving/delivery truck or garbage truck. To verify that the design criteria was met, asphalt coring was performed at twenty-three (23) locations spaced approximately 250 feet apart and/or at other specifically selected areas. The subgrade soils were evaluated to determine if the soils were suitable for typical residential traffic. To evaluate the subgrade soils, shallow hand auger borings with dynamic cone penetrometer testing (DCP) and Static Cone Penetrometer testing (SCP) were performed at twenty-three locations to depths up to 4 below the asphalt roadway. Based on our evaluation, it appears that the roadways bear on residual, clayey sand soils at most of the test locations, however no grading plan was provided to verify the cut/fill grading. The condition of the asphalt roadway varied throughout the neighborhood. Fatigue and alligator cracking in the existing asphalt roadways were observed at multiple locations. Cracking can be the result of the asphalt mix and/or installation issues, inadequate pavement and/or stone base thicknesses, and/or inadequate subgrade soils. Greystone Cottages PAGE 2 EAS Project No Greer, South Carolina November 30, 2017

3 Image 1: Fatigue Cracking at the intersection of Bradstock Drive and Ashler Drive (Core #3). Image 2: Fatigue Cracking at the intersection of Ashler Drive and Shandwick Drive (Core #23). Greystone Cottages PAGE 3 EAS Project No Greer, South Carolina November 30, 2017

4 The layer of Hot Mix Asphalt (HMA) was not placed continuously throughout the neighborhood. Various cold joints were observed at intersections of adjacent streets and the transition between phases. Image 3: Cold Joint along Ashler Drive separating Phase 2 and Phase 4. Image 4: Cold Joint located at the intersection of Ashler Drive and Bradstock Drive. Greystone Cottages PAGE 4 EAS Project No Greer, South Carolina November 30, 2017

5 Locations were observed in all four phases with cracked curbing with obvious crack repairs in Phases 3 and 4. There were areas in Phase 4 where sections of curbing had been replaced. Image 5: 90 Bradstock Drive at Road Bend Image 6: No Control Joint at Edge of Driveway Greystone Cottages PAGE 5 EAS Project No Greer, South Carolina November 30, 2017

6 Image 7: Caulking in Concrete Cracks in Phase 2 along Shandwick Drive. RESULTS The soil underlying the pavement was found to be residual, moist, red, clayey sand/sandy clay with traces of gravel. SCP test results were correlated to approximate CBR (California Bearing Ratio, ASTM D1883) values at each coring location. The California Bearing Ratio (CBR) test method is primarily intended for evaluating the strength of materials of pavement subgrade, subbase, and base course materials. Project specifications provided to EAS did not indicate the CBR value used for design of the pavement sections. However, correlated CBR values of 7% or higher are typically indicative of sandy clay/clayey sand soils that have been compacted to at least 95% of the standard Proctor (ASTM D698) maximum dry density (as required by the plans) or are indicative of suitable, residual cut subgrade soils. The table below gives individual asphalt and stone thicknesses for each location and the attached Coring Location Plan shows the core locations. Core Location Phase Asphalt Thickness (inch) CABC Thickness (inch) SCP Correlated California Bearing Ratio (CBR) (1) / / / / / / Greystone Cottages PAGE 6 EAS Project No Greer, South Carolina November 30, 2017

7 Core Location Phase Asphalt Thickness (inch) CABC Thickness (inch) SCP Correlated California Bearing Ratio (CBR) (1) / / / / / /4 6 1/ /4 7 1/ / /4 5 3/ / /4 6 3/ / / (1) California Bearing Ratio ASTM D1883 Asphalt thicknesses ranged from 3/4 inches to 2 3/4 inches, except for Core #19, 5 3/4 inches. Stone base was observed at 19 or 23 core locations ranging from 3 inches to 8 inches thick. 1. Cores performed at locations 13, 15, 20, and 23 did not have the specified 2 inches of asphalt. 2. Cores performed at locations 2, 3, 18, and 20 did not have the specified 6 inches of CABC below the asphalt. 3. Cores performed at locations 14, 17, 19, and 22 did not have any CABC below the asphalt. Hand auger borings, DCP, and SCP test results indicated that the roadways bear on residual, clayey sand soils. Correlated CBR values indicated that the subgrade CBR values range from 7% to 16% and appear to be suitable for support of the specified 2 inches of asphalt over 6 inches of CABC. Approximately 1/2 to 1 inch of settlement was observed along curb and gutters along Bradstock drive, Ashler Drive in phase 1, and Shandwick Drive. Approximately 1/2 to 2 inches of settlement was observed around water and sewer lids and in areas that contained underground utilities. These issues may have been caused by improper leveling of the utility lids or inadequate compaction of structural fill soils along the curbing following the utility installation. CONCLUSION Based on the core results, 17% of the core locations had insufficient asphalt thickness and 39% with insufficient stone base thickness. Twelve of the 23 core locations did not meet the overall pavement specification of 2 inches of asphalt and 6 inches of stone base. The overall condition Greystone Cottages PAGE 7 EAS Project No Greer, South Carolina November 30, 2017

8 of the asphalt appeared to be in relatively good condition, however areas were observed where the surface appeared to be poorly finished throughout the development. Significant asphalt subgrade failure or deterioration throughout the development was not observed; however, some apparent construction and/or other heavily loaded vehicles/equipment traffic has occurred resulting in the surface damage that was observed. Visual inspection of the concrete curbs, gutters, and sidewalks were performed throughout the neighborhood. Concrete curbing contained saw cuts that were spaced approximately 9 to 11 feet apart. The improper placement of control joints and repetitive vehicle and truck loads during construction and moving operations on the concrete curbs resulted in most driveways having cracks within the driveway intersections, the center of the concrete curbing panels, and along curb curves. Construction, equipment, and/or delivery traffic likely contributed significantly to the damaged curbing. Also, some settlement resulting in curb cracking was observed. Based on our testing of the existing subgrade soils and/or structural fill soils, the soil subgrade is suitable for residential traffic. Based on the apparent settlement of several of the curbing sections, some of the curbing subgrade may not have been prepared properly to provide longterm support of the curbing. The failure areas noted through the report are typically at water collection/low lying areas in the roadway and at utility trenches or along the curbing can be indicative of poor subgrade preparation and/or compaction as well. Greystone Cottages PAGE 8 EAS Project No Greer, South Carolina November 30, 2017

9 SITE VICINITY MAP N Geotechnical and Environmental Engineering Construction Materials Testing Land Surveying Specialty Services 9 Pilgrim Road, Greenville, South Carolina (864) EAS PROJECT NO. EAS Greystone Cottages Greer, South Carolina SCALE NOT TO SCALE DATE 11/30/2017 FIGURE NO. 1

10 9 Pilgrim Road Greenville, SC Phone (864) Fax (864) DYNAMIC/STATIC CONE PENETROMETER LOG EAS Personnel: EAS Date of Observation: November 9-14, 2017 Client: Greystone Cottages HOA Project: Greystone Cottages Road Evaluation Greer, SC EAS Personnel: A. Erny, J. Jimenez, J. Robinson Engineering Technicians Test No. 1 2 Depth DCP (SCP) Test Location Description 0 (26) 2-1/4 Asphalt, 6 ABC RESIDUAL- moist, red/tan, Clayey SAND with Silt Entrance of Faux Drive (23) 2 Asphalt, 4.5 ABC RESIDUAL- moist, red, Clayey SAND SW corner of Ashler Drive 3 0 (20) 2 Asphalt, 4.5 ABC Intersection of RESIDUAL- moist, red, Clay with trace SAND and GRAVEL Bradstock Drive and Ashler Drive (32) 2 Asphalt, 6 ABC North RESIDUAL- moist, red, Clayey SAND intersection of Castlestone Drive and Ashler Drive 0 (33) 2.5 Asphalt, 6 ABC RESIDUAL- moist, red, Clayey SAND Entrance of Castlestone Drive 6 0 (40) 2 Asphalt, 6 ABC RESIDUAL- moist, red, Clayey SAND and GRAVEL NW corner of Bradstock Drive 7 0 (35) 2.5 Asphalt, 5 ABC RESIDUAL- moist, red, Clayey SAND and GRAVEL SW corner of AR at 16 Bradstock Drive Geotechnical, Environmental, Construction Materials and Forensic Engineering Construction Materials Testing Laboratory Testing Land Surveying Specialty Inspections

11 Test No Depth DCP (SCP) Test Location Description 0 (40) 2-1/3 Asphalt, 6 ABC RESIDUAL- moist, red, Clayey SAND and GRAVEL Entrance of Bradstock Drive (37) 2-1/4 Asphalt, 9 ABC South intersection RESIDUAL- moist, red, Clayey SAND of Cannongate Drive and Ashler Drive 0 (40) 2.5 Asphalt, 7 ABC RESIDUAL- moist, red, Clayey SAND Middle of Cannongate Drive (30) 2.5 Asphalt, 7 ABC NE of the north RESIDUAL- moist, red, Clayey SAND intersection of Cannongate Drive and Ashler Drive 0 (32) 2 Asphalt, 8 ABC RESIDUAL- moist, red, Micaceous Sandy CLAY Middle of Shandwick Drive (30) South intersection 1.5 Asphalt, 8 ABC of Shandwick RESIDUAL- moist, red, Micaceous Sandy CLAY Drive and Ashler Drive 0 (55) 2.5 Asphalt RESIDUAL- moist, red, Micaceous Clay with SAND Entrance of Shandwick Drive (25) 1-3/4 Asphalt, 6-1/4 ABC NE of the north RESIDUAL- moist, red, Clay with SAND intersection of Shandwick Drive 3 and Ashler Drive 0 (25) 2-1/4 Asphalt, 7-1/4 ABC Intersection of RESIDUAL- moist, red, Clay with SAND Ashler Drive and Ashler Drive /4 Asphalt Greystone Cottages Road Evaluation PAGE 2 EAS Project No Greer, South Carolina November 9-14, 2017

12 Test No. Depth DCP (SCP) Test Location NE corner of Ashler Drive Description Rock/recycled concrete found +/- 12 below grade, could not be broken (35) 2-1/4 Asphalt, 5-3/4 ABC RESIDUAL- moist, red, Clay with SAND East corner of Ashler Drive 3 (35) 0 (36) 5-1/4 Asphalt West corner of RESIDUAL- moist, red, Micaceous Sandy CLAY Ashler Drive (47) 1-3/4 Asphalt, 6-3/4 ABC North Ashler RESIDUAL- wet, red, Clay with SAND Drive between Ashler Drive and Cannongate Drive 0 (25) 2 Asphalt, 3 ABC Intersection of RESIDUAL- moist, red, Clayey SAND Ashler Drive and Faux Drive North Ashler 2-3/4 Asphalt Drive between RESIDUAL- dry, red, Clayey SAND Castlestone Drive and Cannongate Drive 0 (40) 3/4 Asphalt, 11 ABC North RESIDUAL- moist, red, Micaceous Sandy CLAY intersection of RESIDUAL- moist, red, Clay with SAND Shandwick Drive and Ashler Drive Comments: ABC- Aggregate Base Course. AR- Auger Refusal. Greystone Cottages Road Evaluation PAGE 3 EAS Project No Greer, South Carolina November 9-14, 2017

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