Charlotte, NC, United States
Charlotte, NC, United States

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Rowland M.G.,S and ME Inc. | Evans W.D.,Ohio Dam Safety Program
Association of State Dam Safety Officials Annual Conference 2014, Dam Safety 2014 | Year: 2014

To satisfy unique site requirements and meet a timely need for increased storage capacity, a double-sided Mechanically Stabilized Earth (MSE) wall system was designed and constructed to increase the height of a large, on-stream, ash storage dam. Cardinal Fly Ash Reservoir No. 2 (FAR2) dam is a Coal Combustion Residual (CCR) or coal ash dam located in eastern Ohio. The dam was originally constructed as a zoned earth dam in 1985 and featured an inclined clay core and full height chimney drain. In 1997, the dam was raised to a height of 237 feet through the use of an upstream block of roller compacted concrete (RCC) in conjunction with a downstream earth fill. In 2011, the owner desired to raise the dam again. Initially a conventional downstream raising approach was assessed which would have required a half million cubic yards of engineered fill. A structural parapet wall was also examined which would have required a costly foundation system. In both cases, it was doubtful that work could be completed over the course of a single construction season. The double-sided MSE wall system that was ultimately developed overcame both site constraints and achieved the timely need for additional capacity. This innovative design resulted from the unusual geometry of the existing dam crest coupled with the owner's desire to complete construction over the course of single season. To control seepage, a cementbentonite slurry wall was constructed which penetrated into the existing clay core. A non-structural vinyl sheet pile wall was then inserted full depth through the slurry wall and extended to the top of the raised dam in between the MSE reinforced zones. The raised dam also includes a modified auxiliary spillway composed of mass concrete, and a precast service spillway extension. The design engineer and owner worked closely with state dam safety officials to permit this unique structure, including evaluating a variety of seepage and stability failure modes as well as the potential for corrosion of the reinforced concrete wall panels.

Fox P.J.,University of California at San Diego | Sura J.M.,Willmer Engineering Inc | Nye C.J.,S and ME Inc
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2015

This paper presents an experimental investigation of the dynamic internal shear strength of a hydrated woven/nonwoven needlepunched geosynthetic clay liner (GCL) for monotonic (i.e., single direction) loading conditions. Displacement-controlled shear tests were conducted using a large direct shear machine for four normal stress levels ranging from 141 to 1,382 kPa and seven shear displacement rates R ranging from 0.1 to 30,000 mm=min. For each normal stress, peak shear strength first increased and then decreased with increasing displacement rate. Maximum values of peak strength occurred for R = 100-10,000 mm=min and were 16-23% higher than corresponding static values measured at R = 0.1 mm=min. For each normal stress, residual shear strength first decreased and then increased with increasing displacement rate, with minimum values occurring at R = 1 mm=min. On a relative basis, residual strengths show greater dependence on displacement rate than peak strengths. The standard displacement rate for static shear tests of hydrated GCLs (0.1 mm=min) generally yielded conservative values of peak shear strength but unconservative values of residual shear strength, especially for higher normal stress levels. The GCL experienced large post-peak strength reduction for all test conditions. © 2015 American Society of Civil Engineers.

Rainwater N.R.,S and ME Inc. | McDowell L.A.,Geotechnical Engineering Section | Drumm E.C.,University of Tennessee at Knoxville
Geotechnical Testing Journal | Year: 2012

The small range of moisture contents measured with typical filter paper media in test method ASTM D5298 Measurement of Soil Potential (Suction) Using Filter Paper, require that the mass of the paper be measured to 0.0001 g. The accuracy and resolution of several readily available filter papers was investigated, along with investigating a polymer material as a possible alternative media. The importance of calibrating the filter paper was supported by the study, and suggested that because the slope of the calibration curve varies from paper to paper, the filter papers with the capability of measuring a broad range of water contents (low slope of the water content suction calibration curve) provide increased measurement resolution. The polymer media strips were found to have a much greater range of the moisture content than any of the filter papers, providing even greater resolution in the prediction of suction. The polymer strips performed just as well as the filter papers and showed repeatability in the measured suction values. The primary limitation in using polymer material is the lack of mass production of the material in a form suitable for suction measurements. Copyright © 2012 ASTM International.

Ladd B.E.,S and ME Inc.
Forensic Engineering 2015: Performance of the Built Environment - Proceedings of the 7th Congress on Forensic Engineering | Year: 2015

Deep seated slope movements can manifest as small, slow movements and be defined as slope creep. Over a period of time, enough movement can occur that results in damage to property and structures. Site reconnaissance alone cannot identify slope movement along a deep seated shear plane and can occur at depths greater than explored by test borings, especially for lightly loaded structures. This case history discusses a site in upstate South Carolina that experienced two episodes of slope movement between December 2009 and January 2014. Subsequent to a $3.5 million legal claim that a "slope failure" caused damage to a house, the defendant's expert witness team developed an exploration and laboratory testing program to help determine the cause of the slope movement. Observations made during site reconnaissance are presented and the subsurface conditions revealed by the field exploration programs are described. Evaluation of inclinometer data is shown to disclose a deep seated slope movement that was not contemplated during initial site characterization. The data indicated that the slope moved intermittently and was very slow. Lastly, triggering mechanisms that potentially initiated the slope movement are presented. Inclinometers typically thought of as an instrument for monitoring slope performance, not as an exploration tool, were proved essential for use in site characterization in detecting the deep shear plane. Failing to reach an eleventh hour settlement, the case went to trial. The jury found in favor of the defendant, ruling that they were not negligent during their initial site characterization. © 2016 ASCE.

Esposito III M.P.,Clemson University | Andrus R.D.,Clemson University | Camp III W.M.,S and ME Inc.
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2014

The procedures used to freeze and sample a Pleistocene sand deposit near Charleston, South Carolina to preserve and study the effects of diagenesis are presented in this paper. Based on the results of geotechnical tests and a feasibility ground freezing study, a freezing system with a central freeze pipe was installed to target a column of clean sand 1 m in radius and 2.3 m in length. Liquid nitrogen was continuously supplied to the freeze pipe fabricated to freeze the sand between depths of 1.8 and 3.8mbelow the ground surface for 270 h. Frozen sand cores taken from five locations 0.65 to 0.7 m away from the central freeze pipe indicate the ground was frozen between depths of 1.8 and 3.8 m at all but one location. Ground temperature measurements, growth of the frozen zone, and the amount of liquid nitrogen consumed are presented and compared with predicted values. Recorded temperatures indicate that the freezing was influenced by the direction of groundwater flow, the flow rate of liquid nitrogen, and the location of the liquid nitrogen inlet pipe within the central freeze pipe. © 2014 American Society of Civil Engineers.

Ross J.D.,S and ME Inc | Fox P.J.,University of California at San Diego
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2015

This paper presents an experimental investigation of the dynamic shear strength of a composite liner consisting of a high-density polyethylene (HDPE) textured geomembrane (GMX) over a hydrated nonwoven/nonwoven needle-punched geosynthetic clay liner (GCL) for monotonic (i.e., single direction) loading conditions. Displacement-controlled shear tests were conducted using a large direct shear machine for five normal stress levels ranging from 13 to 2071 kPa and five shear displacement rates ranging from 0.1 to 30,000 mm=min. GCL internal failures occurred at high normal stress and low displacement rate. As normal stress decreased or displacement rate increased, failure mode transitioned to the GMX/GCL interface. Peak strength envelopes are slightly nonlinear (concave-down) and show dependence on displacement rate at higher normal stress. Large-displacement strength envelopes show greater dependence on displacement rate at higher normal stress due to the effect of changing failure mode. The standard displacement rate for static shear tests of GMX/GCL composite liners (1 mm=min) yielded conservative values of peak shear strength but unconservative values of large-displacement shear strength for some normal stress conditions. The GMX/GCL composite liner experienced significant post-peak strength reduction for all test conditions. © 2015 American Society of Civil Engineers.

Hossain A.M.,Clemson University | Andrus R.D.,Clemson University | Camp III W.M.,S and ME Inc.
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2013

Explicit empirical relationships for correcting liquefaction resistance of unsaturated soil below the groundwater table using compression wave velocity (VP) and shear wave velocity (VS) are derived and evaluated in this paper. The relationships are derived using published laboratory test data for four different sands and one silt material. The laboratory test data based on VP exhibit less scatter than the test data based on the ratio VP/VS. For this reason, the VP-based relationship is recommended for correcting the liquefaction resistance of unsaturated soil. The influence of loading cycles and relative density on the recommended relationship is investigated. From a review of 40 field case history sites, it is found that in the critical layers at 20% of the sites, average VP is less than 1,400 m/s, indicating unsaturated conditions. Liquefaction resistances computed for eight field case histories with VP < 1,200 m/s in the critical layers are corrected and plotted on penetration-and VS-based liquefaction evaluation charts. The results support the use of the correction for unsaturated conditions below the groundwater table. © 2013 American Society of Civil Engineers.

Fox P.J.,University of California at San Diego | Ross J.D.,S and ME Inc | Thiel R.S.,Thiel Engineering
Geosynthetics International | Year: 2011

Several large-scale laboratory tests were conducted on multi-interface geomembrane liner specimens to assess damage effects from static pressure, cyclic loading, and largedisplacement static shear. The specimens consisted of compacted subgrade soil, an LLDPE or HDPE smooth geomembrane, and overlying potash salt. The subgrade soil was gravelly sand with 25% gravel content. Failure occurred at the geomembrane/soil interface for each shear test. Cyclic loading data indicated that the LLDPE geomembrane had slightly lower values of interface shear stiffness and damping ratio than the HDPE geomembrane. Shear stiffness was essentially constant and damping ratio decreased with continued cycling for both geomembranes. Geomembrane damage for the static pressure and cyclic loading tests consisted of minor to moderate dimpling, with no holes created. Damage was considerably more severe for the large-displacement shear tests, and consisted of deep scratching and gouging of the geomembranes. Two holes were created in the LLDPE specimen and no holes were created in the HDPE specimen as a result of shear displacement. The findings indicate that severe geomembrane damage can result from shear displacement against a compacted subgrade soil with gravel. Considering that shear displacements commonly occur within landfill liner systems due to such mechanisms as waste settlement, the findings suggest that additional research is needed on expected levels of shear-induced damage for geomembranes placed adjacent to soil layers with coarse particles, including compacted clay liners containing gravel. © 2011 Thomas Telford Ltd.

Stehmeyer E.H.,Parsons Brinckerhoff | Canivan G.J.,S and ME Inc. | Camp W.M.,S and ME Inc.
Ports 2016: Port Engineering - Papers from Sessions of the 14th Triennial International Conference | Year: 2016

Improvements to existing wharfs frequently involve larger design loads and hence the need to evaluate the structure's capacity to accommodate that load. Minimizing renovation to the existing structure, especially the substructure, is ideal from both a cost and facility disruption standpoint. Therefore, maximizing the loads that can safely be supported by the existing substructure is often a goal in a renovation design. This paper presents a case study of high-strain dynamic pile testing performed on 30-year old 18 in. (457 mm) and 20-year old 24 in. (610 mm) square prestressed concrete (PSC) piles to determine the maximum allowable loads the existing piles could support, thereby reducing the number of new piles required to support the increased demands from larger ship-to-shore (STS) cranes. The case study discussion includes a description of the wharf construction, pile testing, results, wharf reconstruction, concluding with the study result's impact to the overall project design and subsequent construction cost. Following the case study, recommendations for this method's application to other wharf renovation projects will be provided along with a discussion on balancing the needs of an operational terminal during the in-situ testing. © 2016 ASCE.

Ashcraft N.,SandME Inc.
Proceedings of the American Gas Association, Operating Section | Year: 2014

A presentation covers the types of materials and construction related anomalies; arsenal of tools; types of assessment; and leading edge technologies. This is an abstract of a paper presented at the 2014 AGA Operations Conference Proceedings (Pittsburgh, PA 5/20-23/2014).

Loading S and ME Inc. collaborators
Loading S and ME Inc. collaborators