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Geotechnical Services

Geotechnical investigations are required for many projects, especially in areas with unusual or challenging geology. R. W. Gillespie & Associates' staff of professional engineers, certified geologists, and other engineers, scientists, and technicians make an exceptional team in terms of advanced educational background and project experience. This base of knowledge is supported by the latest technologies for analyzing site characteristics and building materials applications.
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Geohydrologic Services

The quantity, quality, and characteristics of groundwater resources and anticipated impacts to them are major factors in determining whether or not a project design is feasible. Many construction projects cannot advance without acquiring permits, which rely upon detailed observation of groundwater conditions and expert analysis of contamination potential. Our geohydrologists and certified geologists are experienced in developing the documentation required by regulatory agencies. We work closely with our clients to provide the information needed to minimize impacts, so that projects can proceed smoothly through the permitting process.
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Materials Testing Services

R. W. Gillespie & Associates offers essential field and laboratory services for ensuring and controlling project quality through selection, design, and installation of materials most suitable for function and site characteristics. The firm's engineers, scientists, and technicians are experienced in assessing material properties and monitoring the installation and performance of various types. Our Construction Materials Testing group actively participates in CCRL and AASHTO reference sample programs in which our results are compared to standards. Our performance has been excellent.
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Foundation Investigations

Our staff members have experience investigating sites representing a wide range of types of geologic situations from steep slopes to submarine. Investigations have been conducted for both pre-development and post-development evaluations, correction of construction hazards, and for a wide array of structures and deep foundations, including piles and drilled piers. Subsurface exploration methods range from conventional boring and sampling techniques to sophisticated in situ testing such as borehole pressuremeter. Where applicable, field instrumentation including vibrating wire piezometers, settlement platforms, inclinometers, and seismographs are employed to monitor and verify performance during construction.

Slope Stability/Landslides

Strength and safety of earthen slopes and embankments are issues common to site design in steep slope areas and landslide risk analysis. Our professional staff members have evaluated landslides and slopes in 16 states and have designed hundreds of projects addressing these situations. Projects have ranged from minor sloughs to landslides covering 30 acres. Recent studies have included stability of soft clays along an actively eroding marine shoreline and a riverbank subject to long-term sloughing.

Foundation Investigations

Principal and senior engineers have extensive experience in geotechnical investigations required for design of dams and diversion structures. Dam failure investigations, safety inspections, and seepage and stability enhancement projects have also been completed. Experience includes work in high-risk seismic areas and on structures that previously had failed on multiple occasions.

Site Explorations

State-of-the-art field and laboratory tests determine how groundwater conditions will affect structure. Based upon these tests, site specific engineering solutions are developed and materials recommendations are made.

New Well Development

Developing and registering a new groundwater supply requires selecting a location with sufficient quality and yield and determining and mapping the "cone of influence," or the land surface area from which the well draws. Aquifer hydraulics are measured using in situ borehole permeability tests and various pumping test designs. Groundwater modeling has served as a useful tool in delineating wellhead protection areas and potential risk factors. This information is essential not only for registering new groundwater or surface drinking water supplies, but also for discharge permit applications. Our staff is experienced in providing these services for both deep rock and gravel wells, for private clients, and for municipalities.

Monitoring Wells

Installation of wells is frequently required to monitor water quality in areas near public water supplies, sanitary landfills, wastewater treatment plants, and other projects such as golf courses and large residential complexes. Our staff has designed such systems for public and commercial landfills, public water supply protection, hazardous waste site remediation projects, new residential subdivisions, industrial and underground fuel storage tank facilities, and for projects involving land application of waste water.

Computer Modeling

Computer programs use numerical methods to predict groundwater movement and environmental outcomes. Modeling is a useful tool in delineating wellhead protection areas. It is used frequently to provide convincing evidence regarding the acceptability of a project in terms of groundwater protection or to demonstrate the effectiveness of proposed contamination mitigation measures. Our company uses sophisticated software, such as Visual MODFLOW, MT3D, AQTESOLV, MOC, and Hydropal Other frequently used software includes SURFER, HELP (leachate generation by landfills), 3DTOPO, and various statistical/probabilistic packages including SPSS. While groundwater modeling can be expensive in terms of initial costs, the derived benefits usually return dividends with respect to developing monitoring and sampling program designs.

Documentation

Applications for groundwater discharge and withdrawal permits and many other requirements of state, federal, and local agencies must be based upon accurate and carefully documented research and analysis. Our staff is experienced in compiling and presenting this documentation, and in acting as a liaison between our clients and the permitting authorities.

In the Field

Field services include density analysis of soils and pavement materials using state-of-the-art nuclear densometers. Our staff is qualified in concrete composition analysis (air content, strength, unit weight, and temperature) pile load testing, proof and performance testing of ground anchors, vibration monitoring, and evaluation of control blasting measures.

In the Laboratory

The company maintains its own laboratory for testing soils, and for determining the compressive and tensile strengths of concrete, mortar, and grout cylinders. Marshall method equipment is available for determining flow, stability, and component percentages of asphaltic concrete mixtures. Sophisticated methods and equipment assist our staff in designing concrete mixes and determining the bearing ratio of on-site soils. Other testing areas within our service scope include specific gravity, absorption, freeze-thaw, and sulfate soundness. Our laboratory is also equipped to perform conformance testing services for landfills. This includes clay permeability testing for landfill liner and cover systems.

Construction Observation

Construction observation for excavation, dewatering, foundations, and paving is another service we offer. Observation and supervision by the same consulting group that generates and interprets critical soils, water, and materials data maintains consistent high-quality construction.

Environmental Quality

Staff environmental experts provide monitoring services regarding environmental quality protection. For numerous projects - such as wetland replication, wastewater disposal, or construction in sensitive areas - observation and analysis are essential to ensure consistency with environmental protection requirements. In many cases, monitoring requirements are incorporated into conditions for groundwater discharge and other permits.

Special Inspections

Our company can provide structural compliance inspections to verify that the structural components of your project are constructed in accordance with the project plans and specifications. We have extensive experience working with standard reinforced prestressed and post-tension concrete, reinforced masonry, and light- and heavy-gauge structural steel construction materials.

Code Compliance

We have developed an extensive working knowledge utilizing the following specialized Code document in both Compliance Inspections and development of Construction Specifications.

- American Concrete Institute Building Code (ACI 318)
- Concrete Reinforcing Steel-Institute Standard (CR5I)
- Portland Cement Association Masonry Handbook (PCA)
- American Society for Testing and Materials (ASTM)—numerous

Special Services

R. W. Gillespie & Associates can also provide a number of special quality assurance services to supplement the other services listed above. These include field and plant inspection and testing services. We are experienced in providing dimensional inspection and quality assurance testing on a variety of products:

- Reinforced Concrete Drainage
- Reinforced & Prestressed Concrete Structural Product Fabrication
- Structural Steel Fabrication
- Fireproofing of Structural Components

Depending on the size, location, and scope of your project, we can mobilize a full-time staff and dedicated site testing laboratory for your project to reduce travel expenses and better serve your inspection and testing needs.