Typically, we perform field density testing of soils and stone base material per ASTM D 6938 using nuclear density gauges to determine the moisture content and in-place density. Soil testing can be performed on a full time basis when multiple lifts of fill will be placed during our inspection or on an as-needed basis when the contractor only places one or two lifts in a day. Some projects require verification of nuclear density results by performing sand cone tests per ASTM D 1556. When laboratory proctors are not available, we can determine the maximum density of the tested soil in the field by comparison of a one point proctor with established family of curves per VTM-12.
Prior to the placement of fill soil we evaluate the suitability of the existing subgrade by observing proof rolling operations performed by the contractor using loaded rubber tire vehicles. Areas of unstable soil are identified in the field and, if required, test pits are excavated to determine the depth, extent and cause of the unstable soils.
We then recommend the best means of stabilization, whether drying, stabilizing the soils with lime or cement or undercutting. During site work activities, we can monitor borrow pits and fill soil materials, soil moisture content, truck counts, topsoil stripping, as well as monitor lift thicknesses, slope reconstruction and placement of stabilization geotextiles.
We have the equipment and personnel to test and monitor concrete for slump, temperature, additives, air content, and mix time. Air content is monitored with either pressure meters or volumetric meters if light weight concrete is used. We sample concrete for compressive strength testing in either 4”x8” or 6”x12” cylinder molds. We can also cast 6”x6” beams for flexural strength testing. We are capable of performing these compressive and flexural strength tests in our laboratory or the equipment can be placed in an on-site job trailer for larger jobs. Cylinders and beams are cured in water baths in our laboratories at the required temperature range.
Reinforcing Steel Inspection
We can perform reinforcing steel inspections, checking installed reinforcing steel against provided plans and details. During these inspections, we examine the size, number, splice length and clearance placed in anticipation of concrete placement for footings and cast-in-place structures and within the cells of Concrete Masonry Units (CMUs) prior to the placement of grout. We can also check for the presence and spacing of reinforcing steel in completed structures using an electromagnetic reinforcing steel finder.
We can inspect all load-bearing or fire-rated Concrete Masonry Unit (CMU) walls during construction. Our inspection includes the placement of reinforcing steel, alignment and plumb of the wall, head and bed joints of the mortar and placement, positioning, sizing and splice lap of the reinforcing steel. In addition, we can observe the placement of grout to verify all placement procedures are correct, including casting compressive strength samples of the grout, and of the mortar, as well.
We can monitor pile driving activities to ensure that piles are of specified type, size and depth and that the piles are properly installed. Prior to installation, most specifications require some type of capacity verification by either a pile load test or evaluation of the pile driving equipment using dynamic formulas or analytical tools such as the Shear Wave Equation. These test methods help to define the installation and conditions that establish the desired pile capacity. Pile driving logs are maintained continuously during the installation and are summarized on daily reports.
We perform inspections on EIFS (Exterior Insulation Finish Systems) at various stages of construction to confirm the substrate, moisture barrier, base coat, EPS foam and final coat are properly applied at appropriate temperatures and weather conditions and in accordance with manufacturer’s recommendations. Our staff has attended EIFS certifications seminars to maintain current certification status. The application materials are examined to check for acceptance by the type of EFIS system required and for proper on-site storage prior to them being installed.
Our inspectors can perform structural steel inspections for anchor bolts, column plumb, bolted and welded connections, metal decking, Nelson studs and other structural steel elements. We can perform fabrication inspections to verify that the plants have the necessary quality control program to meet the requirement of the project and that the materials are properly marked. We provide AWS certified welding inspections for critical full penetration welds and when ultrasonic examination is required by the plans or specifications. When questions arise in the field, we assist in submitting RFIs (“Request for Information”) for clarification as needed from the structural engineer. Non-conforming or potential non-conforming work is documented with digital cameras so that the structural engineer can see the conditions our inspector has found to see if any further action is required. This documentation can avoid the need for the structural engineer to make a special trip to the site and avoid construction delays.
It has been our experience that the majority of the fireproofing inspection program effort should deal with verification of application thicknesses. Bond strength tests will be performed initially to verify the material submittal data. Dry density determinations are typically performed on one random member of each type, per floor or roof per 10,000 SF of floor space. In-place depth measurements are made using a varying number of individual readings at a test location, depending on ASTM and VL requirements. It will be necessary to define which format is to be followed on a given project. Measured deficiencies will be reported immediately to the Owner's site representative and the Contractor.
We can perform roofing inspections on the different types of roof systems that are commonly utilized. Our inspections verify that the installed system meets the project requirements and the roof manufacturer’s specifications.
Parking Lot and Drive Lanes
Although parking lots and drive lanes for the majority of projects is normally excluded from Special Inspection testing requirements, we can monitor the placement of the stone base and asphalt to ensure that the work is being completed appropriately. Most specifications reference standards such as Virginia Department of Transportation or Federal Aviation Administration for acceptance of materials and testing. Field testing using Roller Patterns and Control Strips can allow our personnel to establish field target densities for compaction testing using a thin lift nuclear gauge. We also monitor asphalt laydown temperatures using infrared thermometers and can calculate application rates based on the paver width and length to spread tonnage of materials. In addition, core samples of the pavement system can be obtained to verify final thicknesses and bulk specific gravity of the delivered materials.
VDOT projects, including highways, collector roads, turn lanes into and out of private properties and subdivision roadways are tested by our VDOT certified technicians. Our technicians are certified in VDOT Soils, Concrete and Asphalt to ensure that our test results are accepted during the review process.
Our VDOT testing includes the testing of the subgrade soils, to include compaction testing and proofrolling, as well as CBR analysis to verify pavement designs. We also test the stone base and asphalt for both compaction and thickness. Concrete for curb and gutter, sidewalks and cast-in-place drainage structures is also tested when required by VDOT. We also monitor the placement of all utilities in the VDOT right-of-way, to include storm and sanitary sewer placement, bedding of the pipes and appropriate backfilling of the trenches.