Service Information

Soil Borings

All raw land sites require geotechnical investigations for self-supporting, guyed tower, and monopole foundations. Most soil borings are obtained by using drill rigs with conventional rubber tires capable of accessing rough terrains. Some locations require site clearing and an all terrain rig, which will add to your cost.

Some foundation design engineers do not require recommendations and only require adequate depth boring logs containing the following information:

• Date and sampling method
• Soil strata classification per USCS and their depth
• Standard penetration test blow counts
• Groundwater elevation

Others say that reliance upon only soil borings requires them to provide a more conservative design and they can more adequately serve the client if the following information is obtained.

Industry recommendations for geotechnical investigations and reports include:

Boring Logs and Reports:

• Date, sampling methods, number and type of samples
• Description of the soil strata according to the Unified Soil Classification System
• Depths at which strata changes occur referenced to a site benchmark elevation
• Standard Penetration Test blow counts for each soil layer
• Soil density for each soil layer. Unit weight of the soil, buoyant unit weight, if submerged
• Ultimate bearing capacities for each soil layer or at the recommended bearing depths.
• Allowable bearing pressure (values versus depth and settlement expected), mainly at tower base
• For expansive soil conditions, the active zone of influence and recommendations for design
• Elevation of free water encountered and the ground water depth below grade to be considered for design as well as seasonal levels
• Maximum and average frost penetration depth and frost depth to be considered for design
• Soil electrical resistivity, Ph values and corrosive nature of soil
• Recommendation of the foundation design best suited for existing soil conditions and recommendations for alternate foundation types
• Report of construction problems anticipated, including any casing required, etc.
• Pertinent soil design data and recommendations and any other variables that will affect the installation and design

For Drilled Pier foundations, the following information should be provided:

• Ultimate tip bearing capacity
• Ultimate skin friction for each soil layer
• Lateral modulus of soil reaction for each soil later
• Ultimate soil strain at 50% of ultimate compression for each soil layer

For Rock Anchors, the following information should be provided:

• Type and condition of rock
• Rock quality designation, RQD
• Percent of rock sample recovered
• Ultimate bond stress in the interface between the rock and grout
• Ultimate sheer strength   

We recommend that you contact our listed geotechnical professionals to obtain additional information about their services, capabilities and experience.

Pricing varies according to scope

Pricing for reports and recommendations are project specific based upon the additional services and tests being requested. In example, if a client requested a resistivity test it would increase the cost approximately $500.00; sieve analysis, $75.00; direct shear test, $150.00; unconfined compression test, $100.00; Atterberg limits, $75.00; chemical analysis, $75.00.

The following soil boring pricing can be used for budgetary purposes. The borings, as a minimum, would provide:

• Date and sampling method
• Soil strata classification per USCS and their depth
• Standard penetration test blow counts
• Groundwater elevation

Although no recommendations would be provided, the boring logs would be sealed by a geotechnical engineer registered in the state in which the site is located. If fill is encountered, extend the boring depth another 10’ to 20’.