2022-075A - Laserfiche WebLink

Home Browse Search

North County Library Addition Geotechnical Exploration Report 1001 County Road #512, Sebastian, Florida April 24, 2020 GFA Project No. 20-9197.00 Page 5 of 10 2.2 Field Exploration Two (2) standard penetration test (SPT) borings, advanced to an approximate depth of 20 feet below the existing ground surface, were performed for this study. The boring depths were established based upon our knowledge of vicinity soils and confined to the zone of soil likely to be influenced by the planned construction. The locations of the borings are illustrated on the Test Location Plan in in Appendix B. The Standard Penetration Tests (SPT) were performed in general accordance with ASTM D 1586, "Standard Test Method for Standard Penetration Test (SPT) and Split -Barrel Sampling of Soils." The SPT test procedure consists of driving a 1.4 -inch I.D. split -barrel sampler into the soil profile using a 140 -pound hammer falling 30 inches. The number of blows per foot, for the second and third 6 -inch increment, is referred to as the N -value. The N -value has been empirically correlated with various soil properties and provides an indication of soil strength. Site specific survey staking of the borings was not provided for our field exploration. The indicated depth and location of each boring was approximated based upon existing grade at the time of drilling, the provided site plan, and estimated distances and relationships to the existing building and other landmarks at the property. 2.3 Visual Classification Soil samples recovered from our field exploration were returned to our laboratory where they were visually classified by a geotechnical engineer in general accordance with the Unified Soil Classification System (ASTM D 2487). After reviewing the samples, no laboratory testing was deemed necessary. The samples will be retained in our laboratory for 30 days and then discarded unless we are notified otherwise in writing. The recovered samples were not evaluated, either visually or analytically, for chemical composition or environmental hazards. GFA will be pleased to perform these services for an additional fee, if required. 2.4 Geomorphic Conditions The geology of the site as mapped on the USDA Soil Survey website consists of EauGallie fine sand (3). These are sandy soils and organic soils are not indicated. Note that the Soil Survey generally extends to a maximum depth of 80 inches below ground surface and is not indicative of deeper soil conditions. Boring logs resulting from our field exploration are presented in Appendix D - Log of Boring Records. The boring logs contain the soil descriptions and the standard penetration test (SPT) N -values logged during the drilling and sampling activities. The soil boring data reflect information from a specific test location only and the soil conditions may vary between the strata interfaces indicated on the logs. The soil classifications and descriptions shown on the logs are generally based upon visual characterizations of the recovered samples using the Unified Soil Classification System. See Appendix E - Discussion of Soil Groups, for a detailed description of various soil groups. 6 FF