1. Atlantic Testing Laboratories
Subsurface Investigation
and
Geotechnical Evaluation
NYSCHSA
January 22, 2013

2. Topics
 Designing a Subsurface Investigation Program
 Subsurface Investigation Methodologies
 Subsurface Investigation Log Review
 CPT Log Review
 Soil Classifications
 Engineering Properties of Soil
 Geotechnical Evaluation

3. Designing a Subsurface Investigation
 Determining the Number of Soil Borings
 Former NYS Building Code
 The Building Code of NYS 2002 (based on IBC 2000)
 As a Rule of Thumb – 1 Boring for every 2,500 to 5,000 s.f.
of building footprint

4. Seismic Site Classification
Determination
 Code does not require a 100 foot boring
 Calculate the average soil properties in the
top 100 feet. (either soil shear wave velocity,
Standard Penetration resistance, of soil
undrained shear strength)
 Section 1615.1.1 allows the register design
professional to assume based on knowledge
of local geology

5. Seismic Site Classification
Determination
 Use table 1615.1.1 to determine Seismic Site
Classification (class A, B, C, D, E, or F)
 Obtain the maximum considered earthquake ground
motion of 0.2 sec spectral response (Ss)
 Obtain the maximum considered earthquake ground
motion of 1 sec spectral response (S1)

6. Seismic Site Classification
Determination
 Can be obtained from the maps in the code,
the CD prepared by ICC, or USGS web page
 Adjust Ss and S1 based on coefficients
presented in Tables 1615.1.2(1) and
1615.1.2(2)

7. Seismic Site Classification
Determination
 Central New York sites typically fall into site
class B, C, or D
 Glacial till and/or bedrock is often found at
shallow depths.
 Exception is Onondaga Lake area, bedrock
and/or glacial till in excess of 300 feet

8. Subsurface Investigation
Methodologies
 ConventionalSoil Borings
 Cone Penetration
Testing (CPT)
 Geoprobe
 Test Pits

9. Conventional Drilling
 Hollow Stem Augers
 Flush Joint Casing
 Split Spoon Sampling
 Undisturbed Samples
 Bedrock Coring

10. Hollow Stem Augers
 Auger Flights around a center sampling tube
 Size refers to diameter of
sampling tube
 Advantages
 Quick
 More Economical
 Water not necessary
 Ability to collect bulk samples

11. Flush Joint Casing
 Can be Driven or Spun-in the ground
 Advantages
 Can be advanced through
cobbles and boulder
 Can be advanced to depths
of around 300 feet
 Provides a stable hole for
special testing such as
permeability testing

12. Split Spoon Sampling
 In accordance with ASTM D 1586
 Sample for soil classification and future
laboratory testing
 Retained in sealed glass jars

13. Undisturbed Samples
 In accordance with ASTM D 1587
 Obtained from cohesive soils
 Returned to the laboratory for
multiple analyses
 Provides accurate representation
of in-situ conditions

14. Bedrock Coring
 In accordance with ASTM D 2113
 Double tubed core barrel with a diamond
cutting shoe
 Samples are returned for classification, RQD
determination, and laboratory analysis

16. Cone Penetration Testing
 Pushes a “cone” with
electronic sensors
 In accordance with ASTM D
3441
 Determines:
 Tip resistance
 Side friction
 Pore water pressure
 Seismic shear wave
velocity

17. Cone Penetration Testing
 Advantages
 Rapid: Can advance 200 to 400 feet per day
 Accurately determines to Seismic Site Classification
 Replicates pile driving
 Useful in cohesive and sand soils

18. Cone Penetration Testing
 Disadvantages
 Not able to be pushed in dense soils or bedrock
 No sample recovered, soil classifications relies on
soil properties
 Requires a large drill rig for reaction weight

19. Typical CPT Log

20. Cone Penetration Testing

21. Geoprobe
Data: Environmental
Sampling, Soil
Classification, Bedrock
Profile, and Groundwater
Elevation

22. Geoprobe

23. Test Pits
Advantages
 Good for fill sites
 Groundwater
information
 Collect bulk samples
Disadvantages
 Limited depth
 Cannot determine
Seismic Site
Classification

24. Subsurface Investigation Log
Review
 Contain a wealth of information
 Soil types
 Soil consistency
 Groundwater information

29. Soil Classification
 Several Systems Used
 Burmister
 Unified Soil Classification System
 NYSDOT
 USDA

30. Burmister Soil Classification
 Visual-manual procedure
 Performed by the drillers in the field
 Soil classification verified in the laboratory

31. Burmister Soil Classification
BOULDERS: > 12” Particle Size
COBBLES: 3” – 12” Particle Size
GRAVEL: Course: 3” - 1” Sieve Size
Medium: 1” – ½” Sieve Size
Fine: ½” - #4 Sieve Size
SAND: Course: #4 - #10 Sieve Size
Medium: #10 - #40 Sieve Size
Fine: #40 - #200 Sieve Size
SILT: #200 Sieve (0.074 mm) to 0.005 mm
CLAY: <0.005 mm Particle Size

32. Unified Soil Classification System
 In accordance with ASTM D 2487 and ASTM
D 2488
 ASTM D 2487 - laboratory analysis
 ASTM D 2488 - visual manual procedure
performed in laboratory

33. Unified Soil Classification

34. Engineering Properties of Soil
 Natural Moisture Content
 Atterberg Limits
 Liquid Limit
 Plastic Limit
 Plasticity Index
 Shear Strength
 Internal Friction Angle
 Consolidation Potential

35. Soil Property Uses
 Bearing Capacity
 Lateral Earth Pressures
 Slope Stability
 Frost Heave Potential

36. Geotechnical Evaluation
 Geotechnical Report Contents
 Optional Services
 Site Visit

37. Thank You

38. Question & Answer
How deep can you
drill with hollow stem
augers?

39. Question & Answer
In what type of soil
conditions is a
Shelby Tube most
conducive?

40. Question & Answer
Does a 100 foot
boring need to be
drilled to determine
the seismic site
classification?

41. Question & Answer
True or False:
Determining the
groundwater
table is extremely
important.

42. Question & Answer
What type of soil parameter
does Cone Penetration
Testing (CPT) determine that
conventional soil borings can
not?

43. Thank You