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APPENDIX 2F
MODEL SPECIFICATIONS
Chapter 2
Helical Foundation Systems
The alignment load (AL) should be the minimum load required to align the testing
apparatus and should not exceed 5% of the Design Test Load (DTL). The verification
test helical soil nail shall be monitored for creep at 1.50 DTL. At the discretion of the
Owner, either 10 minute or 60 minutes creep tests shall be performed at the maximum
test load (1.5 DTL). The creep period shall start as soon as the maximum test load is
applied, and the helical nail movement shall be measured and recorded at 1 minute,
2, 3, 5, 6, and 10 minutes. Where the helical nail movement between 1 minute and 10
minutes exceeds 0.08 inch, the maximum test load shall be maintained until the helical
nail movement is less than 0.08 inch for any one log cycle increment (i.e., 2 minutes and
20 minutes, etc.).
13.6 A helical soil nail shall be considered acceptable when the following criteria are met:
13.6.1 For verification tests, a total creep movement of less than 0.08 inch per log cycle of
time between the 6 and 60 minute readings, and the creep rate is linear or decreasing
throughout the creep test load hold period.
13.6.2 For proof tests, a total creep movement of less than 0.08 inch is measured between
the 1 and 10 minute readings, or a total creep movement of less than 0.08 inch is
measured between the subsequent log cycles, and the creep rate is linear or decreasing
throughout the creep test load hold period.
13.6.3 For verification and proof tests, a pullout failure does not occur at the maximum test
load. Pullout failure is defined as the load which results in continued pullout (creep)
movement of the test helical soil nail.
13.7 If the pre-production verification test nail does not meet the criterion in Section 13.6, it shall be
rejected and the Installing Contractor shall propose alternative methods and install replacement
verification test helical nails. Successful proof tested helical soil nails meeting the above test
acceptance criteria may be used as production nails, provided the number of helix plates on the
test nail is such that the helical nail length is equal to or greater than the specified length. If the
production proof test nail does not meet this criterion, it shall become sacrificial and shall be
replaced with an additional production helical nail installed.
13.8 The Owner may require the Installing Contractor to replace some or all of the installed production
soil nails between a failed proof test soil nail and the adjacent passing proof test nail. Or, the
Owner may require the installation and testing of additional proof test helical nails to verify that
adjacent previously installed production nails have sufficient load carrying capacity.
14
CLEANUP
14.1 Within one week of completion of the work, the Installing Contractor shall remove any and all
material, equipment, tools, debris or other items belonging to the Installing Contractor or used
under the Installing Contractor’s direction.
