Technical Manual

Inc.

p 186

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.

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.