Pile Design and Construction Practice, Fifth edition

326 Piles to resist uplift and lateral loading
used in grout mixes provided that they do not contain materials liable to cause corrosion of
the tendons. Resin grouts are permitted.
BS EN 1537 gives detailed consideration to the selection, design, fabrication, and installation
of plastics sheathing used for corrosion protection. Temporary anchors are not required
to be sheathed provided that they have protection from corrosion suitable for their design life.
Drilling for anchorages is required to be within a deviation limit of not more than 1/30 of
the anchor length. The procedure for making permeability tests in the drilled holes using
water and grout to investigate the possibility of grout loss is described.
BS EN 1537 defines three types of test on anchorages:
(1) Investigation test
(2) Suitability test
(3) Acceptance test
The investigation test is made to establish the ultimate resistance of the anchor at the
grout/ground interface and to determine the characteristics of the anchorage in the working
load range. The suitability test is made to confirm that a particular anchorage system will be
adequate for the ground conditions on the project site. In the case of permanent anchorages,
the test is made with sheathed tendons and is required to establish acceptable limits of creep
or load loss at the proof and lock-off loads. In cases where no investigation tests are made
the suitability test is undertaken to demonstrate anchorage characteristics and to provide
criteria for acceptance creep and load loss.
The acceptance test is made at the project construction stage on each working anchor with
the following requirements:
(1) To demonstrate that the proof load can be sustained
(2) To determine the apparent tension free length
(3) To ensure that the lock-off load is at the design load level, excluding friction and
(4) To determine creep or load loss characteristics at the serviceability limit-state where
necessary.
The acceptance tests are to be made after lock-off and before the anchorage becomes
operational.
BS EN 1537 gives detailed information on the procedure for conducting anchorage tests,
the interpretation of the results, monitoring of behaviour, and record keeping. Items such as
health and safety, and environmental matters including air and water pollution, noise and
vibration are dealt with.
For the purpose of design verification characteristic values of anchorage resistance R ak
obtained from pull-out tests are divided by the partial factor � a to determine the design
resistance R ad.
R ad � R ad /� a
(6.10)
values of � a related to the Ground Resistance R series (see Section 4.1.4) are shown in
Table 6.4. Correlation factors can be applied to obtain R ad from suitability tests. Figures for
these factors are not given in Annex A of EC7, but it is specified that at least three tests
should be made for each distinct condition of ground and structure.