Pile Design and Construction Practice, Fifth edition

In addition to dealing with the use of anchorages for restraining uplift on structures, EC7
(Section 8) makes recommendations covering anchorages for retaining walls, slopes, cuttings
and tunnels. Only their applications relevant to uplift on structures will be described below.
EC7 requires tension piles, where used as anchors, to be designed as described for compression
piles in Section 7 of the Code. In the case of anchorages formed by grouting tendons into
drilled holes, EC7 requires their design and installation to be in accordance with BSEN
1537: 1999, Ground anchors, which could eventually supersede the more comprehensive
BS8081 referred to above.
BSEN 1537 defines temporary anchors as those with a design life of less than two years,
and permanent anchors as those with a design life of two years or more. The ultimate limit-
states to be considered are the same as those listed at the beginning of this section. In addition,
BSEC7 and EN 1537 require design measures against the following:

(1) Structural failure of the anchor head
(2) Distortion or corrosion of the anchor head

324 Piles to resist uplift and lateral loading

3.2

3.0

L 2.8

2.6

2.4

2.2

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

1.8(a)

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

30 40 50 60 70 80 90

Angle of inclination θ of anchor to (Vertical)

horizontal in degrees

Volume of cone

Vc

Overlap

volume DV

u

30 ° 30 °

Anchor

n

m/L

n/L

Vc/L 3

m/L

and

n/L

Vc

/L

3

m

Figure 6.17(a) Chart for calculating volumes of single or over-lapping cones with vertical or inclined axes.