Pile Design and Construction Practice, Fifth edition

(3) loss of anchorage force by excessive displacement of the anchor head or by creep and
relaxation
(4) failure or excessive distortion on parts of the structure due to the applied anchorage
force and
(5) interaction of groups of anchorages with the ground and adjoining structures.

BSEN 1537 requires construction steel in anchors to be in accordance with EC2 and EC3.
Prestressing steel used for tendons is to comply with pr EN 10138, Design of prestressing
steel, and EC2 part 1–5, Use of unbonded and external prestressing tendons. Cement grouts
are to comply with BSEN 445, 446 and 447; resin grouts may be used subject to appropri-
ate tests for the particular application. Admixtures and inert fillers are permitted to be

Piles to resist uplift and lateral loading 325

2.0

2.0

1.8

1.8

1.6

1.6

1.4

1.4

1.2

1.2

1.0

1.0

0.8

0.8

0.6

0.6

0.4

0.4

0.2

0

0 0.2

Surface of rock

Volume of cone

for single

anchor 5 Vc

Overlap volume Vm

M number of ranks

Anchor positions

N number of lines

Overlap volume

Vn

Total volume enclosed by group of overlapping cones

ppp

S

S

S

Anchors

5 V 5 Vc [MN–N(M–1) ]

Vm

Vc

Vn

Vc

• M(N–1)

S

m

P

n

P

L

S

L

L m L n S m

5

5

×

×

P/n

(^) &

Vm
Vc
(^) V
V m
c &
nP
&
Vn
Vc
S/m (^) &
(^) 
V Vn
c
(b)
Figure 6.17(b) Charts for calculating total volume of rock enclosed by groups of anchors arranged
on rectangular grid pattern.