Bsi bs en 01993 5 2007 na + a1 2012

NA+A1:2012 to BS EN 1993-5:2007

BSI Standards Publication

UK National Annex to
Eurocode 3: Design of
steel structures –
Part 5: Piling


NA+A1:2012 to BS EN 1993-5:2007

NATIONAL ANNEX

Publishing and copyright information
The BSI copyright notice displayed in this document indicates when the
document was last issued.
© The British Standards Institution 2012
Published by BSI Standards Limited 2012
ISBN 978 0 580 78488 0
ICS 91.010.30; 91.080.10
The following BSI references relate to the work on this standard:
Committee reference B/525/31
Draft for comment 08/30128156 DC, 12/30260809 DC

Publication history
First published July 2009

Amendments issued since publication
Date

Text affected

July 2012

A1: see Introduction.

Summary of pages
This document comprises a front cover, an inside front cover,
pages 1 to 8, an inside back cover and a back cover.


NATIONAL ANNEX



NA+A1:2012 to BS EN 1993-5:2007

National Annex (informative) to
BS EN 1993-5:2007, Eurocode 3: Design
of steel structures – Part 5: Piling

Introduction
This National Annex is published by BSI Standards Limited, under
licence from The British Standards Institution. This National Annex has
been prepared by BSI Subcommittee B/525/31, Structural use of steel.
In the UK it is to be used in conjunction with BS EN 1993‑5:2007.
The start and finish of text introduced or altered by National
Amendment No.1 is indicated in the text by tags . Minor
editorial changes are not tagged.

NA.1Scope
This National Annex gives:
a) the UK decisions for the Nationally Determined Parameters
described in the following subclauses of BS EN 1993-5:2007:
—— 3.7 (1)

—— 5.2.2 (13)

—— 7.2.3 (2)

—— 3.9 (1)P

—— 5.2.5 (7)

—— 7.4.2 (4)

—— 4.4 (1)

—— 5.5.4 (2)

—— A.3.1 (3)

—— 5.1.1 (4)

—— 6.4 (3)

—— B.5.4 (1)

—— 5.2.2 (2)

—— 7.1 (4)

—— D.2.2 (5)

b) the UK decisions on the status of BS EN 1993-5:2007 informative
annexes;
c) references to non-conflicting complementary information.



NA.2 Nationally Determined Parameters
UK decisions for the Nationally Determined Parameters described in
BS EN 1993-5:2007 are given in Table NA.1.



NA.3 Decisions on the status of the informative
annexes
Informative annexes B, C and D may be used.



NA.4 References to non-contradictory
complementary information
The following references contain non-contradictory complementary
information for use with BS EN 1993-5:2007.
•

PD 6695-5.

•

For further information on the durability of steel piles, see
the Piling Handbook 8th edition [1] and the Corus brochure,
A corrosion protection guide for steel bearing piles in temperate
climates [2].
â The British Standards Institution 2012 ã

1


NA+A1:2012 to BS EN 1993-5:2007

NATIONAL ANNEX

•

For additional information concerning ALWC, reference should be
made to CIRIA document C634 [3].

•

Further information and guidance on the selection of values
for bB is available from the Steel Piling Group website at
www.steelpilinggroup.org

•

Further information and guidance on the selection of values
for bD is available from the Steel Piling Group website at
www.steelpilinggroup.org.

2 ã â The British Standards Institution 2012


Nationally Determined
Parameter

Minimum yield
strength of high
strength steel fy,spec,max

Lowest service
temperature

Values for corrosion
rates

Subclause

3.7 (1)

3.9 (1)P

4.4 (1)

BS EN 1993-5:2007,
Table 4.1 and

Table 4.2

0,00
0,15
0,20
0,18
0,50

Undisturbed natural soils (sand, silt, clay,
schist…)
Polluted natural soils and industrial sites
Aggressive natural soils (swamp, marsh,
peat…)
Non-compacted and non-aggressive fills
(clay, schist, sand, silt…)
Non-compacted and aggressive fills
(ashes, slag…)

2,00

0,70

1,00

0,75

0,30

25
years

3,25

1,20

1,75

1,50

0,60

50
years

4,50

1,70

2,50

2,25

0,90

75
years

5,75

2,20

3,25

3,00

1,20

100
years

7,00

2,70

4,00

3,75

1,50

125
years

NOTE 2 The values given for 5 years and 25 years are based on measurements, whereas the
other values are extrapolated.

NOTE 1 Corrosion rates in compacted fills are lower than those in non-compacted ones. In
compacted fills the figures in the table should be divided by two.

5

years

Required design working life

Table 4.1 – Loss of thickness (mm) per face due to corrosion of bearing piles and sheet
piles in soils, with or without groundwater

Tables 4.1 and Table 4.2 are replaced by:

−15 °C

Use the recommended value.

500 N/mm2

None

UK decision

Eurocode
recommendation

Table NA.1  UK decisions for Nationally Determined Parameters described in BS EN 1993-5:2007

NATIONAL ANNEX
NA+A1:2012 to BS EN 1993-5:2007

© The British Standards Institution 2012  • 

3

Subclause

Nationally Determined
Parameter

Eurocode
recommendation

4 ã â The British Standards Institution 2012
0,15
0,30

0,55

0,25

Common fresh water (river, ship canal) in
the zone of high attack (water line)
Brackish or very polluted fresh water
(sewage, industrial effluent…) in the
zone of high attack (water line)
Sea water in temperate climates in the
high tide splash zone or in the low water
zone (see Note 3)
Sea water in temperate climates in the
zone of permanent immersion or in the
intertidal zone

0,90

1,90

1,30

0,55

25
years

1,75

3,75

2,30

0,90

50
years

2,60

5,60

3,30

1,15

75
years

3,50

7,50

4,30

1,40

100
years

4,40

Protection
system
required

5,30

1,65

125
years

NOTE 3 The values in this table for corrosion loss in the low water zone apply to situations
where the effects of Accelerated Low Water Corrosion (ALWC) are not a design requirement.
ALWC is a particularly aggressive form of corrosion associated with bacterial activity at low

water level in marine conditions. Attack is random both within and between locations and
typically at or just above the lowest astronomical tide (LAT) level. Due to the high rate of steel
loss when ALWC occurs, the life expectancy of a pile will be short and it is recommended that
a protection system is used to control the situation rather than reliance on sacrificial steel.
Suitable options may be painting or cementitious coating but it is also recommended that
consideration is given to installation of a cathodic protection system either immediately or at a
later date if necessary. Whilst this phenomenon might not affect every location, if ignored, this
rapid form of attack can result in costly repair and maintenance works at an unexpectedly early
stage in the life of a structure.

NOTE 2 The values given for 5 years and 25 years are based on measurements, whereas the
other values are extrapolated.

NOTE 1 The highest corrosion rate is usually found in the splash zone or at the low water level
in tidal waters. However, in most cases, the highest bending stresses occur in the permanent
immersion zone (see BS EN 1993-5:2007, Figure 4-1).

5
years

Required design working life

Table 4.2 – Loss of thickness (mm) per face due to corrosion of bearing piles and sheet
piles in fresh water or seawater

UK decision

Table NA.1  UK decisions for Nationally Determined Parameters described in BS EN 1993-5:2007 (continued)

NA+A1:2012 to BS EN 1993-5:2007

NATIONAL ANNEX


Values of partial
factors, cM0, cM1, and

Values of factor bB
for single and double
U-piles

Length l of continuous
intermittent butt welds

Value of factor bR

Height of head h

Value of factor bD

Values of partial
factors, cM2, and
cM3,ser

Value of factor kt

5.1.1 (4)

5.2.2 (2)

5.2.2 (13)

5.2.5 (7)

5.5.4 (2)

6.4 (3)

7.1 (4)

7.2.3 (2)

1,0

Limiting values for
fu/fy and eu/ey

Value of factor ηsys

Required density or
stiffness of tube filling

A.3.1 (3)

B.5.4 (1)

D.2.2 (5)

None

fu/fy = 1,1 and

eu/ey = 15

Design procedure for
pile couplers

None

0,6

cM2 = 1,25 and
cM3,ser = 1,10

None

5 m

0,8

500 mm

None

Given in
BS EN 1993-1-1

Eurocode
recommendation

7.4.2 (4)

cM2

Nationally Determined
Parameter

Subclause

No additional information is provided.

Use the recommended value.

Given in NA to BS EN 1993-1-1.

No design information additional to that already provided in BS EN 1993-1-8:2005,
BS EN 1993-5:2007 and BS EN 12699:2001 is given for the design of pile couplers.

Only in cases where the structural detailing of the location where the anchor rod is joined to
the wall is such that bending moments are avoided at that location, the recommended value
for kt may be chosen as kt = 0,9.

NOTE  The recommended value for kt is kt = 0,6. This is motivated for cases where possible
bending in the anchor as an effect of actions is not made explicit.

Use the recommended value.

Use the recommended values.

The recommended values for the factor bD applicable to UK designs are given in Table NA.2.

Use the recommended value.

Use the recommended value.

Use the recommended value.

The recommended values for the factor bB applicable to UK designs are given in Table NA.2.

Use values given in NA to BS EN 1993-1-1.

UK decision

Table NA.1  UK decisions for Nationally Determined Parameters described in BS EN 1993-5:2007 (continued)

NATIONAL ANNEX
NA+A1:2012 to BS EN 1993-5:2007

© The British Standards Institution 2012  • 

5


NA+A1:2012 to BS EN 1993-5:2007

NATIONAL ANNEX

Table NA.2  Reduction factors for U shaped sheet piles.
Type of
U-pile unit

Number of

structural
support levels
(see Note 1)

Reduction factors bB and bD referred to in 5.2.2 (2); 5.2.2 (9); 5.2.3 (2); 6.4 (3)
(see Notes 2, 3, 4, and 5)
Highly unfavourable
conditions

Unfavourable
conditions

(see Note 6)

(see Note 7)

Favourable conditions
(see Note 8)

bB

bD

bB

bD

bB

bD

Singles or
uncrimped
doubles

0

0,40

0,30

0,50

0,35

0,60

0,40

1

0,55

0,35

0,60

0,40

0,70

0,45

>1

0,65

0,45

0,70

0,50

0,80

0,55

Crimped
or welded
doubles

0

0,70

0,60

0,75

0,65

0,80

0,70

1

0,80

0,70

0,85

0,75

0,95

0,80

>1

0,90

0,80

0,95

0,85

1,00

0,90

NOTE 1  Any restraint device which leads to the shear force changing from positive to negative or vice versa
may be considered as a structural support. The toe of the piles should not be considered as a restraint. The
benefit of the restraint should only be taken into account for design situations following installation of the
restraint. Restraints may be regarded as structural supports only when designed as such in accordance with
relevant standards.
NOTE 2  If interlocks are not treated with sealants or lubricants, the coefficients may be increased by +0,05 (to
a maximum value of 1,0).
NOTE 3  The interlocks of single or uncrimped U-piles should be connected after installation by a structural
weld (minimum 6 mm fillet) near the top. The minimum length of this weld should be 100 mm for walls
with retained heights up to 2,5 m; for greater retained heights, an additional 100 mm of weld should be
provided for every additional 1 m of retained height, up to a maximum of 500 mm (applies to retained heights
above 6,5 m). Provision of this weld permits the bB coefficients to be increased by +0,1, 0,15 or 0,2 respectively
for highly unfavourable, unfavourable and favourable conditions (to a maximum value of 1,0); and the bD
coefficients likewise by +0,15, 0,2 or 0,25 (to a maximum value of 1,0).
NOTE 4  The enhancement of b values by additional methods may be considered by the designer subject
to demonstration, by calculation, testing or by other means, that the appropriate degree of shear force
transmission will take place to justify higher coefficients than those values obtained from this table and notes.
NOTE 5  The bB and bD coefficients for the entire pile should be selected according to the most unfavourable
conditions that apply.
NOTE 6  Highly unfavourable conditions are:
•

retaining substantial depths of free water;

•

significant presence of very low strength fine soil or very loose coarse soil (as defined in BS EN ISO 14688-1)

below formation;

•

artificial loosening by pre-augering in fine soil below final excavation level (unless it can be demonstrated
by testing or other means, that the pre-augered soil offers friction equivalent to or better than that of a
low strength fine soil or loose coarse soil, in which case better conditions may be assumed);

•

artificial loosening of fine soil by water jetting at a rate exceeding 240 L/min (see Annex D.2 of
BS EN 12063:1999); or

•

artificial loosening of coarse soil by water jetting at a rate exceeding 480 litres per minute (see Annex D.2
of BS EN 12063:1999).

NOTE 7  Unfavourable conditions are:
•

significant presence of low strength fine soil or loose coarse soil (as defined in BS EN ISO 14688-1) below
formation;

•

artificial loosening by pre-augering in coarse soil below final excavation level (unless it can be
demonstrated by testing or other means, that the pre-augered soil offers friction equivalent to or better
than that of a medium dense soil, in which case better conditions may be assumed); or

•

artificial loosening of fine soil by water jetting at a rate between 60 L/min and 240 L/min (see Annex D.2 of
BS EN 12063:1999) or when coarse soil has been artificially loosened at a rate between 240 L/min and 480 L/min.

NOTE 8  Favourable conditions may be assumed if none of the highly unfavourable or unfavourable
conditions apply.

6 ã â The British Standards Institution 2012


NATIONAL ANNEX

NA+A1:2012 to BS EN 1993-5:2007

Bibliography

Standards publications
For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including
any amendments) applies.
BS EN 1993-1-1, Eurocode 3 – Design of steel structures – Part 1-1:
General rules and rules for building
BS EN 1993-1-8:2005, Eurocode 3 – Design of steel structures – Part 1-8:
Design of joints
BS EN 12063:1999, Execution of special geotechnical work – Sheet
pile walls
BS EN 12699:2001, Execution of special geotechnical work –
Displacement piles
BS EN ISO 14688-1, Geotechnical investigation and testing –

Identification and classification of soil – Part 1: Identification and
description
NA to BS EN 1993-1-1, UK National Annex to Eurocode 3 – Design of
steel structures – Part 1-1: General rules and rules for building
PD 6695-5, Background paper to the UK National Annex to
BS EN 1993-5 1)


Other publications
[1] The Piling Handbook 8th edition, Arcelor.
www.sheet-piling.arcelor.com
[2] Corus, A corrosion protection guide for steel bearing piles in
temperate climates. www.corusgroup.com
[3] CIRIA document C634, Management of Accelerated Low Water
Corrosion in Steel Maritime Structures. www.ciria.org

1)

In preparation.
© The British Standards Institution 2012  • 

7


NA+A1:2012 to BS EN 1993-5:2007

8 ã â The British Standards Institution 2012

NATIONAL ANNEX

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