DS/EN 1997-1 DK NA:2013webshop.ds.dk/Files/Files/Products/M284340_attachPV.pdf · This national annex (NA) is a revision of DS/EN 1997-1 DK NA:2010-09 and replaces the latter on 2013-05-15

Page 1 of 33 DS/EN 1997-1 DK NA:2013

DS/EN 1997-1 DK NA:2013 National Annex to

Eurocode 7: Geotechnical design – Part 1: General rules _______________________________________________________________________

Foreword

This national annex (NA) is a revision of DS/EN 1997-1 DK NA:2010-09 and replaces the latter on

2013-05-15. For a transition period until 2013-09-01, this National Annex as well as the previous

National Annex will be applicable.

Previous versions, addenda and an overview of all National Annexes can be found at

www.Eurocodes.dk

This NA specifies the conditions for the implementation in Denmark of DS/EN 1997-1 for building

according to the Danish Building Act or the Danish building legislation and for civil engineering

works subject to the Road Rules of the Road Directorate and the Railway Codes published by

Banedanmark. Other parties can put this NA into effect by referring thereto.

The national choices may be in the form of nationally applicable values, an option between methods

given in the Eurocode, or the addition of complementary guidance.

This National Annex includes:

national choices and an overview of all clauses where national choices are allowed;

descriptions of national choices;

complementary (non-contradictory) information which may assist the user of the Eurocode.

Page 2 of 33 DS/EN 1997-1 DK NA:2013

National choices and an overview of all clauses where national choices

are allowed

Clause Subject

Choice

2.1(8)P

Design requirements

The manner in which these minimum

requirements are satisfied may be

given in the National Annex.

The national minimum requirements are

given in Annexes D, K and L of this Na-

tional Annex.

2.4.6.1(4)P

Design values of actions The values of the partial factors may

be set by the National Annex.

Values of the partial factors are given in

clauses A.2, A.3 and A.4 of this National

Annex.

2.4.6.2(2)P

Design values of geotechnical pa-

rameters The values of the partial factors may



clauses A.2, A.3 and A.4 of this National

Annex.

2.4.7.1(2)P

Ultimate limit states - General The values of the partial factors may



clauses A.2, A.3.1 and A.4 of this National

Annex.

2.4.7.1(3)

Ultimate limit states - General The values of the partial factors may



clause A.6 of this National Annex.

2.4.7.1(4) Ultimate limit states - General

The values of the partial factors may



clauses A.2, A.3.1 and A.4 of this National

Annex.





clause A.3.1 of this National Annex.






COPYRIGHT © Danish Standards Foundation. Not for commercial use or reproduction. DS/EN 1997-1 DK NA:2013 English

Page 3 of 33 DS/EN 1997-1 DK NA:2013

Clause Subject

Choice

2.4.7.2(2)P

Verification of static equilibrium

(EQU) The values of the partial factors may




2.4.7.3.2(3)P

Design effects of actions The values of the partial factors may




2.4.7.3.3(2)P

Design resistances The values of the partial factors may




2.4.7.3.4.1(P)

Design approaches - General NOTE 1 - The way to use equations

(2.6) and (2.7) and the particular de-

sign approach to be used may be giv-

en in the National Annex.

NOTE 1 – The way to use equations (2.6)

and (2.7) refers in DK to design approach

3.

2.4.7.4(2) Verification procedure and partial

factors for uplift

(2) Additional resistance to uplift

may also be treated as a stabilising

permanent vertical action (GStb;d)

The paragraph corresponds to the

content of 10.2(2)P as changed by

corrigendum DS/EN 1997-

1/AC:2010 and should be as follows:

(2) If allowed by the National Annex,

resistance to uplift by friction or an-

chor forces may also be treated as a

stabilising permanent vertical action

(Gstb;d).

Resistance to uplift by friction or anchor

forces is not to be treated as a stabilising

permanent vertical action (Gstb;d).

2.4.7.4(3)P

Verification procedure and partial

factors for uplift The values of the partial factors may




2.4.7.5(2)P

Verification of resistance to failure

by heave due to seepage of water in

the ground (HYD) The values of the partial factors may





Page 4 of 33 DS/EN 1997-1 DK NA:2013

Clause Subject

Choice

2.4.8(2)

Serviceability limit states The values of the partial factors may




2.4.9(1)P

Limiting values for movements of

foundations The permitted foundation movements

may be set by the National Annex.

Permitted foundation movements are given

in Annex H and the National Appendix to

Annex H.

2.5(1)

Design by prescriptive measures Reference to such conventional and

generally conservative rules may be

set by the National Annex.

Conventional and generally conservative

rules are given in Annexes D, K and L of

this National Annex.

7.6.2.2(8)P

Ultimate compressive resistance

from static load tests The values of the correlation factors




7.6.2.2(14)P


from static load tests The values of the partial factors may




7.6.2.3(4)P


from ground test results The values of the partial factors may




7.6.2.3(5)P Ultimate compressive resistance

from ground test results The values of the correlation factors




7.6.2.3(8)


from ground test results If this alternative procedure is ap-

plied, the values of the partial factors

b and s recommended in Annex A

may need to be corrected by a model

factor larger than 1,0. The value of

the model factor may be set by the

National Annex.

The specifications are not applicable in

DK.


Page 5 of 33 DS/EN 1997-1 DK NA:2013

Clause Subject

Choice

7.6.2.4(4)P


from dynamic impact tests The values of the partial factors and

correlation factors may be set by the

National Annex.


clauses A.3.1 and A.3.2 of this National

Annex.

7.6.3.2(2)P

Ultimate tensile resistance from

pile load tests The values of the partial factors may




7.6.3.2(5)P


pile load tests The values of the correlation factors




7.6.3.3(3)P


ground test results The values of the partial factors may




7.6.3.3(4)P


ground test results The values of the correlation factors




7.6.3.3(6)


ground test results If this alternative procedure is ap-

plied, the values of the partial factor

s,t recommended in Annex A may

need to be corrected by a model fac-

tor larger than 1,0. The value of the

model factor may be set by the Na-

tional Annex.

The model factor applied in DK is taken as

1,0 where design is based on the analytical

method for determining bearing resistance

specified in Annex L of this National An-

nex.

8.5.2(2)P

Design values of pull-out resistance

determined from the results of

tests The value of the partial factor may be





Page 6 of 33 DS/EN 1997-1 DK NA:2013

Clause Subject

Choice

8.5.2(3)

Design values of pull-out resistance

determined from the results of

tests NOTE - 8.5.2(3) refers to those types

of anchorage that are not individually

checked by acceptance tests. If a cor-

relation factor a is used, it is to be

based on experience or be set by the

National Annex.

NOTE - 8.5.2(3) applies to all types of

anchorage. The value of the correlation

factor a is given in clause A.3.3 of this

National Annex.

8.6(4)

Serviceability limit state design The value of the model factor may be


No value of a model factor is given in DK.

Reference is made to clause A.6 of this

National Annex.

10.2(2)P Failure by uplift

The third sentence:

“Resistance to uplift by friction or

anchor forces may also be treated as

a stabilising permanent vertical ac-

tion (Gstb;d)"

is replaced by

If allowed by the National Annex,




(Gstb;d).

The correction appears from corri-

gendum DS/EN 1997-1/AC:2010,

but is incorrectly stated for 10.2(3)

Resistance to uplift by friction or anchor

forces shall not to be treated as a stabilis-

ing permanent vertical action (Gstb;d).


Page 7 of 33 DS/EN 1997-1 DK NA:2013

Clause Subject

Choice

10.2(3) Failure by uplift

Modification 23 in corrigendum

DS/EN 1997-1/AC:2010 refers to

clause 10.2 as follows (quote)

Part (3):

Replace the entire 1st paragraph

with the following:

“If allowed by the National Annex,




(Gstb;d).

NOTE - The values of the partial

factors may be set by the National

Annex.”

The modification (entered by CEN) refers

incorrectly to clause 10.2.3(3) but should

refer to clause 10.2(2).

The original text:

”(3) In simple cases, the check of equation

(2.8) in terms of forces may be replaced by

a check in terms of total stresses and pore-

water pressures.”

is maintained.

11.5.1(1)P

Stability analysis for slopes The values of the partial factors may




A.2 Partial factors for equilibrium lim-

it state (EQU) verification

Partial factors and consequence factors are

given in clause A.2 of this National An-

nex.

A.3.1 Partial factors on actions (F) or

the effects of actions (E)

Partial factors and consequence factors are

given in clause A.3.1 of this National An-

nex.

A.3.2 Partial factors for soil parameters

(M)

Partial factors are given in clause A.3.1 of

this National Annex.

A.3.3.1 Partial resistance factors for

spread foundations

Partial resistance factors (R) for spread

foundations are not used in DK, cf. clause

A.3.1 of this National Annex.1

A.3.3.2 Partial resistance factors for pile

foundations

Partial resistance factors for pile founda-

tions are given in clause A.3.1 of this Na-

tional Annex.

A.3.3.3 Correlation factors for pile founda-

tions

Correlation factors for pile foundations are

given in clause A.3.2 of this National An-

nex.


Page 8 of 33 DS/EN 1997-1 DK NA:2013

Clause Subject

Choice

A.3.3.4 Partial resistance factors for pre-

stressed anchorages Partial resistance factors for pre-

stressed and non pre-stressed anchor-

ages.

Partial resistance factors for anchorages

applicable to pre-stressed as well as non

pre-stressed anchorages are given in clause

A.3.1 of this National Annex. Correlation

factors to derive characteristic values on

the basis of static load tests and soil pa-

rameters, respectively, determined from

geotechnical investigations are given in

clause A.3.3.

A.3.3.5 Partial resistance factors (R) for

retaining structures

Partial resistance factors (R) for retaining

structures are not used in DK, cf. clause

A.3.1 of this National Annex.

A.3.3.6 Partial resistance factors (R) for

slopes and overall stability

Partial resistance factors (R) for slopes

and overall stability are not used in DK, cf.


A.4 Partial factors for uplift limit state

(UPL) verifications

Partial factors and consequence factors for

uplift limit state (UPL) verification are

given in clause A.4 of this National An-

nex.

A.5 Partial factors for hydraulic heave

limit state (HYD) verification

Partial factors for hydraulic heave limit

state (HYD) verification in DK are those

applied for uplift limit state (UPL) verifi-

cation, cf. clause A.5 of this National An-

nex.


Page 9 of 33 DS/EN 1997-1 DK NA:2013

Complementary (non-contradictory) information

Clause Subject Choice

2.4.7.3.4.4 Design approach 3 NOTE 2 applies in DK also for the deter-

mination of earth pressure.

7.6.2.2(9)


from static load tests


DK.

7.6.2.3(7)


from ground test results


DK.

A.6 Partial factors, correlation factors and

model factors for serviceability and

accidental limit states verification.

Partial factors, correlation factors and

model factors for serviceability and acci-

dental limit states verification are given in


Annex Subject

Choice

D Spread foundations Analytical meth-

od for bearing resistance calculation

Bearing resistance equations in combina-

tion with the partial factors for spread

foundations securing the safety required in

Denmark, are given in Annex D of this

National Annex..

H Limiting values of structural defor-

mation and foundation movement Complementary information regarding

conventional building structures is given in

the Appendix to Annex H.

K Special conditions for geotechnical

investigations and parameters

Particular Danish conditions for geotech-

nical investigations are given in Annex K

of this National Annex.

L Pile foundations. Analytical method

for bearing resistance calculation.

An analytical method for determining the

bearing resistance of piles is given in An-

nex L of this National Annex.


Page 10 of 33 DS/EN 1997-1 DK NA:2013

National choices

Annex A - normative

Partial and correlation factors for ultimate limit states and serviceability limit

states

A.1 Partial factors and correlation factors

(1)P The partial factors () for ultimate limit states and serviceability limit states in persistent and

transient design situations and the correlation factors ( ) for pile foundations and anchorages in all

design situations, are given in this Annex.

(2)P The partial factors for soil parameters (M) and resistance (R) as well as the correlation factors

() for pile foundations and anchorages are stated for design situations, where the safety evaluation

shall be performed using the lower design values. Where the safety evaluation is to be performed

using the upper design values, reciprocal values of the partial factors and correlation factors given

shall be applied.

NOTE – The partial factors apply to soil parameters determined taking account of the considerations specified in

DS/EN 1997-1, clause 3.3.6(1)P.

A.2 Partial factors for equilibrium limit state (EQU) verification

(1)P The partial factors () and consequences factors (KFI) are given in Table A.2-1.

(2)P For equilibrium limit state (EQU) verification, the partial factors on actions (F) and for soil

parameters (M) stated in Table A.2-1 shall be used.

The consequence factor KFI depends on the consequences class:

High consequences class CC3: KFI = 1,1

Medium consequences class CC2: KFI = 1,0

The low consequences class CC1 is not applied for geotechnical structures.

For the factor for the combination value of a variable action, ψ0, see DS/EN 1990.


Page 11 of 33 DS/EN 1997-1 DK NA:2013

Table A.2 - Partial factors for EQU design

Partial factors on actions γF

Per

man

ent

acti

on

Self-weight,

in general 1)

Unfavoura-

ble G;dst 1,1·KFI

Favourable G;stb 0,9

Self-weight

of soil and

(ground) water, ge-

otechnical

structures 2)

Unfavoura-

ble G;dst 1,1·KFI


Var

iab

le a

ctio

n

Buil

din

gs Leading

Unfavoura-ble

Q,1 1,5·KFI

Accompany-

ing

Unfavoura-

ble Q,i 1,5·ψ0·KFI

Var

iab

le a

ctio

n

Bri

dges

3) Leading

Unfavou-rable

Q,1 1,4·KFI5)

Accom-

panying

Unfavou-

rable Q,i 1,5·ψ0·KFI

Partial factors for soil parameters

γM

Angle of shearing resistance 7) ’ γφ 1,2

Effective cohesion γc’ 1,2

Undrained shear strength γcu 1,8

Unconfined strength γq 1,8

Weight density γγ 1,0

1) For structural actions, which include all types of permanent actions: cf. clause 2.1 in DS/EN 1991-1-1 2) Geotechnical actions, which comprise the self-weight of soil and (ground) water interacting with the geotechnical structure: cf. clause 1.5.2.1 in

DS/EN 1997-1 and clause A.3.1(2)P, NOTE, in DS/EN 1997-1 DK NA:2013

3) For variable actions on railway and road dams, quays i.a., the same partial factors are to applied as for bridges 5) For heavy carriages on rails (SW/2): 1,2 ∙KFI and 1,2, respectively

7) The partial factor is valid for tan φ


Page 12 of 33 DS/EN 1997-1 DK NA:2013

A.3 Partial factors for structural (STR) and geotechnical (GEO) limit states

verification

A.3.1 Partial factors on actions (F) or the effects of actions (E), for soil parameters (M)

and for resistance (R)

(1)P Partial factors () and consequence factors (KFI) are given in Table A.3-1 for spread

foundations, earth pressures and stability, and in Table A.3-2 for piles and anchors.

(2)P For structural (STR) and geotechnical (GEO) limit states verification, design approach 3 shall

be used with:

Combination: (A1* or A2†) "+" M2 "+" R3

and the partial factors on actions (F), for soil parameters (M) and for resistance (R) according to

Tables A.3-1 and A.3-2, as well as a factor (γ0) to the partial factor for strength parameters and re-

sistances of structural materials, cf. DS/EN 1992 – DS/EN 1996 and DS/EN 1999.

The consequence factor, KFI, depends on the consequences class:



The low consequences class, CC1, is not applied for geotechnical structures.


NOTE – Partial factors as stated for “Self-weight, in general” are to be assigned to structural actions referred to ge-

otechnical actions.

(3) The load combinations 1-5 in Tables A.3-1 and A.3-2 refer to all types of geotechnical struc-

tures where the load constitutes combinations of structural actions, earth pressures and/or water

pressures. The verifications refer to the equations:

(2.6a) with the design value of the effect of actions Ed = E{γF Frep; Xk/γM; ad}

(2.7a)with the design value of the resistance to an action Rd = R{F Frep; Xk/M; ad}

(2.7b) with the design value of the resistance to an action Rd = R{F Frep; Xk; ad}/R.

NOTE 1 In all 5 load combinations the partial factors for the strength parameters and for the bearing capacity of the

structural materials related to DS/EN 1992 – DS/EN 1996 and DS/EN 1999, are to be factorised by 0. For the ground

parameters and ground resistances related to DS/EN 1997-1, 0 is incorporated in the partial factors M and R.

NOTE 2 For structures not being exposed to geotechnical actions, the verification may be carried out solely by load

combinations 1 and 2.

NOTE 3 For structures solely exposed to geotechnical actions, the verification may exclude load combinations 1 and 2.

NOTE 4 Load combination 5 is to be used for verification of STR for structural materials in geotechnical structures. In

this verification the partial factors for the structural materials as stated in the respective structural Eurocodes are to be

factorised by 0. The partial factors for ground parameters and ground resistances is to be 1,0 in load combination 5.


Page 13 of 33 DS/EN 1997-1 DK NA:2013

This load combination will typically be critical for geotechnical structures, where water pressures constitute the essen-

tial part of the actions.

(4)P The partial factors for spread foundations ensure that the required Danish safety is attained

when the equations for resistance given in Annex D are applied.

(5)P Partial factors for piles and anchors shall be used in combination with the correlation factors

specified in clauses A.3.2 and A.3.3.

(6)P For Geotechnical Category 1, the partial factors given for soil parameters and resistances given

shall be multiplied by a model factor s = 1,25.

(7)P For excavation supports, temporary excavations and other geotechnical structures under con-

struction, partial factors shall be used with values taken as (M)α and (R)

α, where α is a number for

which the following applies: 0 ≤ α ≤ 1. Where failure involves the risk of personal injury or damage

to third party buildings and/or areas with heavy road and rail traffic, or will have considerable social

consequences, partial factors corresponding to α = 1 shall be used.

NOTE - Where failure of retaining structures, temporary excavations and other geotechnical structures during construc-

tion do not have serious consequences, partial factors corresponding to α = 0,5 or, circumstances permitting, corre-

sponding to α values closer to α = 0 (partial factor 1,0) may be used.


Page 14 of 33 DS/EN 1997-1 DK NA:2013

Table A.3-1 Partial factors for STR/GEO design: Spread foundations, earth pressure and stability

Design approach 3

Limit state STR/GEO STR

Load combination 1 2 3 4 5

Partial factors on actions

see equation (2.6a) 8) F A1* or A2†

Per

man

ent

acti

on

6)

Self-weight,

general 1)

Unfa-vourable

G;sup 1,2·KFI 4) 1,0·KFI

1,2 4) 1,0 1,0

Favoura-

ble G;inf 1,0 0,9 1,0 0,9 1,0

Self-weight of soil and (ground)

water, geotech-

nical structures 2)

Unfa-vourable

G;sup 1,0 1,0 1,0 1,0 1,0

Favoura-

ble G;inf 1,0 1,0 1,0 1,0 1,0

Var

iab

le a

c-

tio

n,

Buil

din

gs

Bygn

inger

Leading Unfa-vourable

Q,1 0 1,5·KFI 0 1,5 0

Accompanying Unfa-

vourable Q,i 0 1,5·ψ0·KFI 0 1,5·ψ0 0

Var

iab

le a

c-

tio

n,

Bri

dges

3) Leading

Unfa-

vourable Q,1 0 1,4·KFI

5) 0 1,4 5) 0

Accompanying Unfa-vourable

Q,i 0 1,5·ψ0·KFI 0 1,5·ψ0 0


see equation (2.7a) M

9) M2

Angle of shearing resistance 7) φ 1,2 1,2 KFI 1,0

Effective cohesion c’ 1,2 1,2 KFI 1,0

Undrained shear strength cu 1,8 1,8 KFI 1,0

Unconfined strength q 1,8 1,8 KFI 1,0

Weight density γ 1,0 1,0 1,0

Partial factors for ground resistances

See equation (2.7b) R

9) R3

Spread foundations b - - -

Earth pressure and stability R;e - - -

Factor to partial factor to strength parame-

ters and bearing capacity for structural

materials, cf. DS/EN 1992 – DS/EN 1996 og

DS/EN 1999

0 1,0 1,0 KFI KFI 1,2·KFI 4)

1) Structural actions, which include all types of permanent actions: cf. clause 2.1 in DS/EN 1991-1-1

2) Geotechnical actions, which comprise the self-weight of soil and (ground) water interacting with the geotechnical structure: cf. clause 1.5.2.1 in DS/EN 1997-1 and clause A.3.1(2)P, NOTE, in DS/EN 1997-1 DK NA:2013

3) For variable actions on railway and road dams, quays i.a., the same partial factors are to applied as for bridges

4) For bridges: 1,25∙KFI and 1,25, respectively 5) For heavy carriages on rails (SW/2): 1,2 ∙KFI and 1,2, respectively


Page 15 of 33 DS/EN 1997-1 DK NA:2013

6) The characteristic values to all permanent actions from one single source are to be multiplied byG;sup if the total resulting action effect is unfa-

vourable and byG;inf if the total resulting action effect is favourable. As an example all actions originating from the self-weight of the structure may be considered as coming from one source.

7) The partial factor is valid for tan φ.

8) Reference is also made to DS/EN 1990, equations (6.10a) and (6.10b).

9) For ground parameters and ground resistances, 0 is incorporated in the partial factors M and R.


Page 16 of 33 DS/EN 1997-1 DK NA:2013

Table A.3-2 Partial factors for STR/GEO design: Piles and anchors

Design approach 3

Limit state STR/GEO STR

Load combination 1 2 3 4 5

Partial factors on actions

see equation (2.6a) 8) F A1* or A2†

Per

man

ent

acti

on

6)

Self-weight,

general 1)

Unfa-vourable

G;sup 1,2·KFI 4) 1,0·KFI

1,2 4) 1,0 1,0

Favoura-

ble G;inf 1,0 0,9 1,0 0,9 1,0

Self-weight of soil and

(ground) water,

geotechnical structures 2)

Unfa-

vourable G;sup 1,0 1,0 1,0 1,0 1,0

Favoura-

ble G;inf 1,0 1,0 1,0 1,0 1,0

Var

iab

le a

c-

tio

n,

Buil

din

gs

Leading Unfa-

vourable Q,1 0 1,5·KFI 0 1,5 0


Q,i 0 1,5·ψ0·KFI 0 1,5·ψ0 0

Var

iab

le a

c-

tio

n,

Bri

dg

es 3

)

Leading Unfa-

vourable Q,1 0 1,4·KFI

5) 0 1,4 5) 0


Q,i 0 1,5·ψ0·KFI 0 1,5·ψ0 0


see equation (2.7a) M

9) M2

Angle of shearing resistance 7) φ - - -

Effective cohesion c’ - - -

Undrained shear strength cu - - -

Unconfined strength q - - -

Weight density γ 1,0 1,0 1,0

Partial factors for resistance

see equation (2.7b) R

9) R3

Base resistance of compression piles b 1,3 1,3 KFI 1,0

Shaft resistance of compression piles s 1,3 1,3 KFI 1,0

Total/combined resistance of compression

piles t 1,3 1,3 KFI 1,0

Face of compression piles s;t 1,3 1,3 KFI 1,0

Anchorage resistance a 1,3 1,3 KFI 1,0

Factor to partial factor to strength parame-

ters and bearing capacity for structural

materials, cf. DS/EN 1992 – DS/EN 1996

and DS/EN 1999

0 1,0 1,0 KFI KFI 1,2·KFI 4)

1) - 9) See Table A.3-1.


Page 17 of 33 DS/EN 1997-1 DK NA:2013

A.3.2 Correlation factors for pile foundations

A.3.2.1 Correlation factors to derive characteristic values from static pile load tests

(1)P When determining the characteristic ultimate resistance, Rc;k, from values of Rc;m, measured in

one or several pile load tests, allowance shall be made for the variability of the ground conditions

and the effect of pile installation. The characteristic ultimate resistance is determined as:

mc

kc

RR

;

;

where

= 1,1 for the actual test loaded piles

= 1,25 for other piles where the pile load tests are representative.

A.3.2.2 Correlation factors to derive characteristic values from soil parameters determined

by geotechnical investigations

(3) The characteristic ultimate resistance:

berc

kc

RR ;

;

shall be derived from design rules based on verified correlations between the results of static load

tests and the results of field or laboratory tests. These design rules shall be such that the ultimate

resistance when applying the characteristic value Rc;k does not exceed the measured ultimate re-

sistance divided by

= 1,5

(4)P The design rules shall be based on recognised documentation. An analytical method for deter-

mining the bearing resistance is given in Annex L of this National Annex.

(5)P The bearing resistance for bored piles shall be determined according to the specifications given

in Annex L of this National Annex.

NOTE The resistance of CFA piles is to be determined as for bored piles.

A.3.2.3 Correlation factors to derive characteristic values from driving resistance

(1)P The characteristic ultimate resistance:

mc

kc

RR

;

;

shall be derived from design rules based on verified correlations between the results of static load

tests. These design rules shall be such that the average ultimate resistance when applying the char-

acteristic value Rc;k does not exceed the measured ultimate resistance divided by


Page 18 of 33 DS/EN 1997-1 DK NA:2013

= 1,5 where the resistance is based on a pile driving formula

= 1,25 where wave equation analysis has been used to assess the resistance of the pile con-

sidered

= 1,4 for the piles where the wave equation analysis is representative.

(2) For end-bearing piles driven into non-cohesive, the characteristic ultimate resistance may be

determined using the "Danish Pile Driving Formula", see Annex L of this National Annex and the

values given.

A.3.3 Correlation factors for resistance of pre-stressed and non pre-stressed anchorages

(1)P When deriving the characteristic anchorage resistance (ultimate resistance), Ra;k, from values

of Ra;m, measured in one or several load tests, allowance shall be made for the variability of the

ground conditions and the effect of the construction method. The characteristic ultimate resistance

shall be determined as:

a

ma

ka

RR

;

;

where

a = 1,1 for the actual test loaded anchors and

a = 1,25 for other anchors where the load tests are representative.

(2)P When deriving the characteristic anchorage resistance (ultimate resistance), Ra;k, from values

of Ra;ber determined using design rules, these rules shall be based on verified correlations between

the results of static load tests and the results of field or laboratory tests. The characteristic ultimate

resistance shall be determined as:

a

bera

ka

RR

;

;

The design rules shall be such that the ultimate resistance using the characteristic value, Ra;k, does

not exceed the measured ultimate resistance divided by

a =1,75.

(3) Where documented experience is available, the resistance may be determined on the basis of

design rules in accordance with the principles specified in Annex L of this National Annex.

(4)P Special consideration shall be given to the risk of progressive debonding.


Page 19 of 33 DS/EN 1997-1 DK NA:2013

A.4 Partial factors for uplift limit state (UPL) verifications

(1)P The partial factors () and consequence factors (KFI) are given in Tables A.4-1 and A.4-2.

(2)P For uplift limit state (UPL) verification, the partial factors on actions (F), soil parameters (M)

and for resistance (R) stated in Tables A.4-1 and A.4-2 shall be used.

The consequence factor KFI depends on the consequences class:



The low consequences class, CC1, is not applied for geotechnical structures.


Table A.4-1 Partial factors for UPL verification

Partial factors on actions F

Per

man

ent

acti

on

Self-weight, general

1)

Unfa-vourable

G;dst 1,1·KFI

Favoura-

ble G;stb 0.9

Self-weight of soil and (ground) water,

geotechnical struc-

tures 2)

Unfa-

vourable G;dst 1,1·KFI

Favoura-

ble G;stb 0,9

Var

iab

le a

c-

tio

n,

Buil

din

gs

Leading Unfa-vourable

Q,1 1,5·KFI

Accompanying Unfa-

vourable Q,i 1,5·ψ0·KFI

Var

iab

le a

c-

tio

n,

Bri

dges

) Leading Unfa-vourable

Q,1 1,4·KFI5)

Accompanying Unfa-

vourable Q,i 1,5·ψ0·KFI

Partial factors for soil parameters M

Angle of shearing resistance

7) ’ φ 1,2

Effective cohesion c’ 1,2

Undrained shear strength cu 1,8

Partial factors for resistance R

Shaft resistance, piles in tension s;t 1,3

Pull-out resistance for

anchors a 1,3


Page 20 of 33 DS/EN 1997-1 DK NA:2013




5) For heavy carriages on rails (SW/2): 1,2 ∙KFI and 1,2, respectively 7) The partial factor is valid for tan φ.


Page 21 of 33 DS/EN 1997-1 DK NA:2013

Table A.4-2 Partial factors for UPL verification

- valid solely for structures where water pressures have been fixed to the limits by overflow arrangements;

- no stabilising adhesive and frictional actions on the vertical sectional surfaces may be taken into account.

Partial factors on actions F

Per

man

ent

acti

on

Self-weight, general

1)

Unfavoura-

ble G;dst 1,0·KFI


Self-weight of soil

and (ground) water, geotechnical struc-

tures 2)

©(Unfa-vourable

G;dst 1,05·KFI


Var

iab

le a

c-

tio

n,

Buil

din

gs

Leading Unfavoura-

ble Q,1 1,5·KFI

Accompanying Unfavoura-


Var

iab

le a

c-

tio

n,

Bri

dges

3) Leading

Unfavoura-

ble Q,1 1,4·KFI

5)

Accompanying Unfavoura-


Partial factors for soil parameters M

Angle of shearing resistance

7) ’ φ 1,2

Effective cohesion c’ 1,2

Undrained shear strength cu 1,8

Partial factors for resistance R

Shaft resistance, piles in tension s;t 1,3

Pull out resistance for an-chors

a 1,3




5) For heavy carriages on rails (SW/2): 1,2 ∙KFI and 1,2, respectively

7) The partial factor is valid for tan φ.

(3)P For pure uplift problems (e.g. for dry docks, basins and basements), the verification shall be

based on either the values stated in Table A.4-1 with partial factor γG,stb = 0.9 on the permanent ac-

tions and partial factor γG,dst = 1.1 KFI on the buoyancy or the values stated in Table A.4-2 with par-

tial factor γG,stb = 1.0 on the permanent actions and partial factor γG,dst = 1.05·KFI on the buoyancy,

disregarding shear forces on the vertical sectional surfaces. The most adverse, realistic water level

as well as carefully assessed permanent actions are to be considered.

(4) Pure uplift problems refer to verifications, unequivocally related to the uplift limit state (UPL).

The contrast to this is the uplift related to stability analyses and design of spread foundations, where

the uplift is an integrated part of the structural (STR) and geotechnical (GEO) limit states analysis.


Page 22 of 33 DS/EN 1997-1 DK NA:2013

(5)P The two sets of partial factors in 3(P) may be used at the designers’ discretion for verifying the

UPL limit state provided that the underlying assumptions of the two methods are obeyed. The par-

tial factors in Table A.4-1 represent the basic case, where stabilising shear forces can be included.

The partial factors given in Table A.4-2 can be applied solely for structures, where the water pressu-

res have been fixed to well-defined limits by overflow arrangements, and where stabilising shear

forces on the vertical sectional surfaces are ignored. NOTE Overflow arrangements may be a combination of overflow via the top edge or openings in walls and/or via

goosenecks through the floor structure. Requisite capacity with respect to quantity and distribution throughout the struc-

ture is to be ensured by the arrangement of drains. Overflow of water constitutes a stabilising element, and water is not

to be pumped away, until the water pressures have been stabilised at an acceptable level.

(6) For geotechnical structures where the weight of parts of the structure and water are the leading

forces, the use of structural means to provide well-based assumptions with a relatively low degree

of associated design safety may often be preferred instead of verifying greater design safety with

less established assumptions. For example, to secure a structure against erosion and uplift, it will

usually not be sufficient solely to apply a partial factor for the water pressure. It will be necessary to

protect the structure by structural measures.

(7)P To the extent that the verification of uplift is based upon tensile elements, the block effect shall

be verified by using the same partial factors as applied for the individual tensile element.

(8)P The configuration of a group of tensile structural elements shall ensure that the individual ten-

sile element as well as the group is counteracted by the effective weight of a ground volume, at least

corresponding to ξ γ Rd and ξ γ ΣRd, respectively. ξ is the correlation factor, γ is the partial factor,

and Rd and ΣRd are the requisite design resistances of the individual tensile element and the group

of elements, respectively.

NOTE Shear forces may be taken into account for the active part of the anchorages (the tensile elements), even though

shear forces along vertical sectional surfaces are not to be included when using Table A.4-2.

(9)P If a tensile element has been incorporated for obtaining static equilibrium, this element shall be

designed to compensate the out of balance static equilibrium.

(10)P The level in the ground, above which the stabilising ground volume is defined, is the level at

which compatibility between deformations and forces are achieved for the tensile element.

NOTE In engineering practice, the stabilising ground volume is often calculated as a truncated cone, inclined 1:2 (hori-

zontal/vertical). For conventional bond type ground anchors this truncated cone has the starting level halfway down the

anchor bond length, as no forces are transmitted along the free length of the tendon. For compression type ground an-

chors the nadir top point may refer to the very anchor toe.For piles, the stabilising soil volume will depend on the distri-

bution of the shear resistance along the pile shaft.

A.5 Partial factors for hydraulic heave limit state (HYD) verification

(1)P Partial factors for hydraulic heave limit state (HYD) verification in DK are those applied for

uplift limit state (UPL) verification.

NOTE Piping and erosion require special considerations.


Page 23 of 33 DS/EN 1997-1 DK NA:2013

A.6 Partial factors, correlation factors and model factors for serviceability

and accidental limit states verification

(1)P For serviceability limit states and accidental situations, partial factors M=1,0 for the strength

and deformation parameters of ground and structural materials shall be used. For piles and anchors,

partial factors R = 1,0 and correlation factors =1,0 are applied. Design values of actions are

determined according to DS/EN 1990 (Table A.1.3).

(2) Model factors for actions in serviceability limit states should be determined on the basis of an

interaction analysis using varying stiffness for the ground, the anchors and the structure. The value

of the model factor is determined such that the safety of the anchor resistance always corresponds to

the safety at the ultimate limit state.

(3) The factors for the combination values of variable actions, ψ0, ψ1 and ψ2, in DS/EN 1990

should be applied taking into account the duration of the action and the ground properties.


Page 24 of 33 DS/EN 1997-1 DK NA:2013

Annex D - informative

Spread foundations - Analytical method for bearing resistance calculation

D.1 General

(1) The design vertical bearing resistance, Rd, of a foundation should be examined both for undrained

and drained conditions.

(2) Allowance should be made for the effects of the following:

• the strength of the ground, generally represented by the design values of cu, c' and φ';

• eccentricity and inclination of design loads;

• the shape, depth and inclination of the foundation;

• the slope of the ground surface;

• ground water pressures and hydraulic gradients;

• the variability of the ground, especially layering.

(3) It is not possible to provide a general definition of deposits able to resist loads. Examples of

deposits that may not be considered to be resisting without special measures include gyttja, peat,

post-glacial clay, topsoil, uncontrolled fill, and re-excavated or frozen soil.

(4) Frost-safe depth for foundations may in DK normally be taken as 0,9 m for conventional

buildings and 1,2 m for detached structures. The depth may be reduced by heating or insulation.

(5) For foundations on clay with IP >15 %, desiccation and water absorption may cause

considerable vertical and horizontal movements which may be met by using a fortified foundation

(extra foundation depth, reinforcement) and by specifying restrictions on vegetation close to the

foundation.

D.2 Analytical method

D.2.1 General information regarding the analytical method

(1) The following symbols are used in Annex D.

A' = B' L‘ the design effective foundation area

b the design values of the factors for the inclination of the foundation, with subscripts c, q and B the foundation width

B' the effective foundation width

e the eccentricity of the resultant action, with subscripts B and L

H the horizontal load

i the inclination factors of the load, with subscripts cohesion c, surcharge q and weight density L the foundation length

L' the effective foundation length

m exponent in formulas for the inclination factor i

N the bearing capacity factors, with subscripts for c, q and q overburden or surcharge pressure at the level of the foundation base

q' the design effective overburden pressure at the level of the foundation base


Page 25 of 33 DS/EN 1997-1 DK NA:2013

s the shape factors of the foundation base, with subscripts for c, q and V the vertical load

the inclination of the foundation base to the horizontal

δ structure-ground interface friction angle

' the design effective weight density of the soil below the foundation level

(2) The equations given in clauses D.2.2 and D.2.3 for the design vertical bearing resistance may be

used with the following clarification: for design purposes, the strength of the ground, generally rep-

resented by the design values of cu, c’ and ’, is assumed to be constant for the ground volume gov-

erning the limit state considered.

D.2.2 Undrained conditions

(1) The design resistance is calculated from:

qisbcAR cccdud ;2'/ (D.1)

with the dimensionless factors for:

• the inclination of the foundation base:

2

21

cb

• the shape of foundation:

'/'2,01 LBsc

• the inclination of the load, caused by a horizontal load H:

du

ccA

Hi

;'11

2

1

where ducAH ;'


Page 26 of 33 DS/EN 1997-1 DK NA:2013

D.2.3 Drained conditions

(1) The design resistance is calculated from:

isbNBisbNqisbNcAR qqqqccccdd ''5,0'''/ (D.2)

with the design values of dimensionless factors for:

• the bearing resistance:

)2/'45(tan2tan

dqdeN

dqc NN 'cot1

2/3'cos14/1 dqNN provided that 2/'d (rough base)

• the inclination of the foundation base:

'tan/1 dcqqc Nbbb

2'tan1 dq bb

• the shape of foundation:

'/'2,01 LBss cq

'/'4,01 LBs

• the inclination of the load, caused by a horizontal load H:

2

qii

2

'cot''1

ddd

dcq

cAV

Hii


Page 27 of 33 DS/EN 1997-1 DK NA:2013

Appendix to Annex H - informative

As a supplement to the provisions given in Annex H, it may be specified as guidance for conventio-

nal building structures that settlements for floors on the ground should not exceed the settlements of

the adjoining walls by more than 5 mm.


Page 28 of 33 DS/EN 1997-1 DK NA:2013

Annex K - informative

Special conditions for geotechnical investigations and parameters

K.1 General

(1) Deposits lying below stiff, late-glacial deposits, or older strata are generally characterised by good

strength and deformation properties. Important exceptions are:

late-glacial Allerød deposits;

inter-glacial marine and marsh deposits;

fissured clay, where the exception relates to normal structural actions;

clays characterised by IP >15 %, where the exception relates to seasonal variations of water con-

tent (vegetation);

calcareous deposits crushed by ice or disintegrated (dissolved) by percolation of surface water

("sinkholes").

(2) A geological evaluation is to be made of soil samples or of soil strata on site in order to ensure that

the investigation covers all significant soil strata, including in particular:

highly compressible deposits consisting of gyttja, peat, post-glacial clay, topsoil, uncontrolled

fill and remoulded soil;

swelling clays;

deposits susceptible to sliding.

The investigation is normally to be performed down to stiff late-glacial deposits or older strata. If this

is not possible, the investigation is to be carried out to a depth beyond which the strata have no sub-

stantial influence on the resistance of the structure to failure, or on its movements and deformations.

K.2 Design investigations

(1) Design investigations comprise various types of geophysical surveys, mechanical explorations,

test drillings or test pits with sampling, vane tests and registration of water tables, measurement of

pore water pressures, pumping tests and laboratory analyses. The laboratory analyses comprise geolo-

gical evaluation and soil description, classification tests and more specialised tests to determine

strength, deformation properties, permeability and geochemical properties, etc. It is practical to divide

design investigations into three phases:

Site investigations, which will typically include a few separate investigation points (boreholes,

CPT etc.) to give a rough estimate of the foundation conditions of a given site. At the same time

it could be investigated whether the site is contaminated. The object of such investigation will

e.g. be to point out the most appropriate areas for placing of the building.

Parameter investigations, which will typically be investigations to determine which kind of

foundation will be appropriate for a given project. Such investigations will normally be perfor-

med to such an extent that they can form the basis for a foundation project. In case of contami-

nation, tests from the drillings will often be analysed to estimate the environmental conditions.

Optimisation investigations, which are usually performed to obtain an economic optimisation

of a foundation project. In this connection it might be advantageous to assign the project to

Geotechnical Category 3.


Page 29 of 33 DS/EN 1997-1 DK NA:2013

(2) For the extent of design investigations, reference is made to DS/EN 1997-2.

K.3 Geotechnical categories

(1) Structures of Geotechnical Category 1 are not to involve the risk of damaging neighbouring struc-

tures, sewage and supply pipes, public traffic areas, etc.

(2) Structures with spread foundations, fillings and floors supported directly on the soil should only be

assigned to Geotechnical Category 1 when the foundation bed consists of stiff, late-glacial deposits or

older deposits, which are not included in the exceptions specified in clause K.1.

(3) The following are examples of structures or parts of structures which can be assigned to Geotech-

nical Category 1:

light buildings with a maximum design foundation action of 250 kN for spread footings and 100

kN per m for continuous footing, for which no special requirements regarding settlement condi-

tions etc. are made;

0,30 m and 0,40 m thick in situ cast concrete basement walls subject to earth pressure; wall sec-

tions up to 10 m2 and 15 m

2, when the walls are supported only by transverse walls and base-

ment floor, respectively, and 15 m2 and 20 m

2, respectively, when the basement wall is also re-

strained on top by e.g. a floor. It is assumed that walls do not have openings for windows or

doors;

gravity walls and retaining walls for excavations, where the difference in the ground levels does

not exceed 2 m;

fillings with a maximum depth of 3 m;

pipes and drainage which can be laid in accordance with standard procedures as specified in the

relevant standards;

compacted sand fillings below floors not exceeding 0,6 m;

floor slabs and pavements established with dimensions according to common practice without

detailed design analyses;

cuttings with inclinations not exceeding 1 vertical to 1,5 horizontal and a maximum difference

in level of 4 m.

(4) The design action of Geotechnical Category 2 is not to exceed 5 000 kN for spread foundations or

1 000 kN per m strip foundation. For structures with such foundations, the design bearing pressure of

the effective area is not to exceed 1 000 kN/m2 in Geotechnical Category 2.

(5) Where a project, e.g. by excavation, pile driving or ground water lowering, involves a risk of dam-

aging neighbouring structures, sewage and supply lines, public traffic areas, or similar, the geotech-

nical investigations and calculations with regard to these neighbouring structures should at least corre-

spond to Geotechnical Category 2, adapted to the nature, size and foundation of these structures.

(6) Where permanent damage to structures or bearing strata can occur without prior warning due to

the absence or failure of ground water lowering or drainage systems, the structure should be assigned

to Geotechnical Category 3.


Page 30 of 33 DS/EN 1997-1 DK NA:2013

(7) Foundation on chalk with cavities and on Tertiary high plasticity clay is to be analysed and assig-

ned to Geotechnical Category 3.

(8) In deposits where the permeability increases with depth, excavations considerably below the water

table is to be assigned to Geotechnical Category 3.

K.4 Geotechnical parameters

(1) For plane strain conditions, the angle of shearing resistance, ’pl, for sand and gravel should be

determined by increasing the angle of shearing resistance determined by triaxial measurement, cor-

responding to ’pl = (1 + 0,1 ID) ’tr.

NOTE When the analytical methods are applied to determine bearing resistances of foundations according to DS/EN

1997-1 DK NA, clause D.2, the plane angle of shearing resistance may be used.

(2) For unloading (excavation and active earth pressure) in fissured clay and clay with slickensides,

c’ = 0 is assumed. For loading conditions (resistance or passive pressure) fully developed failure,

particularly for normally consolidated deposits, may cause deformations of a magnitude that only

allows the corresponding strength parameters to be defined by applying deformation dependent fai-

lure criteria.

NOTE Apart from unloading for fissured clay and clay with slickensides, effective cohesion in the ground may be

taken into account when the effective normal stress on the failure surface is positive.


Page 31 of 33 DS/EN 1997-1 DK NA:2013

Annex L - informative

Pile foundations. Analytical method for bearing resistance calculation

(1) The bearing resistance of individual prismatic or cylindrical piles with the base into cohesive

soil should be determined by:

bersberb

kc

RRR

;;

;

for compression piles

bers

kt

RR

;

; for tension piles

where

buberb AcR 9; in cohesive soil

si

n

i

ubers AcrmR

1

; in cohesive soil

sim

n

i

mbers AqNR '

1

;

in non-cohesive soil

bA cross-sectional area

siA surface area in ground layer i

6,0mN for compression piles

2,0mN for tension piles

steelfor

concrete for

woodfor

m

7,0

0,1

0,1

(2) For driven piles with the base in very firm glacial clay, the following empirical expression may

be used:

buberb AcR 18;

(3) The regeneration factor r will depend on the strength of the clay, and r will decrease with in-

creasing strength. Where a precise determination is not made, the regeneration factor for cohesive

soil may be taken as r = 0,4, when the strengths used in the calculations do not exceed cu = 500

kN/m2 . For geostatic calculation of the downdrag r = 1,0 should be assumed.

(4) For calculation of the pile base resistance, the strength in the layers above as well as below the

pile base level should be taken into account.


Page 32 of 33 DS/EN 1997-1 DK NA:2013

(5) For driven piles with the base in non-cohesive soil, the geostatic calculation is so unreliable that

it should not be used for the final determination of the compressive resistance.

(6) For bored cast in situ piles, the resistance may be considerably lower than for corresponding

driven piles. A shaft resistance greater than 30% of the shaft resistance of the corresponding driven

pile or a design base resistance greater than 1000 kN/m2 should not be assumed, unless recognised

documentation allowing a larger bearing resistance is available.

(7) Where a pile driving formula is applied to determine the resistance of compression piles, the

validity of the formula is to be based either on recognised documentation or measured in static load

tests on the same pile type, of similar length and cross-section, and in similar conditions.

(8) For piles driven into conhesionless soil, the characteristic ultimate resistance can be determined

using the "Danish Pile Driving Formula".

(9) In Geotechnical Category 1, the ”Danish Pile Driving Formula” is allowed being used when the

pile base is driven below the compressible layers.

(10) The characteristic ultimate bearing resistance, Rc,k, of piles driven by drop hammer may be

determined using the "Danish Pile Driving Formula”:

mdyn

kdynkc

RRR

;

;;

where

0

;5,0 ss

hGR mdyn

EA

hGLs

b

p20

)tan1(0

efficiency factor

0 efficiency factor for vertical lead

friction coefficient between hammer and lead

inclination of the lead

G weight of the drop hammer

h vertical component of the drop height

s is the permanent subsidence of pile per blow

Lp pile length

Ab cross-sectional area of the pile

E modulus of elasticity of the pile.


Page 33 of 33 DS/EN 1997-1 DK NA:2013

The formula assumes the use of the following values of the moduli of elasticity:

Concrete piles E = 20 · 106

kN/m 2

Wooden piles E = 10 · 106

kN/m 2

Steel piles E = 210 · 106

kN/m 2 .

For piles shorter than 20 times the pile width, the mean value of the actual pile length and 20 times

the pile width should be inserted in the pile driving formula. For wooden piles, the mean diameter is

used for calculating the area Ab. For steel piles, Ab is the cross-sectional area of the steel.

(11) For minor pile foundations, the serviceability limit state analysis may normally be reduced to

an analysis of the influence of downdrag on the settlements, provided there are no highly compress-

ible deposits below the pile bases. The analysis may be performed as a substitute calculation, sub-

ject to the following conditions:

R

bersberb

negdc

RRFF

;;

;

Fc;d design axial compression load in the ultimate limit state with the square-root of

partial factors for load combination STR/GEO without contribution from

downdrag

Fneg design downdrag of the pile using partial factor γR = 1,0 and correlation factor =

1,0, determined as the lower value of the shaft resistance above the underside of

compressible strata or the action generating settlements

Rb;ber, Rs;ber part of the design resistance of the pile due to the strata below the compressible

deposits

correlation factor according to clause A.3.2 of this National Annex

R partial factor in accordance with Tables A.3-2, A.4-1 and A.4-2 of this National

Annex.

(12) For geostatic calculation of downdrag, the upper characteristic values of the soil strength

should be applied.


Documents

DS/EN 1997-1 DK NA:2013webshop.ds.dk/Files/Files/Products/M284340_attachPV.pdf · This national annex (NA) is a revision of DS/EN 1997-1 DK NA:2010-09 and replaces the latter on 2013-05-15