NA To SS EN 1992-2-2012

NA To SS EN 1992-2-2012
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NA to SS EN 1992-2 : 2012 (ICS 91.080.40; 91.010.30; 93.040)

SINGAPORE STANDARD

Singapore National Annex to Eurocode 2 : Design of concrete structures – Part 2 : Concrete bridges – Design and detailing rules

Published by

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NA to SS EN 1992-2 : 2012 (ICS 91.080.40; 91.010.30; 93.040)

SINGAPORE STANDARD

Singapore National Annex to Eurocode 2 : Design of concrete structures – Part 2 : Concrete bridges – Design and detailing rules

ISBN 978-981-4353-42-7 

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NA to SS EN 1992-2 : 2012 This Singapore Standard was approved by the Building and Construction Standards Committee on behalf of the Standards Council of Singapore on 11 October 2012. First published, 2012

The Building and Construction Standards Committee appointed by the Standards Council consists of the following members: Name Chairman

Capacity

: Mr Goh Peng Thong

Member, Standards Council

1 Dy Chairman : Mr Lee Chuan Seng

Member, Standards Council

st

nd

2

Dy Chairman : Mr Tan Tian Chong

Member, Standards Council

Secretary

: Ms Lee Hiok Hoong

SPRING Singapore

Members

: Mr Boo Geok Kwang Er. Chan Ewe Jin Mr Chan Kok Way Er Chee Kheng Chye Mr Chng Chee Beow

Singapore Civil Defence Force Institution of Engineers, Singapore Individual Capacity Housing & Development Board Real Estate Developers’ Association of Singapore Land Transport Authority National Environment Agency Singapore Contractors Association Ltd Ministry of Manpower Singapore Institute of Architects Building and Construction Authority Nanyang Technological University Association of Property and Facility Managers Association of Consulting Engineers, Singapore Urban Redevelopment Authority National University of Singapore Singapore Manufacturers’ Federation Individual Capacity JTC Corporation Singapore Institute of Surveyors and Valuers

Mr Paul Fok Mr Anselm Gonsalves Mr Desmond Hill Mr Ismadi Mohd Mr Benedict Lee Khee Chong Ms Andris Leong Assoc Prof Leong Eng Choon Dr Lim Lan Yuan Er. Lim Peng Hong Mr Larry Ng Lye Hock Assoc Prof Gary Ong Khim Chye Mr Davis Ong Wee Choon Dr Tam Chat Tim Mr Tang Pei Luen Mr Teoh Wooi Sin Co-opted Member

National University of Singapore

: Prof Choo Yoo Sang

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NA to SS EN 1992-2 : 2012 The Technical Committee on Building Structure and Sub-structure appointed by the Building and Construction Standards Committee and responsible for the preparation of this standard consists of representatives from the following organisations: Name

Capacity

Chairman

:

Er. Lim Peng Hong

Member, Building and Construction Standards Committee

Co-Chairman

:

Er. Chew Keat Chuan

Building and Construction Authority

Secretary

:

Ms Lee Hiok Hoong

SPRING Singapore

Members

:

Mr Pheilip Bay

Er. Tang Pei Luen Assoc Prof Susanto Teng

Ready-Mixed Concrete Association of Singapore Institution of Engineers, Singapore Singapore Contractors Association Ltd Singapore Structural Steel Society Housing & Development Board Land Transport Authority Singapore Concrete Institute Setsco Services Pte Ltd Individual Capacity Individual Capacity National University of Singapore Association of Consulting Engineers Singapore JTC Corporation Nanyang Technological University

Prof Richard Liew Jat Yuen

National University of Singapore

Er. Chan Ewe Jin Mr Chua Sey Kok Mr Ho Wan Boon Er. Kwong Sin Keong Mdm Neo Bian Hong Assoc Prof Gary Ong Khim Chye Mr Sze Thiam Siong Dr Tam Chat Tim Dr Tan Guan Prof Tan Kiang Hwee Dr Tan Teng Hooi

Co-opted Member

:

The following Technical Experts contributed in their individual capacity to the preparation of this standard: Er. Fred Lee Ka Wing Mr Leung Yew Wah Dr Gary Ong Khim Chye (Convenor) Er. Phang Siew Kheong Er. Tan See Chee Er. K Thanabal Er. Thung Sek Kwang (Secretary) Ms Iveena Toh Mr Xu Cheng The organisations in which the experts are involved are: AECOM Building and Construction Authority CPG Consultants Pte Ltd Fong Consult Pte Ltd National University of Singapore Land Transport Authority T.Y.Lin International Pte Ltd YWL Engineering Pte Ltd 3 COPYRIGHT

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NA to SS EN 1992-2 : 2012

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NA to SS EN 1992-2 : 2012

Contents Page National Foreword

6

CLAUSES NA.1

Scope

7

NA.2

Nationally determined parameters

7

NA.3

Decisions on the status of informative annexes

17

NA.4

References to non-contradictory complementary information

19

TABLES NA.1

Singapore decisions for nationally determined parameters in SS EN 1992-2:2012

NA.2

Recommended values of wmax and relevant combination rules

Bibliography

8 17

20

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NA to SS EN 1992-2 : 2012

National Foreword This National Annex was prepared by the Technical Committee on Building Structure and Substructure under the purview of the Building and Construction Standards Committee. This standard is an adoption of the UK National Annex (NA to BS EN 1992-2:2005) to “Eurocode 2 : Design of concrete structures – Part 2 : Concrete bridges – Design and detailing rules” and is implemented with the permission of the British Standards Publishing Ltd. Acknowledgement is made to BSI for the use of information from the above publication. This Singapore NA contains information on those parameters which are left open in EN 1992-2 for national choice, known as nationally determined parameters. The Singapore NA is to be read in conjunction with the SS EN 1992-2 : 2012 – Eurocode 2 : Design of concrete structures – Part 2 : Concrete bridges – Design and detailing rules. Attention is drawn to the possibility that some of the elements of this Singapore Standard may be the subject of patent rights. Enterprise Singapore shall not be held responsible for identifying any or all of such patent rights.

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NA to SS EN 1992-2 : 2012

Singapore National Annex to Eurocode 2 : Design of concrete structure – Part 2 : Concrete bridges – Design and detailing rules NA.1 Scope This National Annex gives: a)

the Singapore decisions for the Nationally Determined Parameters described in the following subclauses of SS EN 1992-2 : 2012: 

3.1. 2 (102)P

 5.3.2.2 (104)

6.8.1(102)

9.1 (103)

3.1.6 (101)P

 5.5 (104)

6.8.7 (101)

9.2.2 (101)

3.1..6 (102)P

 5.7 (105)

7.2 (102)

9.5.3 (101)

3.2.4 (101)P

 6.1 (109)

7.3.1 (105)

9.7 (102)

4.2 (105)

 6.1 (110)

7.3.3 (101)

9.8.1 (103)

4.2 (106)

 6.2.2 (101)

7.3.4 (101)

11.9

4.4.1.2 (109)

 6.2.3 (103)

8.9.1 (101)

113.2 (102)

5.1.3 (101)P

 6.2.3 (107)

8.10.4 (105)

113.3.2 (103)

5.2 (105)

 6.2.3 (109)

8.10.4 (107)

b)

the Singapore decisions on the status of SS EN 1992-2 : 2012 informative annexes; and

c)

references to non-contradictory complementary information.

NA.2 Nationally determined parameters NA.2.1 General Singapore decisions for the nationally determined parameters described in SS EN 1992-2 : 2012 are given in Table NA.1 and Table NA.2 (see also NA.2.2).

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NA to SS EN 1992-2 : 2012 Table NA.1 – Singapore decisions for nationally determined parameters in SS EN 1992-2 : 2012 Subclause

Nationally determined parameter

Eurocode recommendation

Singapore decision

Foreword

Definition of National Authorities

None given

The body with a statutory responsibility for the safety of the structure.

3.1.2 (102)P

Value of Cmin

C30/37

Use the recommended value

3.1.2 (102)P

Value of Cmax

C70/85

C70/85. However the shear strength of concrete classes higher than C50/60 should be determined by tests, unless there is evidence of satisfactory past performance of the particular mix including the type of aggregates used. Alternatively shear strength of concrete strength classes higher than C50/60 may be limited to that of C50/60.

3.1.6 (101)P

Value of αcc

0.85

1.0 except in the following clauses where it should be taken as 0.85:              

3.1.6 (102)P

Value of αct

1.00

3.1.7 5.8 6.5.2 (1) 6.5.4 6.7 8.3 (3) 8.6 (5) 10.9.2 (2) 10.9.4.3 (3) 10.9.5.2 (1) 10.9.5.2 (2) 12.6.1 (3) 12.6.5.2 (1) J.104.1 (103)

Use the recommended value.

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NA to SS EN 1992-2 : 2012 Subclause

Nationally determined parameter

Eurocode recommendation

Singapore decision

3.2.4 (101)P

Classes of reinforcement to be used in bridges.

Class B and Class C

Use the recommended Class (B and C).

4.2 (105)

Exposure class for a concrete surface protected by waterproofing.

XC3

Use the recommended class.

4.2 (106)

Distance x

6.0 m

Not applicable to Singapore

4.2 (106)

Distance y

6.0 m

Not applicable to Singapore

4.2 (106)

Exposure classes for surfaces directly affected by de-icing salts.

XD3 and XF2 or XF4

Not applicable to Singapore

4.4.1.2 (109)

Required cover to reinforcement where insitu concrete is placed against an existing concrete surface.

The cover needs only satisfy the requirements for bond, provided the following conditions are met:

Use the recommended requirement.

 the existing concrete surface has not been subject to an outdoor environment for more than 28 days;  the existing concrete surface is rough;  the strength class of the existing concrete is at least C25/30.

5.1.3 (101)P

Simplifications to load arrangements.

None given.

No simplifications recommended.

5.2 (105)

Value of 0

1/200

Use the recommended value.

5.3.2.2 (104)

Value of t

t = breadth of the bearing

Use the recommended value.

5.5 (104)

Values for k1, k2, k3, k4, and k5

k1 = 0.44

Use the recommended values.

k2 = 1.25 (0.6 + 0.0014/cu2) k3 = 0.54 k4 = 1.25 (0.6 + 0.0014/cu2) k5 = 0.85 5.7 (105)

Details for acceptable methods for nonlinear analysis and safety format.

When using non-linear analysis the following assumptions should be made: 9 COPYRIGHT

Non-linear analysis should be undertaken using model factors and material models which give

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NA to SS EN 1992-2 : 2012 Subclause

Nationally determined parameter

Eurocode recommendation  For reinforcing steel, the stress-strain diagram to be used should be based on Figure 3.8, curve A. In this diagram, fyk and kfyk should be replaced by 1.1fyk and 1.1kfyk  For prestressing steel, the idealised stressstrain diagram given in 3.3.6 (Figure 3.10, curve A) should be used. In this diagram fpk should be replaced with 1.1fpk  For concrete, the stress-strain diagram should be based on expression (3.14) in 3.1.5. In this expression, and in the k-value, fcm should be replaced by cf ·fck, with cf = 1.1·S /C The following design format should be used:  The resistance should be evaluated for different levels of appropriate actions which should be increased from their serviceability values by incremental steps, such that the values of G·Gk and Q·Qk are reached in the same step. The incrementing process should be continued until one region of the structure attains the ultimate strength, evaluated taking account of αcc, or there is global failure of the structure. The corresponding load is referred to as qud.  Apply an overall safety factor O and obtain the corresponding strength R

ud

.

 One of the following inequalities should be satisfied:

Rd

 qud    O 

E  GG   QQ   R 

or 10 COPYRIGHT

Singapore decision results that err on the safe side. Typically, this may be achieved by using design material properties and applying design actions. However, in some situations, underestimating stiffness through the use of design properties can lead to unsafe results. Such situations can include cases where indirect actions such as imposed deformations are significant, cases where the failure load is associated with a local brittle failure mode, and cases where the effect of tension stiffening is unfavourable. In such situations, sensitivity analyses should be undertaken to investigate the effect of variations in material properties, including spatial variations, to provide confidence that the results of the analysis do err on the safe side. For non-linear analysis which considers only direct and flexural effects, reference may be made to 5.8.6. Such analysis should account for the effects of long term loading. Effects not considered directly in the analysis should be considered separately in accordance with Section 6. Non-linear analysis which determines shear and torsional strength directly has not yet reached a stage where it can be fully codified. Particular analyses may be used when they have been shown by comparison with tests to give reliable results, with the agreement of the Authority.

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NA to SS EN 1992-2 : 2012 Subclause

Nationally determined parameter

Eurocode recommendation

Singapore decision

 qud    Rd  O 

E  GG   QQ   R 

 qud    O ‘ 

(i.e.) R  or

 qud    O 

 Rd Sd E  gG   qQ  R  where:

Rd is the partial factor for model uncertainty for resistance, Rd = 1.06, Sd is the partial factor for model uncertainty for action/action effort, Sd = 1.15, O is the overall safety factor, O = 1.20. Refer to Annex PP for further details. When model uncertainties Rd and Sd are not considered explicity in the analysis (i.e. Rd = Sd = 1), O’ = 1.27 should be used. 6.1 (109)b

Value of fctx

fctm

fctk,0.05

6.1 (109)

Applicable methods for avoiding brittle failure.

a, b or c

Use any of the recommended applicable methods.

6.1 (110)ii

Value of kcm

2.0

Use the recommended value.

6.1 (110)iii

Value of kp

1.0

Use the recommended value.

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NA to SS EN 1992-2 : 2012 Subclause 6.2.2 (101)

Nationally determined parameter Value of CRd,c,vmin and k1

Eurocode recommendation CRd,c = 0.18/c vmin = 0.035 k

3/2

1/2

Singapore decision In expression (6.2.a) CRd,c should be taken as either:

fck

i)

k1 = 0.15

0.18/c , or

ii) (0.18/c)(2d/α) provided that the shear force VEd is not multiplied by  [6.2.2 (6)] and the longitudinal reinforcement is fully anchored at the support, where α is the distance from the edge of the support (or centre of bearing where flexible bearings are used) to the position at which the shear resistance is considered. In other cases CRd,c should be taken as 0.18/c. Use the recommended values for vmin and k1. See also 3.1.2 (102)P for recommendations for concrete class > C50/60.

6.2.3 (103)

Values of v1 and αcw

v1 = v

v1 = v (1 – 0.5 cos α)

However, if the design stress of the shear reinforcement is below 80% of the characteristic yield stress fyk, v1 may be taken as:

However, if the design stress of the shear reinforcement is below 80% of the characteristic yield stress fyk, v1 may be taken as:

v1 = 0.6 for fck  60 MPa

v1 = 0.54 (1 – 0.5 cos α) MPa

v1 = 0.9 – fck/200 > 0.5 for fck  60 MPa αcw is as follows: 1 for non-prestressed structures (1 + σcp/fcd)

for 0 < σcp  0.25 fcd

1.25

for 0.25 fcd < σcp  0.5 fcd

2.5 (1 – σcp/fcd)

for 0.5 fcd < σcp < 1.0 fcd

where: σcp is the mean compressive stress, measured positive, in the concrete due to the design axial force. This should be obtained by averaging it over the concrete section taking account of the 12 COPYRIGHT

for fck  60

v1 = (0.84 – fck/200) (1-0.5 cos α) > 0.5 for fck  60 MPa αcw is as follows: 1 for members without axial compressive forces (1 + σcp/fcd)

for 0 < σcp  0.25 fcd

1.25

for 0.25 fcd < σcp  0.5 fcd

2.5 (1 – σcp/fcd)

for 0.5 fcd < σcp < 1.0 fcd

where: σcp is the mean compressive stress, measured positive, in the concrete due to the design axial

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NA to SS EN 1992-2 : 2012 Subclause

Nationally determined parameter

Eurocode recommendation

Singapore decision

reinforcement. The value of σcp need not be calculated at a distance less than 0.5d cot θ from the edge of the support.

force. This should be obtained by averaging it over the concrete section taking account of the reinforcement. The value of σcp need not be calculated at a distance less than 0.5d cot θ from the edge of the support.

In the case of straight tendons, a high level of prestress (σcp/fcd >0.5) and thin webs, if the tension and the compression chords are able to carry the whole prestressing force and blocks are provided at the extremity of beams to disperse the prestressing force (see fig. 6.101), it may be assumed that the prestressing force is distributed between the chords. In these circumstances, the compression field due to shear only should be considered in the web (αcw = 1).

NOTE – The values of ν1 and αcw should not give rise 2 to a value of VRd,max greater than 200bw at sections more than a distance d from the edge of a support. For this purpose, the value of bw does not need to be reduced for ducts.

In the case of straight tendon s, a high level of prestress (σcp/fcd > 0.5) and thin webs, if the tension and the compression chords are able to carry the whole prestressing force and blocks are provided at the extremity of beams to disperse the prestressing force (see fig. 6.101), it may be assumed that the prestressing force is distributed between the chords. In these circumstances, the compression field due to shear only should be considered in the web (αcw = 1). See also 3.1.2 (102)P for recommendations for concrete class > C50/60.

6.2.3(107)

Guidance on the superposition of different truss models.

In the case of bonded prestressing, located within the tensile chord, the resisting effect of prestressing may be taken into account for carrying the total longitudinal tensile force. In the case of inclined bonded prestressing tendons in combination with other longitudinal reinforcement/tendons the shear strength may be evaluated, by a simplification, superimposing two different truss models with different geometry (Figure 6.102N); a weighted mean value between θ1 and θ2 may be used for concrete stress field verification with Expression (6.9).

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Use the recommended guidance.

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NA to SS EN 1992-2 : 2012 Subclause

Nationally determined parameter

Eurocode recommendation

Singapore decision

6.2.3 (109)

Absolute minimum value of hred.

Absolute minimum value of hred = 0.5h

Use the recommended value.

6.8.1 (102)

Structures and structural elements for which fatigue verification is generally not necessary.

A fatigue verification is generally not necessary for the following structures and structural elements:

Additional rules. Fatigue verification for road bridges is not necessary for the local effects of wheel loads applied directly to a slab spanning between beams or webs provided that:

a) footbridges, with the exception of structural components very sensitive to wind action; b) buried arch and frame structures with a minimum earth cover of 1.00 m and 1.50 m respectively for road and railway bridges; c) foundations; d) piers and columns which are not rigidly connected to superstructures; e) retaining walls of embankments for roads and railways; f)

abutments of road and railway bridges which are not rigidly connected to superstructures, except the slabs of hollow abutments;

a) the slab does not contain welded reinforcement, or reinforcement couplers; b) the clear span to overall depth ratio of the slab does not exceed 18; c) the slab acts compositely with its supporting beams or webs; d) either: i) the slab also acts compositely with transverse diaphragms; or ii)

the width of the slab perpendicular to its span exceeds three times its clear span.

g) prestressing and reinforcing steel, in regions where, under the frequent combination of actions and Pk only compressive stresses occur at the extreme concrete fibres. 6.8.7 (101)

Value of k1

k1 = 0.85

Use the recommended value.

7.2 (102)

Value of k1

k1 = 0.6

k1 = 0.5

7.2 (102)

Maximum increase in stress limit above k1fck

10%

Use the recommended value.

7.3.1 (105)

Value of wmax, definition of decompression and its application.

Refer to Table 7.101N

Refer to NA.2.2 and Table NA.2

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NA to SS EN 1992-2 : 2012 Subclause

Nationally determined parameter

Eurocode recommendation

Singapore decision

7.3.3 (101)

Details of a simplified method for control of cracking without calculation.

The recommended method is that given in EN 1992-1-1, 7.3.3 (2) to (4).

The recommended method given in SS EN 19921-1:2008, 7.3.3 (2) to (4) should be used; however account should also be taken of the effects of restrained thermal and shrinkage strains.

7.3.4 (101)

Method of calculating crack width

The recommended method is that given in EN 1992-1-1, 7.3.4

The recommended method given in SS EN 19921-1:2008, 7.3.4 should be used; however account should also be taken of the effects of restrained thermal and shrinkage strains. The value of c used for the calculation of crack width should be taken as cnom.

8.9.1 (101)

Restrictions on the use of bundled bars.

No additional restrictions recommended.

No additional restrictions recommended.

8.10.4 (105)

Value of X and the maximum percentage of tendons coupled at a section.

50% and 67% respectively.

Use the recommended values.

8.10.4 (105)

Distance α Construction depth, h

Distance, α

 1.5 m

1.5 m

1.5 m < h < 3.0 m

α=h

 3.0 m

3.0 m

Use the recommended values.

8.10.4 (107)

Additional rules relating to the provision of openings and pockets on the upper side of carriageway slabs.

No additional rules recommended.

No additional rules recommended.

9.1 (103)

Additional rules concerning minimum thickness of structural elements and minimum reinforcement.

No additional rules recommended.

No additional rules recommended.

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NA to SS EN 1992-2 : 2012 Subclause 9.2.2 (101)

Nationally determined parameter Permitted forms of shear reinforcement.

Eurocode recommendation The recommended forms of shear reinforcement are: 

links enclosing the longitudinal tension reinforcement and the compression zone (see Figure 9.5 of EN 1992-1-1);

bent-up bars;

or a combination of the two.

Singapore decision Use the recommended forms.

Minimum diameter of transverse reinforcement in a column

min = 6 mm

9.7 (102)

Maximum spacing of bars in the faces of beams.

Smesh is the lesser of the web thickness or 300 mm.

Use the recommended values.

9.8.1 (103)

Minimum bar diameter for main tensile reinforcement in pile caps.

dmin = 12 mm

Use the recommended values.

11.9 (101)

Additional restrictions on the use of bundled bars in lightweight aggregate concrete.

No additional restrictions recommended.

No additional restrictions recommended.

113.2 (102)

Minimum unbalanced uplift or horizontal wind pressure at execution stage for ULS verification of structural equilibrium for segmental bridges built by balanced cantilever

x = 200 N/m

113.3.2 (103)

Value of k

k = 1.0

9.5.3. (101)

Use the recommended values.

min,mesh = 5 mm

2

x = calculated ULS value of unbalanced vertical or horizontal wind pressure at execution stage, 2 subject to a minimum of 200 N/m .

Use the recommended value.

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NA to SS EN 1992-2 : 2012 NA.2.2 Recommended values of wmax, definition of decompression and its application The value of wmax is given in Table NA.2. The decompression limit requires that all concrete within a certain distance of bonded tendons or their ducts should remain in compression under the specified loading. The distance within which all concrete should remain in compression should be taken as the value of cmin,dur. Where the most tensile face of a section is not subject to XD or XS exposure but another face is, the decompression limit should require all tendons within 100 mm of a surface subject to XD or XS exposure to have a depth cmin,dur of concrete in compression between them and surfaces subject to XD or XS exposure. Table NA.2 – Recommended values of wmax and relevant combination rules

Exposure class

A)

Reinforced members and prestressed members without bonded tendons Quasi-permanent load B) combination mm c)

Prestressed members with bonded tendons Frequent load combination mm

B)

X0, XC1

0.3

0.2

XC2, XC3, XC4

0.3

0.2

XD1, XD2, XD3, XS1, XS2, XS3

0.3

0.2 and D) and F) decompresson

D) and F) E)

A)

B)

C)

D)

E) F)

The exposure class considered, including at transfer, applies to the most severe exposure the surface will be subject to in service. For the crack width checks under combinations which include temperature distribution, the resulting member forces should be calculated using gross section concrete properties and self-equilibrating thermal stresses within a section may be ignored. For X0, XC1 exposure classes, crack width has no influence on durability and this limit is set to guarantee acceptable appearance. In the absence of appearance conditions this limit may be relaxed. For these exposure classes, in addition, concrete tensile stress to be limited to zero under the quasi-permanent combination of loads. 0.2 applies to the parts of the member that do not have to be checked for decompression. For these exposure classes, in addition, concrete tensile stress to be limited to 0.75 f ctm or 0.4 characteristic combination of load as uncracked members.

under the

NA.3 Decisions on the status of informative annexes COMMENTARY ON NA.3 The informative annexes of EN 1992-2 call for the application of the corresponding informative annexes of EN 1992-1-1, wholly, in part and/or with modifications. The following text therefore gives decisions on the status of informative annexes of 1992-1-1 for use with SS EN 1992-2, where applicable.

SS EN 1992-1-1:2008, informative Annexes A, D and G, as called up in SS EN 1992-2:2012, informative Annexes A, D and G respectively, may be used. SS EN 1992-2:2005, informative Annexes B and PP are not applicable. SS EN 1992-1-1:2008, informative Annex B, as called up in SS EN 1992-2:2012, informative Annex B may be used.

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NA to SS EN 1992-2 : 2012 SS EN 1992-2:2012, informative Annex E (and by implication SS EN 1992-1-1: 2008, informative Annex E) is not applicable. SS EN 1992-1-1:2008, informative Annex F, as modified/extended by SS EN 1992-2:2012, may be used, subject to the following amendments: Delete

“The optimum reinforcement, corresponding to  = 45°, is indicated by superscript ’, and related concrete stress are determined by:”

and replace with

“The optimum reinforcement, corresponding to  = 45° in (F.2), (F.3) and (F.4), is indicated by superscript ’, and related concrete stress are determined by:”

Delete

“where  is the angle of the principal concrete compressive stress to the x-axis.”

and replace with

“where  is the angle of the plastic compression field to the x-axis.”

SS EN 1992-1-1:2008, informative Annex H is not applicable, as stated in SS EN 1992-2:2012 informative Annex H. SS EN 1992-1-1:2008, informative Annex I, as modified by SS EN 1992-2:2012, may be used. )

PD 6687:20061 , informative Annex B (which is the UK replacement for BS EN 1992-1-1:2004, informative Annex J), as extended by BS EN 1992-2:2005, informative Annex J, may be used. NOTE – In EN 1992-2:2005, J.104.2 (101) and (104) there are references to 8.10.3 of EN 1992-1-1 and 8.10.3 (4) of EN 1992-1-1, respectively. These references are incorrect and should read 8.10.3 of EN 1992-2 and 8.10.3 (104) of EN 1992-2, respectively.

SS EN 1992-2:2012 informative Annex KK may be used, subject to the following amend ment: Delete KK.7 and replace with the following: (101) Forces at time t may be calculated for those structures that undergo changes in support conditions (span-to-span construction, free cantilever construction, movements at supports, etc.) using a simplified approach. The effects of creep redistribution at time t may be represented, as a first approximation, by a change in internal force distribution occurring after the construction process equal to:  , t 0   t c , t 0 (K.119) S  Sc – S0 1   , t c

   

where: S0

is the value of the internal actions obtained from the construction sequence build up. For prestressed bridges, the loss of prestress considered should be taken equal to that at the time of the change to the structural system;

Sc

is the value of the internal actions obtained assuming that the whole structure is built in one go. For prestressed bridges, the loss of prestress considered should be taken equal to that at the time of the change to the structural system;

t0

is the concrete age on application of the load;

tc

is the age of the concrete when the support conditions are changed.

1) This Published Document is being revised and is to be renumbered PD 6687-1. informative Annex B will remain unchanged in the revised document.

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It is anticipated that

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NA to SS EN 1992-2 : 2012 The final force distribution, S, should be derived by adding the redistribution effects from (KK.119) to the forces derived from the construction sequence build up at time t, S0,, in accordance with (KK.120). For prestressed structures, S0, should include all long term losses of prestress, based on the force distribution derived from following the construction sequence, but ignoring the effects of creep redistribution. S = S0, + S

(KK.120)

SS EN 1992-2:2012, informative Annex LL may be used subject to the following amendments: In expression (LL.101), “fcm” is replaced by “fcd”. In expression (LL.112), “fcm” is replaced by “fcd”, and “fctm” is replaced by “fctd”. Equation (LL.123) is deleted and replaced with “1 = x cos 0 + y sin  0” 4

4

Delete clause LL.112 and replace with the following: (112) The outer layers should be designed as membrane elements. The design rules of Clause 6.109 and Annex F or an alternative realistic membrane element should be used. SS EN 1992-2:2012 informative Annexes MM, NN, OO and QQ may be used.

NA.4 References to non-contradictory complementary information The following is a list of references that contain non-contradictory complementary information for use with SS EN 1992-2:2012. PD 6687-1:2010, Background paper to the National Annexes to BS EN 1992-1 and BS EN 1992-3 PD 6687-2:2008, Recommendations for the design of structures to BS EN 1992-2:2005

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NA to SS EN 1992-2 : 2012

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. SS EN 1992-1-1:2008, Eurocode 2: Design of concrete structures – Part 1: General rules and rules for buildings PD 6687-1:2010, Background paper to the National Annexes to BS EN 1992-1 and BS EN 1992-3 PD 6687-2:2008, Recommendations for the design of structures to BS EN 1992-2:2005

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NA to SS EN 1992-2 : 2012

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