SIST EN 1998-2:2006

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Eurocode 8 - Design of structures for earthquake resistance - Part 2: BridgesEurocode 8 - Calcul des structures pour leur résistance aux séismes - Partie 2: PontsEurocode 8 - Auslegung von Bauwerken gegen Erdbeben - Teil 2: BrückenTa slovenski standard je istoveten z:EN 1998-2:2005SIST EN 1998-2:2006en93.040Gradnja mostovBridge construction91.120.25YLEUDFLMDPLSeismic and vibration protectionICS:SIST ENV 1998-2:1995+D1:20011DGRPHãþDSLOVENSKI
STANDARDSIST EN 1998-2:200601-maj-2006







EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 1998-2November 2005ICS 91.120.25; 93.040Supersedes ENV 1998-2:1994
English VersionEurocode 8 - Design of structures for earthquake resistance -Part 2: BridgesEurocode 8 - Calcul des structures pour leur résistance auxséismes - Partie 2: PontsEurocode 8 - Auslegung von Bauwerken gegen Erdbeben -Teil 2: BrückenThis European Standard was approved by CEN on 7 July 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2005 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 1998-2:2005: E



EN 1998-2:2005 (E) 2 TABLE OF CONTENTS
FOREWORD.7 1 INTRODUCTION.11 1.1 SCOPE.11 1.1.1 Scope of EN 1998-2.11 1.1.2 Further parts of EN 1998.12 1.2 NORMATIVE REFERENCES.12 1.2.1 Use.12 1.2.2 General reference standards.12 1.2.3 Reference Codes and Standards.12 1.2.4 Additional general and other reference standards for bridges.12 1.3 ASSUMPTIONS.13 1.4 DISTINCTION BETWEEN PRINCIPLES AND APPLICATION RULES.13 1.5 DEFINITIONS.13 1.5.1 General.13 1.5.2 Terms common to all Eurocodes.13 1.5.3 Further terms used in EN 1998-2.13 1.6 SYMBOLS.15 1.6.1 General.15 1.6.2 Further symbols used in Sections 2 and 3 of EN 1998-2.15 1.6.3 Further symbols used in Section 4 of EN 1998-2.16 1.6.4 Further symbols used in Section 5 of EN 1998-2.17 1.6.5 Further symbols used in Section 6 of EN 1998-2.18 1.6.6 Further symbols used in Section 7 and Annexes J, JJ and K of EN 1998-220 2 BASIC REQUIREMENTS AND COMPLIANCE CRITERIA.23 2.1 DESIGN SEISMIC ACTION.23 2.2 BASIC REQUIREMENTS.24 2.2.1 General.24 2.2.2 No-collapse (ultimate limit state).24 2.2.3 Minimisation of damage (serviceability limit state).25 2.3 COMPLIANCE CRITERIA.25 2.3.1 General.25 2.3.2 Intended seismic behaviour.25 2.3.3 Resistance verifications.28 2.3.4 Capacity design.28 2.3.5 Provisions for ductility.28 2.3.6 Connections - Control of displacements - Detailing.31 2.3.7 Simplified criteria.35 2.4 CONCEPTUAL DESIGN.35 3 SEISMIC ACTION.38 3.1 DEFINITION OF THE SEISMIC ACTION.38 3.1.1 General.38 3.1.2 Application of the components of the motion.38 3.2 QUANTIFICATION OF THE COMPONENTS.38 3.2.1 General.38



EN 1998-2:2005 (E)
3 3.2.2 Site dependent elastic response spectrum.39 3.2.3 Time-history representation.39 3.2.4 Site dependent design spectrum for linear analysis.40 3.3 SPATIAL VARIABILITY OF THE SEISMIC ACTION.40 4 ANALYSIS.44 4.1 MODELLING.44 4.1.1 Dynamic degrees of freedom.44 4.1.2 Masses.44 4.1.3 Damping of the structure and stiffness of members.45 4.1.4 Modelling of the soil.45 4.1.5 Torsional effects.46 4.1.6 Behaviour factors for linear analysis.47 4.1.7 Vertical component of the seismic action.50 4.1.8 Regular and irregular seismic behaviour of ductile bridges.50 4.1.9 Non-linear analysis of irregular bridges.51 4.2 METHODS OF ANALYSIS.51 4.2.1 Linear dynamic analysis - Response spectrum method.51 4.2.2 Fundamental mode method.53 4.2.3 Alternative linear methods.57 4.2.4 Non-linear dynamic time-history analysis.57 4.2.5 Static non-linear analysis (pushover analysis).59 5 STRENGTH VERIFICATION.61 5.1 GENERAL.61 5.2 MATERIALS AND DESIGN STRENGTH.61 5.2.1 Materials.61 5.2.2 Design strength.61 5.3 CAPACITY DESIGN.61 5.4 SECOND ORDER EFFECTS.63 5.5 COMBINATION OF THE SEISMIC ACTION WITH OTHER ACTIONS.64 5.6 RESISTANCE VERIFICATION OF CONCRETE SECTIONS.65 5.6.1 Design resistance.65 5.6.2 Structures of limited ductile behaviour.65 5.6.3 Structures of ductile behaviour.65 5.7 RESISTANCE VERIFICATION FOR STEEL AND COMPOSITE MEMBERS.73 5.7.1 Steel piers.73 5.7.2 Steel or composite deck.74 5.8 FOUNDATIONS.74 5.8.1 General.74 5.8.2 Design action effects.75 5.8.3 Resistance verification.75 6 DETAILING.76 6.1 GENERAL.76 6.2 CONCRETE PIERS.76 6.2.1 Confinement.76 6.2.2 Buckling of longitudinal compression reinforcement.80 6.2.3 Other rules.81 6.2.4 Hollow piers.82 6.3 STEEL PIERS.82



EN 1998-2:2005 (E) 4 6.4 FOUNDATIONS.82 6.4.1 Spread foundation.82 6.4.2 Pile foundations.82 6.5 STRUCTURES OF LIMITED DUCTILE BEHAVIOUR.83 6.5.1 Verification of ductility of critical sections.83 6.5.2 Avoidance of brittle failure of specific non-ductile components.83 6.6 BEARINGS AND SEISMIC LINKS.84 6.6.1 General requirements.84 6.6.2 Bearings.85 6.6.3 Seismic links, holding-down devices, shock transmission units.86 6.6.4 Minimum overlap lengths.88 6.7 CONCRETE ABUTMENTS AND RETAINING WALLS.90 6.7.1 General requirements.90 6.7.2 Abutments flexibly connected to the deck.90 6.7.3 Abutments rigidly connected to the deck.90 6.7.4 Culverts with large overburden.92 6.7.5 Retaining walls.93 7 BRIDGES WITH SEISMIC ISOLATION.94 7.1 GENERAL.94 7.2 DEFINITIONS.94 7.3 BASIC REQUIREMENTS AND COMPLIANCE CRITERIA.95 7.4 SEISMIC ACTION.96 7.4.1 Design spectra.96 7.4.2 Time-history representation.96 7.5 ANALYSIS PROCEDURES AND MODELLING.96 7.5.1 General.96 7.5.2 Design properties of the isolating system.97 7.5.3 Conditions for application of analysis methods.103 7.5.4 Fundamental mode spectrum analysis.103 7.5.5 Multi-mode Spectrum Analysis.107 7.5.6 Time history analysis.108 7.5.7 Vertical component of seismic action.108 7.6 VERIFICATIONS.108 7.6.1 Seismic design situation.108 7.6.2 Isolating system.108 7.6.3 Substructures and superstructure.110 7.7 SPECIAL REQUIREMENTS FOR THE ISOLATING SYSTEM.111 7.7.1 Lateral restoring capability.111 7.7.2 Lateral restraint at the isolation interface.113 7.7.3 Inspection and Maintenance.113 ANNEX A (INFORMATIVE) PROBABILITIES RELATED TO THE REFERENCE SEISMIC ACTION. GUIDANCE FOR THE SELECTION OF DESIGN SEISMIC ACTION DURING THE CONSTRUCTION PHASE.114 ANNEX B (INFORMATIVE) RELATIONSHIP BETWEEN DISPLACEMENT DUCTILITY AND CURVATURE DUCTILITY FACTORS OF PLASTIC HINGES IN CONCRETE PIERS.115 ANNEX C (INFORMATIVE) ESTIMATION OF THE EFFECTIVE STIFFNESS OF REINFORCED CONCRETE DUCTILE MEMBERS.116



EN 1998-2:2005 (E)
5 ANNEX D (INFORMATIVE) SPATIAL VARIABILITY OF EARTHQUAKE GROUND MOTION: MODEL AND METHODS OF ANALYSIS.118 ANNEX E (INFORMATIVE) PROBABLE MATERIAL PROPERTIES AND PLASTIC HINGE DEFORMATION CAPACITIES FOR NON-LINEAR ANALYSES .125 ANNEX F (INFORMATIVE) ADDED MASS OF ENTRAINED WATER FOR IMMERSED PIERS.131 ANNEX G (NORMATIVE) CALCULATION OF CAPACITY DESIGN EFFECTS
..........................................................................................................133 ANNEX H (INFORMATIVE) STATIC NON-LINEAR ANALYSIS (PUSHOVER) ......................................................................................................135 ANNEX J (NORMATIVE)
VARIATION OF DESIGN PROPERTIES OF SEISMIC ISOLATOR UNITS.138 ANNEX JJ (INFORMATIVE)
λ-FACTORS FOR COMMON ISOLATOR TYPES
..........................................................................................................140 ANNEX K (INFORMATIVE)
TESTS FOR VALIDATION OF DESIGN PROPERTIES OF SEISMIC ISOLATOR UNITS.143



EN 1998-2:2005 (E) 6 Foreword This European Standard EN 1998-2, Eurocode 8: Design of structures for earthquake resistance: Bridges, has been prepared by Technical Committee CEN/TC250 «Structural Eurocodes», the Secretariat of which is held by BSI. CEN/TC250 is responsible for all Structural Eurocodes. This European Standard shall be given the status of a National Standard, either by publication of an identical text or by endorsement, at the latest by May 2006, and conflicting national standards shall be withdrawn at latest by March 2010. This document supersedes ENV 1998-2:1994. According to the CEN-CENELEC Internal Regulations, the National Standard Organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Background of the Eurocode programme In 1975, the Commission of the European Community decided on an action programme in the field of construction, based on article 95 of the Treaty. The objective of the programme was the elimination of technical obstacles to trade and the harmonisation of technical specifications. Within this action programme, the Commission took the initiative to establish a set of harmonised technical rules for the design of construction works which, in a first stage, would serve as an alternative to the national rules in force in the Member States and, ultimately, would replace them.
For fifteen years, the Commission, with the help of a Steering Committee with Representatives of Member States, conducted the development of the Eurocodes programme, which led to the first generation of European codes in the 1980s.
In 1989, the Commission and the Member States of the EU and EFTA decided, on the basis of an agreement1 between the Commission and CEN, to transfer the preparation and the publication of the Eurocodes to CEN through a series of Mandates, in order to provide them with a future status of European Standard (EN). This links de facto the Eurocodes with the provisions of all the Council’s Directives and/or Commission’s Decisions dealing with European standards (e.g. the Council Directive 89/106/EEC on construction products - CPD - and Council Directives 93/37/EEC, 92/50/EEC and 89/440/EEC on public works and services and equivalent EFTA Directives initiated in pursuit of setting up the internal market).
1 Agreement between the Commission of the European Communities and the European Committee for Standardisation (CEN) concerning the work on EUROCODES for the design of building and civil engineering works (BC/CEN/03/89).



EN 1998-2:2005 (E)
7 The Structural Eurocode programme comprises the following standards generally consisting of a number of Parts: EN 1990 Eurocode: Basis of structural design
EN 1991 Eurocode 1: Actions on structures EN 1992 Eurocode 2: Design of concrete structures EN 1993 Eurocode 3: Design of steel structures EN 1994 Eurocode 4: Design of composite steel and concrete structures EN 1995 Eurocode 5: Design of timber structures EN 1996 Eurocode 6: Design of masonry structures EN 1997 Eurocode 7: Geotechnical design EN 1998 Eurocode 8: Design of structures for earthquake resistance EN 1999 Eurocode 9: Design of aluminium structures Eurocode standards recognise the responsibility of regulatory authorities in each Member State and have safeguarded their right to determine values related to regulatory safety matters at national level where these continue to vary from State to State. Status and field of application of Eurocodes The Member States of the EU and EFTA recognise that Eurocodes serve as reference documents for the following purposes: − as a means to prove compliance of building and civil engineering works with the essential requirements of Council Directive 89/106/EEC, particularly Essential Requirement N°1 – Mechanical resistance and stability – and Essential Requirement N°2 – Safety in case of fire; − as a basis for specifying contracts for construction works and related engineering services; − as a framework for drawing up harmonised technical specifications for construction products (ENs and ETAs). The Eurocodes, as far as they concern the construction works themselves, have a direct relationship with the Interpretative Documents2 referred to in Article 12 of the CPD, although they are of a different nature from harmonised product standards3. Therefore, technical aspects arising from the Eurocodes work need to be adequately considered by
2 In accordance with Art. 3.3 of the CPD, the essential requirements (ERs) shall be given concrete form in interpretative documents for the creation of the necessary links between the essential requirements and the mandates for harmonised ENs and ETAGs/ETAs. 3 In accordance with Art. 12 of the CPD the interpretative documents shall: a) give concrete form to the essential requirements by harmonising the terminology and the technical bases and indicating classes or levels for each requirement where necessary ; b) indicate methods of correlating these classes or levels of requirement with the technical specifications, e.g. methods of calculation and of proof, technical rules for project design, etc.; c) serve as a reference for the establishment of harmonised standards and guidelines for European technical approvals. The Eurocodes, de facto, play a similar role in the field of the ER 1 and a part of ER 2.



EN 1998-2:2005 (E) 8 CEN Technical Committees and/or EOTA Working Groups working on product standards with a view to achieving full compatibility of these technical specifications with the Eurocodes. The Eurocode standards provide common structural design rules for everyday use for the design of whole structures and component products of both a traditional and an innovative nature. Unusual forms of construction or design conditions are not specifically covered and additional expert consideration will be required by the designer in such cases. National Standards implementing Eurocodes The National Standards implementing Eurocodes will comprise the full text of the Eurocode (including any annexes), as published by CEN, which may be preceded by a National title page and National foreword, and may be followed by a National annex. The National annex may only contain information on those parameters which are left open in the Eurocode for national choice, known as Nationally Determined Parameters, to be used for the design of buildings and civil engineering works to be constructed in the country concerned, i.e.: − values and/or classes where alternatives are given in the Eurocode, − values to be used where a symbol only is given in the Eurocode, − country specific data (geographical, climatic, etc.), e.g. snow map, − the procedure to be used where alternative procedures are given in the Eurocode. It may also contain
− decisions on the use of informative annexes, and
− references to non-contradictory complementary information to assist the user to apply the Eurocode. Links between Eurocodes and harmonised technical specifications (ENs and ETAs) for products There is a need for consistency between the harmonised technical specifications for construction products and the technical rules for works4. Furthermore, all the information accompanying the CE Marking of the construction products which refer to Eurocodes shall clearly mention which Nationally Determined Parameters have been taken into account. Additional information specific to EN 1998-2 The scope of this Part of EN 1998 is defined in 1.1.
Except where otherwise specified in this Part, the seismic actions are as defined in EN 1998-1:2004, Section 3.
4 see Art.3.3 and Art.12 of the CPD, as well as 4.2, 4.3.1, 4.3.2 and 5.2 of ID 1.



EN 1998-2:2005 (E)
9 Due to the peculiarities of the bridge seismic resisting systems, in comparison to those of buildings and other structures, all other sections of this Part are in general not directly related to those of EN 1998-1:2004. However several provisions of EN 1998-1:2004 are used by direct reference.
Since the seismic action is mainly resisted by the piers and the latter are usually constructed of reinforced concrete, a greater emphasis has been given to such piers.
Bearings are in many cases important parts of the seismic resisting system of a bridge and are therefore treated accordingly. The same holds for seismic isolation devices.
National annex for EN 1998-2 This standard gives alternative procedures, values and recommendations for classes, with notes indicating where national choices may have to be made. Therefore the National Standard implementing EN 1998-2 should have a National annex containing all Nationally Determined Parameters to be used for the design of buildings and civil engineering works to be constructed in the relevant country. National choice is allowed in EN 1998-2:2005 through clauses: Reference Item 1.1.1(8) Informative Annexes A, B, C, D, E, F, H and JJ 2.1(3)P Reference return period TNCR of seismic action for the no-collapse requirement of the bridge (or, equivalently, reference probability of exceedance in 50 years, PNCR). 2.1(4)P Importance classes for bridges
2.1(6) Importance factors for bridges 2.2.2(5) Conditions under which the seismic action may be considered as accidental action, and the requirements of 2.2.2(3) and 2.2.2 (4) may be relaxed. 2.3.5.3(1) Expression for the length of plastic hinges
2.3.6.3(5) Fractions of design displacements for non-critical structural elements
2.3.7(1) Cases of low seismicity 2.3.7(1) Simplified criteria for the design of bridges in cases of low seismicity 3.2.2.3 Definition of active fault
3.3(1)P Length of continuous deck beyond which the spatial variability of seismic action may have to be taken into account 3.3(6) Distance beyond which the seismic ground motions may be considered as completely uncorrelated
3.3(6) factor accounting for the magnitude of ground displacements occurring in opposite direction at adjacent supports 4.1.2(4)P ψ21 values for traffic loads assumed concurrent with the design seismic action



EN 1998-2:2005 (E) 10 4.1.8(2) Upper limit for the value in the left-hand-side of expression (4.4) for the seismic behaviour of a bridge to be considered irregular
5.3(4) Value of ovestrength factor γo 5.4(1) Simplified methods for second order effects in linear analysis 5.6.2(2)P b Value of additional safety factor γBd1 on shear resistance 5.6.3.3(1)P b Alternatives for determination of additional safety factor γBd on shear resistance of ductile members outside plastic hinges 6.2.1.4(1)P Type of confinement reinforcement
6.5.1(1)P Simplified verification rules for bridges of limited ductile behaviour in low seismicity cases
6.6.2.3(3) Allowable extent of damage of elastomeric bearings in bridges where the seismic action is considered as accidental action, but is not resisted entirely by elastomeric bearings
6.6.3.2(1)P Percentage of the compressive (downward) reaction due to the permanent load that is exceeded by the total vertical reaction on a support due to the design seismic action, for holding-down devices to be required. 6.7.3(7) Upper value of design seismic displacement to limit damage of the soil or embankment behind abutments rigidly connected to the deck. 7.4.1(1)P Value of control period TD for the design spectrum of bridges with seismic isolation 7.6.2(1)P Value of amplication factor γIS on design displacement of isolator units 7.6.2(5) Value of γm for elastomeric bearings
7.7.1(2) Values of factors δw and δb for the lateral restoring capability of the isolation system J.1(2) Values of minimum isolator temperature in the seismic design situation J.2(1) Values of λ-factors for commonly used isolators



EN 1998-2:2005 (E)
11 1 INTRODUCTION 1.1 Scope 1.1.1 Scope of EN 1998-2 (1) The scope of Eurocode 8 is defined in EN 1998-1:2004, 1.1.1 and the scope of this Standard is defined in 1.1.1. Additional parts of Eurocode 8 are indicated in EN 1998-1
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