UNI EN 1998-4 : 2006

FOREWORD
1 GENERAL
  1.1 SCOPE
  1.2 NORMATIVE REFERENCES
      1.2.1 General reference standards
  1.3 ASSUMPTIONS
  1.4 DISTINCTION BETWEEN PRINCIPLES AND APPLICATIONS RULES
  1.5 TERMS AND DEFINITIONS
      1.5.1 General
      1.5.2 Terms common to all Eurocodes
      1.5.3 Further terms used in EN 1998
      1.5.4 Further terms used in EN 1998-4
  1.6 SYMBOLS
  1.7 S.I. UNITS
2 GENERAL PRINCIPLES AND APPLICATION RULES
  2.1 SAFETY REQUIREMENTS
      2.1.1 General
      2.1.2 Ultimate limit state
      2.1.3 Damage limitation state
      2.1.4 Reliability differentiation
      2.1.5 System versus element reliability
      2.1.6 Conceptual design
  2.2 SEISMIC ACTION
  2.3 ANALYSIS
      2.3.1 Methods of analysis
      2.3.2 Interaction with the soil
      2.3.3 Damping
            2.3.3.1 Structural damping
            2.3.3.2 Contents damping
            2.3.3.3 Foundation damping
            2.3.3.4 Weighted damping
  2.4 BEHAVIOUR FACTORS
  2.5 SAFETY VERIFICATIONS
      2.5.1 General
      2.5.2 Combinations of seismic action with other actions
3 SPECIFIC PRINCIPLES AND APPLICATION RULES FOR SILOS
  3.1 INTRODUCTION
  3.2 COMBINATION OF GROUND MOTION COMPONENTS
  3.3 ANALYSIS OF SILOS
  3.4 BEHAVIOUR FACTORS
  3.5 VERIFICATIONS
      3.5.1 Damage limitation state
      3.5.2 Ultimate limit state
            3.5.2.1 Global stability
            3.5.2.2 Shell
            3.5.2.3 Anchors
            3.5.2.4 Foundations
4 SPECIFIC PRINCIPLES AND APPLICATION RULES FOR TANKS
  4.1 COMPLIANCE CRITERIA
      4.1.1 General
      4.1.2 Damage limitation state
      4.1.3 Ultimate limit state
  4.2 COMBINATION OF GROUND MOTION COMPONENTS
  4.3 METHODS OF ANALYSIS
      4.3.1 General
      4.3.2 Hydrodynamic effects
  4.4 BEHAVIOUR FACTORS
  4.5 VERIFICATIONS
      4.5.1 Damage limitation state
            4.5.1.1 General
            4.5.1.2 Shell
            4.5.1.3 Piping
      4.5.2 Ultimate limit state
            4.5.2.1 Stability
            4.5.2.2 Shell
            4.5.2.3 Piping
            4.5.2.4 Anchorages
            4.5.2.5 Foundations
  4.6 COMPLEMENTARY MEASURES
      4.6.1 Bunding
      4.6.2 Sloshing
      4.6.3 Piping interaction
5 SPECIFIC PRINCIPLES AND APPLICATION RULES FOR ABOVE-GROUND
  PIPELINES
  5.1 GENERAL
  5.2 SAFETY REQUIREMENTS
      5.2.1 Damage limitation state
      5.2.2 Ultimate limit state
  5.3 SEISMIC ACTION
      5.3.1 General
      5.3.2 Seismic action for inertia movements
      5.3.3 Differential movement
  5.4 METHODS OF ANALYSIS
      5.4.1 Modelling
      5.4.2 Analysis
  5.5 BEHAVIOUR FACTORS
  5.6 VERIFICATION
6 SPECIFIC PRINCIPLES AND APPLICATION RULES FOR BURIED
  PIPELINES
  6.1 GENERAL
  6.2 SAFETY REQUIREMENTS
      6.2.1 Damage limitation state
      6.2.2 Ultimate limit state
  6.3 SEISMIC ACTION
      6.3.1 General
      6.3.2 Seismic action for inertia movements
      6.3.3 Modelling of seismic waves
      6.3.4 Permanent soil movements
  6.4 METHODS OF ANALYSIS (WAVE PASSAGE)
  6.5 VERIFICATIONS
      6.5.1 General
      6.5.2 Buried pipelines on stable soil
      6.5.3 Buried pipelines under differential ground
            movements (welded steel pipes)
  6.6 DESIGN MEASURES FOR FAULT CROSSINGS
ANNEX A (INFORMATIVE)
SEISMIC ANALYSIS PROCEDURES FOR TANKS
ANNEX B (INFORMATIVE)
BURIED PIPELINES

Describes principles and application rules for the seismic design of the structural aspects of facilities composed of above-ground and buried pipeline systems and of storage tanks of different types and uses, as well as for independent items, such as for example single water towers serving a specific purpose or groups of silos enclosing granular materials, etc.