ENV 1998-4 : 1998

Foreword
1 General
  1.1 Scope
  1.2 Safety Requirements
      1.2.1 General
      1.2.2 Serviceability limit state
      1.2.3 Ultimate limit state
      1.2.4 Reliability differentiation
      1.2.5 System versus element reliability
      1.2.6 Conceptual design
  1.3 Seismic action
  1.4 Analysis
      1.4.1 General
      1.4.2 Behaviour factors
      1.4.3 Damping
      1.4.4 Interaction with the soil
  1.5 Safety verifications
      1.5.1 General
      1.5.2 Combinations of seismic action with other
            actions
2 Specific rules for silos
  2.1 Reliability differentiation
  2.2 Combination of ground motion components
  2.3 Analysis
  2.4 Verifications
      2.4.1 Serviceability limit state
      2.4.2 Ultimate limit state
3 Specific rules for tanks
  3.1 Reliability differentiation
  3.2 Compliance criteria
      3.2.1 General
      3.2.2 Serviceability limit state
      3.2.3 Ultimate limit state
  3.3 Combination of ground motion components
  3.4 Methods of analysis
      3.4.1 General
      3.4.2 Behaviour factors
      3.4.3 Hydrodynamic effects
  3.5 Verifications
      3.5.1 Serviceability limit state
      3.5.2 Ultimate limit state
  3.6 Complementary measures
      3.6.1 Bunding
      3.6.2 Sloshing
      3.6.3 Piping interaction
4 Specific rules for pipelines
  4.1 General
  4.2 Requirements
      4.2.1 Reliability differentiation
      4.2.2 Serviceability requirements
      4.2.3 Safety requirements
  4.3 Seismic action
      4.3.1 General
      4.3.2 Earthquake vibrations
      4.3.3 Modelling of seismic waves
      4.3.4 Permanent soil movements
  4.4 Methods of analysis
      4.4.1 Buried pipelines
      4.4.2 Above ground pipelines
  4.5 Verifications
      4.5.1 General
  4.6 Design measures for fault crossings
Annexes
Annex A (Informative) Seismic analysis procedures for
        tanks
Annex B (Informative) Underground pipelines

Covers principles and application rules for the seismic design of the structural aspects of integrated facilities which are composed of pipeline systems and of storage tanks of different types and destinations, as well as independent items, e.g. single water towers that serve a specific purpose or groups of silos enclosing granular materials, etc. This may also be used as a basis for evaluating the amount of strengthening needed existing facilities to bring them up to present standards.