ATLAS thermosiphon project Piping design and seismic analysis framework Délio Ramos EN/MME,

Outline Piping layout Regulations and standards Strength analysis to EN Seismic analysis – Calculation method – Assumptions and requirements – Seismic actions – Load combination Conclusion

Layout Design goal: A. Define supports layout in order to allow enough flexibility for thermal loads B. Provide sufficient piping restraints to limit static deflection and dynamic (seismic) load consequences From A. Bitadze

Regulations and standards General Safety Instruction GSI-M2 - Standard Pressure Equipment European Directive 97/23/EC CERN European regulations Eurocode 8 EN General EN Silos, tanks and pipelines EN – Metallic industrial piping ATLAS Seismic requirements Actions (from national regulations) Piping Design

EN Strength analysis Permanent mechanical loads Occasional or exceptional loads Thermal and variable loads M A + M B obtained directly from the FE model. k=1.2 for seismic loads. Applied moments and their combination From Ansys 3D modelExcel or Ansys post-processor k=1 CriteriaAllowable stresses N U=1

Preliminary design D. Ramos, Piping analysis for the ATLAS thermosiphon project - Preliminary engineering analysis, EDMS , Pipe DN25Pipe DN50

Earthquake: Methods of analysis Options provided by EN for the design of buildings: – Linear static analysis (“lateral force” method or “equivalent static”) – Modal response spectrum analysis – Non-linear static – Non-linear dynamic (time-history) Implemented in Ansys but requires post- processing to combine loads from X, Y and Z action spectrum

Response spectrum analysis Mode combination Structure response Eigenmode-eigenvalue analysis Specified response spectrum

Combination of modal responses Sum of squares of modal responses (SRSS) – When all relevant modal responses may be regarded as independent of each other (Tj<=0.9Ti) Complete quadratic combination (CQC) – If Tj<=0.9Ti not satisfied Both available in Ansys Clause , EN

Modelling requirements Clause 5.4.1, EN ok ! !

Seismic actions specification Benincasa and Schmidt, 2000

Combination of X, Y, Z action’s effects SRSS combination – Is the reference method (conservative) – Yields the expected result if the modal contributions have been combined using the CQC rule 30% rule as an alternative Clause , EN Easier implementation in Ansys

Conclusion Strength analysis of the piping to EN has been performed on a preliminary design and will be repeated once the layout has been completely approved. The requested seismic analysis can be performed following the procedures of Eurocode 8 – Through a response spectrum analysis (linear) – CQC modal contribution combination + SRSS action combination – For specified X, Y and Z spectra applied to all supports The seismic analysis will not take into account the – Effects of the supporting structure dynamics – Influence in the actions from the difference in elevation