On the seismic fragility of pipe rack—piping systems considering soil–structure interaction

• Published in: Bulletin of earthquake engineering Vol. 18; no. 6; pp. 2723 - 2757
• Main Authors: Di Sarno, Luigi, Karagiannakis, George
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.04.2020; Springer Nature B.V
• Subjects: Accounting; Aseismic buildings; Boundary conditions; Building codes; Civil Engineering; Codes; Construction; Deformability; Dynamic analysis; Earth and Environmental Science; Earth Sciences; Earthquakes; Environmental Engineering/Biotechnology; Formability; Fragility; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Ground motion; Hydrogeology; Liquefied natural gas; Modelling; Nonstructural members; Original Research; Petroleum refineries; Pipes; Pipework; Piping; Probability theory; Racks; Risk assessment; Seismic activity; Seismic engineering; Seismic response; Soil; Soil dynamics; Soil-structure interaction; Soils; Structural Geology; Structural members; Submarine pipelines; Technical literature; Uncertainty; Pipe rack; Dynamic coupling; Piping; Soil–structure interaction; Fragility curves; Seismic input
• ISSN: 1570-761X; 1573-1456
• DOI: 10.1007/s10518-020-00797-0

Piping systems constitute the most vulnerable component in down- and mid-stream facilities posing immediate threat to human lives, communities financial robustness and environment. Pipe racks present several mechanical and geometrical idiosyncrasies compared to common buildings and the seismic response is governed by the pipework layout. Important design requirements e.g. dynamic interaction between pipelines and supporting structure are commonly overlooked during pipe racks design process and uncertainties relevant to modelling of soil or seismic input are not quantified. In the present work, after reviewing the technical literature and codes, a 3D RC rack was used as a testbed and analysed as coupled and decoupled with a non-seismic code conforming piping system accounting for soil–structure interaction. Incremental dynamic analysis was adopted as an assessment methodology for deriving fragility curves considering ground motions in near- and far-field conditions. It was deduced that the modelling (boundary conditions of pipes) was the most considerable uncertainty since it increased the probability of collapse limit state of structural members from 0 to 59%. It was also demonstrated that soil deformability as well as source conditions altered considerably the dispersion of intensity measure conditional on engineering demand parameter of structural and nonstructural members. The results may be another indication that code provisions should be more normative regarding industrial pipe racks.