Beitrag zur Auslegung von Industrieanlagen auf seismische Belastungen
Holtschoppen, Britta; Meskouris, Konstantin (Thesis advisor)
Aachen : Publikationsserver der RWTH Aachen University (2009)
Dissertation / PhD Thesis
Industrial facilities must be thoroughly designed to withstand seismic action as they exhibit an increased loss potential due to the possibly wide-ranging damage consequences and the valuable process engineering. The design must consider both the primary structure and the architectural or technical secondary structures. In this work integrated design concepts are developed for both parts. Regarding the load carrying system (primary structure) the design approach is based on the well-established nonlinear-static capacity spectrum method. The method is expanded to consider the unique situation in plant engineering in respect of large eccentricities between the floor mass- and stiffness centres, the influence of higher vibration modes and the numeric modelling of existing structures. As it is a displacement based design procedure it directly provides maximum expected relative displacements for the design of deformation-sensitive secondary structures like pipes and multi-storey distillation columns. It facilitates performance based design which can easily be used to optimize the structure in order to minimise repair costs and possible down time in case of minor earthquakes. The design concept is illustrated by an application example of a typical production unit. Studies of past earthquakes have shown that in highly industrialised regions the damage of or because of secondary structures can widely exceed the primary damage. Several international codes and standards offer simplified design approaches to cover non-structural components. These design expressions are analysed, and it is shown, that they are not sufficiently general for the most typical practical cases in plant engineering. To amend this, an alternative design approach is developed interpreting the characteristics of floor spectra. The new approach takes the natural periods of the primary and the secondary structure into account and realistically considers the amplification effects of resonance of the non-structural component with higher vibration modes of the primary structure. The concept is validated by comprehensive numerical parameter studies. It furnishes easy-to-use design expressions which can be universally applied to acceleration-sensitive non-structural elements, leading to cost-efficient design alternatives.