Nonbuilding and Special Structures
Adjacent industrial structures are often coupled structurally by piping, electrical trays, and mechanical equipment components. Despite these structures sharing common elements, they are usually analyzed independently as it is the simplest and most cost effective method for completing the engineering and design. There are key factors which determine when a combined analysis of coupled industrial structures subjected to seismic loading is more appropriate to accurately capture the overall structural system behavior. The mass of the supported equipment and pipe is one of these factors since the added mass of these components can become the driver of the natural frequencies of the structural system and affect the seismic response. Another factor affecting the seismic response of coupled industrial structures is the relative stiffness and damping of interconnecting components. Currently, there is no guidance within the codes and standards that specifies whether a combined analysis of coupled structures is necessary to accurately model the seismic behavior of the structural system. A parametric study is performed on an analysis model of two adjacent coupled structures; the study evaluates the effect of mass, stiffness, and damping of the structures and their interconnecting systems on the overall structural system response. A set of threshold conditions or “triggers” for combined analysis are obtained through this study The proposed triggers provide guidance to practicing engineers regarding the conditions in which a combined analysis of industrial structures is required in order to appropriately capture the behavior of coupled structural systems subjected to seismic loading.