Seismic Design of Geothermal Pipeline Supports

Seismic loading is a critical factor in the structural design of piping systems for geothermal power plants in Iceland. It has been shown that the design of piping systems which is based on response spectrum static analysis can lead to overdesigned systems. The loading on the supports will be overestimated and, hence, the supports tend to be too stiff. This increased stiffness both increases the cost and reduces the quality of the seismic design. The systems response is highly dependent on the support stiffness. In this work, the design of a typical expansion loop with respect to seismic loading is discussed, with the goal being to minimize the loading from the ground acceleration. A typical pipe support is modelled, and its stiffness characteristics are evaluated and optimized. Finally, recommendations are made for improvements in pipeline support design.