Conceptual design and feasibility for an effective elastic-plastic pipe support on seismic response reduction

Abstract

The objectives to extend the available range of pipe supports up to plastic region are below; one is to enlarge the loading capacity, and the other is to add damping to piping systems using the absorption effect of seismic energy due to the elastic-plastic hysteresis property. However, the pipe support design that balances these two functions is difficult. In this study, a design concept to achieve both of these functions is proposed and its feasibility is shown. First, the effectiveness of the elastic-plastic design with the allowable load for the existing elastic-plastic pipe supports was compared. The results showed that although an increase in loading capacity can be expected due to elastic-plastic pipe supports, the damping effect depends on the shape of the supports, so that damping due to plasticity cannot be expected much. To obtain sufficient damping effect, an additional design process is required to adjust the yield load for each support. Next, to overcome this drawback, an elastic-plastic pipe support with a hybrid structure of frame type structure and cantilever structure was proposed. The frame-type structure ensures pipe support and prevents excessive deformation of the piping, and the cantilever structure increases the damping effect. This proposed design makes it easy to optimize both functions.

Keywords

• elastic-plastic pipe support
• seismic design
• elastic-plastic design
• piping system
• pipe support
• loading capacity
• hysteresis
• damping
• seismic response reduction