NEHRP Clearinghouse
- Title
- Behaviour of Underground Lifelines in Seismic Environment.
- File
- PB275217.pdf
- Author(s)
- Weidlinger, P.
- Source
- National Science Foundation, Washington, D.C. Research Applied to National Needs., July 1977, 25 p.
- Identifying Number(s)
- IR-4
- Abstract
- The research attempts to formulate a comprehensive procedure based on a consistent theory for the analysis and design of underground lifelines in seismic environment. Current procedures of engineering seismology are not sufficient for this purpose, and the detailed definition of the displacement field due to seismic motion needs to be extended to include spatial and temporal variations in a broader frequency range. The displacement field may interact weakly or strongly with a buried pipeline, depending on the pipe's dynamic characteristics as modified by the surrounding soil. The effect of this interaction is presented in an 'Interference Spectrum' which gives the peak response of a damped oscillator, subject to simultaneous excitation at two spatially separated points. Spectral amplitudes are used to determine the response of the system, in terms of a 'Damage Matrix' which quantifies the failure parameters of a system consisting of various types of pipes, joints and other details. For purposes of risk analysis, optimalization and cost-benefit studies of existing or planned systems, covering large areas, a statistical method is developed which provides the expected value of free field gradients, as affected by subsurface and geology. These gradients are used to estimate the probable performance of the system during an earthquake defined by a power spectral density function.
- Keywords
- Earthquake resistant structures; Seismic detection; Risk analysis; Subsurface structures; Seismic risk; Earthquake engineering; Power spectra; Piping systems; Pipelines; Earthquakes