NEHRP Clearinghouse
- Title
- Development of Interference Response Spectra for Lifelines Seismic Analysis.
- File
- PB275215.pdf
- Author(s)
- Nelson, I.; Weidlinger, P.
- Source
- National Science Foundation, Washington, D.C. Research Applied to National Needs., July 1, 1977, 47 p.
- Identifying Number(s)
- IR-2
- Abstract
- The authors contend that the dynamic response of a pipe network system may be determined by numerical integration of the appropriate equations of motion. An important criterion for failure of underground pipes subjected to seismic loading is the strain, or difference in displacement, between two points along the pipe. The concept of interference spectrum has been introduced to deal with this problem when dynamic effects are significant. The approach required to analyze a multi-degree of freedom pipe network is outlined. The case of only two connected pipes segments is treated in detail, and shown to be equivalent to a single degree of freedom system. The mathematical treatment is described in detail and the computer code developed is described. Numerical results are presented for both the El Centro 1940 and 15250 Ventura Boulevard 1971 input records. Results demonstrate that it may be possible to estimate, or at least bound, interference spectrum without actually computing it. Finally, it is noted that, for long periods, the absolute velocity spectrum is approximately the same as the pseudo-velocity spectrum, which in turn is readily available for most earthquakes.
- Keywords
- Earthquake resistant structures; Seismic detection; Subsurface structures; Dynamic response; Earthquake engineering; Piping systems; Pipelines; Earthquakes