Seismic response

The Seismic Safety Margins Research Program developed a computer code called SMACS (Seismic Methodology Analysis Chain with Statistics) for calculating the seismic responses of structures, systems, and components. This code links the seismic input as ensembles of acceleration time histories with the calculations of the soil-structure interactions, the responses of major structures, and the responses of subsystems. Since uses a multi-support approach to perform the time-history response calculations for piping subsystems, the correlations between component responses can be handled explicitly. SMACS is an example of the codes that are available for calculating seismic response for PSA purposes. 

Fig. 17. Wireline log characteristics, smoothed acoustic impedance curve and 3D seismic response over the Upper Angel Formation at Angel-2. Note that the major dolomite-cemented zones (black bars) are identifiable on the basis of neutron, density, resistivity and sonic log profiles. The zones appear as discrete layers at this location, with a cumulative thickness of 164 m, and are not fully cemented but contain some residual porosity. The dolomite-cemented zones occur both above and below the gas-water contact (GWC). The smoothed acoustic impedance curve shows that the zones produce a visible seismic response which is mappable. For an example of a line through the 3D seismic volume see Ryan-Grigor Schulz-Rojahn (1995 their Fig. 10a,b).

In the Gidgealpa Field, reflection coefficients calculated from the sonic and bulk density logs for carbonate-cemented sandstone interfaces with elastics that lack major carbonate cement are in the order of 0.22-0.26, demonstrating a relatively strong 2D seismic response. The seismic response is the relatively strong, generally continuous two-peak event that occurs immediately above the top of the... 

In both study areas the data showthat the seismic response closely matches the observed occurrence of major carbonate-cemented zones at the well locations. However, thin bed tuning and limitations in seismic resolution prohibit delineation of the thickness and spatial separation of individual carbonate-cemented zones away from the well locations. Only the gross carbonate-cemented intervals... 

Fig. 18. The same line of traverse as shown in Fig. 16, illustrating the variable synthetic seismic response over the major calcite-cemented zones (arrows) in the Lower Namur Sandstone. Note that where the calcite-cemented zones are thickest (Gidgealpa-23) two peaks are produced which are separated by a broad trough. In contrast, where only a relatively thin carbonate-cemented zone is present (Gidgealpa-17) only a small peak is produced. The gross carbonate-cemented interval is mappable on seismic sections below the C horizon (top Cadna-Owie Formation).

Singh, R. (1990) The seismic response of calcite-cemented zones—Gidgealpa. MSc thesis. University of South Australia. 

The seismic responses of reactor structures of seismically isolated KALIMER are significantly reduced for accelerations and relative displacements in honzontal direction For the isolation case, the maximum peak acceleration in honzontal direction is same m all structures and components, i e, 0 llg for OBE and 0 22g for SSE The responses are reduced about 14 times in MX. 9 tunes in EMP and 8 times in reactor vessel liner, support barrel, and core compared with those m non-isolated case However, for the vertical direction, significant response amplifications occur ui whole structures This IS due to the vertical structural frequency of 8 1 Hz located in dormnant excitation frequency band of input motion... 

For the general investigation of core seismic responses, the harmonic excitations subjected to ngid core shroud and core support plate are used in the analyses considering conservative excitation conditions. Table 1 shows the input loading conditions. 

The results of the core seismic response analyses show that. the load case 4, which is the... 

Yoo, B, Lee. J H and Choi, IK, Seismic analysis modeling and seismic response analysis of KALIMER reactor building, KAERI/TR-1062/98, (1998)... 

Source Dobry, R., and Vucetic, M., Dynamic properties and seismic response of soft day deposits. In Proceedings of the International Symposium on Geotechnical Engineering Soils 1, KSMFE, Mexico City, Mexico ... 

Another example of evaluation of seismic response of cohesive soils was given by Tsai et al. (1980). It was concluded that nonlinear deformation, failure, and degradation behavior of the soil profile can have significant influence on seismic response under strong levels of earthquake shaking. 

Singh, R.D., Ricardo, D., Doyle, E.H., and Idriss, I. M. 1981. Nonlinear seismic response of soft clay sites. Journal of the Geotechnical Engineering Division, ASCE, 107, No. GT-9, pp. 1201-1218. 

Keywords ambient vibration Bayesian inference best estimaton conditional probability correlation function modal analysis modal identification nonstationary response seismic response structural health monitoring... 

Chapter 3 presented the Bayesian spectral density approach for the parametric identification of the multi-degree-of-freedom dynamical model using the measured response time history. The methodology is applicable for linear models and can also be utilized for weakly nonlinear models by obtaining the mean spectrum with equivalent linearization or strongly nonlinear models by obtaining the mean spectrum with simulations. The stationarity assumption in modal/model identification for an ambient vibration survey is common but there are many cases where the response measurements are better modeled as nonstationary, e.g., the structural response due to a series of wind gusts or seismic responses. In the literature, there are very few approaches which consider explicitly nonstationary response data, for example, [226,229]. Meanwhile, extension of the Bayesian spectral density approach for nonstationary response measurement is difficult since construction of the likelihood function is nontrivial in the frequency domain. Estimation of the time-dependent spectrum requires a number of data sets, which are associated with the same statistical time-frequency properties but this is impossible to achieve in practice. 

Based on the specific Nuclear Steam Supply System (NSSS) design currently available, the parametric site screening study was performed with the CIASSI computer code to ascertain the site conditions which will produce the largest seismic responses In selected NSSS components. On the basis of this study, the following three representative sites shown in Figure 3.7-4 and described below were selected for further study with the SASSI computer code ... 

Further detailed finite-element modeling and analysis are performed to determine vessel stresses at critical locations such as the vessel/support interfaces and vessel/crossduct intersections. The seismic response loads from the NSSS model are used as input to these models. 

U.S. Nuclear Regulatory Commission. Combining Model Responses and Spatial Components in Seismic Response Analysis. Regulatory Guide 1.92, Revision 1, Washington, DC, February 1976. 

Combined Modal Responses and Spatial Components in Seismic Response Analysis... 

Idriss, I. M., Sun, J. I. (1992). SHAKE91 A computer program for conducting equivalent linear seismic response analyses of horizontally layered soil deposits. Center for Geotechnical Modeling, Department of Civil and Environmental Engineering, University of California, Davis, 130. 

Madabhushi, S. P. G., Zeng,X. (2006). Seismic Response of Flexible Cantilever Retaining Walls with Dry Baekfill, Geomechanics and Geoengineering. International Journal (Toronto, Ont.), 7(4), 275-290. 

Madabhushi, S. P. G., Zeng, X. (2007). Simulating Seismic Response of Cantilever Retaining Walls with Saturated Backfill. ASCE Journal of Geotechnical and GeoEnv. Engineering, 133(5), 539-549. 

SHAKE. 2000 (2000). A computer programfor conducting equivalent-linear seismic response analyses for horizontally layered soil deposits. A modified PC version of the original SHAKE program published in 1972 by Schnabel, Lysmer and Seed (modifications made by Idriss IM, Sum JI). EERI, University of California, Berkley. 

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