Site response analyses

Using the elastic acceleration response spectra calculated as output of site response analyses for each cell, the module calculates the average acceleration response spectrum... 

Table 1 Hazard com Zeytinburnu. patible acceleration time histories selected for site response analyses in...

Ansal, A., Durukal, E. Toniik, G. 2006a. Selection and Scaling of Real Acceleration Time Histories for Site Response Analyses. Proc. of ISSMGE ETC12 Workshop, Athens, Greece. 

Durukal, E., Ansal, A. Toniik, G. 2006. Effect of Ground Motion Scaling and Uncertainties in Site Characterisation on Site Response Analyses. Proceedings of the 100th Anniversary Earthquake Conference Commemorating the 1906 San Francisco Earthquake, San Francisco, USA. 

Many computer programs are available to estimate free-field shear distortions SHAKE (Schnabel et al. 1972), FLUSH (Lysmer et al. 1975), D-MOD (Matasovic 1993), and DEEPSOIL (Hashash et al. 2011 Hashash and Park 2001), among others. One-dimensional site response analyses can be used to characterize the change in the propagating ground motions on variable soil profiles, but these analyses only take into consideration vertically propagating shear waves. However, these are the waves that... 

Hashash et al. (2010) describes the procedure to be used for performing 2D pseudo-static racking analysis of rectangular tunnels (Fig. 15). In this type of analysis, the soil is assumed to be massless and the section deforms in pure shear. In a first step. Fig. 15a, the free-field racking deformation time history is computed from ID site response analyses using hazard-compatible ground motion time histories. 

Site response analyses have been traditionally performed using a one-dimensional (ID) frequency-domain numerical scheme based on the equivalent viscoelastic approach. This approach has been extensively adopted in the last 30 years, and it is widely accepted in the engineering practice, although its limitations are well known. Being based on a total stress formulation, it disregards the buildup of excess pore water pressures in the soil deposit. Additionally, the adopted equivalent viscoelastic material properties cannot properly represent the soil... 

Bardet JP, Tobita T (2001) NERA — a computta program for Nonlinear Earthquake site Response Analyses of layered soil deposits. Department of Civil Engineering, University of Southern California, Los Angeles Bardet JP, Ichii K, Lin CH (2000) EERA — a computer program for Equivalent-linear Earthquake site Response Analyses of layered soils deposits. University of Southern California, Department of Civil Engineering, Los Angeles. User manual Bazzurro P, Cornell CA (2004) Nonlinear soil-site effects in probabilistic seismic hazard analysis. Bull Seismol Soc Am 94 2110-2123... 

A number of benchmarking exercises have also been conducted to evaluate site response analysis tools. A recent key exercise is the PEER benchmarking exercise for total-stress site response analyses (Kwok et al. 2007). Another interesting benchmarking exercise was the evaluation of site response at Turkey Flat (e.g., Kramer 2009). The interesting outcome of... 

Site-specific geotechnical investigation and dynamic site response analysis shall be performed to determine seismic coefficients lor Soil Profile Type Sf-... 

F. Soils requiring site response analysis in accordance with Section 21.1 See Section 20.3.1 of ASCE/SEI 7. 

The Halcrow Group based in London does seismic-hazard analysis, design, and remediation. It also does earthquake site response analysis and liquefaction assessment and remediation. It has done site evaluations for nuclear power plants, dams, and intermediate level nuclear waste stors e. It is a large company with 8,000 employees and many interests. 

Figure 3 Acceleration time histories scaled with respect to PGA and their respective acceleration response spectra used as input motion in the site response analysis.

Figure 6 Variation of short and iong period (T = 0.2 s and T = I s) spectral accelerations on the ground surface in Zeytinburnu determined from site response analysis.

The normal mode method has been widely used in studies of long-period seismology for identifying source mechanisms (e.g.. Ref. 6). The method is composed of two steps, as shown in Figure 2 (1) computation of normal modes representing the free oscillations of the earth, and (2) site response analysis by the combination of these modes ... 

Where the state parameter approach substantially improves on the NCEER method is if the effects of soil properties are included by measurement/calibration rather than correlation. Extension to directly include the effect of soil properties requires measurement of in situ (which is frequently carried out anyway for the site response analysis) and measurement of the soil compressibility A (defined on Figure 8.46, and typically requiring a program of 5 10 triaxial tests). 

The site fundamental period, the other input to the Bray Travasarou method, will have been determined during the site response analysis. 

In choosing between these methods to assess deformations in a lateral spread, the first question must be why is lateral spreading a concern The usual engineering approach for a fill will be to densify that fill so that spreading is not an issue. If a decision is made to leave a vulnerable stratum unimproved, possibly because of the scale of the works, then likely deformations can be estimated using Hamada (1999) as straightforward supplement to the site response analysis. If that is regarded as insufficiently reliable for a particular project, then specialist advice will be needed and almost certainly detailed numerical analysis. 

For liquefaction analysis, seismic load in a soil element is represented by time history of shear stresses (Xdyn) imposed by earthquake shaking, and they can be calculated from a site response analysis using the input ground motions at the damsite and dynamic properties of dam fills and foundation soils. 

A seismic site response analysis ( Site ResptMise 1-D Time Domain Analyses) is commonly performed in a total stress analysis, without including PWP effect, using a ID soil column... 

Upon completion of a site response analysis, cyclic stress ratio (CSR = Xdy /a vo) in each soil zone is calculated by converting the nonuniform cycles of shear stresses from the earthquake to equivalent cycles of uniform shear stresses (Wu 2001) and then normalized to the in situ vertical normal stress (cj vo). 

Hashash et al. (2010) provides a simplified 2D dynamic soil-structure interaction procedure that makes computational effort manageable for design purposes of transverse response of rectangular tuimels. The first step is to perform a 1D site response analysis to obtain the acceleration and displacement time history throughout the soil profile and then obtain the strain-compatible shear wave velocities and damping ratios for the 2D model layers. 

With respect to site response analysis, the use of nonlinear time-domain approaches should be encouraged as a viable alternative to the standard linear equivalent method. It can, in fact, better predict soU deformation, degradation of stiffness, and accumulation of excess pore water pressures throughout the shaking. The issue of the accurate predictiOTi of hysteretic damping with advanced soU constitutive models still remains controversial, as these models can significantly... 

D nonlinear seismic site response analysis 1-D nonlinear site response analysis Onedimensional (1-D) time domain analysis... 

In general, site response analysis methods can be classified based upon the domain in which calculations are performed (frequency domain or time domain), the sophistication of the constitutive model employed (linear, equivalent linear, and/or nonlinear), whether the effects of... 

One-dimensional nonlinear total-stress site response analysis is generally cmiducted using... 

Bounding surface plasticity models may be used to simulate nonlinear stress-strain behavior in one dimension. Example of such models and their application in site response analysis can be found in Borja et al. (2002). 

Kwok et al. (2007) recommended, for most practical applications, use of the full Rayleigh damping formulation in nonlinear (total-stress) site response analysis whereby the first frequency is equal to the fundamental frequency of the soil column, while the second frequency is equal to five times the fundamental frequency. 

Another class of soil constitutive models used in site response analysis is effective-stress models. In these models, the formulation of the... 

A number of individuals and groups have conducted back-analysis exercises to evaluate site response analysis procedures (and programs) versus measured response to strong ground shaking. Most of these studies include use of recordings from downhole vertical arrays. 

Researchers have used a range of inverse analysis techniques that include ad hoc system identification (e.g., Zeghal and Elgamal 1993 Assimaki and Steidl 2007) and evolutionary soil models (e.g., Tsai and Hashash 2007) to calibrate soil constitutive models in site response analysis actual (in situ) soil behavior. 

Tsai C-C, Hashash YMA (2007) A novel framework integrating downhole array data and site response analysis to extract dynamic soil behavior. Soil Dyn Earthq Eng 28(3) 181-197... 

Waalkes, M.P., S. Rehm, C.W. Riggs, R.M. Bare, D.E. Devor, L.A. Poirier, M.L. Wenk, and J.R. Henneman. 1989. Cadmium carcinogenesis in male Wistar [Crl (Wl)BR] rats dose-response analysis of effects of zinc on tumor induction in the prostate, in the testes, and at the injection site. Cancer Res. 42 4282-4288. 

---