3.6 Calibration and Validation

A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows  Spatial variation of motion. Typically, Bullet remove defined by an assumed wave propagation d in the mechanism. X GC3 20/2.1 rewrite The link between both sentences is not clear of Chapte r 2. For soil-structure interaction (SSI) analyses, description of the soil configuration (layering or stratigraphy) and characterization of the dynamic (material) properties of the subsurface materials, including the uncertainties associated to them, shall be GC4 29/3.1 investigated and a soil profile for the site, in a Alain form suitable for design purposes, shall be determined together with associated uncertainties.

What about lateral variations?

GC5 29/3.1 Therefore, large scale geological Alain investigations are required to define the lateral and in-depth extent of the various strata, the underground topography, the possible existence of basins (large-scale structural

Page 1 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows formation of rock strata formed by tectonic warping of previously flat-lying strata, structural basins are geological depressions, and are the inverse of domes), the depth to the bedrock, the elevation of the water table, etc.

See IRSN1 reviewer comments.

“….simplified rules proposed in the outcome of the European research project NERA (2014) [3]”

The NERA project was intended to propose simplified aggravation factors for EC8 revision. It GC6 30/3.1 is based on simple basin shape filled with soil Alain defined by smoothly varying velocities with depth. Other studies aim at assessing such aggravation factors based on simple basins like the following ones and others : Bard and Bouchon (1985) Meza-Fajardo et al. (2016)

GC7 30/3.1 “….Pitilakis et al, (2015) [4] tentatively Alain concluded the following based on extensive numerical analyses, involving linear and equivalent linear soil constitutive models:” A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows Pitilakis et al. (2015) do not mention equivalent linear modelling but only linear elastic analysis. In the NERA final document (deliverable D11.5 “Code cross-check, computed models and list of available results”), it is mentioned that wave propagation modelling in nonlinear soils is performed with one code (ABAQUS) and for clays (page 9: “The material non-linearity is described according to the constitutive model of Anastasopoulos et al. (2011) and degradation curves corresponding to the Ishibashi and Zhang model for clays with a plasticity index of 50 and a mean confining pressure of 10 kPa.”)

GC8 30/3.1  The aggrevation factors for locations close Alain to the valley edges are smaller than 1.0,

This is different from what is written in the NERA project deliverable (summary of deliverable D11.5 “Code cross-check, computed models and list of available results”) : “A preliminary analysis indicates that these AGF are found in the range 1.3 – 2 in most cases, with a maximum near the valley edges and sometimes in the center of embanked valleys, while they almost systematically exhibit some deamplification (AGF values smaller than 1) on the very edges of valleys (over dipping Page 3 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows sediment-basement interface). These aggravation factors decrease with increasing input ground motion because of non-linearity, while they may increase in case of pronounced 3D geometries. The final objective (not yet fully achieved) is to propose simple formulae relating these AGF to the geometrical and mechanical characteristics of the valley and the receiver position.”

GC9 30/3.1  The aggrevation factors for location in the Alain central part of the valley depend on the fundamental period of the valley: they are slightly larger than 1.0 if the basin period is small, typically less than 3.0s, and therefore 2D effect may be considered of minor importance; they may reach high values if the basin period is large.

In Pitilakis et al. (2015) : Based on the above thorough parametric analysis it is believed that we have convincing arguments to propose, in case of normal shaped basins of trapezoidal shape, a short- period aggravation factor AGFS (T≤0.75T0) and a long-period aggravation factor AGFL (T>0.75T0) for the seismic design of structures with fundamental vibration periods Τ falling within these period bands (T0 is the fundamental period A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows at the center of the basin). The proposed aggravation factor should multiply in each period range the spectral value of the design elastic response spectrum of EC8. Spatial distribution of AGFS and AGFL along the basin showed that for the region above the inclined part of the basin, both AGFS and AGFL are in general below 1.0, thus, in order to be on the safe side, the design response spectrum, (i.e. normally the seismic code values) can be used without any further modification for basin edge effects. On the contrary, for the region above the constant-depth part of the basin, median short-period aggravation factors AGFS are around 1.1 with 84th percentiles not greater than 1.2; median long-period aggravation factors AGFL are around 1.0 for basins with low T0, while vary from 1.1 to 1.4 for basins with higher T0. Corresponding AGFL 84th percentiles are 1.1 for low-T0 basins and can be as high as 1.8 for high-T0 basins. The limit value of T0 for the distinction between low- and high-T0 basins could be indicatively set to 3.0s (Figure 9). These aggravation factors should be mainly used for ordinary structures, while detailed site- specific analyses should be performed for important structures. And in conclusions : Extensive parametric 2D

Page 5 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows numerical analyses of the seismic response of homogeneous alluvial basins were performed at a second stage to explore the basin-induced amplification and its sensitivity to parameters related to the basin geometry and the properties of the soil sediments. The computed maximum AGF were found as high as 2.8 for some specific geometries and soil conditions. Median and 84th percentiles values are proposed for ordinary engineering applications with the introduction of a short- (for periods T≤0.75T0, where T0 is the fundamental period at the center of the basin) and a long-spectral period (T>0.75T0) aggravation factor, which should multiply the present spectral value of the elastic response spectrum in order to account for the extra amplification in case of basins. The extra median factors vary from 1.0 to 1.4 with the largest values corresponding to the deeper basins, with corresponding 84th percentiles ranging from 1.1 to 1.8.

“….constitute helpful guidelines to estimate the potential for 2D effects.smaller than 0.5.” GC10 30/3.1 Alain And what about 3D ? what about 2D SV and 2D SH ? A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows “However, it is frequently assumed that a one- . dimensional situation prevails and simpler models can then be used to describe the salient GC11 33/3.2 features of the soil response.” Alain What if 2D/3D effects take place? Link with part 6.3.3 (page 101-104) should be done

“High frequency motions induce smaller strains and therefore should be assigned less damping.” GC12 33/3.3.2 Alain Add references to the paper of Kausel and Asimaki (2002) that introduced Frequency-Dependent Shear Modulus and Damping ? The essential parameters that need to be determined are the parameters entering the Alain, GC13 43/3.4 constitutive models described in Section 3.2. Boris, See table. (JJJ-cannot connect with table JJJ unless it is the table to be produced) Boris’s note: Add a bit on other parameters that are important, like density, Alain, GC14 43/3.4 void ratio, number of loading cycle… Boris, JJJ Provide table.

Page 7 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows As indicated in Section 3.1, this parameter is a good proxy to decide of the importance of 2D Alain, GC15 45/3.5.1 effects in presence of a basin. Boris, JJJ See table. (JJJ-what table?) GC16 45/3.5.1 This method consists in measuring the ambient Alain, Boris, noise in continuous mode with velocity meters JJJ (not accelerometers) and then computing the ratio between the horizontal and vertical Fourier amplitude spectra (Nakamura, 1989) [24]. Guidelines were produced by the SESAME research programme (SESAME 2004) [25] to implement this technique, which is now reliable and robust. H/V measurements can provide the fundamental frequency of the studied site under some conditions (but not the associated response amplitude) but can also be used to assess the depth to bedrock and its possible lateral variation when the technique is implemented along profiles. However, in this case, care should be taken when interpreting along the edge of basins, where the bedrock is significantly sloping, because 1-D geometry is assumed in the interpretation of measurements. The knowledge of the soil profile natural frequency is also important to A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows validate the numerical model used for the analyses.

See table. (JJJ-what table?)

What about arrays using ambient noise to get 1D GC17 45/3.5.1 Alain soil profiles? See table. (JJJ-what table?) Measurement of seismic events is recommended with installation of instruments that allow recording, on site or in the vicinity, ground motions induced by real earthquakes. Based on these free-field records, "site to reference" transfer functions can be determined at various locations across the site. Alain, GC18 45/3.5.1 Boris, The site to reference transfer functions are JJJ useful to assess site amplification with respect to the reference and to calibrate the numerical model, at least in the linear range, provided that the “reference” site is characterized.

See table. (JJJ-what table?) GC19 45/3.5.1 Alain, What about installing accelerometers for strong Boris, JJJ motion recording ?

Page 9 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows See table. (JJJ-what table?)

“….interpretation of MASW measurements implicitly assumes that the site is horizontally layered; therefore, they are not accurate for subsurface sloping layers.” GC20 46/3.5.2 Alain Other techniques, like array measurements or high resolution seismic reflexion, allow to reach higher depths.

GC21 47/3.5.3 “….retrieving truly undisturbed samples in Alain cohesionless uniform materials is still a challenge. Laboratory tests can be classified in three categories:”

The authors should add that it is physically impossible, in a strict sense, to obtain undisturbed samples in borings because of the undesirable effects resulting from the unloading caused by removal from confinement, and from shipping or handling. About cohesionless soils, there are no standard, or generally accepted, methods for undisturbed sampling. Such soils can be recovered by in situ freezing or chemical stabilization to preserve the natural A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows structure.

GC22 49/3.6 3.6 CALIBRATION AND VALIDATION Alain

And code verification. “However, validation shall not be overlooked: results should be critically examined since, as indicated previously, those constitutive models are only valid for strains smaller than a given

threshold v. If results of analyses indicate GC23 50/3.6 larger strains, then the constitutive models Alain should be modified and nonlinear models should be advocated.

More precision about this threshold parameter v and how to measure/calculate it should be given. LM24 62/5.1.1 Earthquake Source: the slippage (shear failure) X Boris change of a fault. Initial slip propagates along the fault d – and radiates mechanical, earthquake waves. excelle Depending on predominant movement along nt. the failed fault,

There is not an initial slip propagating.

Page 11 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows

An earthquake is produced by a rapid stress drop in the crustal medium with a consequent release of energy. Part of this energy alows the rupture propagation along the fault plane. An other part of energy propagates in the crustal medium as elastic waves. Under a kinematic pov, the seismic source is described as a slip distribution starting from a nucleation point and propagating along the fault plane at a given velocity rupture. The seismic moment is defined as the product between the crust rigidity, the fault area and the average slip. The moment magnitude is given by log10(M0) = 1.5 Mw +9.1 (if M0 is expressed in Nm)

The source mechanism is described using 3 angles: strike (orientation of the fault plane respect to the north), dip (orientation respect to the vertical) and rake (orientation of the slip).

LM25 62/5.1.1 Depending on predominant movement along X Change the failed fault, we distinguish (a) dip slip and d (b) strike slip sources. Size and amount of slip on fault will release different amounts of energy, and will control the earthquake magnitude. A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows

Maybe you mean the rake ? “….mechanical waves propagate….” Change LM26 62/5.1.1 X d Should be “elastic” “Spatial distribution (deep geology) and Change stiffness of rock will control wave paths, d which will affect amplitude of waves that radiate toward the surface. LM27 62/5.1.1 X I would write that the crust is characterised by heterogenous mechanic and rheological properties; such an heterogeneity affect the elastic wave propagations. LM29 62/5.1.1 Shallow, surface layers Response: seismic Boris, Need JJJ, to body waves propagating from rock and deep Alain discuss soil layers to the surface and interacting with the ground surface create surface seismic waves.

Pay attention, surface waves play an important role in site response, but they are not limited at this framework. When a strong event occurs somewhere on Earth, the teleseimic records are dominated by surface waves and you can include them in the path term.

Page 13 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows Here you are specifically writing about the soil effects. This passage deserve a carefully redaction.

In general, seismic motions at surface and Need to shallow depths consist of (shallow) body discuss waves (P, SH, SV) and surface waves . Boris (Rayleigh, Love, etc.). It is possible to analyze added some SSI effects using a 1D simplification, where a Boris, clarific LM30 63/5.1.1 full 3D wave field is replaced with a 1D wave JJJ, ation. field. It is advisable that effects of this Alain Why use simplification on SSI response be carefully term assessed. (shallo w)? Too generic to be informative. LM31 63/5.1.1 A usual assumption about propagation of Boris, Need JJJ, to seismic waves (P and S) is based on Snell’s Alain discuss law about wave refraction.Seismic waves . JJJ travel from great depth (many kilometers) and concur s with as they travel through horizontally layered change media (rock and soil layers), where each layer . features different wave velocity (stiffness) that decreases toward surface, waves will bend toward vertical (Aki and Richards, 2002). However, even if rock and soil layers are ideally horizontal, and if the earthquake source is very deep, seismic waves will be few A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows degrees off vertical, depending on layering (usually 5-10 degrees off vertical) when they reach the surface.

If the scope of the paragraph is to describe a phenomenon, occurring at hundreds of meters of depth why go back to the crustal scale? As result, the sentence become confusing. Moreover, the shallow geology can have a predominant role on the surface wave generation.

For a sake of clarity, I suggest: first to introduce the different kind of waves (body and surface) in the Path term. Then in the surface layer term discuss the aspects related to the locale surface waves generation (the site response). However, such deviation from vertical will Added. produce surface waves, the presence of which GC32 63/5.1.1 can have practical implications for SSI X analysis.

Or generated at valleys/basin edges. LM33 65/5.1.2 “Prior to the early 1990s, skepticism existed in X In this time period, there was significant scepticism some quarters as to the wave propagation behavior about near surface of seismic waves in the free-field and their spatial variations of motion, variation with depth in the soil.” especially when implementing Page 15 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows This sentence should be supported by citations. deconvolution analyses and the results thereby produced. In addition, there was even scepticism concerning convolution results when taking into account earth berms that were constructed on site. Limitations on reductions of free-field motion at depth was strictly enforced for all site conditions not simply the envelope of the various soil cases analyzed. LM34 65/5.1.2 “This skepticism arose from several sources; X Modifi ed: one of which was the lack of recorded data to “This provide evidence of a general variability of skeptic motion with depth in the soil profile due to ism arose wave propagation phenomena. from several This sentence is unclear and sounds as the author sources personal pov. ; one of which The influence of soil property on seismic waves is was the analytically described in the elasticity equations. lack of recorde Moreover during the 1977 san Fernando d data earthquakes sites effects were observed. at shallo w Or I’m misunderstanding the sentence. depths to A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows provide recorde d eviden ce of the variabil ity of motion with depth in the soil profile as predict ed by wave propag ation theory. ” LM35 65/5.1.2 A non-vertical incident plane wave will X Boris considered this and concluded it was created a horizontally propagating(surface) appropriate. wave at some apparent phase velocity, and will induce ground motion having identical amplitudes but with a shift in phase in the horizontal direction associated with the apparent horizontal propagation velocity of the wave.

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Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows

Repetition For example, earthquake records from Need to different geological settings are used to discuss develop GMP equations for specific geologic Boris, GC36 67/5.3 settings (again, different from those where JJJ, recordings were made) at locations of interest. Alain

What is it refered to ? Host-to-target ? single station sigma ? This should go to chapter 4. Need 3D versus 1D Records/Motions. to discuss In this chapter authors are using the vertical incidence plane wave approximation for the real Boris, LM37 68/5.3.1 data interpretation. As result the text is quite JJJ, confusing. Moreover, the question on how to Alain model the vertical motion is never faced. I find the accelerograms interpretation quite naïve; information on focal distance azimuth, necessary for a correct interpretation, should be delivered. LM38 68/5.3.1 Recordings of earthquakes around the world Boris, Need JJJ, to show that earthquakes are almost always Alain discuss featuring all three components (E-W, N-S, U- D). There are very few known recorded events where one of the components was not present or is present in a much smaller magnitude. A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows Presence of two horizontal components (E-W, N-S) of similar amplitude and appearing at about the same time is quite common.

I suppose that you are reffering to the nodal plane. The sentence should be improved. “….signify arrival of Primary (P) waves Need (hence the name). Boris, to LM39 68/5.3.1 JJJ, discuss Alain Repetition On the other hand presence of vertical motions Need to at about the same time when horizontal discuss motions appear (these vertical motions appear Boris, LM40 68/5.3.1 after first passage of P waves), JJJ, Alain The movement appear at the same time on the three components. And after the P there are the S. I disagree with the proposed analysis. GC41 68/5.3.1 “….indicates presence of Rayleigh surface X Boris change waves.” s: “On the It could be S waves arriving at a non-vertical other incidence angle. hand, the presenc e of vertical Page 19 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows motion s at about the same time when horizon tal motion s appear (these vertical motion s appear after first passag e of P waves), indicat es presenc e of incline d S waves and, more import antly, Raylei gh A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows surface waves. ” GC42 68/5.3.1 . If vertical motions are not present (or have Boris, Need JJJ, to very small magnitude) during occurrence of Alain discuss horizontal motions indicates that Rayleigh . JJJ – surface waves are not present. we should lead This may be Love waves. Polarization analysis are into important to identify different kind of waves. this sub- section “Polar ization analysi s is import ant to identif y differe nt kinds of waves. ” And then procee d. Perha ps,

Page 21 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows send the propos ed revisio ns to GC for concur rence. Lack of Rayleigh (surface) waves is a very Need to rare occurrence, where a combination of addres source, path and local site conditions produce s or GC43 68/5.3.1 a plane shear (S) waves that surfaces (almost) Boris reject. vertically.

This sentence is not clear. Note almost complete lack of vertical motions Need to at around the time of occurrence of two addres components of horizontal motions, indicating s or LM44 69/5.3.1 Boris absence of Rayleigh surface waves. reject.

They seem S waves. GC45 70/5.3.2 X Analytic Earthquake Models Chan ged to: Is is an earthquake or ground motion analytical Analy model ? tic Earth A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows

quake , Grou nd Motio ns, Analy tic Mode ls

JJJ sugge sts: “Eart hquak e Grou nd Motio ns: Analy tic(al) Mode ls and “Eart hquak

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Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows

e Grou nd Motio ns: Nume rical Mode ls” Large scale regional models that encompass Boris revised source (fault) and geology in great detail, are . currently able to model seismic motions of up to 5Hz.

LM46 71/5.3.2 Source cannot be modelled in “great detail”. X Indeed, the slip distribution and stress drop control the high frequency content. The slip distribution is always unknown before the earthquake occurrence. The stress-drop can be measured on the recorded seismicity of the region, but it is always affected by large uncertainties. LM47 71/5.3.2 It is important to note, again, that accurate X Boris added: modeling of ground motions in large scale as well regions is predicated by knowledge of regional as and local geology. proper (quite uncerta And strong hypothesis on the source, the epistemic in) A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows uncertainties related to the modelling deserve to be modelli investigated. ng of seismic source.

JJJ suggest s: New sentenc e “In additio n (to knowle dge of the regiona l and local geolog y, signific ant emphas is should be placed on import ant hypoth eses associa

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Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows ted with the source and the signific ant episte mic uncerta inties associa ted with them.” LM48 71/5.3.3 Earthquakes start at the rupture zone (seismic Boris Need to source), propagates through the rock to the addres surface soils layers. All three components in s or this process, the source, the path through the reject. rock and the site response (soil) feature significant uncertainties, which contribute to the uncertainty of ground motions. These uncertainties require use of Probabilistic Seismic Hazard Analysis approach to characterizing uncertainty in earthquake motions (Hanks and Cornell; Bazzurro and Cornell, 2004; Budnitz et al., 1998; Stepp et al., 2001).

This sentence contains a shortcome making it A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows imprecise.

Source uncertainty is controlled mainly by the Need to stress drop function (Silva, 1993; Toro et al., addres 1997). s or reject. LM49 71/5.3.3 Boris This is true for strong ground motion simulation JJJ: Should but not for sources in PSHA where faults we add geometry, catalogues accurancy (…) feed the this? source uncertanty GC50 76/5.4.2 It is very important to note that all current Boris It is very models for modeling incoherent seismic import motions make an ergodic assumption. This is ant to very important as all the models assume that note that all a variability of seismic motions at a single current site – source combination will be the same as models variability in the ground motions from a data for modeli set that was collected over different site and ng source locations. Unfortunately, there does incoher not exist a large enough data set for any ent seismic particular location of interest (location of a motion nuclear facility), that can be used to develop s make site specific incoherence models. an ergodic This part is not clear assump tion. Page 27 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows Replac e “make” with “rely on the” In this approach, motions at each depth are Need to assumed independent. This assumes that addres incoherence functions may apply at any depth s or within the near surface domain (< 100m). reject. GC51 76/5.4.2 Therefore, by randomizing the energy at each Boris depth, a set of full 3-D incoherent ground motion are created. What about vertical correlation length? GC53 89/6.2 The GMPE of interest may be only that of JJJ JJJ: The peak ground acceleration (PGA). Then, GMP selected values of PGA will anchor spectral E of shapes, such as standard response spectra or interes t may others. be only Not clear – value of interest from GMPE ? period that of of interest ? peak groun d accele ration (PGA) . Then, A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows values of PGA associ ated with selecte d freque ncies of excee dance Then, selecte d values of PGA will anchor spectr al shapes , such as standa rd respon se spectr a or others.

Page 29 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows

 Site response analysis may be needed to The weight define or provide guidance on the soil of the material properties to be used in the SSI structur analyses e is often unkno In this case, is the weight of the structure taken wn at into account ? the stage JJJ GC54 89/6.2 of the site respons e analysi s. Theref ore, not include d. GC55 89/6.2 “….soil island;” Boris/JJJ “ If the free- field What is it ? ground motion is defined by numeri cal source A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows models , then one of the purpos es of site respons e analysi s is to generat e the input motion from the source to the soil island bounda ries for definiti on of the input to the nonline ar SSI analysi s. The soil

Page 31 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows island encom passes the model of the structur e and the adjacen t soil.” GC56 92/6.2 In all cases, when the DBE ground motion is JJJ JJJ revised defined at TOG, structures to be analyzed are : “In modeled including embedment, and three all deterministic soil profiles are used in the SSI cases, when analyses (best estimate, lower bound, and the upper bound), the resulting envelope of the DBE three at the TOG shall be verified to be equal ground motion to or greater than the TOG DBE ground is motion. defined at TOG Why only 3? any guideline reference ? and structur es to be analyze d are modele d includi ng embed ment, A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows multipl e determi nistic soil profiles are used in the SSI analyse s. Often, three profiles are analyze d, i.e., best estimat e, lower bound, and upper bound. To verify that the TOG DBE ground motion is

Page 33 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows adequa tely represe nted by the multipl e soil profiles , site respons e analyse s are perfor med for each of the soil profiles and the resultin g envelo pe at the TOG is verifie d to be equal to or greater than the TOG DBE A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows ground motion. If the resultin g envelo pe does not adequa tely match or envelo pe the TOG DBE, additio nal soil profiles may be added or higher FIRS may need to be conside red.”

GC57 92/6.2 If not, additional soil profiles or higher FIRS JJJ See respons may need to be considered. e to

Page 35 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows GC56. Why? Convolution. GC58 95/6.3.1 X This only regards frequency domain modeling. The PSHA intermediate output at hard rock is Chapter 4 is rewritten and does not go into this detail, the seismic hazard curves at a range of discrete but references IAEA SSG- natural frequencies - usually 5-20 frequencies, 9. such as 0.1, 2.5, 5, 10, 25, 100 Hz or some other combination - as a function of annual frequencies of exceedance (AFE). The frequencies of calculation are referred to as “conditioning frequencies” in some applications. To define a UHRS at AFE, the GC59 95/6.3.1 discrete values of acceleration (or spectral X acceleration) at the requested AFE of each of the natural frequency hazard curves is selected and the values are connected by segmented lines or fit with a curve. This becomes the UHRS at AFE at the location of interest and form of interest (in-soil or outcrop).

This part should be in chapter 4. NRC practice. A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows The convolution analysis (deterministic or JJJ to addres probabilistic) is not tied to PSHA results only, s e.g., a site with a significant mismatch of simult impedance values where a soft soil overlies a aneous ly with stiff soil or rock, site independent ground other response spectra may be defined on a WG GC60 97/6.3.1 hypothetical outcrop at the interface and then JJJ memb ers’ site response analysis is performed to calculate comme TOG and/or FIRS for locations of foundations nts. between impedance mis-match and foundation location.

This sentence is not clear. The first alternative has been implemented in Delete France for the post-Fukushima evaluations for d. which the BDE was specified at the ground surface as 1.5 times the DBE; most of the time GC61 98/6.3.1 this large motion was incompatible with the JJJ profile chaacteristics.

This sentence has to be removed. This is not relevant here. GC62 102/6.3.3 For a given wave length λ that is modeled, it is Boris Need to suggested/required to have at least 10 linear addres interpolation finite elements (8 node bricks in s or

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Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows 3D, where representative element size is ∆hLE reject. ≤ λ/10) or at least 2 quadratic interpolation finite elements (27 node bricks in 3D, where representative element size is ∆hQE ≤ λ/2) for modeling wave propagation.

De Martin (2010) showed that 30 nodes per wavelength are required for FEM results to match Haskell-Thomson ones GC63 103/6.3.3 Recent increase in use of 3×1D models (1D Boris, Need JJJ, to ask: material models for 3D wave propagation) Alain What requires further comments. Such models might is 1D- be appropriate for seismic motions and 2C modell behaviour of soil that is linear elastic. In ing? addition, it should be noted that vertical motions recorded on soil surface are usually a result of surface waves (Rayleigh). Only very early vertical motions/wave arrivals are due to compressional, primary (P) waves. Modeling of P waves as 1D vertically propagating waves is appropriate. However, modeling of vertical components of surface (Rayleigh) waves as vertically propagating 1D waves is not appropriate. Recent work by (Elgamal and He, 2004) provides nice description of vertical wave/motions modeling problems. A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows

What about 1D-2C modelling ? “….frequently targeted to a 50% or 84% Define NEP.” d here. GC64 104/6.3.3 X NEP defined in chapter 7 Hence, a significant degree of conservatism is In general, broad-banded response spectra do not added when broad-banded response spectra represent a single event, define the control motion. because they are developed from an Why ? ensemble of recorded motions. Therefore, for GC65 104/6.3.3 X structures that respond at multiple frequencies, it is conservative to assume that all frequencies are excited simultaneously by the spectral values in the broad-banded response spectra. LM66 108/6.5  Implement spectral matching software, JJJ JJJ to addres such as RSPMatch2005 and its derivatives, s which modify recorded motions through simult introduction of wavelets at selected aneous ly with frequencies to better match the target other spectra. (Abrahamson [6-4]; Hancock et WG al. [6-5]) memb ers’ Page 39 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows comme nts. RSPMATCH2005 has non-zero displacement, RSPmatch 2009 Al Atik & Abrahamson corrected this bias. For each member of the set of three spatial JJJ to addres components of time histories, the following s conditions should be met: simult aneous How do you define the vertical component? ly with other WG memb LM67 109/6.5 JJJ ers’ comme nts. This should be addres sed in Chapt er 5. LM68 109/6.5  Duration of the time histories should be JJJ JJJ to addres chosen in relation with the earthquake s magnitude of the earthquakes scenarios simult determined from DSHA or assessed from aneous ly with deaggregation of the seismic hazard curves other for PSHA. Duration is the effective WG duration defined as the time for Arias memb ers’ intensity to build up from 5% to 95% of its A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows full value. comme nts. Seifried Baker Criterion on Arias intensity.  Response spectra calculated from the time JJJ to addres histories for comparison with the target s spectrum should be at frequency simult increments corresponding to a minimum of aneous ly with JJJ LM69 109/6.5 100 points per frequency decade. other WG If RSPMatch is used it is better to use dense memb frequency sample. ers’ comme nts.  The general relationships of (peak JJJ to addres acceleration)-to-(peak velocity)-to-(peak s displacement) for the single time history or simult average of the multiple time histories aneous ly with should be maintained. other JJJ LM70 110/6.5 WG If the relationships are PGA (M,R) how to verify memb this condition for PSHA or we are talking of PGA, ers’ comme PGV PGD values after matching. nts. PGV PGD strongly depend on signal filtering how to tackle this point? LM71 110/6.5 “ … .Other indicators like Arias intensity, JJJ JJJ to addres Cumulative AbsoluteVelocity should also s

Page 41 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows ideally be preserved. This holds for the simult aneous standard response spectra based on published ly with guidance and for the governing earthquakes other WG for the site specific response spectra as memb determined from deaggregation of the seismic ers’ comme hazard curves.” nts.

What if multiple scenarios? LM72 110/6.5 For linear or equivalent linear seismic Boris, Need JJJ, to analyses, acceleration time histories meeting Alain discuss these conditions are appropriate and adequate. . A For nonlinear seismic analyses, actual protio n of recorded time histories may be preferred. the variabi I agree but how to deal the variability? lity issue is how many earthq uake simula tions should be used (as discuss ed in e-mails A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows by Boris, Alain, and Neb). The numbe r is strongl y influen ced by the purpos e of the analys es and the definiti on of the target input respon se apectr a. Import ant consid eration s are:

Page 43 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows Is variabi lity of the soil- structu re system to be incorp orated, i.e., variabi lity of soil and structu re materi al proper ties, variabi lity of stratig raphy, etc. ? Is convol ution of the end results with seismic A TECDOC on Seismic Soil Structure Interaction – IAEA draft TECDOC (Chapter 1-7 of the R0 Version))

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows hazard curves to be perfor med (if so, need to be careful about double - counti ng issues) ? Permeability of soil (k) can range from k > 10−2m/s for gravel, 10−2m/s > k > 10−5m/s for sand, 10−5m/s > k > 10−8m/s for silt, to k < 10−8m/s for clay.

CC73 141/7.4.2 The permeability values could be lower than the Alain one listed, according to the fabric and content of fines in the matrix. For information, there exist sand-graves which could liquefy due to a sufficient low permeability to generate water pressure during the seismic loading with undrained conditions. CC74 141/7.4.2 Thus a simple rule is that for earthquake Alain loading, for gravel, sand and permeable silt,

Page 45 of 46 COMMENTS BY REVIEWER RESOLUTION Reviewer: Celine Gelis (GC); Maria Lancieri (LM); Christophe Clement (CC) JJJohnson (Issues remaining = 7) Country/Organization: FRANCE / IRSN Date: February 2017 Alain (Issues to be addressed = 16) Boris (Issues to be addressed = 6) Boris, JJJ, and Alain (Issues to be addressed = 17)

Accept ed, but Reason for Comment No. Page/Section Comment Accepted modifi Rejected modification/rejection ed as follows relative rate of loading and seepage requires use of drained analysis. For clays, and impermeable silt, it might be appropriate to use (locally) undrained analysis for such short loading.

This statement does not consider the lithological series which can modify the drainage of layers to be taken into account a numerical modelling namely; a layer of gravel between two layers of clay will present undrained conditions. Accordingly, a warning in the text must be included regarding the geological context and its potential impact on the consideration undrained or drained conditions to consider in the numerical modelling.