# Effects of Soil-Foundation-Interaction on the Seismic Response of a Cooling Tower by 3D-FEM Analysis

^{1}

^{2}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Case Study

#### 2.1. Geology and Seismicity of Area

_{W}= 5.4), it caused deaths, injuries, and widespread damage due to the soft-soil conditions and construction deficiencies [23].

#### 2.2. Geotechnical Soil Properties

- -
- S1: backfill (0.00–2.00 m depth), calcarenites (2.00–2.40 m depth), yellow quartz sand (2.40–2.80 m depth), sandy silty clay (2.80–5.00 m depth), clayey sand (5.00–5.80 m depth), calcarenites (5.80–7.40 m depth), yellow quartz sand (7.40–9.70 m depth), and marly clay (9.70–30.00 m depth).
- -
- S2: backfill (0.00–1.00 m depth), sandy calcarenites and quartz sand (1.00–4.00 m depth), sandy clay (4.00–6.00 m depth), clayey sand (6.00–8.50 m depth), sandy clay (8.50–9.70 m depth), sandy silty clay (9.70–15.50 m depth), and marly clay (15.50–30.00 m depth).
- -
- S3: backfill (0.00–1.00 m depth), calcarenites (1.00–1.40 m depth), calcarenite sands and gravel sand (1.40–2.90 m depth), calcarenites and yellow calcarenite sands (2.90–4.40 m depth), brown silty clayey sand (4.40–8.50 m depth), yellow gravel sand (8.50–10.00 m depth), calcarenites (10.00–10.50 m depth), yellow gravel sand (10.50–12.00 m depth), clayey sand (12.00–12.60 m depth), sandy clay (12.60–13.50 m depth), and marly clay (13.50–30.00 m depth).
- -
- S4: backfill (0.00–3.00 m depth), brown sandy-silty alluvial deposits (3.00–8.00 m depth), sandy alluvial deposits with included volcanic and calcarenite stones (8.00–18.00 m depth), and blue-grey clay (18.00–30.00 m depth).

_{S}values ranged from 160 to 360 m/s. Higher values were reported for depths between 11 and 19 m.

#### 2.3. Petrochemical Facilities

## 3. Model Geometry and Boundary Conditions of Soil

_{0}) and gave indications about the average shear wave velocity and the depth of seismic bedrock. The analysis of the noise measurements using the spectral ratios HVSR (Horizontal to Vertical Spectral Ratio) showed the lowest values of f

_{0}(0.69–1.37 Hz) along the coastal area under consideration (Figure 5). Moreover, the results indicated that the most important geotechnical unit in terms of soil response is the blue clay with an average shear wave velocity of 600 m/s. The same value of V

_{S}is also reported by Tortorici [35]. Finally, the results allowed us to identify the surface that generates the amplifications at the base of the blue-grey clays, which constitutes the seismic bedrock [33,34]. The thickness of the blue-grey clay is equal to 73 m in the studied area [36]. The soil model is shown in Table 3, where V

_{S}values are obtained from D-H tests and from previous considerations. The values of the unit weight have been provided by the laboratory tests. Finally, the water head has been imposed at a depth of 11 m.

_{S}is the shear wave velocity in the soil deposit of thickness H. The fundamental natural frequency of the soil deposit is equal to 1.37 Hz.

_{S,min}is the lowest wave velocity and f

_{max}is the maximum frequency component of the input wave. The number of elements is 308,703.

## 4. Full-Coupled FEM Model

#### 4.1. Mohr-Coulomb Model

#### 4.2. Structural Elements and Loads

_{s}) at a particular point is given by:

_{max}is the equivalent local skin resistance at that point.

_{pile}, is given by:

_{max}is the base resistance and F

_{skin}is the axial skin resistance [46,47].

_{p}= base area of pile, c

_{u}= undrained cohesion at the base of the pile, N

_{c}= bearing capacity factor, assumed to equal 9, and ${\mathsf{\sigma}}_{\mathrm{v}0,\mathrm{p}}$ = vertical total stress at the base of the pile.

_{i}is the local shear stress resistance of the interface, φ

_{i}and c

_{i}are the friction angle and the cohesion of the interface, φ

_{soil}and c

_{soil}are the friction and the cohesion of the correspondent soil layer, R

_{inter}is the strength reduction factor, and σ’

_{n}= (σ’

_{2}+ σ’

_{3})/2 is the normal stress.

_{inter}has been assumed to be 2/3.

_{1}, Young’s modulus in the second axial direction E

_{2}, in-plane shear modulus G

_{12}, out-of-plane shear modulus related to shear deformation over the first direction G

_{13}, out-of-plane shear modulus related to shear deformation over the second direction G

_{23}and Poisson’s ratio ν

_{12}. The material behavior has been considered as orthotropic. Therefore:

^{2}, ν = 0.2, γ = 25kN/m

^{3}).

_{o}, is the empty weight of equipment plus the maximum weight of contents (fluid load) during a normal operation [5]. It has been simulated as a cylindrical column with a total weight of 294 kN.

_{W}= 6.1 struck the Emilia Romagna Region of Italy and a small portion of the Lombardia region caused 27 deaths and considerable damage [52]. The MRN station is located at an epicentral distance of 13 km and is classified as a C site [42]. Therefore, a deconvolution analysis has been performed to obtain the appropriate input motion at the bedrock (PGA = 0.30 g, f

_{p}= 1.93 Hz) (Figure 23).

#### 4.3. Results

_{e,max}= 1.94 g at T = 0.25 s is obtained, while, for the SSI alignment (Figure 26b), the maximum spectral acceleration S

_{e,max}= 1.21 g at T = 0.24 s is found. A second less important period T = 0.58 s can be observed in the SSI condition.

_{e,max}= 1.46 g at T = 0.25 s is obtained for the free-field condition (Figure 26a), while, for the SSI alignment (Figure 26b), the maximum spectral acceleration S

_{e,max}= 1.20 g at T = 0.25 s is found. A second less important period T = 0.05 s can be observed in FF and SSI conditions.

_{e,max}= 0.41 g at T = 0.23 is obtained, while, for the SSI alignment, the maximum spectral acceleration S

_{e,max}= 0.32 g at T = 0.25 is found.

_{FF}(I) = f

_{SSI}(I) = 2.1 Hz and f

_{FF}(II) = f

_{SSI}(II) = 3.7 Hz. Therefore, A(f) peaks move toward greater frequencies in comparison with the fundamental natural frequency of the soil (f

_{0}= 1.37 Hz). These results are due to the higher predominant frequencies of the input motions.

_{STRU,FB}) can computed by the following expression [5]:

_{STRU, SSI}, is equal to 0.95 s (f

_{STRU,SSI}= 1.05 Hz). In this case, a spectral acceleration of 0.65 g has been obtained, according to NTC 2018 [51], while lower values of 0.37 g (FF alignment) and 0.40 g (SSI alignment) have been found from FEM numerical analysis. SSI has beneficial effects because the spectral accelerations are lower than those required for the period of the fixed-base structure.

- (a)
- inertia forces on the superstructure transmitted on the heads of the piles in the form of axial and horizontal forces and moment;
- (b)
- soil deformations arising from the passage of seismic waves, which impose curvatures and, thereby, a lateral strain on the piles along their whole length.

_{1}+ σ

_{2}+ σ

_{3})/3, where σ

_{1}is the largest compressive principal stress and σ

_{3}is the smallest compressive principal stress (σ

_{1}≤ σ

_{2}≤ σ

_{3}). The variation of the stress state in the area close to the pile tips is likely related to a more pronounced interaction effect of the piles in the group with respect to the fixed connection of the top.

## 5. Conclusions

- to better understand the intent behind certain provisions of seismic design codes, so that they can be more properly and uniformly applied to structures and systems typically found in petrochemical facilities;
- to provide background information on technical areas that are related to the seismic evaluation of petrochemical facilities;
- to provide specific guidance to the seismic evaluation of petrochemical facilities;
- to provide practical analytical guidance specifically applicable to petrochemical facilities.

- The FEM analyses show a strong amplification in the last 20 m up to ground level for both Free-Field (FF) and soil-structure interaction (SSI) alignments using the 2012 and 1693 seismic inputs. The 1990 accelerogram induces a larger amplification in the upper 10 m of soil. Moreover, the presence of the structure generates a lower amplification as compared to the free-field condition;
- The influence of the soil-structure interaction is also indicated by reducing the maximum spectral acceleration at the main period of T = 0.25 s. However, a second, less important, period T = 0.58 s, corresponding to a spectral acceleration of 1.0 g, can be observed in the SSI condition using the 1693 seismogram;
- Taking into account the SSI effects, a beneficial effect can be observed. The spectral accelerations obtained when considering the structure resting on the soil are lower than what is required for fixed-base structure’s period;
- The main resulting frequencies for the SSI condition are equal to: f
_{SSI}(I) = 2.1 Hz and f_{SSI}(II) = 3.7 Hz. They are far from the frequency of the structure f_{STRU,SSI}= 1.05 Hz. - The soil amplification factors R derived for SSI and FF alignments using the 1990 and 1693 input motions are greater than the amplification value provided by the Italian Technical Code [51]. Instead, lower values are obtained using the 2012 accelerogram. The comparison between the elastic response spectra obtained by numerical analyses using the 1693 and 2012 seismic inputs and the same provided by NTC 2018 shows that FEM spectral accelerations are lower than those given by NTC 2018 for periods greater that 0.30 s. In particular, for the period of the structure under consideration (T
_{STRU,SSI}= 0.95 s), the spectral acceleration given by NTC 2018 is equal to 0.65 g. - To investigate the effect of the kinematic and inertial interaction on pile bending moments, the distribution of the peak pile bending moments has been studied. It can be observed that the maximum bending moments occur at a depth of about 12.5 m, and it can result in a kinematic interaction effect between the piles and the surrounding soil.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

- Paolacci, F.; Giannini, R.; De Angelis, M. Analysis of the seismic risk of major-hazard industrial plants and applicability of innovative seismic protection systems. Petrochemicals
**2012**. [Google Scholar] [CrossRef] [Green Version] - Kalantari, A.; Abdi, D.; Feshki, B.A. Seismic fragility assessment of equipment and support structure in a unit of a petrochemical plant. SN Appl. Sci.
**2020**, 2, 1345. [Google Scholar] [CrossRef] - Romeo, R.W. Seismic Risk Analysis of an Oil-gas Storage Plant. In Seismic Design of Industrial Facilities: Proceedings of the on Seismic Design of Industrial Facilities (SeDIF-Conference); Klinkel, S., Butenweg, C., Lin, G., Holtschoppen, B., Eds.; Springer: Berlin/Heidelberg, Germany, 2014; pp. 17–26. [Google Scholar]
- Paolacci, F.; Giannini, R.; De Angelis, M. Seismic vulnerability of major-hazard industrial plants and applicability of innovative seismic protection systems for its reduction. In Proceedings of the 11th World Conference on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures, Guangzhou, China, 17–21 November 2009. [Google Scholar]
- American Society of Civil Engineers (ASCE). Guidelines for Seismic Evaluation and Design of Petrochemical Facilities, 2nd ed.; ASCE: Reston, Virginia, 2011. [Google Scholar] [CrossRef]
- Ferraro, A.; Grasso, S.; Maugeri, M.; Totani, F. Seismic response analysis in the southern part of the historic centre of the City of L’Aquila (Italy). Soil Dyn. Earthq. Eng.
**2016**, 88, 256–264. [Google Scholar] [CrossRef] - Ferraro, A.; Grasso, S.; Massimino, M.R. Site effects evaluation in Catania (Italy) by means of 1-D numerical analysis. Ann. Geophys.
**2018**, 61. [Google Scholar] [CrossRef] - Grasso, S.; Massimino, M.R.; Sammito, M.S.V. New Stress Reduction Factor for Evaluating Soil Liquefaction in the Coastal Area of Catania (Italy). Geosciences
**2021**, 11, 12. [Google Scholar] [CrossRef] - Zhang, W.; Esmaeilzadeh Seylabi, E.; Taciroglu, E. An ABAQUS toolbox for soil-structure interaction analysis. Comput. Geotech.
**2019**, 114, 103143. [Google Scholar] [CrossRef] - Seylabi, E.E.; Jeong, C.; Dashti, S.; Hushmand, A.; Taciroglu, E. Seismic response of buried reservoir structures: a comparison of numerical simulations with centrifuge experiments. Soil Dyn. Earthq. Eng.
**2018**, 109, 89–101. [Google Scholar] [CrossRef] - Massimino, M.R.; Abate, G.; Corsico, S.; Louarn, R. Comparison Between Two Approaches for Non-linear FEM Modelling of the Seismic Behaviour of a Coupled Soil–Structure System. Geotech. Geol. Eng.
**2019**, 37, 1957–1975. [Google Scholar] [CrossRef] - Castelli, F.; Maugeri, M.; Mylonakis, G. Numerical analysis of kinematic soil-pile interaction. In Proceedings of the MERCEA 2008, Seismic Engineering International Conference Commemorating the 1908 Messina and Reggio Calabria Earthquake, Reggio Calabria/Messina, Italy, 8–11 July 2008; Volume 1, pp. 618–625. [Google Scholar] [CrossRef]
- Kavitha, P.E.; Beena, K.S.; Narayanan, K.P. Numerical Investigations on the Influence of Soil Structure Interaction in the Dynamic Response of SDOF System. Procedia Technol.
**2016**, 25, 178–185. [Google Scholar] [CrossRef] [Green Version] - Deghoul, L.; Gabi, S.; Hamrouni, A. The influence of the soil constitutive models on the seismic analysis of pile-supported wharf structures with batter piles in cut-slope rock dike. Studia Geotech. Mech.
**2020**, 42, 191–209. [Google Scholar] [CrossRef] - Cavallaro, A.; Castelli, F.; Ferraro, A.; Grasso, S.; Lentini, V. Site Response Analysis for the Seismic Improvement of a Historical and Monumental Building: The Case Study of Augusta Hangar. Bull. Eng. Geol. Environ.
**2018**, 77, 1217–1248. [Google Scholar] [CrossRef] - Di Martire, D.; Ascione, A.; Calcaterra, D.; Pappalardo, G.; Mazzoli, S. Quaternary deformation in SE Sicily: Insights into the life and cycles of forebulge fault systems. Lithosphere
**2015**, 7, 519–534. [Google Scholar] [CrossRef] [Green Version] - Locati, M.; Camassi, R.; Rovida, A.; Ercolani, E.; Bernardini, F.; Castelli, V.; Caracciolo, C.H.; Tertulliani, A.; Rossi, A.; Azzaro, R.; et al. Database Macrosismico Italiano (DBMI15); Versione 3.0; Istituto Nazionale di Geofisica e Vulcanologia (INGV): Catania, Italy, 2021. [Google Scholar] [CrossRef]
- Cavallaro, A.; Massimino, M.R.; Maugeri, M. Noto Cathedral: Soil and foundation investigation. Constr. Build. Mater. J.
**2003**, 17, 533–541. [Google Scholar] [CrossRef] - Grasso, S.; Maugeri, M. Seismic Microzonation Studies for the City of Ragusa (Italy). Soil Dyn. Earthq. Eng.
**2014**, 56, 86–97. [Google Scholar] [CrossRef] - Castelli, F.; Cavallaro, A.; Grasso, S. SDMT soil testing for the local site response analysis. In 1st IMEKO TC4 International Workshop on Metrology for Geotechnics; MetroGeotechnics: Benevento, Italy, 2016; pp. 143–148. [Google Scholar]
- Maugeri, M.; Grasso, S. Liquefaction potential evaluation at Catania Harbour (Italy). WIT Trans Built Environ.
**2013**, 69–81. [Google Scholar] [CrossRef] [Green Version] - Barbano, M.S.; Rigano, R.; Cosentino, M.; Lombardo, G. Seismic history and hazard in some localities of south-eastern Sicily. Boll. Geof. Teor. Appl.
**2001**, 42, 107–120. [Google Scholar] - Maugeri, M.; Castelli, F. Post-earthquake analysis for a seismic retrofitting: the case history of a piled foundation in Augusta (Italy). Chapter: perspectives on earthquake geotechnical engineering. Geotech. Geol. Earthq. Eng.
**2015**, 37, 415–441. [Google Scholar] - Guidoboni, E.; Ferrari, G.; Mariotti, D.; Comastri, A.; Tarabusi, G.; Sgattoni, G.; Valensise, G. CFTI5Med, Catalogue of Strong Earthquakes in Italy (461 B.C.-1997) and Mediterranean Area (760 B.C.-1500); Istituto Nazionale di Geofisica e Vulcanologia (INGV): Catania, Italy, 2018. [Google Scholar] [CrossRef]
- Guidoboni, E.; Ferrari, G.; Tarabusi, G.; Sgattoni, G.; Comastri, A.; Mariotti, D.; Ciuccarelli, C.; Bianchi, M.G.; Valensise, G. CFTI5Med, the new release of the catalogue of strong earthquakes in Italy and in Mediterranean area. Sci. Data
**2019**, 80. [Google Scholar] [CrossRef] - Castelli, F.; Lentini, V.; Grasso, S. Recent developments for the seismic risk assessment. Bull. Earth. Eng.
**2017**, 15, 5093–5117. [Google Scholar] [CrossRef] - Castelli, F.; Cavallaro, A.; Ferraro, A.; Grasso, S.; Lentini, V.; Massimino, M. Dynamic characterisation of a test site in Messina (Italy). Ann. Geophys.
**2018**, 61, SE222. [Google Scholar] [CrossRef] [Green Version] - Castelli, F.; Cavallaro, A.; Ferraro, A.; Grasso, S.; Lentini, V.; Massimino, M.R. Static and dynamic properties of soils in Catania (Italy). Ann. Geophys.
**2018**, 61, SE221. [Google Scholar] [CrossRef] - Ciancimino, A.; Lanzo, G.; Alleanza, G.A.; Amoroso, S.; Bardotti, R.; Biondi, G.; Cascone, E.; Castelli, F.; Di Giulio, A.; D’onofrio, A.; et al. Dynamic characterization of fine-grained soils in Central Italy by laboratory testing. Bull. Earth. Eng.
**2020**, 18, 5503–5531. [Google Scholar] [CrossRef] - European Parliament and of the Council. Directive 2012/18/EU of the European Parliament and of the Council on Control of Major-Accident Hazards Involving Dangerous Substances Amending and Subsequently Repealing Council Directive 96/82/EC; European Parliament and of the Council: Brussels, Belgium, 2012. [Google Scholar]
- Giannelli, G.; Grillone, G.; Muratore, A.; Nastasi, V.; Sferruzza, G. Earthquake Natech Risk: Index Method for critical Plants covered by Seveso III Directive. In Proceedings of the 30th European Safety and Reliability Conference and the 15th Probabilistic Safety Assessment and Management Conference, Venice, Italy, 21–26 June 2020. [Google Scholar]
- Salzano, E.; Garcia Agreda, A.; Di Carluccio, B.; Fabbrocino, G. Risk assessment and early warning systems for industrial facilities in seismic zones. Rel. Eng. Syst. Saf.
**2009**, 94, 1577–1584. [Google Scholar] [CrossRef] - Marzorati, S.; Fiorini, E.; Ameri, G.; Onida, M.; Pacor, F. Rapporti spettrali HVSR in aree densamente industrializzate: ricostruzione di una superficie pleistocenica profonda al di sotto del polo petrolchimico di Priolo Gargallo (SR). In Proceedings of the 27 Convegno GNGTS, Sessione 2.2, Trieste, Italy, 6–8 October 2008. [Google Scholar]
- Fiorini, E.; Onida, M.; Borzi, B.; Pacor, F.; Luzi, L.; Meletti, C.; D’Amico, V.; Marzorati, S.; Ameri, G. Microzonation Study for an industrial site in southern Italy. In Proceedings of the 14th World Conference on Earthquake Engineering, Beijing, China, 12–17 October 2008. [Google Scholar]
- Tortorici, L. Geologia delle aree urbane della Sicilia orientale, in Decanini e Panza. In Scenari di Pericolosità Sismica ad Augusta, Siracusa e Noto; CNR-GNDT: Roma, Italy, 2000; pp. 43–54. [Google Scholar]
- Carbone, S. Augusta: Foglio 641: Note illustrative Della Carta Geologica d’Italia Alla Scala 1:50.000; Regione Sicilia: Ispra, Roma, Italy, 2011. [Google Scholar]
- Kuhlemeyer, R.L.; Lysmer, J. Finite element method accurancy for wave propagation problems. J. Soil Mech. Found. Devision
**1973**, 99, 421–427. [Google Scholar] [CrossRef] - Galavi, V.; Petalas, A.; Brinkgreve, R.B.J. Finite element modelling of seismic liquefaction in soils. Geotech. Eng. J. SEAGS AGSSEA
**2013**, 44, 55–64. [Google Scholar] - PLAXIS 3D. Scientific Manual. 2018. Available online: https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/50826/manuals-archive---plaxis (accessed on 12 December 2020).
- Joyner, W.B.; Chen, A.T.F. Calculation of non linear ground response in earthquake. Bull. Seismol. Soc. Am.
**1975**, 65, 1315–1336. [Google Scholar] - Massimino, M.R.; Abate, G.; Grasso, S.; Pitilakis, D. Some aspects of DSSI in the dynamic response of fully-coupled soil-structure systems. Riv. Ital. Geotec.
**2019**, 44–70. [Google Scholar] - EC8-Part 5. Design of Structures for Earthquake Resistance—Part 5: Foundations, Retaining Structures and Geotechnical Aspects; ENV 1998; Europen Committee for Standard: Brussels, Belgium, 2003. [Google Scholar]
- Sadek, M.; Shahrour, I. A three dimensional embedded beam element for reinforced geomaterials. Int. J. Num. Anal. Meth. Geomech.
**2004**, 28, 931–946. [Google Scholar] [CrossRef] - Smulders, C.M.; Hosseini, S.; Brinkgreve, R.B. Improved embedded beam with interaction surface, ECSMGE 2019. In Proceedings of the XVII European Conference on Soil Mechanics and Geotechnical Engineering, Reykjavik, Iceland, 1–6 September 2019. [Google Scholar]
- Brinkgreve, R.B.J.; Engin, E.; Swolfs, W.M. Plaxis 3D Manual. 2015. Available online: https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/50826/manuals-archive---plaxis (accessed on 10 October 2020).
- PLAXIS 3D. Reference Manual. 2018. Available online: https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/50826/manuals-archive---plaxis (accessed on 18 January 2021).
- Lődör, K.; Móczár, B. Finite element modelling of rigid inclusion ground improvement. In Proceedings of the 9th European Conference on Numerical Methods in Geotechnical Engineering, Porto, Portugal, 25–27 June 2018. [Google Scholar]
- Grasso, S.; Laurenzano, G.; Maugeri, M.; Priolo, E. Seismic response in Catania by different methodologies. In Advances in Earthquake Engineering; Publisher: Billerica, MA, USA, 2005; Volume 14, pp. 63–79. [Google Scholar]
- Laurenzano, G.; Priolo, E.; Klinc, P.; Vuan, A. Near fault earthquake scenarios for the February 20, 1818 M = 6.2 “Catanese” event. In Proceedings of the Fourth International Conference on Computer Simulation in Risk Analysis and Hazard Mitigation: “Risk Analysis 2004”, Rhodes, Greece, 27–29 September 2004; pp. 81–91. [Google Scholar]
- Priolo, E. 2-D spectral element simulations of destructive ground shaking in Catania (Italy). J. Seismol.
**1999**, 3, 289–309. [Google Scholar] [CrossRef] - NTC D.M. New Technical Standards for Buildings. 2018. Available online: https://www.gazzettaufficiale.it/eli/gu/2018/02/20/42/so/8/sg/pdf (accessed on 1 February 2021).
- Fioravante, V.; Giretti, D.; Abate, G.; Aversa, S.; Boldini, D.; Capilleri, P.; Cavallaro, A.; Chamlagain, D.; Crespellani, T.; Dezi, F.; et al. Earthquake geotechnical engineering aspects of the 2012 Emilia-Romagna earthquake (Italy). In Proceedings of the Seventh International Conference on Case Histories in Geotechnical Engineering and Symposium in Honor of Clyde Baker, Chicago, IL, USA, 29 April–4 March 2013. [Google Scholar]
- Boschi, E.; Basili, A. Contributi allo studio del terremoto della Sicilia orientale del 13 Dicembre 1990; Istituto Nazionale di Geofisica: Rome, Italy, 1991. [Google Scholar]
- Okamoto, S. An Introduction to Earthquake Engineering, 2nd ed.; University of Tokyo Press: Tokyo, Japan, 1983. [Google Scholar]
- Nishizawa, T.; Tajiri, S.; Kawamura, S. Excavation and response analysis of a damaged rc pile by liquefaction. In Proceedings of the 8th World Conference on Earthquake Engineering, San Francisco, CA, USA, 1 January 1984; pp. 593–600. [Google Scholar]
- EEFIT. The Mexican Earthquake of 19 September 1985; Institution of Civil Engineers (ICE): London, UK, 1986. [Google Scholar]
- Mizuno, H. Pile damage during earthquake in Japan (1923–1983). In Dynamic Response of Pile Foundations: Experiments, Observation and Analysis; Nogami, T., Ed.; ASCE: New York, NY, USA, 1987; pp. 53–78. [Google Scholar]
- Mizuno, H.; Jiba, M.; Hirade, T. Pile damage during 1995 Hyougoken-Nanbu earthquake in Japan. In Proceedings of the 11th World Conference on Earthquake Engineering, Acapulco, Mexico, 23–28 June 1996. [Google Scholar]
- Tokimatsu, K.; Mizuno, H.; Kakurai, M. Building damage associated with geotechnical problems. In Soils and Foundations, Special Issue Geotechnical aspects of the January 17, 1995 Hyogoken-Nambu Earthquake; Japanese Geotechnical Society: Tokyo, Japan, 1996. [Google Scholar]
- Nikolaou, S.; Mylonakis, G.; Gazetas, G.; Tazoh, T. Kinematic pile bending during earthquakes: analysis and field measurements. Geotechnique
**2001**, 51, 425–440. [Google Scholar] [CrossRef] - Castelli, F.; Maugeri, M. Post-earthquake analysis of a piled foundation. J. Geotech. Geoenvironmental Eng. ASCE
**2013**, 139, 1822–1827. [Google Scholar] [CrossRef] - Castelli, F.; Lentini, V. Monitoring of Full Scale Diaphragm Wall for a Deep Excavation. In Proceedings of the 1st IMEKO TC-4 International Workshop on Metrology for Geotechnics, Benevento, Italy, 17–18 March 2016; pp. 103–108. [Google Scholar]

**Figure 1.**Geological sketch map of the Hyblean Plateau and adjacent fore deep area (After Di Martire et al. [16], modified).

**Figure 2.**Timeline of earthquakes in the city of Augusta (After Locati et al. [17], modified, INGV database).

**Figure 8.**(

**a**) G [MPa] versus γ [%] curves. (

**b**) D [%] versus γ [%] curves (for the S1C1 soil sample).

**Figure 9.**(

**a**) G [MPa] versus γ [%] curves. (

**b**) D [%] versus γ [%] curves (for the S4C1 soil sample).

**Figure 20.**Embedded beam element (After Brinkgreve et al. [45], modified).

**Figure 21.**Seismogram of 1693 scaled to the value of 0.350 g corresponding to a return period of 975 years in the actual Italian seismic code [51].

**Figure 22.**Accelerogram recorded at Sortino during the earthquake on 13 December 1990 [53].

**Figure 25.**Maximum accelerations along SSI and FF alignments: using the 1990, 2012, and 1693 seismic inputs.

**Figure 26.**Comparison between the elastic response spectra obtained by numerical analyses and the same provided by NTC 2018 [51]: (

**a**) FF alignment. (

**b**) SSI alignment.

**Figure 27.**Amplification functions for each seismic input: (

**a**) FF alignment, and (

**b**) SSI alignments.

**Figure 28.**Uniform cylindrical column (After Reference [5], modified).

**Figure 29.**Bending moments along the plate at the end of the dynamic phase using the 1693 seismic input.

**Figure 31.**Kinematic bending of a free-head pile in a two-layer profile (After Castelli et al. [12], modified).

**Figure 32.**Mean total stresses p = (σ

_{1}+ σ

_{2}+ σ

_{3})/3 at the end of the dynamic phase (for the 1693 seismic input), σ

_{1}being the largest compressive principal stress and σ

_{3}being the smallest compressive principal stress (σ

_{1}≤ σ

_{2}≤ σ

_{3}).

N. | Borehole | Name | Depth [m] |
---|---|---|---|

1 | S1 | C1 | 4.50–5.00 |

2 | S1 | C2 | 13.00–13.50 |

3 | S2 | C1 | 11.40–11.90 |

4 | S2 | C2 | 20.00–20.50 |

5 | S3 | C1 | 14.00–14.50 |

6 | S3 | C2 | 20.40–20.90 |

7 | S4 | C1 | 2.00–2.50 |

8 | S4 | C2 | 4.00–4.50 |

9 | S4 | C3 | 18.00–18.50 |

10 | S4 | C4 | 22.00–22.60 |

Samples | γ [kN/m ^{3}] | γ_{s}[kN/m ^{3}] | w_{n}[%] | w_{l}[%] | w_{p}[%] | I_{P}[%] | I_{C} | c’ [kPa] | ϕ‘ [°] | c_{u}[kPa] |
---|---|---|---|---|---|---|---|---|---|---|

S1C1 | 18.44 | 25.12 | 29.27 | 66.18 | 32.20 | 33.99 | 1.09 | - | - | - |

S1C2 | 18.74 | 25.00 | 34.28 | 57.15 | 28.03 | 29.12 | 0.79 | - | - | - |

S2C1 | 18.84 | 25.02 | 31.22 | 66.84 | 30.32 | 36.52 | 0.98 | - | - | - |

S2C2 | 18.64 | 25.11 | 32.71 | 72.33 | 31.05 | 41.28 | 0.96 | - | - | - |

S3C1 | 18.74 | 26.09 | 24.34 | 37.24 | 23.37 | 13.88 | 0.93 | - | - | - |

S3C2 | 18.93 | 25.11 | 31.14 | 59.44 | 24.89 | 34.55 | 0.82 | - | - | - |

S4C1 | 17.9 | 24.5 | 29.3 | 61.7 | 32.2 | 29.5 | 1.1 | - | - | - |

S4C2 | 17.9 | 25.4 | 43.2 | 54.0 | 32.8 | 21.2 | 0.5 | 24 | 21 | 35 |

S4C3 | 18.4 | 24.4 | 32.6 | 69.4 | 38.3 | 31.1 | 1.2 | 58 | 24 | 114 |

S4C4 | 18.7 | 26.5 | 33.7 | 69.5 | 27.9 | 41.6 | 0.9 | 44 | 25 | 159 |

Layers | From [m] | To [m] | Thickness [m] | V_{S} [m/s] | γ [kN/m^{3}] |
---|---|---|---|---|---|

Backfill | 0 | 2.5 | 2.5 | 202 | 17.9 |

Alluvial Deposits | 2.5 | 12 | 9.5 | 222 | 17.9 |

Sandy Clay | 12 | 17 | 5 | 639 | 18.4 |

Blue-Grey Clay | 17 | 90 | 73 | 600 | 18.7 |

Layers | γ [kN/m^{3}] | E [kN/m^{2}] | ν [[–] | φ’ [°] | c’ [kN/m^{2}] | Ψ [°] | V_{p} [m/s] | V_{p}/V_{s} |
---|---|---|---|---|---|---|---|---|

Backfill | 17.9 | 220,099 | 0.478 | 21 | 24 | 0 | 986 | 4.88 |

Alluvial Deposits | 17.9 | 268,089 | 0.490 | 21 | 24 | 0 | 1634 | 7.36 |

Sandy Clay | 18.4 | 2,227,231 | 0.454 | 24 | 58 | 0 | 2203 | 3.45 |

Blue-Grey Clay | 18.7 | 1,990,245 | 0.450 | 25 | 44 | 0 | 1992 | 3.32 |

Parameter | Symbol | Pile Foundation | Unit |
---|---|---|---|

Young’s modulus | E | 32,587,468 | kN/m^{2} |

Unit weight | γ | 25 | kN/m^{3} |

Beam type | - | Massive circular beam | - |

Diameter | D | 0.5 | m |

Axial skin resistance | T_{skin} | Layer dependent | kN/m |

Strength reduction factor | R_{inter} | 0.67 | - |

Base resistance | F_{max} | 1061 | kN |

Parameter | Symbol | Plate Foundation | Unit |
---|---|---|---|

Thickness | d | 1.2 | m |

Unit weight | γ | 25 | kN/m^{3} |

Type of behavior | - | Elastic, orthotropic | - |

Young’s Modulus | E_{1} = E_{2} | 32,587,468 | kN/m^{2} |

Poisson’s ratio | ν_{12} | 0.2 | - |

Shear Modulus | G_{12} = G_{13} = G_{23} | 13,578,111 | kN/m^{2} |

FF, 1990 | SSI, 1990 | FF, 2012 | SSI, 2012 | FF, 1693 | SSI, 1693 | |
---|---|---|---|---|---|---|

PGA_{input} | 0.10 g | 0.10 g | 0.30 g | 0.30 g | 0.35 g | 0.35 g |

PGA_{output} | 0.16 g | 0.14 g | 0.35 g | 0.32 g | 0.52 g | 0.46 g |

R = PGA_{output}/PGA_{input} | 1.60 | 1.40 | 1.17 | 1.07 g | 1.49 | 1.31 |

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## Share and Cite

**MDPI and ACS Style**

Castelli, F.; Grasso, S.; Lentini, V.; Sammito, M.S.V.
Effects of Soil-Foundation-Interaction on the Seismic Response of a Cooling Tower by 3D-FEM Analysis. *Geosciences* **2021**, *11*, 200.
https://doi.org/10.3390/geosciences11050200

**AMA Style**

Castelli F, Grasso S, Lentini V, Sammito MSV.
Effects of Soil-Foundation-Interaction on the Seismic Response of a Cooling Tower by 3D-FEM Analysis. *Geosciences*. 2021; 11(5):200.
https://doi.org/10.3390/geosciences11050200

**Chicago/Turabian Style**

Castelli, Francesco, Salvatore Grasso, Valentina Lentini, and Maria Stella Vanessa Sammito.
2021. "Effects of Soil-Foundation-Interaction on the Seismic Response of a Cooling Tower by 3D-FEM Analysis" *Geosciences* 11, no. 5: 200.
https://doi.org/10.3390/geosciences11050200