Characterisation of Site Effects by Means of Energy Spectra

The effects of subsoil conditions on surface ground motion are evaluated in terms of energy spectra. Near-field and far-field strong ground motion recorded during recent destructive earthquakes at nearby rock and soil sites characterized by a comprehensive knowledge of the geotecbnical properties are considered. The study suggests that energy spectra at soil sites are amplified with respect to those on rock sites. The maximum spectral amplification is usually well correlated to the natural periods of the sites. The most striking difference between traditional response spectra and energy spectra is the high soil amplification at longer periods, which is not apparent from the consideration of response spectra only

Microwave study of quantum n-disk scattering

We describe a wave-mechanical implementation of classically chaotic n-disk scattering based on thin 2-D microwave cavities. Two, three, and four-disk scattering are investigated in detail. The experiments, which are able to probe the stationary Green's function of the system, yield both frequencies and widths of the low-lying quantum resonances. The observed spectra are found to be in good agreement with calculations based on semiclassical periodic orbit theory. Wave-vector autocorrelation functions are analyzed for various scattering geometries, the small wave-vector behavior allowing one to extract the escape rate from the quantum repeller. Quantitative agreement is found with the value predicted from classical scattering theory. For intermediate energies, non-universal oscillations are detected in the autocorrelation function, reflecting the presence of periodic orbits.Comment: 13 pages, 8 eps figures include

Quasinormal behavior of the D-dimensional Schwarzshild black hole and higher order WKB approach

We study characteristic (quasinormal) modes of a $D$-dimensional Schwarzshild black hole. It proves out that the real parts of the complex quasinormal modes, representing the real oscillation frequencies, are proportional to the product of the number of dimensions and inverse horizon radius $\sim D r_{0}^{-1}$. The asymptotic formula for large multipole number $l$ and arbitrary $D$ is derived. In addition the WKB formula for computing QN modes, developed to the 3rd order beyond the eikonal approximation, is extended to the 6th order here. This gives us an accurate and economic way to compute quasinormal frequencies.Comment: 15 pages, 6 figures, the 6th order WKB formula for computing QNMs in Mathematica is available from https://goo.gl/nykYG

Recorded Motions of the Mw6.3 April 6, 2009 L’Aquila (Italy) Earthquake and Implications for Building Structural Damage: Overview.

The normal-faulting earthquake of 6 April 2009 in the Abruzzo Region of central Italy caused heavy losses of life and substantial damage to centuriesold buildings of significant cultural importance and to modern reinforcedconcrete- framed buildings with hollow masonry infill walls. Although structural deficiencies were significant and widespread, the study of the characteristics of strong motion data from the heavily affected area indicated that the short duration of strong shaking may have spared many more damaged buildings from collapsing. It is recognized that, with this caveat of shortduration shaking, the infill walls may have played a very important role in preventing further deterioration or collapse of many buildings. It is concluded that better new or retrofit construction practices that include reinforcedconcrete shear walls may prove helpful in reducing risks in such seismic areas of Italy, other Mediterranean countries, and even in United States, where there are large inventories of deficient structures.Published651-6844.1. Metodologie sismologiche per l'ingegneria sismicaJCR Journalreserve

Black Holes in Quasi-topological Gravity

We construct a new gravitational action which includes cubic curvature interactions and which provides a useful toy model for the holographic study of a three parameter family of four- and higher-dimensional CFT's. We also investigate the black hole solutions of this new gravity theory. Further we examine the equations of motion of quasi-topological gravity. While the full equations in a general background are fourth-order in derivatives, we show that the linearized equations describing gravitons propagating in the AdS vacua match precisely the second-order equations of Einstein gravity.Comment: 33 pages, 4 figures; two references adde

Hawking emission from quantum gravity black holes

We address the issue of modelling quantum gravity effects in the evaporation of higher dimensional black holes in order to go beyond the usual semi-classical approximation. After reviewing the existing six families of quantum gravity corrected black hole geometries, we focus our work on non-commutative geometry inspired black holes, which encode model independent characteristics, are unaffected by the quantum back reaction and have an analytical form compact enough for numerical simulations. We consider the higher dimensional, spherically symmetric case and we proceed with a complete analysis of the brane/bulk emission for scalar fields. The key feature which makes the evaporation of non-commutative black holes so peculiar is the possibility of having a maximum temperature. Contrary to what happens with classical Schwarzschild black holes, the emission is dominated by low frequency field modes on the brane. This is a distinctive and potentially testable signature which might disclose further features about the nature of quantum gravity.Comment: 36 pages, 18 figures, v2: updated reference list, minor corrections, version matching that published on JHE

On the modelling of infilled RC frames through strut models

Infill panels largely affect the seismic response of framed constructions. The wide variety in their mechanical and geometrical features has produced many different models and assumptions in their analytical representation. In this paper the simplest and most diffuse analytical approach, based on the introduction of equivalent struts, has been checked. An overview is presented, focusing on the strut dimensions, strength and number. Two case-studies, taken by two different experimental campaigns, have been considered and reproduced. The obtained results have been compared to the experimental ones, and some parameters have been checked for selecting the model to use for analysis

Ductility of wide-beam RC frames as lateral resisting system

[EN] Some Mediterranean seismic codes consider wide-beam reinforced concrete moment resisting frames (WBF) as horizontal load carrying systems that cannot guarantee high ductility performances. Conversely, Eurocode 8 allows High Ductility Class (DCH) design for such structural systems. Code prescriptions related to WBF are systematically investigated. In particular, lesson learnt for previous earthquakes, historical reasons, and experimental and numerical studies underpinning specific prescriptions on wide beams in worldwide seismic codes are discussed. Local and global ductility of WBF are then analytically investigated through (1) a parametric study on chord rotations of wide beams with respect to that of deep beams, and (2) a spectral-based comparison of WBF with conventional reinforced concrete moment resisting frames (i.e. with deep beams). Results show that the set of prescriptions given by modern seismic codes provides sufficient ductility to WBF designed in DCH. In fact, global capacity of WBF relies more on the lateral stiffness of the frames and on the overstrength of columns rather than on the local ductility of wide beams, which is systematically lower with respect to that of deep beams.Gómez-Martínez, F.; Alonso Durá, A.; De Luca, F.; Verderame, GM. (2016). Ductility of wide-beam RC frames as lateral resisting system. Bulletin of Earthquake Engineering. 14(6):1545-1569. doi:10.1007/s10518-016-9891-xS15451569146ACI (1989) Building code requirements for reinforced concrete (ACI 318-89). ACI Committee 318, American Concrete Institute, Farmington Hills, Michigan, USAACI (2008) Building code requirements for structural concrete (ACI 318-08) and commentary (318-08). ACI Committee 318, American Concrete Institute, Farmington Hills, Michigan, USAACI-ASCE (1991) Recommendations for design of beam-column connections in monolithic reinforced concrete structures (ACI 352R-91). Joint ACI-ASCE Committee 352, American Concrete Institute, Farmington Hills, Michigan, USAACI-ASCE (2002) Recommendations for design of beam-column connections in monolithic reinforced concrete structures (ACI 352R-02). Joint ACI-ASCE Committee 352, American Concrete Institute, Farmington Hills, Michigan, USAArslan MH, Korkmaz HH (2007) What is to be learned from damage and failure of reinforced concrete structures during recent earthquakes in Turkey? Eng Fail Anal 14(1):1–22ASCE (2007) Seismic Rehabilitation of Existing Buildings, ASCE/SEI 41-06. American Society of Civil Engineers, RestonASCE (2010) Minimum Design Loads for Building and Other Structures, ASCE/SEI 7-10. American Society of Civil Engineers, RestonBenavent-Climent A (2007) Seismic behavior of RC side beam-column connections under dynamic loading. J Earthquake Eng 11:493–511Benavent-Climent A, Zahran R (2010) An energy-based procedure for the assessment of seismic capacity of existing frames: application to RC wide beam systems in Spain. Soil Dyn Earthq Eng 30:354–367Benavent-Climent A, Cahís X, Zahran R (2009) Exterior wide beam-column connections in existing RC frames subjected to lateral earthquake loads. Eng Struct 31:1414–1424Benavent-Climent A, Cahís X, Vico JM (2010) Interior wide beam-column connections in existing RC frames subjected to lateral earthquake loading. Bull Earthq Eng 8:401–420BHRC (2004) Iranian Code of Practice for Seismic Resistant Design of Buildings. Standard Nº 2800, 3rd edn. Building and Housing Research Center, TehranBorzi B, Elnashai AS (2000) Refined force reduction factors for seismic design. Eng Struct 22:1244–1260Borzi B, Pinho R, Crowley H (2008) Simplified pushover-based vulnerability analysis for large-scale assessment of RC buildings. Eng Struct 30:804–820BSI (2004) Eurocode 2: Design of concrete structures: Part 1-1: General rules and rules for buildings. British Standards Institutions, LondonCalvi GM (1999) A displacement-based approach for vulnerability evaluation of classes of buildings. J Earthquake Eng 3(3):411–438CDSC (1994) Seismic construction code, NCSR-94. Committee for the Development of Seismic Codes, Spanish Ministry of Construction, Madrid, Spain (in Spanish)CDSC (2002) Seismic construction code, NCSE-02. Committee for the Development of Seismic Codes, Spanish Ministry of Construction, Madrid, Spain (in Spanish)CEN (2004) Eurocode 8: design of structures for earthquake resistance—part 1: general rules, seismic actions and rules for buildings. European Standard EN 1998-1:2003—Comité Européen de Normalisation, Brussels, BelgiumCEN (2005) Eurocode 8: design of structures for earthquake resistance—part 3: assessment and retrofitting of buildings. European Standard EN 1998-1:2005—Comité Européen de Normalisation, Brussels, BelgiumCheung PC, Paulay T, Park R (1991) Mechanisms of slab contributions in beam-column subassemblages. ACI Spec Publ 123Cosenza E, Manfredi G, Polese M, Verderame GM (2005) A multilevel approach to the capacity assessment of existing RC buildings. J Earthquake Eng 9(1):1–22Crowley H, Pinho R (2010) Revisiting Eurocode 8 formulae for periods of vibration and their employment in linear seismic analysis. Earthquake Eng Struct Dynam 39:223–235CS.LL.PP (2009) Instructions for the application of the technique code for the Constructions. Official Gazette of the Italian Republic, 47, Regular Supplement no. 27 (in Italian)De Luca F, Vamvatsikos D, Iervolino I (2013) Near-optimal piecewise linear fits of static pushover capacity curves for equivalent SDOF analysis. Earthquake Eng Struct Dynam 42(4):523–543De Luca F, Verderame GM, Gómez-Martínez F, Pérez-García A (2014) The structural role played by masonry infills on RC building performances after the 2011 Lorca, Spain, earthquake. Bull Earthq Eng 12(5):1999–2026Decanini LD, Mollaioli F (2000) Analisi di vulnerabilità sismica di edifici in cemento armato pre-normativa. In: Cosenza E (ed) Comportamento sismico di edifici in cemento armato progettati per carichi verticali. CNR—Gruppo Nazionale per la Difesa dei Terremoti, Rome (in Italian)Dolšek M, Fajfar P (2004) IN2—a simple alternative for IDA. In: Proceedings of the 13th World conference on Earthquake Engineering. August 1–6, Vancouver, Canada. Paper 3353Domínguez D, López-Almansa F, Benavent-Climent A (2014) Comportamiento para el terremoto de Lorca de 11-05-2011, de edificios de vigas planas proyectados sin tener en cuenta la acción sísmica. Informes de la Construcción 66(533):e008 (in Spanish)Domínguez D, López-Almansa F, Benavent-Climent A (2016) Would RC wide-beam buildings in Spain have survived Lorca earthquake (11-05-2011)? Eng Struct 108:134–154Dönmez C (2013) Seismic Performance of Wide-Beam Infill-Joist Block RC Frames in Turkey. J Perform Constr Facil 29(1):04014026Fadwa I, Ali TA, Nazih E, Sara M (2014) Reinforced concrete wide and conventional beam-column connections subjected to lateral load. Eng Struct 76:34–48Fardis MN (2009) Seismic design, assessment and retrofitting of concrete, Buildings edn. Springer, LondonGentry TR, Wight JK (1992) Reinforced concrete wide beam-column connections under earthquake-type loading. Report no. UMCEE 92-12. Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USAGómez-Martínez F (2015) FAST simplified vulnerability approach for seismic assessment of infilled RC MRF buildings and its application to the 2011 Lorca (Spain) earthquake. Ph.D. Thesis, Polytechnic University of Valencia, SpainGómez-Martínez F, Pérez García A, De Luca F, Verderame GM (2015a) Comportamiento de los edificios de HA con tabiquería durante el sismo de Lorca de 2011: aplicación del método FAST. Informes de la Construcción 67(537):e065 (in Spanish)Gómez-Martínez F, Pérez-García A, Alonso Durá A, Martínez Boquera A, Verderame GM (2015b) Eficacia de la norma NCSE-02 a la luz de los daños e intervenciones tras el sismo de Lorca de 2011. In: Proceedings of Congreso Internacional sobre Intervención en Obras Arquitectónicas tras Sismo: L’Aquila (2009), Lorca (2011) y Emilia Romagna (2012), May 13–14, Murcia, Spain (in Spanish)Gómez-Martínez F, Verderame GM, De Luca F, Pérez-García A, Alonso-Durá, A (2015c). High ductility seismic performances of wide-beam RC frames. In; XVI Convegno ANIDIS. September 13–17, L'Aquila, ItalyHawkins NM, Mitchell D (1979) Progressive collapse of flat plate structures. ACI J 76(7):775–808Iervolino I, Manfredi G, Polese M, Verderame GM, Fabbrocino G (2007) Seismic risk of RC building classes. Eng Struct 29(5):813–820Inel M, Ozmen HB, Akyol E (2013) Observations on the building damages after 19 May 2011 Simav (Turkey) earthquake. Bull Earthq Eng 11(1):255–283Kurose Y, Guimaraes GN, Zuhua L, Kreger ME, Jirsa JO (1991) Evaluation of slab-beam-column connections subjected to bidirectional loading. ACI Spec Publ 123:39–67LaFave JM, Wight JK (1997) Behavior of reinforced exterior wide beam-column-slab connections subjected to lateral earthquake loading. Report no. UMCEE 97-01. Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USALaFave JM, Wight JK (1999) Reinforced concrete exterior wide beam-column-slab connections subjected to lateral earthquake loading. ACI Struct J 96(4):577–586LaFave JM, Wight JK (2001) Reinforced concrete wide-beam construction vs. conventional construction: resistance to lateral earthquake loads. Earthq Spectra 17(3):479–505Li B, Kulkarni SA (2010) Seismic behavior of reinforced concrete exterior wide beam-column joints. J Struct Eng (ASCE) 136(1):26–36López-Almansa F, Domínguez D, Benavent-Climent A (2013) Vulnerability analysis of RC buildings with wide beams located in moderate seismicity regions. Eng Struct 46:687–702Masi A, Santarsiero G, Nigro D (2013a) Cyclic tests on external RC beam-column joints: role of seismic design level and axial load value on the ultimate capacity. J Earthquake Eng 17(1):110–136Masi A, Santarsiero G, Mossucca A, Nigro D (2013b) Seismic behaviour of RC beam-column subassemblages with flat beam. In: Proceedings of XV Convegno della Associazione Nazionale Italiana di Ingegneria Sismica, ANIDIS. Padova, ItalyMazzolani FM, Piluso V (1997) Plastic design of seismic resistant steel frames. Earthquake Eng Struct Dynam 26:167–191MEPP (2000a) Greek earthquake resistant design code, EAK 2000. Ministry of Environment, Planning and Public Works, AthensMEPP (2000b) Greek code for the design and construction of concrete works, EKOS 2000. Ministry of Environment, Planning and Public Works, Athens (in Greek)Miranda E, Bertero VV (1994) Evaluation of strength reduction factors for earthquake-resistant design. Earthq Spectra 10(2):357–379MPWS (2007) Specifications for buildings to be built in seismic areas. Turkish Standards Institution, Ministry of Public Works and Settlement, Ankara (in Turkish)Mwafy AM, Elnashai AS (2002) Calibration of force reduction factors of RC buildings. J Earthquake Eng 6(2):239–273NZS (2004) Structural design actions. Part 5: earthquake actions, NZS 1170.5. New Zealand Standards, WellingtonNZS (2006) Concrete structures standard: part 1—the design of concrete structures, NZS 3101 part 1. New Zealand Standards, WellingtonPan A, Moehle JP (1989) Lateral displacement ductility of reinforced concrete flat plates. ACI Struct J 86(3):250–258Panagiotakos TB, Fardis MN (2001) Deformations of reinforced concrete members at yielding and ultimate. ACI Struct J 98(2):135–148 [and Appendix 1 (69 pp)]Paulay T, Priestley MJN (1992) Seismic design of concrete and masonry structures. Wiley, New York, USAQuintero-Febres CG, Wight JK (1997) Investigation on the seismic behavior of RC interior wide beam-column connections. Report no. UMCEE 97-15. Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USAQuintero-Febres CG, Wight JK (2001) Experimental study of Reinforced concrete interior wide beam-column connections subjected to lateral loading. ACI Struct J 98(4):572–582Serna-Ros P, Fernández-Prada MA, Miguel-Sosa P, Debb OAR (2001) Influence of stirrup distribution and support width on the shear strength of reinforced concrete wide beams. Mag Concr Res 54(00):1–11Shuraim AB (2012) Transverse stirrup configurations in RC wide shallow beams supported on narrow columns. J Struct Eng 138(3):416–424Siah WL, Stehle JS, Mendis P, Goldsworthy H (2003) Interior wide beam connections subjected to lateral earthquake loading. Eng Struct 25:281–291Tore E, Demiral T (2014) A parametric study of code-based performance limits for wide beams. e-GFOS 5(8):1–11Vamvatsikos D, Cornell CA (2002) Incremental Dynamic Analysis. Earthquake Eng Struct Dynam 31:491–514Vidic T, Fajfar P, Fischinger M (1994) Consistent inelastic design spectra: strength and displacement. Earthquake Eng Struct Dynam 23:507–521Vielma JC, Barbat AH, Oller S (2010) Seismic safety of low ductility structures used in Spain. Bull Earthq Eng 8:135–15

Analytical studies of Hawking radiation and quasinormal modes in rotating linear dilatonic black hole

The rotating linear dilatonic black hole is an asymptotically non-flat solution to Einstein-Maxwell-Dilaton-Axion gravity theory due to the existence of non-trivial matter fields. We have analytically studied the wave equation of scalar field in this background and shown that the radial wave equation can be solved in terms of hypergeometric function. By determining the ingoing and the outgoing fluxes at the asymptotic infinity, we have found the analytical expressions for reflection coefficient and greybody factor for certain scalar modes. In the high frequency regime, we obtain the Hawking temperature by comparing the blackbody spectrum with the radiation spectrum resulting from reflection coefficient. It is shown that the Hawking temperature, which depends only on the linear dilatonic background parameter, does not agree with the temperature calculated from surface gravity. At last, the quasinormal modes of scalar field perturbation are presented, which shows that the rotating linear dilationic black hole is unstable for certain modes apart from the superradiant modes.Comment: 7 pages, 2 figures Comments are welcom