This paper contains ground-motion prediction equations (GMPEs) for average horizontal-component ground motions as a function of earthquake magnitude, distance from source to site, local average shear-wave velocity, and fault type. Our equations are for peak ground acceleration (PGA), peak ground velocity (PGV), and 5%-damped pseudo-absolute-acceleration spectra (PSA) at periods between 0.01 s and 10 s. They were derived by empirical regression of an extensive strong-motion database compiled by the “PEER NGA” (Pacific Earthquake Engineering Research Center’s Next Generation Attenuation) project. For periods less than 1s , the analysis used 1,574 records from 58 mainshocks in the distance range from 0 km to 400 km (the number of available data decreased as period increased). The primary predictor variables are moment magnitude M, closest horizontal distance to the surface projection of the fault plane R JB , and the time-averaged shear-wave velocity from the surface to 30 m VS30. The equations are applicable for M =5–8 , RJB 200 km, and VS30= 180– 1300 m / s. DOI: 10.1193/1.2830434

/pdf/ground-motion-prediction-equations-for-the-average-1pxmyzur8d.pdf

Ground-motion prediction equations for the average horizontal component of PGA, PGV, and 5%-damped PSA at spectral periods between 0.01 s and 10.0 s

We present a new empirical ground motion model for PGA, PGV, PGD and 5% damped linear elastic response spectra for periods ranging from 0.01– 10 s. The model was developed as part of the PEER Next Generation Attenuation (NGA) project. We used a subset of the PEER NGA database for which we excluded recordings and earthquakes that were believed to be inappropriate for estimating free-field ground motions from shallow earthquake mainshocks in active tectonic regimes. We developed relations for both the median and standard deviation of the geometric mean horizontal component of ground motion that we consider to be valid for magnitudes ranging from 4.0 up to 7.5–8.5 (depending on fault mechanism) and distances ranging from 0 – 200 km. The model explicitly includes the effects of magnitude saturation, magnitude-dependent attenuation, style of faulting, rupture depth, hanging-wall geometry, linear and nonlinear site response, 3-D basin response, and inter-event and intra-event variability. Soil nonlinearity causes the intra-event standard deviation to depend on the amplitude of PGA on reference rock rather than on magnitude, which leads to a decrease in aleatory uncertainty at high levels of ground shaking for sites located on soil. DOI: 10.1193/1.2857546

/pdf/nga-ground-motion-model-for-the-geometric-mean-horizontal-1yqfspz2c2.pdf

NGA Ground Motion Model for the Geometric Mean Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra for Periods Ranging from 0.01 to 10 s

The true performance of ground-motion prediction equations is often not fully appreciated until they are used in practice for seismic hazard analyses and applied to a wide range of scenarios and exceedance levels. This has been the case for equations published recently for the prediction of peak ground velocity (PGV), peak ground acceleration (PGA), and response spectral ordinates in Europe, the Middle East, and the Mediterranean (Akkar and Bommer 2007a,b). This paper presents an update that corrects the shortcomings identified in those equations, which are primarily, but not exclusively, related to the model for the ground-motion variability.

Strong-motion recording networks in Europe and the Middle East were first installed much later than in the United States and Japan but have grown considerably over the last four decades. The databanks of strong-motion data have grown in parallel with the accelerograph networks, and in addition to national collections there have been concerted efforts over more than two decades to develop and maintain a European database of associated metadata ( e.g. , Ambraseys et al. 2004).

As the database of strong-motion records from Europe, the Mediterranean region, and the Middle East has expanded, there have been two distinct trends in terms of developing empirical ground-motion prediction equations (GMPEs): equations derived from a large dataset covering several countries, generally of moderate-to-high seismicity; and equations derived from local databanks for application within national borders. We refer to the former as pan-European models, noting that this is for expedience since the equations are really derived for southern Europe, the Maghreb (North Africa), and the active areas of the Middle East. The history of the development of both pan-European and national equations is discussed by Bommer et al. (2010), who also review studies that consider the arguments for and against the existence of consistent regional …

Empirical Equations for the Prediction of PGA, PGV, and Spectral Accelerations in Europe, the Mediterranean Region, and the Middle East

Seismic Rehabilitation of Existing Buildings

In code-based seismic design and assessment it is often allowed the use of real records as an input for nonlinear dynamic analysis. On the other hand, international seismic guidelines, concerning this issue, have been found hardly applicable by practitioners. This is related to both the difficulty in rationally relating the ground motions to the hazard at the site and the required selection criteria, which do not favor the use of real records, but rather various types of spectrum matching signals. To overcome some of these obstacles a software tool for code-based real records selection was developed. REXEL, freely available at the website of the Italian network of earthquake engineering university labs (http://www.reluis.it/index_eng.html), allows to search for suites of waveforms, currently from the European Strong-motion Database, compatible to reference spectra being either user-defined or automatically generated according to Eurocode 8 and the recently released new Italian seismic code. The selection reflects the provisions of the considered codes and others found to be important by recent research on the topic. In the paper, record selection criteria are briefly reviewed first, and then the algorithms implemented in the software are discussed. Finally, via some examples, it is shown how REXEL can effectively be a contribution to code-based real records selection for seismic structural analysis.

/pdf/rexel-computer-aided-record-selection-for-code-based-seismic-1u1l0tkvjj.pdf

REXEL: computer aided record selection for code-based seismic structural analysis

In 2009, we described a possible founder effect of autosomal dominant Segawa disease in Córdoba (Spain) due to mutation c.265C>T (p. Q89*) in the GCH1 gene. We present a retrospective multicentre study aimed at improving our knowledge of Segawa disease in Spain and providing a detailed phenotypic-genotypic description of patients.Clinical-genetic information were obtained from standardized questionnaires that were completed by the neurologists attending children and/or adults from 16 Spanish hospitals.Eighty subjects belonging to 24 pedigrees had heterozygous mutations in GCH1. Seven genetic variants have been described only in our cohort of patients, 5 of which are novel mutations. Five families not previously described with p. Q89* were detected in Andalusia due to a possible founder effect. The median latency to diagnosis was 5 years (IQR 0-16). The most frequent signs and/or symptoms were lower limb dystonia (38/56, 67.8%, p = 0.008) and diurnal fluctuations (38/56, 67.8%, p = 0.008). Diurnal fluctuations were not present in the phenotypes other than dystonia. Fifty-three of 56 symptomatic patients were treated with a levodopa/decarboxylase inhibitor for (mean ± SD) 12.4 ± 8.12 years, with 81% at doses lower than 350 mg/day (≤5 mg/kg/d in children). Eleven of 53 (20%) patients had nonresponsive symptoms that affected daily life activities. Dyskinesias (4 subjects) were the most prominent adverse effects.This study identifies 5 novel mutations and supports the hypothesis of a founder effect of p. Q89* in Andalusia. New insights are provided for the phenotypes and long-term treatment responses, which may improve early recognition and therapeutic management. 

Genetic landscape of Segawa disease in Spain. Long-term treatment outcomes

Quasi-static cyclic tests of two U-shaped reinforced concrete walls under diagonal loading

Am 27. Februar 2010 um 3.34 Uhr Ortszeit ereignete sich im südlichen Zentral-Chile ein sehr starkes Erdbeben mit der Magnitude Mw = 8,8. Es ist damit eines der größten, jemals aufgezeichneten Beben. Chile gehört zu den Ländern mit großer Seismizität und hat bereits in der jüngeren Vergangenheit einige starke Erdbeben entlang seiner Küste erfahren (1835, 1906, 1928, 1960 und 1985). Das Epizentrum des diesjährigen Erdbebens lag 330 km südlich der Hauptstadt Santiago etwa 20 km vor der Küste der Region Le Maule in einer Tiefe von ungefähr 35 km (Bild 1). Die Bruchfläche erstreckte sich über eine Länge von 460 km. Das Beben forderte 577 Todesopfer, ein großer Teil davon als Folge der entstandenen Flutwellen bis 11 m Höhe, die bereits nach 30 Minuten die ersten Küstenorte erreichten. Die gesamten Sachschäden werden auf USD 30 Milliarden geschätzt [EERI10]. Chile ist weltweit eines der wenigen Länder mit hoher Seismizität, in welchem fast alle höheren Gebäude mittels Stahlbetontragwänden für horizontale Kräfte ausgesteift werden. Einige davon wurden beim Erdbeben vom 27.2.2010 unerwartet stark beschädigt. Im folgenden werden typische Schadensbilder von Stahlbetontragwandgebäuden präsentiert und mögliche Gründe für die Schäden diskutiert. In den meisten übrigen Ländern mit hoher Seismizität werden Stahlbetonrahmengebäude bevorzugt (z.B. in Japan, Neuseeland, Griechenland und Italien). An der Westküste der USA wurden ebenfalls in der Vergangenheit Rahmentragwerke bevorzugt, in den letzten Jahren hat jedoch eine Trendwende eingesetzt und viele der neuen Hochhäuser verwenden nun Stahlbetonkerne als Aussteifung. Ferner ist Chile ein Land, in dem bereits seit sehr langer Zeit Erdbebennormen existieren und mit Erfolg umgesetzt wurden. Die mehrgeschossigen Stahlbetongebäude sind deshalb allesamt auf Erdbeben bemessen. Die gemeinsame französisch-schweizerische Erkundungsmission der Association française du génie parasismique (AFPS) und der Schweizer Gesellschaft für Erdbebeningenieurwesen und Baudynamik (SGEB) bot daher eine seltene Gelegenheit, das Verhalten von auf Erdbeben bemessenen Stahlbetontragwandgebäuden zu studieren und daraus Folgerungen für mitteleuropäische Verhältnisse zu ziehen [Mar+10]. Der Beitrag beginnt mit einem kurzen Abriss der Geschichte der Erdbebennormen und einen Überblick über das Schadensausmaß bei Gebäuden, gefolgt von der ausführlichen Beschreibung der Schäden an ausgewählten neueren Stahlbetontragwandgebäuden. Zum Abschluss werden mögliche Ursachen für die Schäden an Stahlbetontragwandgebäuden diskutiert und einige Aspekte der chilenischen Erdbebennorm mit denjenigen des Eurocodes 8 verglichen. Das Verhalten von Gebäuden mit Stahlbetontragwänden während des Erdbebens Centro-Sur in Chile am 27.2.2010

Das Verhalten von Gebäuden mit Stahlbetontragwänden während des Erdbebens Centro-Sur in Chile am 27.2.2010

We use spherical cap harmonic (SCH) basis functions to analyse and reconstruct the morphology of scanned genus-0 rough surface patches with open edges. We first develop a novel one-to-one conformal mapping algorithm with minimal area distortion for parameterising a surface onto a polar spherical cap with a prescribed half angle. We then show that as a generalisation of the hemispherical harmonic analysis, the SCH analysis provides the most added value for small half angles, i.e., for nominally flat surfaces where the distortion introduced by the parameterisation algorithm is smaller when the surface is projected onto a spherical cap with a small half angle than onto a hemisphere. From the power spectral analysis of the expanded SCH coefficients, we estimate a direction-independent Hurst exponent. We also estimate the wavelengths associated with the orders of the SCH basis functions from the dimensions of the first degree ellipsoidal cap. By windowing the spectral domain, we limit the bandwidth of wavelengths included in a reconstructed surface geometry. This bandlimiting can be used for modifying surfaces, such as for generating finite or discrete element meshes for contact problems. The codes and data developed in this paper are made available under the GNU LGPLv2.1 license.

Spherical Cap Harmonic Analysis (SCHA) for Characterising the Morphology of Rough Surface Patches

This paper describes the procedure on the evaluation of the masonry chapter for the next generation of Eurocode 8, the European Standard for earthquake-resistant design. In CEN, TC 250/SC8, working group WG 1 has been established to support the subcommittee on the topic of masonry on both design of new structures (EN1998-1) and assessment of existing structures (EN1998-3). The aim is to elaborate suggestions for amendments which fit the current state of the art in masonry and earthquake-resistant design. Focus will be on modelling, simplified methods, linear-analysis (q-values, overstrength-values), nonlinear procedures, out-of-plane design as well as on clearer definition of limit

/pdf/next-generation-of-eurocode-8-masonry-chapter-4pns53kxq3.pdf

Katrin Beyer

Papers

Genetic landscape of Segawa disease in Spain. Long-term treatment outcomes

Quasi-static cyclic tests of two U-shaped reinforced concrete walls under diagonal loading

Das Verhalten von Gebäuden mit Stahlbetontragwänden während des Erdbebens Centro-Sur in Chile am 27.2.2010

Spherical Cap Harmonic Analysis (SCHA) for Characterising the Morphology of Rough Surface Patches

Next generation of Eurocode 8, masonry chapter