Box-girder bridges supported by single reinforced concrete (RC) columns are expected to sustain seismic shocks with minor structural damages in seismically active regions where transportation is substantially required for rescuing and evacuating tasks. Such viaducts are vulnerable to damage when they are subjected to strong ground motions and acceleration pulse records, especially when responding in a flexural mode or having relatively low core confinement. Using a nonlinear dynamic solver that applies the fibre element method, global and local damage curves are computed based on the dissipated energy under hysteretic curves and based on constitutive curves, respectively. The RC bridge with seismic isolation bearing is used as an alternative system to control the damage, and modelled using linkage elements between the substructure and super structure. It was found that seismic isolation can be controlled to dissipate partial seismic energy so that the RC column gains the least possible minor damage. Using a MatLab program, a fibre element nonlinear model was built using a simplified iterative process and simplified constitutive relations. The number of fibres and elements under the dynamic loading was found to be affecting the final results of the analysis. Using crack growth modelling based on fracture mechanics, the combined discrete element/finite element explicit-Elfen code was applied to investigate the crack growth in 3D dynamically loaded RC columns. Despite its excessive computational cost and time, this code provides reliable information about local damage in the RC column core. Earthquake records with the pulse acceleration phenomenon have a severe damage potential on the structure. The difference in damage intensities was detected by crack growth modelling for the same problem using different loading rates. Critically stressed zones can be investigated independently by using the relative response technique, in which responses from the numerically analysed structure are re-used as applied loads onto a small-scale crack model for the critical member. Two general conclusions can be obtained; bridges with single RC columns designed by the demand/capacity criterion could suffer severe damage and possible collapse when subjected to strong ground motions. Secondly; hysteresis-based methods provide a global damage evaluation based on strength and ductility only regardless of the damage growth inside the concrete core and the buckling of bars, which could lead to progressive collapse.

abstract: Understanding topography developed above an active blind thrust fault is critical to quantifying the along-strike variability of the timing, magnitude, and rate of fault slip at depth. Hillslope and fluvial processes respond to growing topography such that the existing landscape is an indicator of constructional and destruction processes. Light detection and ranging (lidar) data provide a necessary tool for fine-scale quantitative understanding of the topography to understand the tectonic evolution of blind thrust faulting. In this thesis, lidar topographic data collected in 2014 are applied to a well-studied laterally propagating anticline developed above a blind thrust fault in order to assess the geomorphic response of along-strike variations in tectonic deformation. Wheeler Ridge is an asymmetric east-propagating anticline (10 km axis, 330 m topographic relief) above a north-vergent blind thrust fault at the northern front of the Transverse Ranges, Southern San Joaquin Valley, California. Wheeler Ridge is part of a thrust system initiating in the late Miocene and is known to have significant historic earthquakes occur (e.g., 1952 Mw 7.3 Kern County earthquake). Analysis of the lidar data enables quantitative assessment of four key geomorphic relationships that may be indicative of relative variation in local rock uplift. First, I observe remnant landforms in the youngest, easternmost section of Wheeler Ridge that indicate the erosional history of older deposits to the west. Second, I examine the central portion of Wheeler Ridge where drainages and hillslopes are closely tied to uplift rates. Third, I observe the major wind gap within which a series of knickpoints are aligned at a similar elevation and tie into the local depositional and uplift history. Finally, I survey the western section and specifically, the fold backlimb where high-resolution topography and field mapping indicate long ridgelines that may preserve the uplifted and tilted alluvial fan morphology. I address changing landforms along the fold axis to test whether backlimb interfluves are paleosurfaces or the result of post-tectonic erosional hillslope processes. This work will be paired with future geochronology to update the ages of uplifted alluvial fan deposits and better constrain the timing of along-strike uplift of Wheeler Ridge. / Dissertation/Thesis / Masters Thesis Geological Sciences 2015

abstract: There is a need to understand spatio-temporal variation of slip in active fault zones, both for the advancement of physics-based earthquake simulation and for improved probabilistic seismic hazard assessments. One challenge in the study of seismic hazards is producing a viable earthquake rupture forecast—a model that specifies the expected frequency and magnitude of events for a fault system. Time-independent earthquake forecasts can produce a mismatch among observed earthquake recurrence intervals, slip-per-event estimates, and implied slip rates. In this thesis, I developed an approach to refine several key geologic inputs to rupture forecasts by focusing on the San Andreas Fault in the Carrizo Plain, California. I use topographic forms, sub-surface excavations, and high-precision geochronology to understand the generation and preservation of slip markers at several spatial and temporal scales—from offset in a single earthquake to offset accumulated over thousands of years. This work results in a comparison of slip rate estimates in the Carrizo Plain for the last ~15 kyr that reduces ambiguity and enriches rupture forecast parameters. I analyzed a catalog of slip measurements and surveyed earth scientists with varying amounts of experience to validate high-resolution topography as a supplement to field-based active fault studies. The investigation revealed that (for both field and remote studies) epistemic uncertainties associated with measuring offset landforms can present greater limitations than the aleatoric limitations of the measurement process itself. I pursued the age and origin of small-scale fault-offset fluvial features at Van Matre Ranch, where topographic depressions were previously interpreted as single-event tectonic offsets. I provide new estimates of slip in the most recent earthquake, refine the centennial-scale fault slip rate, and formulate a new understanding of the formation of small-scale fault-offset fluvial channels from small catchments (<7,000 m2). At Phelan Creeks, I confirm the constancy of strain release for the ~15,000 years in the Carrizo Plain by reconstructing a multistage offset landform evolutionary history. I update and explicate a simplified model to interpret the geomorphic response of stream channels to strike-slip faulting. Lastly, I re-excavate and re-interpret paleoseismic catalogs along an intra-continental strike-slip fault (Altyn Tagh, China) to assess consistency of earthquake recurrence. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2016

Past earthquakes have demonstrated that Indian sub-continent is highly vulnerable to earthquake hazards. It has been estimated that about 59 percent of the land area of the Indian subcontinent has potential risk from moderate to severe earthquakes (NDMA, 2010). Major earthquakes in the last 20 years such as Khillari (30th September 1993), Jabalpur (22nd May 1997), Chamoli (29th March 1999) and Bhuj (26th January 2001) earthquakes have resulted in more than 23,000 deaths and extensive damage to infrastructure (NDMA, 2010). Although it is well known that the major earthquake hazard prone areas in India are the Himalayan region (inter-plate zone) and the north-east region, (subduction zone) the seismicity of Peninsular India cannot be underestimated. Many studies (Seeber et al., 1999; Rao, 2000; Gangrade & Arora, 2000) have proved that the seismicity of Peninsular India is significantly high and may lead to earthquakes of sizeable magnitude. This necessitates a seismic zonation for the country, as well as various regions in it. Seismic zonation is the first step towards an effective earthquake risk mitigation study. Seismic zonation is a process in which a large region is demarcated into small zones based on the levels of earthquake hazard. Seismic zonation is generally carried out at three different levels based on the aerial extent of the region, importance of site and the population. They are micro-level, meso-level and macro-level. The macro-level zonation is generally carried out for large landmass such as a state or a country. The earthquake hazard parameters used for macro-level zoning are generally evaluated with less reliability. The typical example of a macro-level zonation is the seismic zonation map of India prepared by BIS-1893 (2002), where the entire India is demarcated into four seismic zones based on past seismicity and tectonic conditions. Generally the macro-level seismic zonation is carried out based on peak horizontal acceleration (PHA) estimated at bedrock level without giving emphasis on the local soil conditions. Seismic zonation at the meso-level is carried out for cities and urban centers with a population greater than 5,00,000. The earthquake hazard parameters, for the meso-level zonation are evaluated with greater degree of reliability, compared to the macro-level zoning. The micro-level zonation is carried out for sites which host critical installations such as nuclear power plants (NPPs). As the NPPs are considered as very sensitive structures, the earthquake parameters, for the micro-level zonation of the NPP sites are estimated with a highest degree of reliability. The local soil conditions and site effects are properly counted for carrying out the micro as well as the meso-level zonation. Several researchers have carried out meso-level zonation considering effects of all major earthquake hazards such as PHA, site amplification, liquefaction (Mohanty et al., 2007; Nath et al., 2008; Sitharam & Anbazhagan, 2008 etc.) Even though the above definitions and descriptions are available for various levels of zonation, the key issue lies in the adoption of the suitable one for a given region. There are only a few guidelines available regarding the use of a particular level of zonation for a given study area. Based on the recommendation of the disaster management authority, the government of India has initiated the seismic zonation of all major cities in India. As it is evident that large resources are required in order to carry out seismic site characterization and site effect estimation, both the micro and meso-level zonations cannot be carried out for all these cities. Hence there is a need to propose appropriate guidelines to define the suitability of each level zonation for various re-gions in the country. Moreover there are many methodologies available for site characterization and estimation of site effects such as site amplification and liquefaction. The appropriateness of these methodologies for various levels of seismic zonations also needs to be assessed in order to optimize use of resources for seismic zonation. Hence in the present study, appropriate techniques for site characterization and earthquake hazard estimation for regions at different scale levels were determined. Using the appropriate techniques, the seismic zonation was carried out both at the micro and macro-level, incorporating all major earthquake hazards. The state of Karnataka and the Kalpakkam NPP site were chosen for the macro and micro−level seismic zonation in this study. Kalpakkam NPP site is situated in Tamil Nadu, India, 70 kilometres south of Chennai city. The NPP site covers an area of 3000 acres. The site is situated along the Eastern coastal belt of India known as Coromandel coast with Bay of Bengal on the east side. The NPP site host major facilities such as Indira Gandhi Centre for Atomic Research (IGCAR), Madras Atomic Power Station (MAPS), Fast Reactor Fuel Reprocessing (FRFC) Plant, Fast Breeder Test Reactor (FBTR), Prototype Fast Breeder Reactor (PFBR) etc. The state Karnataka lies in the southern part of India, covering an area of 1,91,791 km2, thus approximately constituting 5.83% of the total geographical area of India. Both the study areas lie in the Indian Peninsular which is identified as one of the most prominent and largest Precambrian shield region of the world. The first and foremost step towards the seismic zonation is to prepare a homogenised earthquake catalogue. All the earthquake events within 300 km radius from the boundary of two study areas were collected from various national and international agencies. The earthquake events thus obtained were found to be in different magnitude scales and hence all these events were converted to the moment magnitude scale. A declustering procedure was applied to the earthquake catalogue of the two study area in order to remove aftershocks, foreshocks and dependent events. The completeness analysis was carried out and the seismicity parameters for the two study areas were evaluated based on the complete part of earthquake catalogues. The next major step toward the estimation of earthquake hazard and seismic zonation is the identification and mapping of the earthquake sources. Three source models, mainly; 1) linear source model, 2) point source model and 3) areal source model were used in the present study for characterizing earthquake sources in the two study areas. All the linear sources (faults and lineaments) within 300 km radius from the boundary of two study areas were identified and mapped from SEISAT (2000). In addition to SEISAT (2000), some lineaments were also mapped from the works of Ganesha Raj & Nijagunappa (2004). These lineaments and faults were mapped and georeferenced in a GIS platform on which earthquake events were then super-imposed to give seismotectonic atlas. Seismotectonic atlas was prepared for both the study areas. The point source model (Costa et al. 1993; Panza et al. 1999) and areal source model (Frankel, 1995) were also adopted in this work. Deterministic and probabilistic seismic hazard analysis was found to be appropriated for micro, meso and macro-level zonations. Hence in the present study, the seismic hazard at bedrock level, both at the micro and macro-level were evaluated using the deterministic as well as the probabilistic methodologies. In order to address the epistemic uncertainties in source models and attenuation relations, a logic tree methodology was incorporated with the deterministic and probabilistic approaches. As the deterministic seismic hazard analysis (DSHA) considers only the critical scenario, knowing the maximum magnitude that can occur at a source and the shortest distance between that source and the site and the peak horizontal acceleration (PHA) at that site is estimated using the frequency dependent attenuation relation. Both for the micro as well as the macro-level, the DSHA was carried out, considering grid sizes of 0.001◦ × 0.001◦ and 0.05◦ × 0.05◦respectively. A MATLAB program was developed to evaluate PHA at the center of each of these grid points. The epistemic uncertainties in source models and attenuation relations have been addressed using a logic tree approach (Bommer et al., 2005). A typical logic tree consists of a series of nodes to which several models with different weightages are assigned. Allotment of these weightages to different branch depends upon the degree of uncertainties in the model, and its accuracy. However the sum of all weightages of different branches at a particular node must be unity. Two types of seismic sources are employed in DSHA and they are linear and smoothed point sources. Since both the types of sources were of equal importance, equal weightages were assigned to each of them. The focal depth in the present study was taken as 15 km. The attenuation properties of the region were modelled using three attenuation relations, Viz. Campbell & Bozorgnia (2003), Atkinson & Boore (2006) and Raghu Kanth & Iyengar (2007). The attenuation relation proposed by Raghu Kanth & Iyengar (2007) was given higher weightage of 0.4 since it was devel-oped for the Indian peninsular region. The attenuation relations by Atkinson & Boore (2006) and Campbell & Bozorgnia (2003) which were developed for Eastern North American shield region, shared equal weightages of 0.3. Maps showing spatial variation of PHA value at bedrock level, for both micro and macro-level are presented. Response spectra at the rock level for important location in the two study areas were evaluated for 8 different periods of oscillations, and the results are presented in this thesis. Probabilistic seismic hazard analysis (PSHA) incorporating logic tree approach was per-formed for both micro as well as macro-level considering similar grid sizes as in DSHA. Two types of seismic sources considered in the PSHA are linear sources and smoothed gridded areal sources (Frankel, 1995) with equal weightage distribution in the logic tree structure. Smoothed gridded areal sources can also account the scattered earthquake events. The hypocentral distance was calculated by considering a focal depth of 15 km, as in the case of DSHA method. A MAT-LAB program was developed for PSHA. The same attenuation relations employed in DSHA were used in PSHA as well with the same weightage allotment in logic tree structure. Considering all major uncertainties, a uniform hazard response spectrum (UHRS), showing the variation of PHA values with the mean annual rate of exceedance (MARE), was evaluated for each grid point. From the uniform hazard response spectrum, the PHA corresponding to any return period can be evaluated. Maps showing the spatial variation of PHA value at bedrock level, corresponding to 475 year and 2500 year return periods for both micro and macro-level are presented. Response spectra at the rock level for important location in two study areas were evaluated for eight different periods of oscillations, and the results are presented in this thesis. In order to assess various earthquake hazards like ground motion amplification and soil liquefaction, a thorough understanding of geotechnical properties of the top overburden soil mass is essential. As these earthquake hazards strongly depend on the geotechnical properties of the soil, site characterization based on these properties will provide a better picture of these hazards. In the present study, seismic site characterization was carried both at the micro and macro-level using average shear wave velocity for top 30 m overburden (Vs30). At the micro-level, the shear wave velocity profile at major locations was evaluated using multichannel analysis of surface waves (MASW) tests. MASW is an indirect geophysical method used in geotechnical investigations and near surface soil characterization based on the dispersion characteristics of surface waves (Park et al., 1999). The MASW test setup consists of 24-channel geophones of 4.5 Hz capacity. A 40 kg propelled energy generator (PEG) was used for generating surface wave. Based on the recordings of geophones, the dispersion characteristics of surface waves were evaluated in terms of a dispersion curve. The shear wave velocity (Vs) profile at a particular location was determined by performing inversion analysis (Xia et al., 1999). After the evaluation of V s profile at all major locations, the site characterization at the micro-level was carried out as per NEHRP (BSSC, 2003) and IBC (2009) recommendations. Maps showing the spatial distribution of various site classes at the micro-level are presented in this thesis. Standard penetration tests were also carried out in the site as part of subsurface investigation and in this study a new correlation between V s and corrected SPT-N values was also developed. Apart from carrying out site characterization, low strain soil stiffness profile was evaluated based on SPT and MASW data. In this work, seismic site characterization at the macro-level was also carried out. As it is not physically and economically viable to carry out geotechnical and geophysical testing for such a large area, like the Karnataka state, the seismic site characterization was carried out based on topographic slope maps. Wald & Allen (2007) has reported that the topographic slope is a perfect indicator of site conditions. Based on the correlation studies carried out for different regions, Wald & Allen (2007) has proposed slope ranges corresponding to each site class. In this study, the topographic map for the entire state of Karnataka was derived from ASTER Global Digital Elevation Model GDEM. This thesis also presents a comparison study between the Vs30map generated from topographic slope data and Vs30map developed using geophysical field tests, for Bangalore and Chennai. Based on this study, it is concluded that topographic slopes can be used for developing Vs30maps for meso and macro-level with reasonable accuracy. The topographic map for macro-level was generated at a grid size of 0.05◦ × 0.05◦. Based on the value of slope at a particular grid point, the Vs30for that grid point was assigned as per Wald & Allen (2007). A similar procedure was repeated for all the grid points. Spatial variation of various seismic site classes for the macro-level has been presented in this work. The site amplification hazard was estimated for both micro and the macro-level. The assessment of site amplification is very important for shallow founded structures and other geotechnical structures like retaining walls and dams, floating piles and underground structures as the possible earthquake damages are mostly due to extensive shaking. The site amplification hazard at the micro-level was estimated using 1D equivalent linear ground response analyses. The earthquake motion required for carrying out ground response analysis was simulated from a target response spectrum. 1D equivalent linear analyses were performed using SHAKE 2000 software. Spatial variations of surface level PHA values, site amplification, predominant frequency throughout the study area are presented in this work. As it is not physically viable to assess site amplification hazard at the macro-level using the 1D ground response analysis, the surface level PHA value for the entire state of Karnataka was estimated using a non-linear site amplification technique pro-posed by Raghu Kanth & Iyengar (2007). Based on the site class in which particular grid belongs and bedrock level PHA value, the amplification for that grid point was evaluated using regression equations developed by Raghu Kanth & Iyengar (2007). The liquefaction hazard both at the micro and macro-level was evaluated and included in this thesis. The micro-level liquefaction hazard was estimated in terms of liquefaction potential index (LPI) based on SPTN values (Iwasaki et al., 1982). As the LPI was evaluated by integrating the factor of safety against liquefaction (FSL) at all depths, it can effectively represent the liquefaction susceptibility of the soil column. LPI at the micro-level was evaluated by both deterministic as well as the probabilistic approaches. In the deterministic approach, the FSLat a particular depth was evaluated as the ratio of the cyclic resistance of the soil layer to the cyclic stress induced by earth-quake motion. The cyclic stress was estimated as per Seed & Idriss (1971), while the cyclic soil resistance was characterised from the corrected SPT-N values as proposed by Idriss & Boulanger (2006). However in the probabilistic method, the mean annual rate of exceedance (MARE) of factor of safety against liquefaction at different depth was estimated using SPT field test data by considering all uncertainties. From the MARE curve, the FS L for 475 year and 2500 year return period were evaluated. Once FS L at different depth were evaluated, the LPI for the borehole is calculated by integrating FS L for all depths. The liquefaction hazard at the macro-level was estimated in terms of SPT and CPT values required to prevent liquefaction at 3 m depth, using a probabilistic approach. The probabilistic approach accounts the contribution of several magnitudes acceleration scenarios on the liquefaction potential at a given site. Based on the methodology proposed by Kramer & Mayfield (2007), SPT and CPT values required to resist liquefaction corresponding to return periods of 475 years and 2500 years were evaluated at the macro-level. It has been observed that the spatial distribution of intensity of each these hazard in a region is distinct from the other due to the predominant influence of local geological conditions rather than the source characteristics of the earthquake. Hence it’ll be difficult to assess risk and vulnerability of a region when these hazards are treated separately. Thus, all major earthquake hazards are to be integrated to an index number, which effectively represents the combined effect of all hazards. In the present study, all major earthquake hazards were integrated to a hazard index value, both at the micro as well as macro-level using the Analytical Hierarchy Process (AHP) proposed by Saaty (1980). Both micro and macro-level seismic zonation was performed based on the spatial distribution of hazard index value. This thesis also presents the assessment of earthquake induced landslides at the macro-level in the appendix. Landslide hazards are a major natural disaster that affects most of the hilly regions around the world. This is a first attempt of it kind to evaluate seismically induced landslide hazard at the macro-level in a quantitative manner. Landslide hazard was assessed based on Newmark’s method (Newmark, 1965). The Newmark’s model considers the slope at the verge of failure and is modelled as a rigid block sliding along an incline plane under the influence of a threshold acceleration. The value of threshold acceleration depends upon the static factor of safety and slope angle. At the macro-level, the slope map for the entire state of Karnataka was derived from ASTER GDEM, considering a grid size of 50 m × 50 m. The earthquake motion which induces driving force on the slope to destabilize it was evaluated for each grid point with slope value 10 degree and above using DSHA. Knowing the slope value and peak horizontal acceleration (PHA) at a grid point, the seismic landslide hazard in terms of static factor of safety required to resist landslide was evaluated using Newmark’s method. This procedure is repeated for all grid points, having slope value 10 degree and above.

En las últimas décadas, los investigadores han debatido sobre la representación tradicional de la administración española durante el siglo XVII como ineficaz e impotente. Algunos de ellos argumentan que el régimen del último rey Habsburgo fue decadente e ineficaz. En contraposición a esta imagen,los administradores reales de Lima, capital del Virreinato del Perú, mostraron una gran capacidad de organización y manejo de la crisis después de queun intenso terremoto y posterior tsunami azotaron la ciudad y su puerto en1687. En medio del caos y la destrucción causada por este desastre natural,el virrey y los miembros del cabildo de la ciudad fueron capaces de usar loslimitados recursos disponibles y de atender las crecientes demandas materiales y espirituales de la población de Lima.

On January 28th 1687, a strong earthquake occurred in the province of Angaraes, in Huancavelica, an economically strategic place for the colonial administration, due to the production of mercury which provided sustainability to the silver production. The disaster left nearly 500 dead, many injured and destroyed urban settlements surrounding the mines of Santa Barbara. The quake did not damage the infrastructure of the mines, which allowed the mercury production tocontinue. Years later, the affected cities were still in ruins and demanded to proceed with the repairs and rehabilitation of civil and religious buildings. However, the administrative bureaucracy prioritized the production of mercury. This article is an approach to social and economic issues that arise following the occurrence of a natural disaster in the late seventeenth century; and further, the role that meet certain production sites during a crisis scenario. / El martes 28 de enero de 1687 un intenso terremoto se produjo en la provincia de Angaraes, en Huancavelica, un lugar económicamente estratégico para la administración virreinal, debido a la producción de azogue que daba sostenibilidad a la producción argentífera hispana. El desastre dejó cerca de 500 muertos, mucha población natural damnificada y destruyó los asentamientos urbanos circundantes a las minas de Santa Bárbara. El sismo no perjudicó la infraestructura de los socavones, con lo cual, la producción de mercurio pudo continuar. Años más tarde, las ciudades afectadas continuaban en estado ruinoso y se demandaba dar curso a los reparos y rehabilitación de edificios civiles y religiosos. No obstante, la burocracia administrativa priorizó la producción de mercurio. El presente artículo es una aproximación a las problemáticas sociales y económicas que surgen a raíz de la ocurrencia de un desastre natural a fines del siglo XVII; y más aún, se descubre el rol que ciertos enclaves productivos cumplen en el transcurso de un escenario de crisis.

This article addresses the principal results of the archaeological excavations at the Casa Bodega y Quadra, which uncovered a series of structures beneath the modern structure located on the site, below thick layers of fill. Archaeological excavations provide evidence that these earlier layers were buried in the wake of the  earthquake that devastated the city of Lima in 1746. Comparison between these earlier structures and historical data demonstrates how space within the site was transformed from public to domestic – processes directly related to the evolution of the urban layout of viceregal Lima. / El presente artículo abordará los principales resultados de las excavaciones arqueológicas realizadas en la Casa Bodega y Quadra, que ponen en evidencia una serie de estructuras ubicadas bajo el nivel actual de la casa, bajo gruesas capas de relleno. La investigación arqueológica brindó la información necesaria para determinar el motivo por el cual estos espacios fueron cubiertos y vincular estos sucesos con el gran terremoto que sufrió la ciudad de Lima durante el año de 1746. Por otro lado, las estructuras descubiertas, al ser contrastadas con el dato histórico, demostraron una variación del espacio, que pasa de lo público a lo doméstico; todo ello, relacionado directamente con la evolución de la traza urbana de Lima virreinal.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Os recentes aumentos dos registros de abalos sÃsmicos no Brasil impulsionaram a publicaÃÃo da NBR 15421 (ABNT, 2006) â projeto de estruturas resistentes a sismos - que estabelece os requisitos exigÃveis para a verificaÃÃo da seguranÃa das estruturas relativamente Ãs aÃÃes de terremotos. As recomendaÃÃes desta norma objetivam reduzir os riscos sÃsmicos das novas estruturas de concreto. Com relaÃÃo Ãs estruturas de concreto existentes faz-se necessÃrio um estudo da sua vulnerabilidade sÃsmica. Dentre os vÃrios mÃtodos de avaliaÃÃo de vulnerabilidade sÃsmica encontrados na literatura, o mÃtodo de Hirosawa, mais precisamente o seu primeiro nÃvel de avaliaÃÃo, foi escolhido para adaptaÃÃo à realidade brasileira e sua aplicaÃÃo em larga escala. No processo de adaptaÃÃo do mÃtodo, inicialmente sÃo estudados os parÃmetros da norma brasileira de projetos resistentes a sismos e realizada uma comparaÃÃo desta com as normas sÃsmicas americanas, IBC (ICC, 2006) e SEI7 (ASCE, 2005). O estudo do mÃtodo de Hirosawa permitiu a identificaÃÃo dos ajustes necessÃrios à sua adaptaÃÃo considerando as exigÃncias da NBR 15421 (ABNT, 2006) e as caracterÃsticas construtivas locais. O mÃtodo adaptado foi aplicado em um sistema com um grau de liberdade e em quatro estruturas modelo variando nÃmero de pavimentos e configuraÃÃo estrutural em termos de irregularidade horizontal e vertical. As estruturas modelo procuram representar as edificaÃÃes de uso essencial. Cada uma destas estruturas foi analisada supondo sua exposiÃÃo a todas as aceleraÃÃes sÃsmicas de projeto e executadas em qualquer uma das classes de terrenos abordadas na NBR 15421 (ABNT, 2006). Os resultados sÃo apresentados em forma de tabelas, grÃficos e mapas de vulnerabilidade sÃsmica. Nenhuma estrutura modelo apresentou vulnerabilidade sÃsmica na zona sÃsmica 0; em terrenos de classe E, todas as estruturas modelo apresentaram vulnerabilidade sÃsmica nas zonas 2, 3 e 4; e as estruturas regulares apresentaram melhor desempenho sÃsmico. O significado de vulnerabilidade exposto neste trabalho nÃo està relacionado à obrigatoriedade de desativaÃÃo da edificaÃÃo, mas sim, à necessidade de anÃlises mais detalhadas e complexas do comportamento esperado destas edificaÃÃes frente a um evento sÃsmico. / Recent increases of earthquakes records in Brazil led to the publication of NBR 15421 (ABNT, 2006) - Design of seismic resistant structures - which provides the necessary requirements for security verification of structures in relation to the seismic actions. The recommendations of this code aim to reduce the seismic risk of new concrete structures. With regard to existing concrete structures it is necessary to study their seismic vulnerability. Among the various methods of seismic vulnerability assessment found in literature, the Hirosawa method, more precisely its first level of screening procedure, was chosen to be adapted to the Brazilian reality and make a large scale application. In the adaptation process of the method are initially studied the parameters of the Brazilian design of seismic resistant structures code and a comparison with the American codes, IBC (ICC, 2006) and SEI7 (ASCE, 2005), is carried out. The study of Hirosawa method allowed the identification of the necessary adjustments to adapt the method considering the NBR 15421 (ABNT, 2006) requirements and local constructive characteristics. The adapted method was applied to a single degree of freedom system and to four model structures varying the number of floors and structural configuration in terms of horizontal and vertical irregularity. The model structures intend to represent essential building occupancy. Each one of the structures was analyzed assuming their exposure to all seismic design accelerations and being settled in any site class covered in NBR 15421 (ABNT, 2006). The results are presented in tables, graphs and maps of seismic vulnerability. No model structures presented seismic vulnerability in seismic zone 0; settled in site class E, all model structures presented seismic vulnerability in seismic zones 2, 3 and 4; and the regular structures showed better seismic performance. The meaning of vulnerability exposed in this work is not related to the mandatory off the building, but rather the need for more detailed and complex analysis of the expected behavior of these buildings under a seismic event.

Nesta dissertação emprega-se um método simplificado de análise elástica baseado na técnica do meio contínuo para edifícios altos submetidos a terremoto formados por painéis paredes, pórticos e núcleos de seção aberta de parede delgada. Na ligação dos diferentes painéis, supõe-se que existe uma considerável quantidade de diafragmas horizontais rígidos em seu próprio plano, distribuídos continuamente ao longo da vertical 0z. Levando-se em conta a equação constitutiva dos painéis individuais pode-se obter a solução de analise estrutural para o edifício mediante equações diferenciais acopladas para deslocamento e rotações ao longo do eixo vertical do edifício. Com base nesses resultados, todos os esforços internos podem, então, ser obtidos. O método de análise proposto oferece um simples e rápido meio de obtenção da deformada e das forças internas dos diferentes painéis do edifício alto em fases iniciais do projeto. A utilidade e a aproximação do método são examinadas mediante exemplos numéricos, sendo a solução aproximada comparada com aquela obtida com o emprego do método de elementos finitos elaborado pelo programa SAP2000. / This work presents a simplified method of elastic analysis based on the continuous medium technique for tall building structures formed by shear wall panels, frames and core thin walled sections. In order to connect the various panels, it is assumed that there exist a considerable amount of rigid diaphragms continuously distributed along the vertical 0z. The building is subject to lateral earthquake load. Taking into account the constitutive equation of the individual panel, one can achieve a solution through coupled differential equations for displacement and rotation of the building. Based on that, all of the internal forces can be obtained. The analysis is extended to structures formed by singular panel configuration. The proposed method offers a relatively simple and rapid way to obtain the displacements and internal forces of different structural systems of tall buildings, especially indicated for preliminary stages of calculation. The usefulness of the approach and method are illustrated by numerical examples, where the approximated solution is compared with that obtained by finite element calculations.

Pas de résumé / This thesis consists in two separate parts: one on subcritical fracture experiments, and another one on earthquake statistics. The dynamics of these processes was mainly studied through their scale invariant dynamics, reflected in power law distri- butions of event sizes and times between events. The analyses focuses particularly on the variation of their exponent values and the origins of these variations. Subcritical fracture was studied by two experimental set-ups: creep experiments on paper, and constant-strain fracture of fibre bundles. Paper fracture has been studied in our group for more than 10 years now by visually observing the propaga- tion of the crack. We added acoustic emission monitoring to the experimental set-up in order to compare it to visualisation. The comparison between low frequency image analysis and the high frequency acoustic monitoring allowed to identify the impor- tance of the frequency of analysis for temporally correlated systems, and acoustic emission monitoring revealed the existence of aftershocks in the dynamics of paper fracture. The fibre bundle experiments concentrate on the temporal distribution of the frac- ture events, which follows an Omori law. We studied the influence of the temperature and stress on its exponent, and compared it with results from fibre bundle model analytical predictions and simulations. Our work on earthquakes was initially motivated by the results obtained on pa- per fracture experiments. Hence it starts by a study of aftershock sequences, their Gutenberg-Richter exponent, and the influence of the frequency of analysis on this exponent. By lowering the frequency of the time-magnitude signal we showed that at low frequencies the exponent of the Gutenberg-Richter law depends on the expo- nent of the Omori law. The last chapter of this thesis is concentrated on the early aftershocks. We in- spected the evolution of the properties of an aftershock sequence with time, and observed differences between aftershock occurring shortly after a mainshock, and late aftershocks. These results can be related to the recent proposition of existence of magnitude correlations in earthquakes