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Análise dinâmica elasto-plástica de estruturas metálicas sujeitas a excitação aleatória de sismos.; Dynamics analysis of steel structures with elasto-plastic behavior under random seismic excitation.

Corbani, Silvia
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/11/2006 PT
Relevância na Pesquisa
36.05%
Ações sísmicas ocorrem com pouca freqüência e intensidade no Brasil, porém ocorrem em países da América Latina situados na costa do Pacífico e em Portugal, despertando o interesse da engenharia brasileira nesse assunto. Neste trabalho, apresenta-se um modelo numérico para análise de estruturas metálicas aporticadas planas com comportamento elasto-plástico sob excitação aleatória induzida por sismos. Para simular as vibrações aleatórias, utiliza-se uma simulação tipo Monte Carlo fundamentada no ?Vento Sintético?, proposta pelo Prof. Mário Franco. Nessa simulação, combinações de séries de carregamentos harmônicos são geradas com suas amplitudes extraídas de uma Função de Densidade Espectral de Potência (PSDF) das acelerações do solo e com ângulos de fase obtidos por um algoritmo pseudo-aleatório. A PSDF utilizada é um modelo reduzido do modelo Kanai-Tajimi que determina combinações de séries adimensionais, onde seus resultados para o trecho elástico são calibrados com o espectro de resposta elástica sugerido em norma internacional. A integração numérica passo-a-passo no domínio do tempo é feita para cada função de carregamento adotando-se o método de Newmark. O efeito elastoplástico é modelado pelo conceito de rótulas plásticas...

Homogenization and seismic assessment : review and recent trends

Lourenço, Paulo B.; Milani, G.
Fonte: CISM International Centre for Mechanical Sciences, Springer Publicador: CISM International Centre for Mechanical Sciences, Springer
Tipo: Parte de Livro
Publicado em //2014 ENG
Relevância na Pesquisa
46.01%
The mechanics of masonry structures has been for long underdeveloped in comparison with other fields of knowledge. Presently, non-linear analysis is a popular field in masonry research and advanced computer codes are available for researchers and practitioners. The chapter presents a discussion of masonry behaviour and clarifies how to obtain the non-linear data required by the computations. The chapter also addresses different homogenisation techniques available in the literature in the linear and rigid-plastic case, aiming at defining a catalogue and at discussing the advantages and disadvantages of the different approaches. Special attention is given to stress assumed models based either on a polynomial expansion of the micro-stress field or in the discretization of the unit cell by means of a few constant stress finite elements CST with joints reduced to interfaces. Finally, the aspects of seismic assessment are presented and case studies involving the use of macro-block analysis, static (pushover) analysis and time integration analysis are discussed.

Infill masonry : simple analytical methods for seismic design

Pereira, Manuel Fernando Paulo; Pereira, M. F. Neto; Ferreira, J. E. Dias; Lourenço, Paulo B.
Fonte: International Masonry Society Publicador: International Masonry Society
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 ENG
Relevância na Pesquisa
35.94%
The latest earthquake codes in Europe require the safety assessment of no-structural elements (parapets, masonry wall’s veneer, infill walls, etc.), as their collapse entails risks for people or for the main structure stability. This work made possible th e development of a design method, supported by previous experimental researches by applying cyclic out-of-plane loads to damaged masonry infill in RC frames. Panels tested reproduce Portuguese traditional RC structure construction system and two reinforced solutions were created as innovative solutions. The experimental campaign was carried out in order to determine: masonry properties; out-of-plane panel behaviour with previous in-plane damage; building behaviour subjected to dynamic tests performed in shaking table. Using finite element method to reproduce experimental tests and to broaden the range of samples it was possible to figure out equations according to parametric analysis which was able to reproduce in-plane and out-plane behaviour leading to an estimated load bearing capacity of each model and to determine frame strength and its stiffness. Those equations permit to design or verify the masonry infill panels in RC frames subjected to seismic loads.

Comparative analysis of RC irregular buildings designed according to different seismic design codes

Landingin, J.; Rodrigues, H.; Varum, H.; Arêde, A.; Costa, A.
Fonte: Faculty of Engineering, University of Porto Publicador: Faculty of Engineering, University of Porto
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
36.22%
The present paper presents a comparison of the seismic provisions of the three seismic design codes, namely the Philippine code (National Structural Code of the Philippines or NSCP2010), the European code (Eurocode 8 or EC8), and American code (2009 International Building Code or 2009 IBC), to the most common ordinary residential building of standard occupancy. Two regular and irregular reinforced concrete (RC) frames were analysed and compared for four storey and eight storey buildings. The response spectrum function of NSCP 2010 was considered for the horizontal load action with different load combinations. Response spectrum analysis was performed using SAP2000 software package. Five representative columns for each RC frames were analyzed and based from the results of column axial load - bending moment interaction diagrams, EC8 was found to be conservative as compared to NSCP 2010 and 2009 IBC. The conclusion is that for the design and analysis of ordinary RC residential building with certain irregularity, EC8 provisions were considered to be safer.

Impacts of lateral code changes associated with the 2006 International Building Code and the 2008 California Building Code

Ratley, Desirée Page
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 96 leaves
ENG
Relevância na Pesquisa
26.15%
The 2008 California Building Code (CBC) will adopt the structural section of the 2006 International Building Code (IBC), which includes alterations to the procedure to determine earthquake design loading, and a drastic move to a complicated method to determine design wind pressures. The implementation of the revised 2006 International Building Code, and the subsequent California adoption of the structural section will have significant effects on the design and construction of structures not only in California, but also the rest of the country. Through a comparison of the design of a steel moment-resisting frame low-rise structure, it was determined that the new code will result in design values that differ from those resulting from the previous codes. In order to compare the relevant codes in different areas of the country, this thesis considers three design scenarios for the low-rise structure: seismic loading in Southern California to compare the 2001 CBC, the 2003 and the 2006 IBC, seismic loading in the Midwest to compare the 2003 IBC and the 2006 IBC, and wind loading in Northern California to compare the 2001 CBC and the 2006 IBC.; (cont.) In the first case, the change from the 2001 CBC to the 2003 IBC was an 8 percent increase in base shear...

INNOVATIVE TECHNOLOGIES FOR THE VIBRATION CONTROL OF EQUIPMENT IN CRITICAL FACILITIES

REGGIO, ANNA
Fonte: La Sapienza Universidade de Roma Publicador: La Sapienza Universidade de Roma
Tipo: Tese de Doutorado
EN
Relevância na Pesquisa
66.44%
The present thesis settles in the framework of the dynamic modelling, seismic mitigation and permanent health monitoring of equipment in critical facilities. The main objective is to assess the feasibility and the effectiveness of innovative mitigation Technologies including: the passive isolation of a single equipment (equipment isolation systems); the passive isolation of a raised floor, on which a group of several equipment is anchored (isolated raised-floor systems); a non-conventional Tuned Mass Damper (TMD), realized by converting a large mass already present on the structure, e.g. the mass of an equipment, into a tuned mass, in order to reduce the structural response. The area of research is believed to have the potential for a wide application, since a still limited number of authors has addressed the theoretical and technical issues associated with the seismic design and protection of equipment. As a result, international seismic codes and standards also appear to be inadequate in this regard. Furthermore, the proposed technologies give the opportunity of addressing topics of significant scientific interest: the analysis of the dynamic interaction between an equipment and its supporting structure, generally neglected in current Literature and seismic codes; the definition of reduced-order generalized models...

Safe and Resilient Infrastructure in the Philippines

World Bank Group
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Relatório
EN_US
Relevância na Pesquisa
25.81%
The report presents the results of a detailed vulnerability assessment and summarizes the prioritization methodology developed to guide investment decisions on the strengthening of critical assets in Metropolitan Manila. With support from the World Bank, the engagement on Safe and Resilient Infrastructure has carried out a preliminary structural assessment of over seven hundred public school campuses and twenty hospitals retained by the Department of Health in Metro Manila. The report also highlights the lessons learned from seismic retrofitting programs implemented throughout the world, as showcased during the Forum on Safe and Resilient Infrastructure that took place in Manila, Philippines, in October 2013. This report is divided into three sections. First, it establishes the technical principles of earthquake risk management. Second, it details the experience of the Philippines to date in developing an integrated earthquake risk management program, focusing on the methodology and results of a vulnerability assessment and prioritization conducted under the Safe and Resilient Infrastructure Program. Last...

Seismic Design Criteria for Multi-storey Precast Structures

BIONDINI Fabio; TONIOLO Giandomenico; TSIONIS Georgios
Fonte: International Association for Earthquake Engineering Publicador: International Association for Earthquake Engineering
Tipo: Contributions to Conferences Formato: CD-ROM
ENG
Relevância na Pesquisa
45.94%
This paper presents a simplified method for the capacity design of multi-storey precast concrete frames with hinged beams. A parametric study shows that in the field of ordinary and less flexible structures, the proposed simplified method can be applied with full reliability, in the same way as prescribed by the seismic codes for monolithic cast-in-situ structures. Moreover, the displacement ductility capacity of a range of multi-storey precast concrete structures designed according to the proposed method is investigated.; JRC.G.5-European laboratory for structural assessment

Seismic vulnerability of Modern Architecture building's: Le Corbusier style: a case study

Rodrigues, H.; Fonseca, J.; Costa, A.; Varum, H.; Tostões, A.
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
35.92%
In Portugal, at the end of the World War II, a new generation of architects emerged, influenced by the Modern Movement Architecture, born in Central-Europe in the early twenties but now influenced also by the Modern Brazilian Architecture. They worked with new typologies, such as multifamily high-rise buildings, and built them in the most important cities of the country, during the fifties, reflecting the principles of the Modernity and with a strong formal conception inspired in the International Style’s codes. Concrete, as material and technology, allowed that those “Unity Centre” buildings become modern objects, expressing the five-point formula that Le Corbusier enounced in 1927 and draw at the “Unité d’Habitation de Marseille”, namely: the building lifted in pilotis, the free design of the plan, the free design of the façade, the unbroken horizontal window and the roof terrace. In Lisbon, late forties urban plans transformed and expanded the city, creating modulated buildings repeated in great extensions – that was a progressist idea of standardization. The Infante Santo complex is a successful adaptation to the Lisbon reality of the Modern Urbanism and Architecture. In the fifties, it was built a large number of Modern housing buildings in Lisbon...

Accuracy of the numerical computation of solar g-modes

Moya, A.; Mathur, S.; García, R. A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/03/2010
Relevância na Pesquisa
15.94%
From the recent work of the Evolution and Seismic Tools Activity (ESTA, Monteiro et al. 2006; Lebreton et al. 2008), whose Task 2 is devoted to compare pulsational frequencies computed using most of the pulsational codes available in the asteroseismic community, the dependence of the theoretical frequencies with non-physical choices is now quite well fixed. To ensure that the accuracy of the computed frequencies is of the same order of magnitude or better than the observational errors, some requirements in the equilibrium models and the numerical resolutions of the pulsational equations must be followed. In particular, we have verified the numerical accuracy obtained with the Saclay seismic model, which is used to study the solar g-mode region (60 to 140$\mu$Hz). We have compared the results coming from the Aarhus adiabatic pulsation code (ADIPLS), with the frequencies computed with the Granada Code (GraCo) taking into account several possible choices. We have concluded that the present equilibrium models and the use of the Richardson extrapolation ensure an accuracy of the order of $0.01 \mu Hz$ in the determination of the frequencies, which is quite enough for our purposes.; Comment: 4 pages, 2 figures, Proceedings of the HELAS IV International Conference submitted to Astronomische Nachrichten

Proceedings of the International Workshop on Seismic Design and Reassessment of Offshore Structures

Iwan, Wilfred D.
Fonte: California Institute of Technology Publicador: California Institute of Technology
Tipo: Report or Paper; PeerReviewed Formato: application/pdf
Publicado em 01/01/1992
Relevância na Pesquisa
26.26%
This Executive Summary presents the major conclusions and recommendations of the International Workshop on Seismic Design and Reassessment of Offshore Structures. Full versions of the text of all invited lecturers and complete working group reports are contained elsewhere in these Proceedings. Site Seismic Hazard and Ground Motion Continuous improvements have been made in the state-of-the-art of estimation of seismic ground motion for design and reassessment of offshore platforms. C. B. Crouse of Dames & Moore provides an overview of methods used to determine seismic design parameters for offshore structures. A site﷓specific analysis is generally performed to develop seismic design parameters for a particular site. The first step is to define the seismic sources in the site region, and develop a model of the attenuation of ground motion that is appropriate for the region. Next, probabilistic and/or deterministic analyses are performed to estimate the ground motion parameters. For new designs, both approaches are commonly used. For reassessment and requalification, a probabilistic approach is generally preferred. There are three basic inputs needed for a probabilistic approach; 1) identification of earthquake sources in the site region...

Development and integration of a new course in structural loads & systems in a civil engineering technology program

Aghayere, Abi; Aghayere, Abi
Fonte: American Society for Engineering Education Publicador: American Society for Engineering Education
Tipo: Conferência ou Objeto de Conferência Formato: 75067 bytes; application/pdf
EN_US
Relevância na Pesquisa
16.14%
One of the Civil criteria in ABET TC2K is that programs “apply current knowledge and adapt to emerging applications of technology,” such as, changes in the building codes. Structural design firms also have the expectation that Civil Engineering Technology (CET) graduates should be able to apply current codes to determine structural loads, required for the analysis and design of structures. While most CET programs expose their students to structural analysis and design using instructor or textbook-prescribed loads, few expose students to the detailed calculation of actual structural loads using current codes. Many jurisdictions in the United States, including New York State, have recently adopted the International Building Code (IBC), which contains the latest provisions on structural loads, including wind and seismic loads for buildings. Prior to 2002, in New York State, the building code only required buildings to be designed for wind loads using a very simple tabular method. Seismic loads were not considered. Under that dispensation, it was possible and feasible to integrate the topic of structural loads, dead, live, snow and wind load, into any one of the structural design courses, all-be-it at an elementary level. However...

The status of basic design ground motion provisions in seismic design codes of sub-Saharan African countries: A critical review

Worku,A
Fonte: Journal of the South African Institution of Civil Engineering Publicador: Journal of the South African Institution of Civil Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
Relevância na Pesquisa
46.32%
Basic provisions for design ground motions in seismic design codes of sub-Saharan African countries are critically reviewed. The seismic codes of Ethiopia, Kenya and Uganda are selected to represent the eastern region, Ghana to represent the west and South Africa to represent the south. The specific provisions considered are those pertaining to site effect and the recurrence period of the design earthquake. The codes are also compared with one another and with selected current international codes from the US and Europe, with respect to selected provisions. The provisions are further viewed from the perspective of the state of the art and the state of the practice. It has been concluded that these basic provisions in most of the sub-Saharan African codes considered are inadequate in guaranteeing safety of human life and limiting damage to property, suggesting a need for immediate updating, an exception being the South African code.

Soil-structure-interaction provisions: A potential tool to consider for economical seismic design of buildings?

Worku,A
Fonte: Journal of the South African Institution of Civil Engineering Publicador: Journal of the South African Institution of Civil Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
Relevância na Pesquisa
26.25%
Contemporary seismic design codes have become more stringent with respect to the requirements for design forces and deformations in building design. This paper demonstrates that it could be worthwhile to consider the introduction of soil-structure-interaction provisions into local design codes. This is partly to be able to offset the costs incurred by the high magnitude of base shear demand in most buildings attributed to site amplifications due to soft soil sites, as per the requirements of current codes, including the recent South African seismic design code. This beneficial effect of site soils is as a result of lengthening of the fundamental period and of the increased effective damping of the overall system due to soil-structure interaction, which in most cases lead to reduced design spectral values. The paper shows that, if pertinent provisions in some international codes are properly adapted, a substantial reduction in the base shear force can be achieved, in many cases resulting in structural-work cost saving. With this, the paper attempts to address the legitimate concern of design engineers regarding the potential escalation of construction costs associated with the introduction of stringent requirements of contemporary seismic design spectra...

Principal results and recommendations of the caracas seismic microzoning project

Schmitz,Michael; Hernández,Julio J; Morales,Cecilio; Domínguez,Jean; Rocabado,Víctor; Valleé,Maxlimer; Tagliaferro,Mauricio; Delavaud,Élise; Singer,André; Amarís,Eduin; Molina,Danna; González,Moralis; Leal,Victoria
Fonte: Universidad Central de Venezuela Publicador: Universidad Central de Venezuela
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 EN
Relevância na Pesquisa
36.05%
Caracas has suffered during its history several destructive earthquakes, and the most recent one in 1967 with a magnitude of 6.6 caused the collapse of 4 buildings. By means of multidisciplinary studies, important site effects were evidenced in Caracas valley, pointing to the big sedimentary thickness as partially responsible for the damages. This situation motivated the development of Caracas Seismic Microzoning Project in the years 2005-2009. Broad geological, geotechnical and geophysical investigations were carried out to determine the distribution of the different geological units in the valley, including deep drillholes and subsequent earthquake engineering investigations. For slope areas earthquake-induced landslide hazard was estimated based on available geotechnical information and modern methods (Newmark’s method and Arias intensities) and calibrated experimentally. An up to date analysis of the seismic hazard in bedrock was used as an input for the determination of response spectra at different types of sites depending on the sediment thickness and the soil quality of the upper 30 m (Vs30). The results of the 1D dynamic analysis have been calibrated with spectra from real earthquakes, and compared to international codes; then...