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1
Cook, Jason A. (Jason Andrew). « Structural steel framing options for mid- and high rise buildings ». Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34634.
Texte intégralRésumé :
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.Includes bibliographical references.
Selecting a structural system for a building is a complex, multidisciplinary process. No design project is the same; however, there are certain criteria that are commonly true in the initial phase of evaluating different structural schemes. These criteria encompass all aspects of a full, functioning building, forcing the design team to be creative in their approach of satisfying all facets. An investigation was carried out for several structural steel framing options available to designers. The schemes describe how each successfully resist lateral loads explaining the advantages and disadvantages of each. Many of the structural design tools available for initial structural system evaluation are strength based. The demand for cheaper, more efficient and taller structures has paved the way for performance based design. A simple cantilever beam performance based analysis was utilized to evaluate three common structural framing schemes in order to gain a better understanding of the performance of each. Results give recommendations for efficient structural solutions for proposed buildings as a function of height.
by Jason A. Cook.
M.Eng.
2
Maleck, Andrea Eden. « Second-order inelastic and modified elastic analysis and design evaluation of planar steel frames ». Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/19610.
Texte intégral
3
Xu, Guoqing. « Assessment of risk of disproportionate collapse of steel building structures exposed to multiple hazards ». Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41079.
Texte intégralRésumé :
Vulnerability of buildings to disproportionate (or progressive) collapse has
become an increasingly important performance issue following the collapses of the
Alfred P. Murrah Federal Building in Oklahoma City in 1995 and the World Trade
Center in 2001. Although considerable research has been conducted on this topic, there are still numerous unresolved research issues. This dissertation is aimed at developing structural models and analysis procedures for robustness assessment of steel building structures typical of construction practices in the United States, and assessing the performance of these typical structures.
Beam-column connections are usually the most vulnerable elements in steel buildings structures suffering local damage. Models of three typical frame connections for use in robustness assessment have been developed with different techniques, depending on the experimental data available to support such models. A probabilistic model of a pre-Northridge moment-resisting connection was developed through finite element simulations, in which the uncertainties in the initial flaw size, beam yield strength and fracture toughness of the weld were considered. A macro-model for a bolted T-stub connections was developed by considering the behavior of each connection element individually (i.e. T-stub, shear tab and panel zone) and assembling the elements to form a complete connection model, which was subsequently calibrated to experimental data. For modeling riveted connections in older steel buildings that might be candidates for rehabilitation, a new method was proposed to take advantage of available experimental data from tests of earthquake-resistant connections and to take into account the effects of the unequal compressive and tensile stiffnesses of top and bottom parts in a connection and catenary action.
These connection models were integrated into nonlinear finite element models of structural systems to allow the effect of catenary and other large-deformation action on the behavior of the frames and their connections following initial local structural damage to be assessed. The performance of pre-Northridge moment-resisting frames was assessed with both mean-centered deterministic and probabilistic assessment procedures; the significance of uncertainties in collapse assessment was examined by comparing the results from both procedures. A deterministic assessment of frames with full and partial-strength bolted T-stub connections was conducted considering three typical beam spans in both directions. The vulnerability of an older steel building with riveted connections was also analyzed deterministically. The contributions from unreinforced masonry infill panels and reinforced concrete slabs on the behavior of the building were investigated.
To meet the need for a relatively simple procedure for preliminary vulnerability assessment, an energy-based nonlinear static pushdown analysis procedure was developed. This procedure provides an alternative method of static analysis of disproportionate collapse vulnerability that can be used as an assessment tool for regular building frames subjected to local damage. Through modal analysis, dominant vibration modes of a damaged frame were first identified. The structure was divided into two parts, each of which had different vibration characteristics and was modeled by a single degree-of-freedom (SDOF) system separately. The predictions were found to be sufficiently close to the results of a nonlinear dynamic time history analysis (NTHA) that the method would be useful for collapse-resistant design of buildings with regular steel framing systems.
4
Torres, Filho Rodrigo José de Almeida. « Análise térmica de estruturas de aço utilizadas no sistema light steel framing ». Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2641.
Texte intégralRésumé :
O presente trabalho apresenta uma análise numérica do desempenho térmico de painéis construídos utilizando o sistema light steel framing (LSF) submetido a ação térmica decorrente de um incêndio. O objeto de estudo foram painéis utilizados na construção de duas casas modelo localizadas na Universidade Tecnológica Federal do Paraná campus Curitiba, construídas com materiais disponíveis comercialmente no Brasil e as análises utilizaram propriedades disponibilizadas pelos fabricantes e pela norma brasileira. A análise numérica foi realizada no software ANSYS, com base no método dos elementos finitos em análise térmica transiente. O modelo foi validado com base em comparação com análises experimentais pesquisadas na literatura. Quatro painéis obtidos das casas modelo foram analisados. Os painéis que utilizaram lã de PET para preenchimento da cavidade foram também analisados com preenchimento de lã de vidro. Um painel simples, com a cavidade preenchida por ar foi analisado para ser usado como referência. Por fim, com a utilização de coeficientes de redução da resistência ao escoamento propostos pela ABNT NBR 14323:2001, determinou-se a redução da resistência do aço do perfil de acordo com o tempo de exposição ao incendio e o tempo de resistência ao fogo dos perfis. Com base nos resultados obtidos é possível afirmar que mesmo para os paneis com pior desempenho, a proteção obtida pode ser suficiente, a depender do carregamento aplicado ao montante e do Tempo requerido de resistência ao fogo necessário. O presente trabalho apresenta informação relevante sobre o desempenho térmico em situação de incêndio do sistema LSF constituído com materiais brasileiros.The thermal performance of light steel framing (LSF) panels was the objective of this study. The study subject was panels used in the construction of two model houses located at Federal Technology University – Parana, built with materials commercially available in Brazil. The analysis was set with material properties from the manufacturer and in compliance with the Brazilian regulation, using the finite element method for a transient thermal analysis. The model validation was based on experimental tests available in the literature. Based on the validated model, the four panels have been analyzed. Two of the panels used PET wool in the cavity for insulation and the analysis was repeated with them replacing it for glass wool. A panel with no insulation was also analyzed to be used as reference. Based on the analysis results and the resistance reduction coefficients proposed by ABNT NBR 14323:2001, the resistance decrease of the studs due to the fire exposure and the panels resistance to fire were determined. Based on the obtained results, it can be affirmed that, depending on the applied load and the required Equivalent time of fire exposure, even the less protective configuration of the panels presented can be viable. The current study presented relevant information about the performance of LSF manufactured in Brazil when exposed to fire.
5
Hwa, Ken. « Toward advanced analysis in steel frame design ». Thesis, University of Hawaii at Manoa, 2003. http://proquest.umi.com/pqdweb?index=0&did=765960991&SrchMode=1&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1209158261&clientId=23440.
Texte intégral
6
Coy, Bradly B. « Buckling-Restrained Braced Frame Connection Design and Testing ». Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2030.pdf.
Texte intégral
7
Alemdar, Bulent Nedim. « Distributed plasticity analysis of steel building structural systems ». Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/22220.
Texte intégral
8
Green, Travis P. « Behavior of full-scale partially-restrained beam-to-column T-stubn and shear tab connections under cyclic loading ». Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/20720.
Texte intégral
9
Terim, Belgin Çıkış Şeniz. « A study on "temporary post disaster housing unit" constructed with -light gauge steelframing-(LGSF) system/ ». [s.l.] : [s.n.], 2004. http://library.iyte.edu.tr/tezler/master/mimarlik/T000480.pdf.
Texte intégral
10
Sanchez, Escalera Victor M. « ENHANCING PROGRESSIVE COLLAPSE RESISTANCE OF STEEL BUILDING FRAMES USING THIN INFILL STEEL PANELS ». DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/499.
Texte intégralRésumé :
Progressive collapse occurs when damage from a localized first failure spreads in a domino effect manner resulting in a total damage disproportionate to the initial failure. Recent building failures (e.g., World Trade Center twin towers) highlight the catastrophic outcome of progressive collapse. This research proposes a reliable and realistic retrofit technology which installs thin steel panels into steel building structural frames to enhance the system progressive collapse resistance.
The steel frames with simple beam-to-column connections, under different boundary conditions (i.e., sidesway uninhibited and sidesway inhibited, respectively), and the loss of one bottom story column were retrofitted using the proposed technology (i.e. installing thin steel panels in the structural frames). Performance of these frames was investigated. Two Finite Element (FE) models which require different modeling efforts were developed to capture the system behavior. The first model explicitly models the infill plates to capture the plate buckling behavior. The second model known as strip model represents the infill panels as diagonal strips. In addition to the FE models, a plastic analysis model derived from the prior research on seismically designed Steel Plate Shear Walls (SPSWs) was considered. The system progressive collapse resistance obtained from the two FE models and the plastic analysis procedure were compared and good agreements were observed. It was observed that installing infill plates to steel structural frames can be an effective approach for enhancing the system progressive collapse resistance.
Beyond the strength of the overall system, the Dynamic Increase Factor (DIF) which may be used to amplify the static force on the system to better capture the dynamic nature of progressive collapse demand was evaluated for the retrofitted system. Furthermore, the demands including axial force, shear force and bending moment on individual frame components (i.e., beams and columns) in the retrofitted system were quantified via the nonlinear FE models and a simplified procedure based on free body diagrams (FBDs). Finally, the impact of premature beam-to-column connection failures on the system performance was investigated and it was observed that the retrofitted system is able to provide stable resistance even when connection failures occur in all beams.
11
Elflah, Mohamed A. Hussaen. « Structural behaviour of stainless steel bolted beam to column joints ». Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8545/.
Texte intégralRésumé :
Initially, two experimental programmes studying the structural behaviour of stainless steel beam-to-open column joints and beam-to-tubular column joints under static loads are reported in detail. The joint configurations tested include flush and extended end plate connections, top and seat cleat connections and top, seat and web cleat connections. The full moment-rotation characteristics are reported in detail. It is observed that the connections displayed excellent ductility, superior than that of equivalent carbon steel connections, and attained loads much higher than the ones predicted by design standards for carbon steel joints. Nonlinear FE models have been developed and validated against the experimental results. The FE models are shown to accurately replicate the experimentally determined, initial stiffness, ultimate resistance, overall moment-rotation response and observed failure modes. In addition, a comprehensive parametric study is conducted. The design rules for stainless steel connections, which are based on the specifications of EN 1993-1-8 for carbon steel joints, are reviewed and are found to be overly conservative in terms of strength and inaccurate in terms of stiffness thus necessitating the development of novel design guidance in line with the observed structural response. Hence, simplified mechanical models in line with the observed response are developed.
12
Kim, Yoon Duk. « Behavior and design of metal building frames using general prismatic and web-tapered steel I-section members ». Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33965.
Texte intégralRésumé :
Metal building frames are typically designed using welded prismatic and web-tapered members with doubly-symmetric and/or singly-symmetric cross sections. Until recently, the base U.S. provisions for design of frames with web-tapered members were provided in the AISC ASD (1989) and LRFD (1999) Specifications. Unfortunately, these previous AISC provisions address only a small range of practical designs. As a result, metal building manufacturers have tended to develop their own methods for design of the wide range of nonprismatic member geometries and configurations encountered in practice.
This research develops new design procedures for design of frames using general prismatic members and web-tapered members. An equivalent prismatic member concept utilized in prior research and the prior AISC provisions is generalized to accommodate the broad range of member types and configurations commonly used in metal building industry. Furthermore, the new design procedures incorporate many of the improvements achieved in the AISC (2005&2010) Specifications to metal building frame design. These improvements include a new stability design method, the direct analysis method, more complete considerations of different column buckling limit states (flexural, torsional and flexural-torsional buckling), and improved axial load and flexural resistance provisions. This research develops practical design-based procedures for simplified calculation of the elastic buckling resistances of prismatic and web-tapered members to facilitate the application of the proposed design methods. In addition, this research performs a relatively comprehensive assessment of beam lateral torsional buckling (LTB) behavior and strength of prismatic and web-tapered members using refined virtual test simulation. It is demonstrated that web-tapered members behave in a comparable fashion to prismatic members. Based on the virtual simulation study, recommendations for potential improvement of the AISC LTB resistance equations are provided. Lastly, the strength behavior of several representative metal building frames is studied in detail using the same virtual test simulation capabilities developed and applied for the assessment of the beam LTB resistances.
13
Hewetson, C. G. « Object - oriented steel member design framework / ». Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/249.
Texte intégral
14
Liu, Qiang. « Structural analysis and design of cold formed steel sigma purlins ». Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3364/.
Texte intégralRésumé :
Cold formed steel (CFS) sigma sections are commonly used as purlins in the construction of modern industrial and residential buildings due to their excellent strength-to-weight ratio. This thesis reports investigations on the structural behaviour of CFS sigma purlins in three different parts of modern roof systems. In the first investigation, the pre-buckling, buckling, post-buckling and post-failure behaviour of continuous CFS sigma purlins near internal supports was studied by experimental and numerical methods. In the second investigation, the moment-rotation response as well as the moment resistance of the sleeve connection of sigma purlins was studied by laboratory tests. Engineering models were developed to predict the behaviour of this connection and a good correlation was observed with the experimental data. In the third investigation, the flexural stiffness and moment resistance of CFS sigma purlins fastened to roof sheeting with large screw spacing was studied experimentally. The purlin-sheeting assemblies were subjected to both downward and uplift loadings, from which different behavioural aspects such as flexural stiffness, failure modes and ultimate load were examined. Test results are utilized to develop design proposals for sigma purlins that codes or standards have not yet covered.
15
Al-Azzawi, Hosam Abdullah. « Strength Tuned Steel Eccentric Braced Frames ». PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/4981.
Texte intégralRésumé :
The primary component in eccentrically braced frames (EBF) is the link as its plastic strength controls the design of the frame as well as the entire building within which it is installed. EBFs are the first part of building design and every other component is sized based on the forces developed in the link. Oversized link elements lead to the use of unnecessary materials and can increase construction costs. Additionally, the advantages of using a continuous member of the same depth for both the link and the controller beam (in terms of the cost and the time) motivates researchers to find a way to control the link strength in conventional EBFs. Previous studies on the link-to-column connections in EBF have shown that the links are likely to fail before reaching the required rotation due to fractures at low drift level. Moreover, improving the strength of the links in EBF depends primarily on their ability to achieve target inelastic deformation and to provide high ductility during earthquakes. Therefore, in this study, the concept of tuned link strength properties in EBF, T-EBF, is experimentally introduced as a solution to improve the performance of the link in conventional EBF by cutting out an opening in the link web. Furthermore, a new brace-to-link connection is proposed to bolt the brace member with the link in contrast to the conventional method of welding them. This new idea in continuous beam design was investigated to verify the stability of the tuned eccentrically braced frame, either welded or bolted, with a bracing member. A total of four full-scale cyclic tests were conducted to study the ability of T-EBF to achieve inelastic deformation. The specimens have two different cross sections: W18x76 and W16x67, two different sections where the brace was welded to the link, and two other specimens at different sections where the brace was bolted to the link were examined. The experimental results indicate that the link in T-EBF can achieve high rotation, exceeding 0.15 rad, and an overstrength factor equal to 1.5. Failure involved included web buckling at very high rotation. The T-EBF displayed a very good, non-replaceable ductile link. The experiments were followed by an isotropic kinematic-combined hardening model in the finite element analyses (FEA). The FEA analysis is developed to predict the effect of web opening configuration on the local section stresses and strains and global characteristics of the frame. FEA exhibits good agreement with the experimental results and can capture the inelastic buckling behavior of the sections. The link configuration parameters of the T-EBF were studied extensively on a W18x76 shear link subjected to the 2016 AISC seismic design provisions loading protocol (ANSI/AISC 341-16, 2016). The parametric study also included the performance of a range of wide flange sections. The analysis shows that the reduced web section has effect on the plastic strain in which low plastic strain observed near ends and connections and high at the center of the web. Results also demonstrate that if the shear link is appropriately sized with web opening and intermediate web stiffeners provided, an excellent shear link with high ductility under cyclic loads can be obtained. Changing the configuration of the opening cutout also had a significant effect on reducing the transition zone cracks.
16
Paek, Yong Joon. « Structural design language and a knowledge-based expert system for design of steel building structures / ». The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487587604132742.
Texte intégral
17
Zhao, Congxiao. « Investigations on structural interaction of cold-formed steel roof purlin-sheet system ». Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5199/.
Texte intégralRésumé :
When used as secondary roof purlins, cold-formed steel (CFS) sections are often attached to trapezoidal sheets through self-drilling screws to form a complete roofing system. The load application points are often eccentric to the shear centre, and thus inevitably generate a torsional moment that will induce twisting and/or warping deformations in addition to bending deflection. The connections between purlin and roof sheeting provide a restraining effect on purlin members by preventing such lateral and twisting movements, and hence have a beneficial effect on the load-carrying capacity. In this thesis the interactional behaviour of CFS purlin-sheeting system have been investigated through the following steps: (1) A F-test is carried out to measure the rotational stiffness at the connections, an engineering-orientated model is developed for quantifying the rotational stiffness regardless to purlin and sheet geometry and loading directions; (2) A set of loading tests on Z- and Σ- roof system are conducted to investigate the impact of rotational stiffness on the overall structural performance, load-carrying capacity and buckling behaviour of the system; (3) Finite element simulations of the existing tests are carried out and successfully validated; (4) Numerical parametric studies are established to study other factors that could affect the rotational stiffness.
18
Tahmilci, Fatih. « Analysis Of Blast Loading Effect On Regular Steel Building Structures ». Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609052/index.pdf.
Texte intégralRésumé :
Concern about effect of explosives effect on engineering structures evolved after the damage of Second World War. Beginning from 90&rsquos with the event of bombing Alfred P. Murrah Federal building located in Oklahoma City this concern deepened and with the attack to World Trade Center twin towers on September 11, 2001 it is peaked. Recent design codes mainly focus on earthquake resistant design and strengthening of the structures. These code design methodologies may sometimes satisfy current blast resistant design philosophy, but in general code compliant designs may not provide recognizable resistance to blast effect. Therefore designer should carry out earthquake resistant design with the blast resistant design knowledge in mind in order to be able to select the most suitable framing scheme that provide both earthquake and blast resistance. This is only possible if designer deeply understands and interprets the blast phenomenon. In this study, it is intended to introduce blast phenomenon, basic terminology, past studies, blast loading on structures, blast structure interaction, analysis methodologies for blast effect and analysis for blast induced progressive and disproportionate collapse. Final focus is made on a case study that is carried out to determine whether a regular steel structures already designed according to Turkish Earthquake Code 2007 requirements satisfy blast, thus progressive collapse resistance requirements or not.
19
Muniasamy, D. « Behaviour of semi-rigid composite connections for steel framed buildings ». Thesis, Engineering systems department, 2009. http://hdl.handle.net/1826/3974.
Texte intégralRésumé :
During propped construction the steel-concrete composite action resists dead as well as
imposed loads. Conversely, the steel section alone resists the floor self-weight in unpropped
beams. The major difference between propped and unpropped composite beams lies in the
ductility requirements rather than in the strength requirements. Relatively few studies have
been carried out to assess the rotation requirements for unpropped semi-continuous
composite beams. The outstanding critical factor in the case of unpropped construction is the
dead load stress that must be carried by the steel beam alone prior to hardening of the
concrete.
This research overcomes the difficulties involved in modelling the composite and noncomposite
stages by using a numerical integration technique developed from the basic
principles of structural mechanics. The method incorporates the fully non-linear material
properties and requires very little assumption. The technique was initially validated using the
experimental results from plain steel beam bending tests. The subsequent comparison
between the model predictions and the results from the large-scale frame test carried out for
this research purpose, showed that the method is capable of predicting non-elastic load vs.
end rotation behaviour within a high degree of accuracy. Thus the model can be used with
confidence in order to predict the connection rotation requirements for a wider range of
loading configurations than is practically possible from experimental testing alone.
A parametric study is carried out using the numerical integration technique developed for the
semi-continuous composite beam on a total of 2160 different beam configurations, utilising
different steel grades and loading conditions. In this study the influence of dead load stress on
the connection rotation requirement has been thoroughly evaluated along with several other
factors including span to depth ratio, location within the building frame, ratio between the support (connection) moment capacity and span (beam) moment capacity, loading type, steel
grade and percentage of the beam strength utilised during design. The connection rotation
capacity requirements resulting from this study are assessed to establish the scope for
extending the use of composite connections to unpropped beams.
The large-scale experiment that has been carried out provided an opportunity to investigate
the behaviour of a modified form of composite connection detail for use at perimeter
columns (single-sided composite connections) with improved rebar anchorage.
Additionally, another extensive parametric study is carried out using the numerical
integration technique developed for the steel beam to establish the influence of strainhardening
on elastic-plastic frame instability design.
20
Silva, Vanessa Cristina Soncin da [UNESP]. « Estudo da estabilidade e da capacidade resistente de painéis estruturais do sistema construtivo Light Steel Framing ». Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/91468.
Texte intégralRésumé :
Made available in DSpace on 2014-06-11T19:25:21Z (GMT). No. of bitstreams: 0
Previous issue date: 2013-01-18Bitstream added on 2014-06-13T20:13:40Z : No. of bitstreams: 1
silva_vcs_me_ilha.pdf: 3184592 bytes, checksum: 07b41a4915935f9e6c2c81f09582a3b7 (MD5)O presente trabalho estuda a estabilidade de painéis estruturais do sistema construtivo Light Steel Framing (LSF) a partir da modelagem computacional de painéis estruturais, com o intuito de analisar a instabilidade global, os deslocamentos horizontais de topo e os esforços resistentes dos perfis formados a frio que compõem estas estruturas. Realizaram-se análises lineares, não-lineares e de flambagem de geometrias de painéis comumente empregadas e indicadas na literatura, e de formatos diferenciados, buscando encontrar configurações de travamento que pudessem permitir maior estabilidade e a utilização de perfis mais esbeltos do que os indicados por norma para este tipo de sistema construtivo. Constatou-se que os painéis aqui estudados atingem seus estados-limites quando são utilizados perfis de menores espessuras do que aquelas normalmente indicadas, e que a geometria do painel proposto no estudo efetuado mostrou-se viável, tornando-se uma alternativa às configurações comumente empregadas e recomendadas pela literatura em questão e oferecendo estabilidade, capacidade resistente, segurança e economia de material.
This paper studies the stability of structural panels system constructive Light Steel Framing (LSF) from the computational modeling of structural panels, in order to analyze the global instability, the horizontal displacements of the top and the efforts of resistant cold formed steel composing these structures. Analyses linear, nonlinear and buckling geometry of panels commonly used and indicated in the literature, and different formats, seeking to find locking settings that could allow greater stability and the use of thinner profiles than indicated by standard for this type of construction system. It was found that the panels studied here reach their limits states profiles are used when smaller thicknesses than those normally displayed, and the geometry of the panel proposed in the study performed was feasible, becoming an alternative to commonly used settings and recommended by the literature in question and offering stability, bearing capacity, safety and economy of material.
21
Silva, Vanessa Cristina Soncin da. « Estudo da estabilidade e da capacidade resistente de painéis estruturais do sistema construtivo Light Steel Framing / ». Ilha Solteira, 2013. http://hdl.handle.net/11449/91468.
Texte intégralRésumé :
Orientador: Jefferson Sidney CamachoCoorientador: Renato Bertolino Júnior
Banca: Rogério de Oliveira Rodrigues
Banca: Jorge Munaiar Neto
Resumo: O presente trabalho estuda a estabilidade de painéis estruturais do sistema construtivo Light Steel Framing (LSF) a partir da modelagem computacional de painéis estruturais, com o intuito de analisar a instabilidade global, os deslocamentos horizontais de topo e os esforços resistentes dos perfis formados a frio que compõem estas estruturas. Realizaram-se análises lineares, não-lineares e de flambagem de geometrias de painéis comumente empregadas e indicadas na literatura, e de formatos diferenciados, buscando encontrar configurações de travamento que pudessem permitir maior estabilidade e a utilização de perfis mais esbeltos do que os indicados por norma para este tipo de sistema construtivo. Constatou-se que os painéis aqui estudados atingem seus estados-limites quando são utilizados perfis de menores espessuras do que aquelas normalmente indicadas, e que a geometria do painel proposto no estudo efetuado mostrou-se viável, tornando-se uma alternativa às configurações comumente empregadas e recomendadas pela literatura em questão e oferecendo estabilidade, capacidade resistente, segurança e economia de material.
Abstract: This paper studies the stability of structural panels system constructive Light Steel Framing (LSF) from the computational modeling of structural panels, in order to analyze the global instability, the horizontal displacements of the top and the efforts of resistant cold formed steel composing these structures. Analyses linear, nonlinear and buckling geometry of panels commonly used and indicated in the literature, and different formats, seeking to find locking settings that could allow greater stability and the use of thinner profiles than indicated by standard for this type of construction system. It was found that the panels studied here reach their limits states profiles are used when smaller thicknesses than those normally displayed, and the geometry of the panel proposed in the study performed was feasible, becoming an alternative to commonly used settings and recommended by the literature in question and offering stability, bearing capacity, safety and economy of material.
Mestre
22
Willemse, G. E. (Grant Erin). « Object-oriented steel connection design framework ». Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50048.
Texte intégralRésumé :
Thesis (MScEng)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: Connections are a vitally important part of any structural framework. Thisstatement may seem obvious, yet it is surprisinghow often insufficient attention is given to the design of this essential aspect of steelwork projects. This thesis concentrates on developing a specification for designing steel connections with the main emphasis on the practical and economical design of typical connections. The design methods of the specification are developed according to the new South African design code which is currently in draft form, namely SANS10162:Code of Practice for the Structural Use of Steel: Part 1: Limit States Design of hot-rolled steelwork - 2002. An object-oriented framework and associated graphical user interface for designing the connections are developed and implemented. The primary objectives of the implemented framework are: • Being generic in the sensethat it allows for easy addition of additional connection types, • To implement the design paradigm of the South African code, without fixing specific parameter values programmatically in the implementation and • To build on an existing architecture that allows for structural analysis,structural steel member design and distributed collaboration in the design process.
AFRIKAANSE OPSOMMING: Verbindings vorm In uiters belangrike deel van enige staal struktuur. Alhoewel hierdie stelling dalk vanselfsprekend mag wees, is dit egter verbasend hoe selde voldoende aandag aan die ontwerp van hierdie essensiëleaspek van staalwerk projekte gegee word. Hierdie tesis konsentreer op die ontwikkeling van In spesifikasievir die ontwerp van staal verbindings met die oog op praktiese en ekonomiese ontwerp van tipiese verbindings. Hierdie ontwerpmetodes isgebasseer op die nuwe Suid Afrikaanse ontwerpkode wat tans in proef-vorm is, naamlik SANS 10162: Gebruikskode vir Stoa/bouwerk: Dee/I: Grenstoestandontwerp vir warmgewa/ste staa/werk - 2002. In Objek orienteerde raamwerk en In geassosieerde grafiese gebruikerskoppelvlak word ontwikkel en geimplimenteer. Die primêre mikpunte van hierdie geimplimenteerde raamwerk is: • Om generies te wees in die sin dat dit die byvoeging van addisionele verbinding tipes toelaat, • Om die paradigma van die Suid Afrikaanse kode te implimenteer sonder om enige waardes van spesifieke parameters programmaties vas te lê, en • Om dit op In bestaande argitektuur te bou wat strukturele analise, strukturele ontwerp en verspreide samewerking in die ontwerpproses toelaat.
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Burkholder, Margaux Claire. « Performance Based Analysis of a Steel Braced Frame Building With Buckling Restrained Braces ». DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/715.
Texte intégralRésumé :
This paper provides an assessment of the seismic performance of a code-designed buckling restrained braced frame building using the performance-based analysis procedures prescribed in ASCE 41-06. The building was designed based on the standards of the ASCE 7-05 for a typical office building located in San Francisco, CA. Nonlinear modeling parameters and acceptance criteria for buckling restrained brace components were developed to match ASCE 41-06 design standards for structural steel components, since buckling restrained braces are not currently included in ASCE 41-06. The building was evaluated using linear static, linear dynamic, nonlinear static and nonlinear dynamic analysis procedures. This study showed that the linear procedures produced more conservative results, with the building performing within the intended Life Safety limit, while the nonlinear procedures predicted that the building performed closer to the Immediate Occupancy limit for the 2/3 maximum considered earthquake hazard. These results apply to the full maximum considered earthquake hazard as well, under which the building performed within the Collapse Prevention limit in the linear analysis results and within the Life Safety limit in the nonlinear analysis results. The results of this paper will provide data for the engineering profession on the behavior of buckling restrained braced frames as well as performance based engineering as it continues to evolve.
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Krishnan, Swaminathan. « Three-Dimensional Nonlinear Analysis of Tall Irregular Steel Buildings Subject to Strong Ground Motion ». Thesis, Pasadena : California Institute of Technology, Earthquake Engineering Research Laboratory, 2004. http://caltecheerl.library.caltech.edu.
Texte intégralRésumé :
Thesis (Ph. D.)--California Institute of Technology, 2003."September 2003." Includes bibliographical references. EERL report series available at their website: http://caltecheerl.library.caltech.edu.
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Johann, Matthew A. « Fire-Robust Structural Engineering : A Framework Approach to Structural Design for Fire Conditions ». Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-1219102-155849.
Texte intégralRésumé :
Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: structural engineering; fire safety; framework approach; performance-based design; information management; finite element; lumped-parameter; laboratory tests; steel; beam; restrained; plastic analysis. Includes bibliographical references (p. 180-182).
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Cucchi, Andrea. « Changes in codes, standards, practices following building structural failures and limit states steel design comparison : AISC 13th ed vs. Eurocode 3 (2005) ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2333/.
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Oosthuizen, Frederik du Toit. « Probabilistic based evaluation of the structural reliability achieved for a typical building designed according to SANS 517:2009 and SANS 10162- 2:2010 ». Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17792.
Texte intégralRésumé :
Thesis (MScEng)--Stellenbosch University, 2011.ENGLISH ABSTRACT: This study aims to perform a quantitative probabilistic based evaluation of the reliability achieved in the design of Light Steel Frame Buildings (LSFB) when designed according to the loading code, SANS 517:2009 and the new design code for cold formed steel sections, SANS 10162-2:2010. The evaluation was done as follows: A specific structure, chosen and designed according to the specifications given in SANS 517:2009, was modelled in a structural analysis program. From the analyses done it was possible to identify the most critical element for given failure modes. Spread sheets according to SANS 10162-2:2010 were developed to calculate the resistance or design values for the different failure modes. By using a First Order Reliability Method (FORM), the reliability index for each failure mode could be calculated and evaluated in three different ways. Firstly, the reliability margin implied by the design load was evaluated. It was assumed that the resistance of the profile had a deterministic value while the loads applied to the structure were taken as probabilistic, i.e. following their known distribution functions. From this evaluation it was found that the necessary level of reliability was achieved for all failure modes. Secondly, the reliability margin implied by the resistance of the profile was evaluated. The resistance of the profile was taken as probabilistic with a distribution function that could be determined from the known distribution functions of the profile parameters responsible for the capacity of the profile. The loading was assumed to have a single deterministic value. From this evaluation it could be seen that a very low level of reliability was achieved for the failure modes of shear working in on the strong axis of the profile as well as interaction between bending and axial load. This is due to the strong dependence of this failure mode to the thickness of the profile, to which no partial factor is applied in the design process. Thirdly, the reliability margin implied by both the resistance and loads was evaluated. In a real life situation both loads and resistances would have variability. The resistance and loading values were taken as probabilistic with their known distribution functions. From this evaluation it was found that the necessary level of reliability was only achieved for shear working in on the weakaxis and axial load. All other failure modes achieved a level of reliability slightly lower than the target level of reliability for South Africa. The stiffening effect of wall cladding elements were not taken into account in the analysis. The reliability of connections was also not evaluated. It can be concluded that the element reliability achieved through the use of above-mentioned codes seems to be slightly less that desired. There could be an argument for recalibrating the partial factors to achieve the desired level of element reliability. However, the cladding elements provide significant additional stiffness to the structure and there is no immediate cause for stiffness concern. Future studies should aim to quantify the contribution that the cladding elements make to the overall structural reliability. The influence of connections reliability should also be investigated.
AFRIKAANSE OPSOMMING: Die studie poog om ‘n kwantitatiewe probabilisties-gebaseerde beoordeling van die betroubaarheidsindeks vir Ligte Staalraam Strukture (LSS) te bepaal wanneer dit ontwerp word volgens die belastingskode, SANS 517:2009 en die nuwe ontwerpskode vir koudgevormde staal profiele, SANS 10162-2:2010. Die beoordeling is as volg gedoen. ‘n Spesifieke strukturele model is gekies, ontwerp volgens die spesifiekasies in SANS 517:2009 en toe gemodelleer in ‘n struktuur analise program. Vanuit die analises was dit moontlik om die mees kritieke element te vind vir gegewe falings modusse. Sigblaaie, volgens SANS 10162-2:2010, is ontwikkel om die weerstand van die profile te bereken vir die falings modusse. Dit was moontlik om die betroubaarheidsindeks op drie verskillende maniere te bereken deur gebruik te maak van ‘n Eerste Orde Betroubaarheids Metode (EOBM). Eerstens is die betroubaarheids speling wat deur die belasting geimpliseer was, bepaal. Daar is aanvaar dat die weerstand van die profiel ‘n deterministiese waarde het terwyl die aangewende belasitng as probabilisties geneem is met hul bekende verdelingsfunksies. Uit hierdie beoordeling is gevind dat die nodige vlak van betroubaarheid bereik word vir alle falings modusse. Tweedens is die betroubaarheids speling wat deur die weerstand geimpliseer was, bepaal. Daar is aanvaar dat die weerstand van die profile ‘n probabilistiese verdeling het wat bepaal is uit bekende verdelingsfunksies van die profiel parameters verantwoordelik vir die kapasiteit van die profiel. Daar is aanvaar dat die belasting ‘n enkele deterministiese waarde het. Uit hierdie beoordeling is gevind dat daar ‘n baie lae vlak van betroubaarheid is vir skuif in die rigting van die sterk as, asook interaksie tussen aksiaal-las en momente. Dit is te danke aan die falings modus se sterk afhanklikheid van die dikte van die profiel. Daar word egter geen parsiële faktor aan die dikte toegeken in die ontwerp proses nie. Derdens is die betroubaarheids speling wat deur beide die weerstand en belasting geïmpliseer was, bepaal. In die werklikheid sal beide belasting en weerstand ‘n vlak van onsekerheid hê. Die weerstand en belasting is as probabilistiese waardes geneem met hul bekende verdelingsfunksies. Uit hierdie beoordeling is gevind dat slegs die falings modus vir skuif in die rigting van die swak as en aksiaal-las die nodige vlak van betroubaarheid bereik. Al die ander modusse het steeds ‘n redelike hoë vlak van betroubaarheid. Dit is egter steeds laer as wat voorgeskryf word vir Suid-Afrika. Die verstywings-effek van die bekleding is nie in hierdie ondersoek in ag geneem nie. Die betroubaarheid van die verbindings is ook nie bepaal nie. ‘n Gevolgtrekking kan dus gemaak word dat die element-betroubaarheid wat bereik word deur die bo-genoemde kodes effens laer is as die gewensde. ‘n Argument kan ontstaan vir die herkalibrasie van die parsiële faktore om die gewensde vlak van betroubaarheid te bereik, maar die bekleding bied ‘n noemenswaardige addisionele styfheid aan die struktuuur. Daar is dus geen onmiddellike kommer oor die styfheid van hierdie strukture nie. Verdere studies moet poog om die bydra van hierdie bekledingselemente tot die betroubaarheid van die struktuur te kwantifiseer. Die invloed van die konneksies tot die betroubaarheid van die struktuur sal ook ondersoek moet word.
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Mansour, Masis, Alexander Frid et Souzan Bakr. « Implementering av höghållfast stål i byggbranschen : Analys av hur höghållfasta stålkonstruktioner kan appliceras för byggnadstekniska verk : fördelar, risker och användningsområden ». Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-49352.
Texte intégralRésumé :
Purpose: The purpose of this study has been to investigate the essentials of being able to incorporate high-strength steels (460 MPa and beyond) for structural elements in buildings. As of late, structural steels with a yield point of 355 MPa have been considered standard and have been for the past decade. One of the problems that occur with an increased yield point, is that deflection of structural elements increases, as the Young’s modulus does not increase with increasing yield point. Welding, stability, behavior during fire, and fatigue are also subjects of interest. Method: The study was conducted through several courses of action: a literature review covering the latest research of high-strength steels within the sought-after area of interest, followed by calculations of a truss resting on two columns, being subject to bending moment and compressive force, in both 355 MPa and 700 MPa, in order to review the differences that occur and how they can be counteracted. Lastly, interviews were carried out, where structural engineers gave their thoughts and experiences on the matter at hand. Results: The results show that welding is one of the largest hurdles with being able to utilize high-strength structural steels, though there are newer, more promising methods of welding which can be used, such as electron beam welding. Regarding structural integrity and buckling of structural elements, high-strength steel can be used for trusses, where the structural members are mainly being pulled, opposed to being subject to compressive force. This was shown with the performed calculations, during the interviews, and by the literature overview. Conclusions: The general conclusions of the study is that for welding, further research, education, and training is required for all concerned parts, such as the structural engineers and the on-site welders, which will increase the knowledge regarding how welding of high-strength steels should be performed, but also raise awareness about newer and more modern methods. Fire behavior for high-strength steels are a higher risk factor that should be treated and executed with higher degrees of caution by engineers. Reduction factors for fire affected steel construction elements should be corrected to fit the behavior for high-strength steels as well, as they differ from the current Eurocode 3 for lower class steels. Problems with instability can be counteracted by utilizing the steel in pulled structural members, such as trusses and struts. Lastly, for high-strength steels to be used more widely, structural engineers and manufacturers need to work together for any of the two to profit, as low production rates are costly.
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Kahle, Matthew Gilbert. « Partially restrained composite connections : design and analysis of a prototype structure ». Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/20830.
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Rask, Fredrik. « Life Cycle Assessment and comparison of the climate impact of structural members and floor systems constructed in concrete, steel and timber ». Thesis, KTH, Byggnadsmaterial, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-256506.
Texte intégralRésumé :
In this report the climate impact is determined for some basic structural elements made in steel,>mber and concrete. The aim is to compare the climate impact of these three building materials byquan>fying the emissions related to the produc>on and construc>on of some typical structures.The comparison comprise two parts, were one is the comparison of members in bending,compression and tension and the other part is the comparison of a couple of floor structures.The emissions are determined through a Life Cycle Assessment, LCA. The members are comparedwith respect to their load bearing resistance and the floor structures is compared per square meter.The mo>va>on for this inves>ga>on is that the construc>on industry is a large contributor to the totalamount of greenhouse gas emissions and in order to reduce these emissions new solu>ons andprac>ses must be adopted. A more thoughVul choice of the materials used in structures has thepoten>al of reducing the emissions.The method of determining the climate impact is based on first determining the material quan>>esfor all the inves>gated structures and then calcula>ng the amount of carbon dioxide equivalentsrelated to the produc>on of these materials with the help of a Life Cycle Assessment.The material quan>>es of the structural members is determined based on the load. The dimensionsof the cross sec>on is determined with respect to the required load resistance. The materialquan>>es of the floor structures is based on some exis>ng solu>ons from manufacturers.The study show that the >mber based design solu>ons almost always has a smaller climate impactand that the differences can be considerable. Members made in steel oZen result in very largeamount of greenhouse gas emissions but the sca[er in the results indicate that the origin of the steelhas great importance. Primary steel has a much larger impact as opposed to recycled steel.The comparison of the floor designs show that beyond the material choice itself, also the materialefficiency is important. The hollow core slab made in concrete is a very material efficient design andmay in some cases be on par with >mber based designs.The massive >mber floors made of Cross Laminated Timber, CLT, has a fairly large climate impactbecause of the sheer volume of material and may be on the same level as the floor made in concretefor some scenarios. There is however a wide range in the result based on whether the material istransported a long distance and depending on the choice of insula>on material. If these choices isop>mised, the emissions of the CLT floor is instead on a much lower level, closer to that of the otherlightweight floors inves>gated.The process of evalua>ng and comparing the material choices and structural designs form a lifecycleperspec>ve can be u>lised during the design in order to reduce the emissions. With a be[erknowledge of the climate impact of the design, be[er choices can be made in order to reduce theemissions.
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Durucan, Cengizhan. « Seismic Retrofitting Of Reinforced Concrete Buildings Using Steel Braces With Shear Link ». Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610956/index.pdf.
Texte intégralRésumé :
The catastrophic damage to the infrastructure due to the most recent major earthquakes around the world demonstrated the seismic vulnerability of many existing reinforced concrete buildings. Accordingly, this thesis is focused on a proposed seismic retrofitting system (PSRS) configured to upgrade the performance of seismically vulnerable reinforced concrete buildings. The proposed system is composed of a rigid steel frame with chevron braces and a conventional energy dissipating shear link. The retrofitting system is installed within the bays of a reinforced concrete building frame. A retrofitting design procedure using the proposed seismic retrofitting system is also developed as part of this study. The developed design methodology is based on performance-based design procedure. The retrofitting design procedure is configured to provide a uniform dissipation of earthquake input energy along the height of the reinforced concrete building. The PSRS and a conventional retrofitting system using squat infill shear panels are applied to an existing school and an office building. Nonlinear time history analyses of the buildings in the original and retrofitted conditions are conducted to assess the efficiency of the PSRS. The analyses results revealed that the PSRS can efficiently alleviate the detrimental effects of earthquakes on the buildings. The building retrofitted with PSRS has a more stable lateral force-deformation behavior with enhanced energy dissipation capability than that of the one retrofitted with squat infill shear panels. For small intensity ground motions, the maximum inter-story drift of the building retrofitted with the PSRS is comparable to that of the one retrofitted with squat infill shear panels. But for moderate to high intensity ground motions, the maximum inter-story drift of the building retrofitted with the PSRS is considerably smaller than that of the one retrofitted with squat infill shear panels.
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Ibrahim, Josif, et Ahmad Kateesh. « Comparison of two different materials on frame systems with focus on life cycle analysis ». Thesis, KTH, Byggteknik och design, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278747.
Texte intégralRésumé :
The structural engineer should not only be able to perform design calculations but also findmore efficient solutions for building parts. The purpose of this thesis is to redesign a concreteframe for a house (an apartment building) into a light frame with steel columns andcompartment walls, as well as perform a life cycle analysis for materials on both frames anddetermine the frame with the lowest environmental impact.The result shows that the lightweight frame with steel columns and compartment walls is amuch better choice for the environment as it stands only for 60 000 kg CO2e compared toconcrete frame which stands for 163 000 kg / CO2e. The steel frame emits about 60% lessemissions than the concrete frame.By optimizing steel columns in the upper floors and choosing smaller columns led to ten tonsless mass of steel and less emissions by 15 000 kg / CO2e.The selected compartment wall has a thickness of 309 mm which is 6 mm thicker than theexisting wall which results in a reduction of the area of house by 6 square meters throughoutthe house which can be expensive depending on the location of the house.In conclusion, the material concrete is good when it is needed due to requirements on fire,noise, and durability but also less suitable when not needed. In this case, it is useless with thematerial concrete as the outer wall and can therefore be replaced by a steel columns andcompartment wall instead.Konstruktören ska inte endast kunna utföra beräkningar utan även hitta effektivare lösningar till byggnadsdelar. Syftet med detta examensarbete är att dimensionera om en betongstomme för ett flerbostadshus till en lättstomme med stålpelare och utfackningsväggar samt även utföra en livscykelanalys för material på stommar och bestämma stommen med lägst miljöpåverkan.Resultatet visar att lättstomme med stålpelare och utfackningsvägg är ett mycket bättre val för miljön då står den för 60 000 kg/CO2e jämfört med betongstomme som står för 163 000 kg/CO2e. Stålstommen släpper ut ungefär 60 % mindre utsläpp än betongstommen.Optimering av stålpelare i övre plan och att välja mindre pelare ledde till tio ton mindre massa stål och även mindre utsläpp på 15 000 kg/CO2e.Den valda utfackningsväggen har tjocklek 309 mm vilket är 6 mm tjockare än den befintliga väggen som i sin tur resulterar i en areaförlust med 6 kvadratmeter i hela huset vilket kan vara dyrt beroende på husets läge.Som slutsats är att materialet betong är bra när det behövs på grund av till exempel brand, ljud och beständighet men även mindre lämpligt när det inte behövs. I detta fall är det mindre lämpligt med materialet betong som yttervägg och man kan därför använda utfackningsvägg med stålpelare istället.
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Raby, Douglas Allan. « Development of a system architecture and applications for an integrated computer software system for the analysis and design of steel structures ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0017/MQ48372.pdf.
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Silva, Junior Anorosval Pedro Leirias da. « Monitoramento estrutural baseado na técnica de ondas Lamb para detecção de falhas em estruturas metálicas parafusadas ». Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/3181.
Texte intégralRésumé :
Este trabalho objetiva o estudo e a aplicação de um método de monitoramento da integridade de uma estrutura metálica baseado em ondas Lamb. Para o monitoramento são utilizadas pastilhas piezoelétricas, em função de seu baixo custo monetário. As pastilhas são utilizadas como atuadores e receptores empregando a propriedade dos materiais piezoelétricos que associa a impedância elétrica coma impedância mecânica. O mecanismo da análise parte da criação de um sinal formado por um pulso elétrico no formato de ondas Lamb e sua aplicação em uma pastilha piezoelétrica fixada na estrutura em estudo, causando uma vibração que se propaga ao longo do elemento estrutural. Segue na captação dessa vibração por outra pastilha piezoelétrica também acoplada à estrutura que a converte em um sinal e finaliza na interpretação desse sinal. A onda Lamb que gera o pulso de excitação enviado ao elemento piezoelétrico é uma função Wavelet. A estrutura é monitorada em seu estado íntegro e em seu estado danificado. Com base nos estudos de vibração e uso da Transformada de Wavelet Contínua, comparam-se as leituras de sinais obtidos em ensaios realizados na estrutura íntegra em seguida na estrutura danificada. Utilizando uma métrica que correlaciona essas leituras, definida como Índice de Dano, verifica-se se o método detecta a existência de dano na estrutura. São executados três experimentos consistindo em uma estrutura formada por uma única viga metálica onde são fixados atuadores e receptores em posições variadas. Insere-se um parafuso em sua constituição, com a função de simular o dano. A estrutura contendo o parafuso configura seu estado íntegro e quando o parafuso é retirado da estrutura, tem-se o estado danificado. Os resultados dos ensaios permitem a avaliação qualitativa da detecção, em função da distância relativa à posição do dano. Também se utiliza um acelerômetro como receptor, visando obter um fator de comparação para os resultados obtidos. Decorrente da quantidade de dados observados se utiliza um tratamento estatístico com medidas resumo e dispersões para a análise. Conclui-se que a metodologia apresentada utilizando a técnica das ondas Lamb em conjunto com a aplicação do Índice de Dano produz resultados satisfatórios e pode ser utilizada como uma alternativa na interpretação de sinais onde o objetivo é a detecção de danos, visto que a metodologia foi capaz indicar a existência do dano independente da sua posição na estrutura proposta.This work aims at the study and application of a method of monitoring the integrity of a metal structure based on Lamb waves. For monitoring piezoelectric pads are used, in function on your low monetary cost. The pellets are used as actuators and receivers using the property of piezoelectric materials that associates the electrical impedance with mechanical impedance. The analysis part of the creation of a sign consisting of an electrical pulse in the Lamb waves and your format application in a piezoelectric structure mounted insert in study, causing a vibration that propagate along the structural element. Follows on the uptake of this vibration for piezoelectric other pad also coupled to the structure that converts it into a signal and terminates in the interpretation of this signal. The Lamb wave that generates the excitation pulse sent to the piezoelectric element is a Wavelet function. The structure is monitored in your healthy state and in your damaged state. Based on studies of vibration and use of Continuous Wavelet transform, compare the readings of signals obtained in trials conducted in full structure then the structure damaged. Using a metric that correlates these readings, defined as Damage index, the method detects the existence of damage to the structure. Three experiments are performed. The experiments consisting in the analysis of a structure formed by a single metal beam where actuators and receptors are disposed in various positions. Was inserted a screw in your Constitution, with the function to simulate the damage. The structure containing the screw configures your healthy state and when the bolt is removed from the structure, has been damaged. The results of the tests allow the qualitative evaluation of the discovery, on the basis of distance on the position of the damage. Also uses an accelerometer as a receiver, in order to obtain a comparison factor to the results obtained. Due to the amount of observed data was using a statistical summary measures treatment and dispersions for the analysis. It is concluded that the methodology presented using Lamb wave technique in conjunction with the application of the index of damage produces satisfactory results, and can be used as an alternative in the interpretation of signs where the goal is the detection of damage, Since the methodology was able to indicate the existence of damage regardless of your position in the proposed structure.
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Song, Brian Inhyok. « EXPERIMENTAL AND ANALYTICAL ASSESSMENT ON THE PROGRESSIVE COLLAPSE POTENTIAL OF EXISTING BUILDINGS ». The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281712538.
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Spyridaki, Athina. « Response Variability of Statically Determinate Beam Structures Following Non-Linear Constitutive Laws and Analytical identication of progressive collapse modes of steel frames ». Thesis, 2017. https://doi.org/10.7916/D8GT5SSC.
Texte intégralRésumé :
This thesis is divided into two distinct and independent parts. Part I focuses on the extension of the concept of Variability Response Function (VRF). The focus of research community has recently shifted from the improvement of structural models and enhancement of the performance of computational tools in a deterministic framework towards the development of tools capable of quantifying the uncertainty of parameters of the structural system and their effect on the system response in a probabilistic framework. One limitation to this direction is the inadequacy of information to fully describe the probabilistic characteristics of a structural system.
In effort to bypass this barrier, VRF was introduced by Shinozuka as a tool to calculate
the variability of the response of a system. VRF is a deterministic function and for the case of deterministic structural beams where the uncertain system parameters are modeled as homogeneous stochastic fields, it offers an efficient way to circumvent timely computational analyses.
In this dissertation, a flexibility-based VRF for the case of statically determinate beams
following an arbitrary non-linear constitutive law is proposed. A closed-form analytical
expression of VRF is derived and the constrains of the mechanics approximation embedded are discussed. No series expansion is used, thus the probabilistic part is exact and not limited by any constraint on the relative magnitude of the variations of the parameters.
Part II of this dissertation explores the topic of progressive collapse. The appearance of
damage in structural systems (explosions, design or construction errors, aging infrastructure) is following an upward trend during the last decades, urging for measures to be taken in order to control the damage advancement within the system. There has been an organized effort to update the design codes and regulations, in order to include provisions towards the reinforcement of buildings to eliminate their susceptibility to local damage. These efforts tend to focus on improving redundancy and alternate load paths, to ensure that loss of any single component will not lead to a general structural collapse.
The analysis of a damaged system is a very complicated phenomenon due to its non-linear nature. So far the engineering community has addressed the problem of progressive collapse by employing sophisticated computational finite element methods to accurately simulate an unexpected damaging event. In this framework, damage has been introduced in the model by removing key load-bearing elements of the building and conducting elaborate analyses which almost always require inelastic and loss of stability theories to be considered. The computational complexity renders this kind of analyses almost prohibitive for practicing engineers. In the direction of eliminating sophisticated and computationally expensive analyses, simple, trustworthy tools should be generated for practitioners to easily predict the mechanism of damage propagation and determine the governing collapse mode of a structure.
In this environment, this thesis introduces a simple and less labor demanding analytical
tool/method which can be used to determine the governing progressive collapse mechanism of steel moment frames under the scenario of a column removal. After performing plain elastic analyses, the method develops critical Euler-type ductility curves for each removal scenario by performing straightforward analytical calculations. The response of structural systems under column removals is examined in a 2D and 3D context.
The main objective of Part II is to investigate the response of dierent structural systems
to the event of damage introduction (in this thesis, in the form of column removals in several locations of the system) and to develop a simple analytical framework for the identification of the governing progressive collapse failure modes. Although failure may occur due to a number of reasons (shear beam-to-column connection failure, beam yielding-type mechanism, loss of stability of adjacent columns, global loss of stability of the structural system, etc), in this study focus is being placed in only two of them; The proposed method establishes critical limit state functions which are used to identify whether a specic structure will experience progressive collapse through a yielding-type beam-induced collapse mechanism or through a loss-of-stability-induced column failure collapse mechanism.
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Lam, Dennis, T. C. Ang et S. P. Chiew. « Structural Steelwork : Design to Limit State Theory ». 2003. http://hdl.handle.net/10454/5618.
Texte intégralRésumé :
This classic textbook is a comprehensive introduction to structural steelwork design. It describes the design theory and code requirements for common structures, connections, elements and frames.
The book is structured to meet the needs of courses in structural steelwork, introducing and explaining each concept before allowing the student to test the knowledge with practical examples. Each section is illustrated with exercises for the student to reinforce their learning. It continues to be an indispensable introduction to structural steelwork design for students of structural and civil engineering.
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Lam, Dennis, T. C. Ang et S. P. Chiew. « Structural Steelwork : Design to Limit State Theory ». 2014. http://hdl.handle.net/10454/10720.
Texte intégralRésumé :
NoThe fourth edition of Structural Steelwork: Design to Limit State Theory describes the design theory and code requirements for common structures, connections, elements, and frames. It provides a comprehensive introduction to structural steelwork design with detailed explanations of the principles underlying steel design.
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Govender, Stanton Wesley. « Parametric studies on the temperature dependent behaviour of steel structures within a fire context ». Thesis, 2012. http://hdl.handle.net/10413/9120.
Texte intégralRésumé :
The mechanical and material properties of structural steel at elevated temperatures play
an important role in structural fire design. The South African 350W and S355 structural
steels are common in building structures with S355 slowly replacing the older 350W. The
cost and feasibility of full scale fire tests are some of the causes for the lack of
experimental data on the behaviour of steel structures when exposed to fire. Therefore
excessively conservative design codes based on isolated laboratory experiments are used
in practice which leads to increased material costs. Another area of concern with respect
to building safety is the reusability of structural steels post fire exposure, which is not
effectively addressed within these codes.
This study aims to establish greater insight into structural fire design and simulation on
which further research can be built. Experimental programs on the temperature
dependent behaviour of these steel members loaded axially are conducted and compared
with theory and the Eurocode 3 standard [1]. The reusability of steel exposed to fire and
after being cooled down is investigated and compared to the findings by Outinen [2].
Further testing on material to determine the relationship between remaining life and
hardness degradation after cooling down was conducted.
Experimental data from various external studies are used to develop novel computer
models using the finite element analysis software, SimXpert [3]. These are verified against
the original data and compared to existing design codes. A parametric approach is used
with these models to demonstrate the advantages of computer simulations in structural
fire design. Different cross sections and slenderness ratios are evaluated for their
susceptibility to buckling at elevated temperatures.
The results of this study show that as temperature and exposure time increase the
integrity of steel members decrease. The current design codes accurately predict the
behaviour of isolated specimens but lack data on real situations where the specimen is
part of a complex structure. It was found that steel members can be reused if their
exposure temperature does not exceed 700°C, after which their strength can reduce to
90%. This temperature dependant behaviour was successfully modelled using basic
computer simulations and then demonstrated the ease in which they can be used in place
of experimental regimes. The parametric advantages of these simulations were
demonstrated by predicting the effects of slenderness ratios and geometry cross sections
on the buckling behaviour.Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2012.
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Moreyra, Garlock Maria E. « Design, analysis, and experimental behavior of seismic resistant post-tensioned steel moment resisting frames / ». Diss., 2002. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3073984.
Texte intégral
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Semedo, Hironilsa Lenira da Veiga. « Estruturas mistas de aço-betão e de betão armado em edifícios correntes : dimensionamento e custo ». Master's thesis, 2018. http://hdl.handle.net/10437/9418.
Texte intégralRésumé :
Orientação: Elói João Faria Figueiredo ; co-orientação: Ana Brandão de Vasconcelos, Nuno Miguel de Freitas SilvaNuma economia onde são cada vez mais recorrentes as críticas ao setor da construção civil por atrasos e falta de produtividade, e numa sociedade cada vez mais rigorosa em todos os aspetos técnicos e estéticos, torna-se imprescindível que as empresas realizem os seus planos de trabalho em função das necessidades dos clientes. Neste trabalho foca-se sobre o estudo de um edifício de habitação corrente de betão armado, onde os elementos estruturais foram substituídos por elementos mistos aço-betão. Assim, o estudo consistiu no dimensionamento dos elementos mistos aço-betão e na análise e comparação de custos das duas soluções estruturais aço-betão e betão armado. O dimensionamento dos elementos mistos foi realizado com base em estudos académicos e normativos, apresentando-se os cálculos para o dimensionamento dos elementos estruturais, de acordo com o Eurocódigo 4, tais como lajes mistas com chapa perfilada, vigas de aço e pilares tubulares com secção retangular, onde o aço e o betão trabalham como um único elemento. Posteriormente, recorrendo ao levantamento de medições das duas soluções em questão, foi possível avaliar o custo de execução de cada solução estrutural, de forma a definir a solução mais económica. Por fim, com os resultados dos custos das duas soluções conclui-se que, a estrutura mista aço-betão apresenta menor custo comparado com a estrutura tradicional de betão armado.
In an economy where criticisms of the construction sector are increasingly in competition with delays and lack of productivity, and in an ever more rigorous society in all technical and aesthetic aspects, it is imperative that companies carry out their work plans in customer’s needs. This work focuses on the study of a current residential building of reinforced concrete, where the structural elements were replaced by mixed elements steel-concrete. Thus, the study consisted in the dimensioning of the steel-concrete composite elements and the analysis and cost comparison of the two steel-concrete and reinforced concrete solutions. The sizing was carried out based on academic and normative studies, presenting the calculations for the dimensioning of the structural elements, according to Eurocode 4, such as mixed slabs with profiled sheet, steel beams and tubular pillars with rectangular section, where steel and concrete work as a single element. Later, based on the results of the design, using the measurement of the two solutions in question, it was possible to evaluate the execution cost of each constructive solution, to define the most economical solution. Finally, with the results of the costs of the two solutions, it is concluded that the mixed steel-concrete structure presents a lower cost compared to the reinforced concrete structure.