Recently more and more buildings of light structures have been built in Lithuania as well as in other European and world countries. Nevertheless, timber products are not widely used for floors in this share of construction market. Traditional light timber frame floors are characterized by vibrations, acoustic transmission and low fire resistance. The above-mentioned problems can be rationally solved by using timber-concrete composite (hereinafter TCC) floors. In comparison with entirely timber floors such type of floors are characterised not only by increased strength and stiffness but also by increased fire resistance and better sound insulation. In comparison with reinforced concrete floors manufactured of non-regenerative sources TCC floors are lighter and more economic. These characteristics stimulate usage of TCC floors in newly built buildings. It should also be noted that usage of timber in building structures instead of concrete or steel could substantially decrease energy demand and emission of carbon dioxide during production. In this work author presents TCC structural solution when thin-webbed beams (I-joists) used for timber floor beams instead of solid or glued rectangular beams. Thin-webbed beams are without upper flange of structural timber. Embedding in concrete a part of web of oriented strand board (hereinafter OSB) connects the OSB web and the concrete slab. This concept allows to save structural materials and production costs. Nevertheless, not so many... [to full text]

Diploma thesis deals with analysis of a construction made of concrete and masonry. A model respecting nonlinear material behaviour of masonry was assembled in a finite element based software. Calculated results were used to analyse cracks in masonry. Next, a design of a horizontal construction was carried out - concrete slab with beams to support masonry in an upper floor.

Made available in DSpace on 2014-07-29T15:03:37Z (GMT). No. of bitstreams: 1 dissertacao paulo menezes.pdf: 3080026 bytes, checksum: 27fc4469f9413ad9117d4813295e9db7 (MD5) Previous issue date: 2006-09-14 / In a composite system, a steel beam (laminated, welded or cold formed) is associated with a concrete slab, forming a composite beam. The interaction between concrete and steel can be mechanical, by friction or, in some cases, only by adherence. One of the major advantages of the composite beams is the increase in strength and stiffness due to association of steel and concrete that makes possible the reduction of the height of the structural elements, implicating in material economy. The present research has the purpose to present a general vision of the structural behavior of the composite steel-concrete beams and to proceed to a more detailed study of the behavior of the shear connectors made from cold formed steel. A modeling study of the push-out test is accomplished with the intention to find the factors that influences the resistance and rigidity of the connection. The numerical study consists in the elaboration of a three-dimensional numerical model to simulate the push-out test from which is obtained the force-displacement curve, ultimate load, deformations and tensions along the connector. The numeric results are compared with obtained experimental values of rehearsals accomplished at laboratory for validation of the same ones. For the accomplishment of the numeric modeling the computational program ANSYS® 6.1 was used, which uses non-linear material and geometric Finite Element Method models. The numeric models present as variables of interest the thickness, the height of the shear connectors made of cold formed steel and the resistance of the concrete used in the premolded slab with reinforced concrete lattice joist. Results showed that the thickness of the connector is the most important variable in the connection strength, however the height of the connector also has influence in the resistance and, mainly, in the rigidity of the connection. / Denomina-se sistema misto aço-concreto aquele no qual um perfil de aço (laminado, dobrado ou soldado) trabalha em conjunto com uma laje de concreto, formando uma viga mista. A interação entre o concreto e o perfil de aço pode se dar por meios mecânicos, por atrito, ou, em alguns casos, por simples aderência. Uma das vantagens da utilização de vigas mistas em sistemas de pisos é o acréscimo de resistência e de rigidez propiciados pela associação dos elementos de aço e de concreto, o que possibilita a redução da altura dos elementos estruturais, implicando em economia de material. O presente trabalho tem por finalidade apresentar uma visão geral do comportamento estrutural das vigas mistas aço-concreto e proceder a um estudo mais detalhado do comportamento da ligação com conectores de cisalhamento tipo U em perfil formado a frio. É realizada a modelagem computacional do ensaio de cisalhamento direto (push-out test) com o intuito de determinar os fatores que mais influenciam na resistência e rigidez da ligação A modelagem computacional consiste na elaboração de um modelo numérico tridimensional para simular o ensaio de cisalhamento direto, do qual se obtém a curva força-deslocamento, a força última e as deformações e tensões ao longo do conector. Os resultados numéricos são confrontados com valores experimentais obtidos de ensaios realizados em laboratório para validação dos mesmos. Para a realização da modelagem computacional, foi utilizado o programa comercial ANSYS® 6.1, elaborado com base no Método dos Elementos Finitos, cujas ferramentas disponibilizadas permitem análises em regime de não-linearidade física e geométrica. Os modelos computacionais apresentam como variáveis de interesse a espessura e a altura do conector tipo perfil U formado a frio e a resistência do concreto utilizado na confecção das lajes treliçadas. Os resultados obtidos mostram que a espessura do conector é a variável que mais influência a resistência da ligação, porém a altura do conector também tem influência na resistência e, principalmente, na rigidez da ligação.

A new version of EN 1992-1-1, Eurocode 2 for Design of Concrete Structures, is under development and one of the most discussed topics is shear capacity for prestressed concrete beams without shear reinforcement, partly because shear failure occurs suddenly and can have catastrophic consequences. For the new version of Eurocode, there are a total of three proposed equations to replace the two equations that currently exist in EN 1992-1-1 for shear capacity of prestressed concrete beams without shear reinforcement. One of the proposed equations is intended to replace the equation intended for beam regions where bending cracks do not occur. The other two equations are proposed for beam regions where bending cracks occur. One of the proposed equations for beam regions with bending cracks, is based on critical shear crack theory and takes the normal force in consideration, while the other equation for beam regions with bending cracks is like the one found today in Eurocode, an empirical equation, where the contribution of normal force is empirical. In this thesis, all equations have been set against each other and compared with the help of nonlinear finite element analyzes and experiments which Dr. De Wilder has done in his doctoral thesis. The impact of the prestressing force on the shear force capacity of beams has also been investigated. The results show that the equations for beam regions that do not have bending cracks give identical shear force capacities. While the equation which is based on critical shear crack theory takes the shear span into consideration and captures the effect of the shear span correctly, which the other proposed equation and the one found in Eurocode today do not and are on the unsafe side for increasing shear spans. Furthermore, it turned out that the equation which is based on critical shear crack theory was rather conservative, while the equation that exists today in Eurocode gives approximately the same shear capacity as the other proposed equation. Furthermore, it was found that if the amount of longitudinal reinforcement is reduced, at the same time as the prestressing force is unchanged, an insignificant reduction in the shear capacity on prestressed concrete beams is obtained. / En ny version av EN 1992-1-1, Eurokod 2 Dimensionering av betongkonstruktioner, är under utveckling och ett av de mest diskuterade ämnena är tvärkraftskapacitet för förspända betongbalkar utan skjuvarmering, bland annat eftersom huvudspänningsskjuvbrott uppstår plötsligt och kan få katastrofala konsekvenser. Till den nya versionen av Eurokoden finns det totalt tre föreslagna ekvationer för att ersätta de två ekvationer som för närvarande finns i EN 1992-1-1 för tvärkraftskapacitet för förspända betongbalkar utan skjuvarmering. En av de föreslagna ekvationerna är tänkt att ersätta ekvationen avsedd för balkregioner där böjsprickor ej uppstår. De andra två ekvationerna är föreslagna för balkregioner där böjsprickor uppstår. En av de föreslagna ekvationerna för balkregioner med böjsprickor är baserad på kritisk skjuvsprickteorin och tar hänsyn till normalkraftens bidrag till tvärkraftskapaciteten, medan den andra föreslagna ekvationen för balkregioner med böjsprickor är likt den som idag finns i Eurokoden, en empirisk ekvation, där normala kraftens bidrag är baserad på ett empiriskt tillägg. I detta examensarbete har alla ekvationer ställts mot varandra och jämförts med hjälp utav icke-linjär finit-elementanalyser samt experiment som Dr. De Wilder gjort i sin doktorsavhandling. Vidare har också förspänningskraftens påverkan på balkars tvärkraftskapacitet undersökts. Resultaten visar att ekvationerna för balkregioner som ej har böjsprickor ger identiska tvärkraftskapaciteter. Medan ekvationen som är baserad på kritisk skjuvsprickteorin tar hänsyn till skjuvspännvidd och fångar effekten av skjuvspännvidden korrekt, vilket den andra föreslagna ekvationen och den som finns i Eurokoden idag inte gör och är på den osäkra sidan för ökad skjuvspännvidd. Dessutom visade det sig att ekvationen som är baserad på kritisk skjuvsprickteori är tämligen konservativ, medan ekvationen som finns idag i Eurokoden ger ungefär samma tvärkraftskapacitet som den andra föreslagna ekvationen. Vidare visade det sig att ifall man minskar mängden längsgående armering, samtidigt som förspänningskraften är oförändrad, så fås en obetydlig minskning utav tvärkraftskapaciteten på förspända betongbalkar.

Made available in DSpace on 2016-06-02T20:09:18Z (GMT). No. of bitstreams: 1 5306.pdf: 6510064 bytes, checksum: b7a3095b2eb1b62ba399cfe3a2684382 (MD5) Previous issue date: 2013-07-11 / Financiadora de Estudos e Projetos / This report investigates the structural behavior, procedures for analysis and design of externally prestressed steel-concrete composite beams. Based upon the requirements outlined in ABNT NRB 8800:2008 for conventional composite beams and in the literature review, a systematic procedure was developed to design of externally prestressed steel-concrete composite beams requested the positive bending moment. Was analyzed the main modes of global collapse, especially the ultimate limit state design (ELU), which may occur in this type of structure. Also, elaborated a parametric study aimed to analyze the influence of variation in the level of prestressing and the eccentricity of tendons, as well as the constructive methodology (pretensioning and posttensioning) adopted for the the prestressing steel profile that makes up the of steel-concrete composite beam. The parametric study showed that in both methods the predominant failure mode occurs in 2nd Stage of construction. In models of composite beams analyzed with application of pretensioned when the tendon is positioned above the bottom flange of the profile steel the failure mode occurred for the combined bending and axial compression .As for the composite beams evaluated with posttensioned, independent of the position of the tendon, the failure mode occurred in function of the bending moment more than the allowable flexural strength. However, it is noted that the level of prestressing can be adequately calculated to ensure that there is no loss of carrying capacity of the structure. It was also observed that regardless of the constructive methodology adopted, higher eccentricities result in higher bearing capacity for the steel beam, as exposed in the literature review. While in Brazil is largely unexplored, there was widespread interest in the international literature on the subject in question and their variances, giving rise to theoretical and experimental. Also been mentioned as potential applications in the design of new structures and the renovation and rehabilitation of existing structures. / O presente trabalho discorre sobre o comportamento estrutural, procedimentos de análise e dimensionamento de vigas mistas de aço e concreto protendidas externamente. Embasado nas prescrições expostas na norma ABNT NRB 8800:2008 para vigas mistas convencionais e na revisão bibliográfica, um procedimento de cálculo foi desenvolvido para o dimensionamento de vigas mistas de aço e concreto protendidas externamente e solicitadas a momento fletor positivo. Foram analisados os principais modos de colapso globais, com destaque nos estados limites de últimos (ELU), que podem ocorrer nesse tipo de estrutura. Além disso, elaborou-se um estudo paramétrico que teve como objetivo analisar a influência da variação do nível de protensão e da excentricidade dos cabos de protensão; bem como da metodologia construtiva (pré-tração e pós-tração) adotada para a protensão do perfil de aço que compõe a viga mista de aço e concreto. O estudo paramétrico demonstrou que em ambas as metodologias o modo de colapso predominante ocorre na 2ª Etapa de construção. Nos modelos de vigas mistas analisados com aplicação de pré-tração quando o cabo está posicionado acima da mesa inferior do perfil de aço o modo de falha ocorreu por flexo-compressão. Já para as vigas mistas avaliadas com pós-tração, independe da posição do cabo, ocorre em função do momento fletor solicitante superar o momento fletor resistente da seção. No entanto, observa-se que o nível de protensão pode ser adequadamente dimensionado de maneira que não provoque a perda da capacidade de suporte da estrutura. Observou-se ainda que independente da metodologia construtiva adotada, maiores excentricidades resultam em maior capacidade resistente para a viga de aço, corroborando os estudos expostos na revisão bibliográfica. Embora no Brasil seja pouco explorado, observou-se um amplo interesse na literatura internacional sobre o tema em questão e suas variâncias, dando origem a pesquisas teóricas e experimentais. Também se aponta como potencialidades de aplicação em projetos de novas estruturas bem como na recuperação e reabilitação de estruturas existentes.

Master’s thesis describes the structural design and static analysis of selected elements of prefabricated reinforced concrete industrial building, that will be used as storage hall. Purpose of thesis is elaboration of assembly drawings of the project documentation and drawings of formwork and reinforcement assembly of selected elements. Calculations were performed in computer programs for static analysis SCIA Engineer 16, IDEA StatiCa and FIN EC. Drawing were made in programs Allplan 2016 and AutoCad 2015.

This diploma thesis deals with the analysis of reinforced concrete structure with masonry walls. Scia Engineer was used for finite element analysis. The spatial models include nonlinear behavior of masonry. Furthermore, the ceiling slab above the 1st floor, beams and columns were designed.

The main aim of this master´s thesis is designing parking garage including access ramps situated in Ústí nad Labem. Dimensions of parking garage is 58,6x31,1 m. As a support system of construction are used steel-concrete composite elements. The calcuation was done by manual calcuation.

The experimental studies performed on the behaviour of very thick concrete beams subjected to static loads have revealed that the shear mechanisms play an important role in the overall response and failure behaviour. The aim of this thesis is to recommend suitable design methods for thick concrete beams subjected to off-centre static concentrated load according Eurocode 2 by using non-linear finite element analysis (NLFEA). To achieve this task, Abaqus/Explicit has been used by employing constitutive material models to capture the material non-linearity and stiffness degradation of concrete. Concrete damaged plasticity model and perfect plasticity model has been used for concrete and steel respectively. Three dilation angles (30º, 38º and 45º) and fracture energy from FIB 1990 (76 N/m) and FIB 2010 (142 N/m) has been used to investigate their influence on the finite element model. The dilation angle of 38º and FIB 2010 fracture energy was adopted as the suitable choice that reasonably matched with the experimental results. In verifying and calibrating the finite element model, the experimental results of the thick reinforced concrete beam conducted by the American Concrete Institute have been used. Three design approaches in the ultimate and serviceability limit state according to Eurocode 2 recommendations have been used namely; the beam method, strut and tie method and shell element method. Using the reinforcement detailing of the hand calculations of beam method and strut and tie method and linear finite element analysis of shell element method, non-linear finite element models have been pre-processed and analysed in Abaqus/Explicit. During the post-processing, the results have been interpreted and compared between the three design methods. The results under consideration are hand-calculated load at 0.3 mm crack width, FE-load at 0.3 mm crack width, amount of reinforcement and FE-failure load. The comparison of the results between the three design approaches (beam method, strut and tie method and shell element method) indicates that strut and tie method is better design approach, because it is relatively economic with regards to the quantity of reinforcement bars, has the higher load capacity and has a higher load at crack width of 0.3 mm crack width. / De experimentella studier som utförts på tjocka betongbalkar som utsätts för statisk last har visat att skjuvning spelar en viktig roll i brottmekanismen. Syftet med detta examensarbete är att rekommendera lämpliga dimensioneringsmetoder för tjock betongbalkar utsatt for statisk koncentrerad last enligt Eurokod 2 med hjälp av ickelinjära finita element metod. Abaqus/Explicit användes genom att utnyttja konstitutiva materialmodeller för att fånga materialens icke-linjäritet och minskad styvhet. Tre dilatationsvinklar (30°, 38° och 45°) och två brottenergi från FIB 1990 (76 N/m) och FIB 2010 (142 N/m) tillämpas för att kontrollera deras inverkan på FE-modellerna. Dilatationsvinkel med 38° och FIB 2010 med högre brottenergi valdes i de icke-linjära finita elementanalyserna. Kontroll av FE-modellerna är baserad på ”American Concret Institutes” experimentella resultat på de tjocka betongbalkarna. Handberäkningar av tjocka betongbalkar har utförts i brott- och bruksgränstillstånd med tre dimensioneringsmetoder i Eurokod 2 nämligen balk metoden, fackverksmetoden och linjära-FE skalelementmetoden. Jämförelse har gjorts för de olika dimensioneringsmetoderna, genom att använda de armeringsdetaljer av handberäkningar i de verifierade och kalibrerade icke linjära FE-modellerna i Abaqus/Explicit. Resultaten i fråga är last för 0.3 mm handberäknad sprikvidd, FE-last för 0.3 mm sprikvidd, armeringsmängd och FE-brottlast. Jämförelse av resultaten mellan de tre dimensioneringsmetoder (balkmetod, fackverksmetod och skalelementmetod) visar att fackverksmetod är bättre design metod, eftersom det är relativt ekonomiskt med avseende på armeringsmängd, har högre lastkapacitet och last på 0.3 mm sprickvidd.

Diploma thesis deals with the design and static analysis of an apartment building. The main task of thesis is to design and access the constructions of an expension of an apartment building. The assesment is carried out according to the ČSN EN 1992-1-1.