1,720,999 research outputs found
Lenkiamos kompozitine armatūra armuotos gelžbetoninės konstrukcijos.
No full textOne of the most problematic point in construction is the durability of the concrete especially related to corrosion of the steel reinforcement. Due to this problem the construction sector, introduced the use of Fiber Reinforced Polymer, the main fibers used in construction are Glass, Carbon and Aramid. In this study, the author aim to analyse the flexural behaviour of concrete beams reinforced with FRP. This aim is achieved by the analysis of specimens reinforced with GFRP bars, with theoretical calculations of deflections and comparing the results with the experimental data from the literature. With the theoretical calculations, the main problems are the conservative results obtained from them if compared to the experimental data. To compensate this difference has been used a coefficient of 0.75 in the cracked section moment of inertia to decrease this value obtaining a more coincident results compared to the experiment one
Analysis of damages of reinforced concrete bridges and their influence to bridge stiffness.
No full textIn Master`s thesis was analysed of four span reinforced concrete continuous bridge. Influence of bridge deck stiffness to concrete long term effects, corrosion of reinforcement and concrete cracking was analysed. During the analysis, the influence of concrete age, at the time of first loading, to bridge deck stiffness and bending moment redistribution was determined. To perform linear and non-linear analysis of the investigated bridge deck finite element analysis program “SOFiSTiK” was used. The effective concrete stiffness modulus was decreased by deformation α parameter which takes in to account the concrete cracking in the linear analysis. Effective concrete stiffness modulus was calculated using creep coefficient, which was determined from two different methods: Eurocode and Bažant-Baweja model B3. Results of linear analysis were compared to non-linear analysis results, and more precise results were chosen for further calculations. Also, numerical analysis of reinforced concrete bridge over the river Pyvesa built in 1968 was performed. Bridge deck girder deflections from self-weight and test loads were estimated using linear and non-linear analysis methods and compared to actual data
Punching analysis of reinforced concrete flat slabs.
No full textProject aim – apply Truss method to analyse punching of reinforced concrete flats slabs and compare calculation results to various design codes and experimental test results
Research of CFRP strengthened flexural reinforced concrete beams.
No full textThe doctoral dissertation analyses a review of state-of-the-art research on the reinforced concrete beams strengthened with CFRP and the parameters of the contact zone between CFRP and concrete. Analytical methods that can evaluate the strength, stiffness of composite beams and possible maximum bond force between concrete and CFRP are described. Reinforced concrete beams strengthened with CFRP with and without initial cracks were tested during the experiment. Based on the data of the performed experiment, deflection calculations were performed according to the EC2 methodology. The obtained experimental results are compared with the iteration method, ACI, ISIS and fib norms. An analytical model describing the bond force and shear stress between CFRP and concrete was proposed. The obtained results are compared with the results obtained in the theory of built-up bars. The supplemented analytical method can describe the bond force and shear stress of cracked (low cracking intensity) elements over the length of the element, the results obtained are verified by the FEM. The reinforced concrete beam strengthened with CFRP was also calculated by the FEM, the parameters describing the bond between the CFRP and the concrete were analysed, and the deflection curves from the applied load were obtained, which were compared with the performed experiment
Structural part of project of exhibition center in Klaipėda.
No full textThe scope of the final master project is to design a building of Exhibition Centre in Klaipėda City. The project provides a site plan layout as well as explains and justifies detailed architectural and design decisions. The Constructive part of the particular work provides estimated calculation for structural elements including construction drawings. Regarding the aim of the final work, a comparative cost analysis of roofing panels has been carried out that allows to determine the more efficient type of the boards to be used. The Technological part describes technological processes and examines reinforced concrete ceiling mounting. In the Safety part safety requirements on the construction site are observed and a professional risk assessment analysis during the installation process of prefabricated slabs is carried out. The thesis consists of architectural, structural, technological, organizational and economic and safety parts. The volume of work: 62 pages of text without appendixes, 24 pictures, 13 tables, 6 drawings (A1)
Investigation of stay – in – place formworks with rigid reinforcement.
No full textThe construction industry is focusing on finding efficient structural solutions to ensure greater strength, reliability and durability of building structures. In the industry most commonly used are concrete products that are reinforced with steel rebar, in which case the reinforcement takes tensile forces and the concrete withstands compressive forces. However, in order to provide a greater stiffness, reduce deflections and increase the strength of the vertical shear, concrete structures can also be reinforced with rigid reinforcement, in the case under consideration, I – beam. The composite slab, which is under consideration, consists of two concrete layers cast at different times and encased steel beam. First layer of concrete is manufactured in a factory, it has encased steel beam and are made as permanent formwork. The second concrete layer is cast on site and after hardening the entire structure works as a solid element. Reinforced concrete slab with rigid reinforcement and permanent formwork is an economical solution for structures that require high strength and stiffness, when trying to reduce production and installation costs. In this work two variants of composite slabs with encased steel beam are being examined. The cost of materials and construction is analyzed. All results of mechanical properties and prices are compared with properties of the calculated composite slab with profiled sheeting and the properties provided by the manufacturer of the hollow core slabs
Lenkiamų gelžbetoninių sijų, sustiprintų anglies plaušu, tyrimai.
No full textThe doctoral dissertation analyses a review of state-of-the-art research on the reinforced concrete beams strengthened with CFRP and the parameters of the contact zone between CFRP and concrete. Analytical methods that can evaluate the strength, stiffness of composite beams and possible maximum bond force between concrete and CFRP are described. Reinforced concrete beams strengthened with CFRP with and without initial cracks were tested during the experiment. Based on the data of the performed experiment, deflection calculations were performed according to the EC2 methodology. The obtained experimental results are compared with the iteration method, ACI, ISIS and fib norms. An analytical model describing the bond force and shear stress between CFRP and concrete was proposed. The obtained results are compared with the results obtained in the theory of built-up bars. The supplemented analytical method can describe the bond force and shear stress of cracked (low cracking intensity) elements over the length of the element, the results obtained are verified by the FEM. The reinforced concrete beam strengthened with CFRP was also calculated by the FEM, the parameters describing the bond between the CFRP and the concrete were analysed, and the deflection curves from the applied load were obtained, which were compared with the performed experiment
Research of cracking and stiffness of flexural RC members strengthened by concrete layers.
No full textIt is a popular method to strengthen reinforced concrete structures with additional layer of concrete but there is no information how to accurately evaluate deformation, stress and cracking moment changes. A sudden change appears in deformation diagram where additional layer meets strengthened structure. Because of this breaking point it is impossible to calculate structure as a monolithic section. When additional layer is still not hardened reinforced concrete structure takes over its weight load and becomes slightly deformed. Only when layer is stiff enough the whole structure can take over external loads. There are two deformation and stress calculation methods in this project. Section cracking moment is calculated based on deformation changes of a RC section. To compare methods and results, a strengthened structure has different layers of concrete on the compressed side of section. Different additional layer section and materials were used to analyze deformations in all section elements. Also, monolithic structure was designed to compare differences in deformation and cracking moment
Analysis of frame construction forces redistribution due to foundation settlement.
No full textMaster‘s degree final project is prepared in accordance with existing legislation of the Republic of Lithuania. Firstly, permanent loads, imposed loads for buildings, snow load and wind load operating on the real building are evaluated. A computational scheme is made which is used for further calculations. The reinforced concrete girders of critical transverse frame, two reinforced concrete colums and two shallow foundations are designed, where the ground is sand and clay. The subsidences of separate foundations from forces acting on them are calculated . After subsidences of the foundations are evaluated the girders and the columns are designed again. A comparative analysis is performed for the obtained results
Project of the building structure part of an industrial building with administrative premises.
No full textThe aim of this master's thesis is to design the supporting structures of an industrial building with administrative premises. In addition, it is also aimed to analyse the building's design and construction works, as well as the organization of works. Work project – designed industrial building with administrative premises, whose dimensions are 36.50 x 72.00. The building is designed in Lazdijos str., Lazdijai town. The construction area of the designed building – 2628 m2, site area – 12000 m2. It is planned to design the building in the state land plot located in Lazdijos street, Lazdijai town. The work includes construction regulations and the technical rationing of constructions, building design and architectural solutions. In the project were analyzed the requirements of occupational health and safety, sanitary protection during constructions and fire safety on the construction site. The design part calculates: wooden truss, reinforced concrete column, roof construction, reinforced concrete and metal beam. A description of the beam and floor technology is provided, and the technological card for the installation of beams is formed
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