Civil Engineering Journal 9-10 / 2014


Title: Model research of the shaft spillway in the Les Království Dam

Author: prof. Ing. Vojtěch BROŽA DrSc., Ing. Martin KRÁLÍK Ph.D.

Abstract: The paper deals with the Les Království Dam. A physical model of the shaft spillway in this dam was built in the Hydrotechnical Laboratory and the model was placed into a channel. The paper describes the pressures measured in the spillway and the water level. There were six types of technical options depending on landscaping. The theoretical and measured discharge rating curves are compared, and the course of pressures in the entire length of the outfall structure is determined.

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Title: Analysis of hybrid glass-steel beams

Author:
Ing. Tomáš FREMR, doc. Ing. Martina ELIÁŠOVÁ CSc.

Abstract: The article describes the experimental analysis of hybrid beams composed of steel flange sand discontinuous glass webs. The analytical model of hybrid beams based on truss analogy was verified by experimental results.

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Title: The potential of non-invasive survey of Charles Bridge’s building structure of sandstone blocks

Author:
Ing. Jakub HAVLÍN, Ing. Monika SLAVÍKOVÁ, Ing. Karol BAYER, Ing. Jan VÁLEK Ph.D.

Abstract: The article compares several diagnostic methods tested on part of the face stone masonry of Charles Bridge in Prague. The selected non-destructive techniques of surface ultrasonic, impact-echo and high-resolution georeadar measurements are not commonly used to diagnose the condition of historic structures in the Czech Republic. The achieved results manifest the benefits as well as the limitations of individual techniques, but, at the same time, stress the importance of their mutual combination.

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Title: Dynamic modulus of elasticity of glued laminated timber beams

Author:
Ing. Pavel KLAPÁLEK, Ing. Lenka MELZEROVÁ Ph.D., Ing. Tomáš PLACHÝ Ph.D.

Abstract: The paper discusses a non-destructive test method, the resonance method. It is used to determine the dynamic modulus of elasticity of glued laminated timber beams. It describes in detail the theory of the proper application of the method and the measurement procedure that was used for beams of glued laminated timber. In the end, the dynamic modulus of elasticity is compared against the static modulus of elasticity, which was obtained by another non-destructive method, the penetrating method (using Pilodyn). The suitability of the resonance method for glued laminated timber may be assessed from the comparison of the values reached.

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Title: The influence of Cold-forming on stainless steel mechanical properties

Author:
Ing. Jan Mařík, Ing. Michal Jandera Ph.D.

Abstract: The paper presents tensile coupon tests carried out for several stainless steel grades. The tests describe the stress-strain behaviour of the material depending on the magnitude of previously induced plastic strain and may serve for the calculation of enhanced material properties for cold-formed sections.

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Title: Light concretes based on slag from municipal solid waste incineration

Author:
Ing. Kirill POLOZHIY, Ing. Pavel REITERMAN Ph.D., Ing. Martin KEPPER Ph.D.

Abstract: The majority of municipal solid waste produced in the Czech Republic is still landfilled (54 % in 2012); nevertheless, the importance of waste recycling (30 %) and waste exploitation in power generation is continuously growing.

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Title: Alkali activation of the ground brick body

Author:
Ing. Bohuslav ŘEZNÍK, prof. RNDr. Pavla ROVNANIKOVÁ CSc.

Abstract: Aluminosilicate materials can be transformed into a very well compacted binding material by the process called alkali activation. The present work aims at the possibility of using brick body by-products from the brick industry in the development of geopolymers. Geopolymers based on the fine ground brick body were tested for compressive and flexural strength, bulk density, porosity and the pore size distribution. The microstructure of chosen specimens was examined by means of the SEM and XRD analysis.

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Title: Experimental verification of barrel brick vault’s response to dynamic effects

Author:
prof. Ing. Jiří WITZANY DrSc. dr. h. c., Ing. Radek ZIGLER Ph.D., Ing. Klára KROFTOVÁ Ph.D., Ing. Shota URUSHADZE Ph.D., doc. Ing. Stanislav POSPÍŠIL Ph.D.

Abstract: Experimental research into the dynamic characteristics of non-reinforced barrel vault segments and vaults reinforced by carbon strips was carried out within the research project [1]. New observations and calculations imply that the seismic risks affecting buildings, mainly in the so-called seismic zones of the Czech Republic, have grown and the area of these territories where buildings must be assessed in terms of seismic effects has increased. Vault structures of historic and listed buildings are extremely sensitive to the deformations of their supporting structures and their response to seismic effects may frequently be accompanied by the vault’s mechanical failure. The article describes dynamic experiments performed on masonry barrel vault segments.

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Title: Strengthening of concentrically compressed masonry pillars with carbon strips inserted in bed joints

Author:
prof. Ing. Jiří WITZANY DrSc. dr. h. c., Ing. Jiří KARAS CSc., Ing. Radek ZIGLER Ph.D.

Abstract: The experimental research carried out within the DF12P01VV037 project was focused on the experimental investigation of the effect of carbon strips inserted in the bed joints of masonry pillars. Due to the extensive programme covered by the research project, the scope of testing had to be limited to verifying each reinforcement alternative of masonry pillars on one test piece. This fact, amplified by a considerable variability of masonry and its components, had to be considered during the interpretation of the results of the experimental research performed. The article presents partial achievements of experimental research on six test pieces.

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Title: Reinforcement of masonry pillars by wrapping in non-prestressed CFRP composite strips – the effect of the “composite – masonry“ contact joint

Author:
prof. Ing. Jiří WITZANY DrSc. dr. h. c., doc. Ing. Tomáš ČEJKA Ph.D., Ing. Radek ZIGLER Ph.D., Ing. Jan KUBÁT

Abstract: Reaching the maximum efficiency of the reinforcement of masonry pillars by their wrapping in non-prestresed strips of composites based on high-strength carbon fibres and epoxy resin requires the observation of appropriate principles creating the optimum conditions for the mutual “composite – masonry” interaction. The article presents the results of experimental research carried out within the DF12P01VV037 project oriented towards the issues of the modification of pillar masonry in corners, in places where non-prestressed wrapping strips of carbon composites are applied.

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Title: Additional reinforcement and stabilisation of compressed walls of brick masonry with strips of carbon fabrics

Author:
prof. Ing. Jiří WITZANY DrSc. dr. h. c., doc. Ing. Tomáš ČEJKA Ph.D., Ing. Radek ZIGLER Ph.D., Ing. Jan KUBÁT

Abstract: The DF12P01VV037 research project included theoretical and experimental research into the reinforcement and stabilisation of walls of brick masonry with strips of composites based on high-strength carbon fabrics placed on the surface of masonry walls at several height levels. The paper presents partial results of the initial phase of this research.

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ISSN 1805-2576 (Online)