This paper discusses the unique replacement of three historical bridge spans across the Hracholusky dam in the Czech Republic. The erection of the bridge was performed using longitudinal launching of a new bridge structure onto the old one, connecting and rotating the structure around a longitudinal axis before removing the old span.

AbstractThis paper deals with the issue of spatial modeling of façade frame scaffolding, with the focus on developing a methodology for modeling subfloor components. A laboratory experiment on a standard scaffold base assembly consisting of two spans is described. Load tests were carried out, and additional measuring points were added to the measuring apparatus compared to the standard procedure. The nonlinear stiffness of the numerical models was derived from the measured value. Furthermore, planar models of the scaffold subfloors were created and validated against experiments. Finally, the paper proposes scaffold stiffness in the horizontal direction (perpendicular to the façade and parallel to the façade) that can be used in a full spatial member of the scaffold model.

Dieser Artikel beschreibt den einzigartigen Ersatz von drei historischen Brückenspannweiten über den Hracholusky-Stausee bei Pilsen in der Tschechischen Republik. Bei der Konstruktion wurde die neue Brückenstruktur in Längsrichtung auf die alte aufgesetzt, mit ihr verbunden und um die Längsachse gedreht.

This paper deals with a unique replacement of three bridge spans across the Hracholusky dam in the Czech Republic. The replacement was done by a longitudinal launching of the new bridge structure to the old one, their connection to each other and subsequent rotation of the bridge system around the longitudinal axis for 180°.

The subject of this paper is an experimental and numerical analysis of the stability of the wall panels with one-side board sheathing for timber structures. The reinforcement of the panel is provided using glued timber composite I-shaped element consisting of a web made of a wood-based desk embedded into flanges of solid timber. The mechanism of the behaviour of these panels, mode of the failure and reliable procedure to determine the buckling load-bearing capacity not been fully explored so far. This work describes the behaviour of the wall panel under vertical load and the method of failure using experimental and numerical analysis. The reduction coefficient kJ was determined, which can be used for a simple calculation of the buckling capacity of a wall panel.

The objective of the research is a steel fiber‐reinforced concrete slab in compression in a composite frame joint. EN 1998‐1 relates only to composite joints with common concrete slab. This standard prescribes two mechanisms: mechanism 1 acts in the concrete slab with a concentrated compressive force on the column flange; mechanism 2 consists of struts and tie model, where concrete struts compress the concave parts of the column cross‐section. By these mechanisms, it is prescribed inaccurate formula for the effective width calculation of a common concrete slab in compression in the nodal zone, as the standard procedure does not consider the contribution of the confinement effect to the resistance of mechanism 1. Mechanism 1 represents a direct bearing of the concrete slab against the column flange. There is a concrete slab in compression confined by transverse reinforcement, slab continuity around the column flange and friction on the column flange. Moreover, some publications describe different inclination of the concrete struts of mechanism 2. The resistance of mechanism 2 significantly depends on this inclination. The aim of this work is to derive a more accurate formula for calculation the effective width of the steel fiber‐reinforced concrete slab in compression in the nodal zone. Experiment with real‐sized isolated composite joint, validation of ATENA numerical models and parametric study of composite joints with fiber‐reinforced concrete slab are the main steps of this research.

The objective of this research is a concrete slab in compression in composite steelconcrete joint. en 1998-1 prescribes a simplified formula and it describes two mechanisms. The standard procedure for calculating the effective width of the slab is inaccurate, as it is stated repeatedly in a number of publications. Mechanism 1 acts in the concrete slab with a concentrated compressive force on the column flange. in the standard procedure for calculating the bearing capacity of this mechanism, the positive effect of the state of stress in the concrete slab in the joint region is not taken into account. the goal of this research is to derive more accurate formula for calculation of effective width of fibre-reinforced concrete slab in compression in the nodal zone. New aspects have been taken into account: confinement effect of the mechanism 1 and more precise inclinations of concrete struts. An experiments, a validation of a numerical models and a parametric study of the composite joints with slab made of common concrete and fibrereinforced concrete are main steps of this research.

The subject of this paper is a new knowledge in experimental and numerical analysis of the stability of the wall panels with one-side board sheathing. The reinforcement of the panel is provided by means of glued timber composite I-shaped element consisting of a web made of a wood-based desk – OSB board embedded into flanges of solid timber. At present, the design of wall panels with I-shaped cross-section stiffeners and double-sided sheathing is based on test results and simplified analytical calculation. For the design of wall panels with I-shaped cross-section stiffener rib and one-sided board sheathing, a reliable procedure for determining the buckling load bearing capacity has not been described so far. It is assumed that the base of this work can be used for more effective material use of subtle light timber frames. By optimization of the supporting structure, increased heat-technical properties will be effectively achieved. New outputs of experimental analysis on wall panels in real dimensions, as well as material tests of individual components such as solid wood, OSB board and staples will be presented in this paper. Moreover, this paper presents the results of detailed numerical analysis, which are validated on the basis of the experiments performed.

This research deals with mechanical properties of cold formed area of high strength steel STRENX S960E, which was subjected to welding. Recent standard EN 1993-1-8 deals with welding of high strength steel up to the grade S700 and with a welding in a cold formed area for only the mild steels. Main purpose of this paper is description of toughness, hardness, stress-strain and metallography of 10 mm thick steel sheet made of high strength steel STRENX S960E, which had been cold formed (bent) and subsequently steel sheet of the same material has been welded to the cold formed area by MIG welding procedure. All above mentioned properties will be investigated with respect to bending radius, welding parameters and filler material matching grade.

The currently only applicable regulation for the design and assessment of steel structures is CSN EN 1993-1-1 – Eurocode 3: Design of steel structures – Part 1-1: General rules and rules for buildings. The requirements contained in this standard are related even to steel structures used in underground construction, such as for example, rolled-steel colliery support sections used in driving galleries, excavation of pits and shafts. From the static point of view, steel colliery supports, under the assumption of perfect activation of excavation bracing, is capable of transferring ground pressure loads immediately after their installation. The paper presents a plasticity approach to the assessment of a rectangular construction shaft using a stability calculation. Obr. 1 Šachta vyztužená ocelovou důlní výztuží Fig. 1 Shaft reinforced with steel colliery support tunel_1_16:tunel_3_06 2.3.2016 10:05 Stránka 61

Steel pipelines are an important part of industrial technology equipment in many sectors. Ducts with a ratio of pipe diameter to wall thickness of up to 150 are generally considered as simple beams, ducts with a higher ratio have to be considered as shell elements. Technical literature provides a number of methods for designing such structures stressed by various kinds of loads. Failures that have occurred in recent past suggest that the existing common design method for industrial piping shows some insufficiencies. This paper is focused on the study of stiffened steel shells stressed by temperature changes. Due to a high temperature load, there is a big temperature deformation of the whole system. This deformation caused by temperature differs within particular parts of the system. As the high temperature source is inside the pipe, the highest temperature is on the inner surface of the shell. The variation of the temperature in the shell and the partial warming of the ring stiffener is caused by heat conduction. Due to the different temperatures of the surrounding environment the stiffener is always colder compared to the shell. The research is focused on the shell behaviour close to the ring stiffener, which represents the area most tending to cracks initiation and their expansion due to the low-cycle fatigue phenomenon. The research procedure consists of several sub-parts. In the first part, the authors focus on determining the thermal load based on the theory of heat transfer. The resulting heat transfer coefficients were verified by measurements performed on the real structure. These findings served as boundary conditions for numerical modelling in Ansys. The resulting values of strain and stress were one of the inputs for the subsequent analysis of lifetime prediction from the viewpoint of low cycle fatigue. The number of cycles to failure (creation of macro-cracks) for various types of structural solutions has been determined in the final part of research.

The objective of this article is to show the design process of a liquid-storage tank shell according to Eurocode and compare the results obtained using the norms with those from a finite element method (FEM) analysis. The calculations were performed for an aboveground vertical steel water-storage tank with a variable thickness wall and stiffening ring on top. First, the types of liquid storage tanks are briefly explained. Second, the given tank is described. Third, an analysis of the tank wall according to the Eurocode was carried out. The FEM analysis was performed using the Scia Engineer ver. 17 software. Finally, all the results are presented in tables and compared.

Timber elements with an I-shaped cross-section are used as supporting elements in wall, ceiling and roof panels of light timber frames. The reinforcement of the panel (I-stud) is provided by means of glued timber composite I-shaped element consisting of a web made of a wood-based desk embedded into flanges of solid or glued laminated timber. The stability of the wall panels is usually ensured by sided board sheathing, which prevents buckling of studs in the plane of the wall or their twist. Walls with one-side board sheathing are used for some types of modern timber structures and their load bearing capacity is determined for situation when one-side sheathing burns down during fire or sheathing is not made of a load-bearing material.

ABSTRACTAn advanced analysis of spatial interaction between the elements of tubular scaffolding has been carried out at the Czech Technical University in Prague. Experiments focusing on rotational stiffness of the common couplers have been performed. The resulting stiffness (semi‐rigid connections), eccentricities etc. have been implemented into spatial models and a detailed GNIA analysis followed. The results of calculations performed on simple and complex models and a recommendation for the most effective computation models has been presented. The recommendations have been implemented in the following research of the scaffold anchoring. This paper research was essential for the related development of the new scaffold anchor, which successfully overcomes the problems with insulated building facades.

The aim of this paper is to compare the results of evaluation of mechanical properties of timber by visual assessment, two grading machines, three devices for measuring in-situ and destructive tests. The most important result is the comparison of static and dynamic modulus of elasticity of timber, and further comparison of strength classes obtained by different measuring methods.

In this paper, a new scaffold anchor system is presented. The developed scaffold system overcomes the problems associated with the existing scaffold anchors. The existing scaffold anchors damage the surrounding insulation layers subsequently decreases the stability of scaffold anchors. The developed scaffold system has a new type of the facade anchor and the position pattern used for scaffolding. The developed scaffold system is based on the accurate FE models of the prototype anchor, which have been updated in the light of the experimental results i.e. force-displacement curve. It has been observed that the results of finite element model do not match with experimental results. The modelling of stiffnesses of the joints is considered to be the major source of uncertainty in the finite element model. Subsequently, stiffnesses of joints of anchor have been updated in the light of experimental data. The results have shown that after updating, the predictions of finite element model of scaffold system matches well with experimental results. Subsequently, the loading forces used during the optimization process have been obtained from the updated finite element model of the tubular scaffold construction related to the Eurocode standards. In addition to the problems associated with existing scaffold anchors, the developed scaffold anchor is also effective in transmitting support forces to the facade object along with increasing the stability of scaffold anchors. (C) 2016 Elsevier Ltd. All rights reserved.

The article deals with the methods of the in situ assessment of timber members. In recent years, new methods have emerged based on methods such as on thermography or X-ray radiography. The objective of the research is to determine whether the density of inbuilt timber members may be identified by means of radiometry. Unlike the currently used penetration methods, it is a purely non-destructive method, which is of particular importance mainly in historic timber structures. The measurement was performed on timber specimens of different cross-sections coming from several species of coniferous as well as deciduous trees. In the next phase, acoustic methods were used to determine the mechanical properties, and the resulting values were compared against the values from conclusive tests.

The paper focuses on the updating of the finite element models of the newly developed facade scaffold anchor in the light of the experimental results. The experiments (force-displacement curves) have been carried out on the anchor. The facade scaffold anchor overcomes the problems arising in the process of joining them to the facades through the thermal insulation layers. Using the current methods, the wind load cannot be effectively transferred into the facade and scaffolding stability is decreased. Experimental results are presented and the finite element models of the anchor are developed using non-linear beam and solid elements. It has been observed that the predictions of finite element models that is force-displacement curve do not match with the experiment results. Subsequently, the finite element models of the developed anchor have been updated in the light of experimental results by using the parameter-based finite element model updating method. In case of an anchor, modelling of stiffness of the joints and values of the materials are expected to be dominant sources of inaccuracy in the FE model, assuming that the correct geometric parameters are known. After updating joint stiffness of the anchor joints and material properties, the finite element predictions match with experimental results. The outcomes show that there is a good correlation between the updated finite element models and the experimental data. The accuracy of the updated finite element models is demonstrated by overlaying force-displacement curves with the curve from the experiment, it can be concluded that the updated finite element models of the anchor accurately represent reality.