The article deals with a design of very slender steel columns loaded in compression. The design resistance of common compression columns results from the buckling resistance, which is due to a high slenderness low. Modification of a common column into a stayed prestressed system leads to a multiple increase of its design resistance. The article describes prestressed steel stayed columns with one central crossarm. First the formulas for critical loads of “ideal stayed columns” are presented, second the formulas for maximal resistances of “imperfect stayed columns” are given. The reduction of the maximal resistances by a material partial safety factor results into a design resistances in accordance with Eurocode 1993-1-1. Finally a solved example is presented with a comparison of resistances received for the prestressed (stayed) column and non-prestressed (common) column with a very high slenderness.

The subject of this paper is an experimental and numerical analysis of the stability of the wall panels with one-side board sheating. 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 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. The main aim of this project is to create reliable numerical model using experiments and parametric study for optimized design. Outcome of the work is a design model and dimension tables for one-side board sheating wall panels of light timber structures with a rib in the form of an I-stud.

Fluid fuel combustion technology in coal-fired power plants is also very popular in the Czech Republic, resulting in a relatively high production of a specific by-product – fluidized fly ash, which differs from the classical high-temperature fly ash in mineralogical composition with a high sulphur content of anhydrite CaSO₄. Fluidized ash is not yet used in the production of fired building materials, where it could be used as a cheap source of calcium oxide (for example, the production of porous ceramic tiles). However, the issue of sulphur dioxide leakage during the re-firing of fluidized fly ash in ceramic raw materials mixtures has to be solved. This paper deals with the analysis of the basic properties of domestic fluidized fly ash and provides a reflection on its possible use in building production.

Dowel joints with wooden fasteners are an important part of many timber structures. They have been used especially in historical timber structures. This type of fasteners can be used for the construction of modern wooden structures or for the production of individual wooden structural elements, such as the Holz100 system of the Austrian company Thoma or for similar Brettstapel structural elements. Actual normative materials (principally Eurocode 5) do not provide sufficient safe design description for such structural joints. A complex model of failures in different directions to the grain of wood is missing. The article focuses on a pilot study on the evaluation of mechanical behaviour of dowel joints and presents the results of experiments of all-wood joints with dowels made of various wood species.

The mechanical properties of earthen building material have been intensively investigated for the last fifty years. Different earth mixtures are used for different building technologies, such as walls, bricks or plasters. Therefore, it is almost impossible to set a specific numerical value for a parameter in general. These values may vary significantly and are listed within range. The properties of each earth mixture are dependent on the clay content (type of clay minerals), filler, water and additives. Depending on the building technology several tests can be performed to determine the mechanical properties. This review article discusses mechanical properties of earth, the tests and limit values. These properties include density, binding force, compressive strength, tensile strength, bending tensile strength, bond strength, resistance to abrasion, modulus of elasticity and impact strength of corners.

The paper summarizes latest research on the influence of natural clay materials and earth structures on the quality of indoor microclimate regarding relative humidity. This laboratory research has been carried out at FCE CTU in Prague and UCEEB CTU in Prague and focuses on the dynamic sorption properties of building structures based on natural clays compared to building structures based on common building materials.

Earth is one of the oldest building materials and in many countries still the most common building material, often preffered for its low cost and self-construction possibilities. Also in Europe, soil was used for centuries as a building material and nowadays expanding again because of it´s enviromental characteristics. Unfortunatelly, traditional unstabilized earth buildings are vulnerable to earthquakes and as many earthen buildings are located in earthquake prone areas, serious damages and life-threatening collapse of many houses occurs regullary. This article shows possibilities of seismic protection and earthquake resistant construction techniques of traditional earthen buildings.

Analysis and design of reinforced concrete structures requires knowledge of the mechanical properties of the materials used. In the case of nonlinear analysis, a higher range and detail of mechanical properties of concrete is needed. The article focuses on the description of strength characteristics of concrete, attention is paid to the strength of concrete in the tension. The testing was focused on the split tension test and the three-point and four-point bending test. The obtained mechanical properties of concrete are subsequently applied in the nonlinear analysis of reinforced concrete beam without shear reinforcement, which has been subjected to a load test.

The clay bricks produced by extruding (continuous compression) generally have a high proportion of clay. The use of this bricks in buildings is beneficial in terms of the amount of built-in clay in building structures. The positive effects of these clay materials in the living space are generally known, however, using as a support for clay plaster has some difficulties, which are less known. The issue of the application of clay plaster in extruded clay bricks is the subject of my long-term interest.

Concrete is a composite material with significantly different value of tensile and compressive strength. Tensile strength is usually only 1/10 of compressive strength. With admixture of steel fibers it is possible to enlarge the tensile strength. The paper deals with testing and consequent determination of tensile strength of fiber concrete with the amount of fibers 25, 50, 75 kg/m³. Four series, each with more than 23 specimens, were tested. Tensile strength testing implied a few variant of bending test with different span (500 mm or 600 mm), different load configuration (three or four point bending), with or without notch. Results of cube and cylindrical compressive strength and transverse tensile strength are also presented.

Building objects that have been severely damaged by an explosion of explosives, gas or technological breakdowns threaten surrounding area by their unstable state. Their damage is usually so severe that no repair or reconstruction is considered, and the only possible solution is quick demolition. In these risky situations, the emergency state of the building can be advantageously solved by using special charges with an effect which will ensure a rapid reconstruction of the unstable state of the building without endangering the environment, especially in built-up areas of cities.

Due to increasing amount of construction and demolition waste (C&DW), new recycling methods and applications of secondary raw materials are searched. The biggest part of C&DW is old concrete and mortar which can be used for production of recycled concrete aggregates (RCA). To protect the nature and decrease amount of mined natural aggregates, RCA could partially or totally replace natural aggregates used for production of new concrete. This article presents the factors which have influence on the RCA properties. Properties of three different types of RCA were analysed and results compared with properties of natural aggregates. Description of connection between factors and properties of RCA are discussed. Results showed that not only origin and amount of impurities has influence on applicability of RCA as a replacement of natural aggregates for new concrete production.

The trend of the earth building material use is not only for plaster but also for the construction of buildings, as well as repairs of clay buildings, which also require the need to determine the load-bearing capacity of whole walls, not just bricks. The loadability of the walls and the influence of moisture on brick strength have been subjected to experimental investigation of SHS o.s. within the framework of the OP HRD project, the load-bearing capacity of the pillars was examined by FA and FAST staff within the BUT grants.

Results of the measurement ultrasonic pulse method are influenced by numerous factors. The influence of humidity and the method of sounding, direct and semi-direct on the measurement results was monitored. The influence of moisture and the method of transmission the bricks influences the measurement results by varying degrees. The least is influenced by the results of measurements on calcium silicate bricks and, on the contrary, on clay bricks made of plastic dough. Here shows synergistic effects of the state structures and defects in the head.

Replacing a concept “types” of the landscape by the concept “landscapes” in the content of the graphical part of the territorial development principles (ZÚR) presents a substantial change of content in the expression of conception of the regional development, because for these landscapes the target qualities including territorial conditions for their preservation or accomplishment are established in the territorial development principles (ZÚR). The original definition of the types of landscape, which divided the territory according to the characteristic features and properties, must be gradually replaced by the definition of (real) landscapes. It is a great change, because a type of landscape expresses the characteristic properties, but real landscapes in the sense of landscape itself = specific, characteristic, have substantially different sense – they express most of all individual properties of the landscape. Therefore it is necessary to describe and give reasons for importance and the method of individual (not typological) zonation of the territory of the region into landscapes (real landscapes) corresponding to the sense of the European Landscape Convention.

The façade wall made of low-quality materials (clay and burned full brics) was vertically prestressed using monostrands. The wall strip foudation was strengthened with a transverse ties – strands.

In the paper the refurbishment of riding`s hall roof structure is presented. The combined steel-timber load-bearing structure had visible and high horizontal deformations and the gable wall was pushed out of the building.In the frame of refurbishment the diagnostic survey, structural calculations of the original and the new stage of the structure and the proposal of refurbishment works were worked out.

The work is focused on the investigation of the formation of gaseous thermal degradation products of retarded firwood. Samples of firwood were impregnated with solutions of 6 inorganic salts, thermally loaded and the arising gaseous products analyzed by SPME-GC-MS. There were 20 compounds identified, the highest amount was achieved for acetic acid and 2-furaldehyde as typical representatives of wood degradation. Most compounds were identified by degradation of samples treated with boric acid solution, at least with ammonium dihydrogenphosphate. The smallest amount of acetic acid and 2-furaldehyde was determined by treating of fir samples with sodium tetraborate solution, which appears to be a very suitable wood treatment agent for fire protection.

This paper shows the process of restoration, of a historic wooden ceiling, using a “dry method” – interaction between historic timber joists that are mechanically jointed with wood-based boards.The paper describes reasons for choosing the method and principles of a good design. The experience of using this method on site is also described in this article.