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Sorption Properties of Building Structures and Their Impact in Indoor Environment

6.12.2018 | Ing. Jakub Diviš, Fakulta stavební, ČVUT Praha, Ing. Jan Růžička, Ph.D., Fakulta stavební, ČVUT Praha, pracoviště UCEEB
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.
1 comment, 06.12.2018 14:50

Traditional Earthen Architecture – Vulnerability to Quakes, Resistant Design and Construction Techniques

21.11.2018 | Ing. arch. Eva Neumayerová, VUT v Brně, Fakulta architektury, Ústav stavitelství
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.

Non-linear analysis of reinforced concrete beam without shear reinforcement based on detailed material characteristics

14.11.2018 | Ing. Oldřich Sucharda, Ph.D., VŠB TU Ostrava, Fakulta stavební, katedra stavebních hmot a diagnostiky staveb a Experimentální stavební centrum, Ing. Pavlína Matečková, Ph.D., VŠB TU Ostrava, Fakulta stavební, katedra konstrukcí
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.

Characteristics of Extruded Clay Bricks as a Support for Clay Plaster

8.11.2018 | Mgr. Art. Roman Miškov, ArTUR Trvalo udržitelná architektura
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.
1 comment, 17.11.2018 04:48

Testing and determination of tensile strength of fiberconcrete

30.10.2018 | Ing. Oldřich Sucharda, Ph.D., VŠB TU Ostrava, Fakulta stavební, katedra stavebních hmot a diagnostiky staveb a Experimentální stavební centrum, Ing. Pavlína Matečková, Ph.D., VŠB TU Ostrava, Fakulta stavební, katedra konstrukcí, Ing. Libor Žídek, VŠB TU Ostrava, Fakulta stavební, Laboratoř stavebních hmot
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.
1 comment, 05.11.2018 12:14

Analysis of the Development and the Possibilities of the Use of Cumulative Explosive Charges for Destruction of Structurally Unstable Buildings

29.10.2018 | Ing. Stanislav Lichorobiec, Ph.D., Ing. Miroslav Mynarz, Ing. Petr Lepík, Ph.D., VŠB TU Ostrava, Fakulta bezpečnostního inženýrství
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.

Factors Influencing the Quality of Recycled Concrete Aggregate (RCA)

16.10.2018 | Ing. Iveta Nováková, Ing. Karel Mikulica, VUT FAST Brno, Ústav technologie stavebních hmot a dílců
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.

Waterproofing Gels Testing In-Situ

6.10.2018 | Ing. Jindřich Melichar, prof. Ing. Rostislav Drochytka MBA, DrSc.,, VUT FAST Brno
Almost all types of building structures in our environment are affected by rising wetness. Especially in old historical buildings this could produce huge problem in the statics. One of the most efficient and suitable solutions of this problem is to create waterproofing injection screen in the base of the structure. This screen is realized by gels, that are injected into the lines of boreholes and subsequently penetrates the building material thus create the screen that stops water from rising above it further into the structure. To examine functionality of the injection gels and their ability to create injection screen in various types of building materials also various types of mason mortar must be tested, because of their ability to transmit the injection gel in its structure.

Load Bearing Capacity of Pillars and Walls, Impact of Humidity on Brick Strength, Experimental Investigation

3.9.2018 | doc. Ing. Ivana Žabičková, CSc., VUT FAST Brno
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.
© xavier gallego morel - Fotolia.com

The influence of humidity and the method to the results of the test with the ultrasound method

13.8.2018 | doc. Ing. Jiří Brožovský, CSc., VUT Brno, Ústav technologie stavebních hmot a dílců
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.
© rafalkubiak - Fotolia.com

Defining the boundaries of own lands in the territory of the region as a basis for updating the principles of territorial development

6.8.2018 | Ing. arch. Simona Vondráčková, ČVUT v Praze, Fakulta stavební, katedra urbanismu a územního plánování, doc. Ing. arch. Ivan Vorel, CSc., doc. ThLic. Ing. arch. Jiří Kupka, Ph.D., Fakulta životního prostředí ČZU v Praze, katedra biotechnických úprav krajiny
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.

Vertical Prestressing of Facade Wall Made in Combination of Clay Brics and Burned Full Brics

30.7.2018 | doc. Ing. Zdeněk Bažant, CSc., doc. Ing. Ladislav Klusáček, CSc., Ing. Jiří Strnad, Ph.D., Ústav betonových a zděných konstrukcí, FAST VUT v Brně
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.

Refurbishment of Riding`s Hall Roof Structure - The National Heritage

23.7.2018 | doc. Ing. Jaroslav Sandanus, PhD., doc. Ing. Kristián Sógel, PhD., Katedra kovových a drevených konštrukcií SvF STU v Bratislave
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.

Reconstruction of wooden ceilings – timber joists mechanically jointed with wood-based boards

18.6.2018 | Ing. Zdeněk Vejpustek, Ph.D., doc. Ing. Bohumil Straka, CSc., doc. Ing. Jan Vaněrek, Ph.D., VUT FAST Brno
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.
© smereka - Fotolia.com

The Formation of Gaseous Products at Thermal Degradation of the Retardant Treated Fir Wood

18.6.2018 | Ing. Veronika Veľková, PhD., prof. RNDr. Danica Kačíková, PhD., prof. RNDr. František Kačík, PhD., Ing. Tatiana Bubeníková, PhD., Ing. Katarína Trebulová, Drevárska fakulta, Technická univerzita vo Zvolene
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.
© cpauschert - Fotolia.com

Mediation Principle in Urban Planning

4.6.2018 | Bc. Jan Tichý, Vysoké učení technické v Brně, Fakulta stavební
This paper aims to outline basic requirements for the creation of the mediating institution in the urban planning process. It applies the work of the Austrian School of Economics on the urban planning system. It reviews the current state of the system of urban planning, it’s hierarchy. Decision-making process, the role of public, and the role of private investors and developers. To increase the quality of the urban planning process, it establishes the principle of mediation, which aims to change the positions of all sides involved. The core of the mediation principle is to use the unique knowledge and position of the three main sides of the process, being developers, public, and public administration. Establishing of a productive dialogue between all sides can create a more effective urban development.

Long-term physical-mechanical characteristics of aerial-lime based mortars with guar gum derivatives

28.5.2018 | Ing. Tomáš Žižlavský, Vysoké učení technické v Brně, Fakulta stavební, Ústav chemie
This paper studies the possibility of usage of the guar gum and its derivatives as admixtures for aerial lime-based mortars. The influence on the properties of mortars was studied on the aerial lime–based mortars prepared with quartz fine grained sand and doses of admixtures ranging between 0,5 and 10 ‰. The hardened bulk densities, flexural and compressive strength, carbonation rate, workability though flow table test and air content in fresh mortar were studied. The addition of the hydroxypropyl guar (HPG) lowered the bulk density (due to an air intake), improved workability, slightly increased the strength and slowed carbonation rate. The addition of carboxymethylhydroxypropyl guar (CMHPG) does not impact the bulk density and air content in the fresh mortar, the strengths were increased similarly to HPG: it does not impact carbonation rate significantly, so the long term strengths were comparative with the HPG. The pure guaran was found not to be beneficial for the lime mortars.

Environmental benefits of using recycled wood to produce agglomerated materials (Part 3)

21.5.2018 | doc. Ing. Milan Gaff, Ph.D., Ing. Kamil Trgala, Ph.D., Ing. Tereza Adamová, Česká zemědělská univerzita v Praze (ČZU), Fakulta lesnická a dřevařská, katedra dřevěných výrobků a konstrukcí
Wood and the materials on its basis fulfil the requirements of an ever-evolving and accelerating society. In addition to naturally grown wood, wood-based materials are frequently used as a basic material for production of furniture and for building constructions as well. Looking at changes in waste management, a significant shift from the waste to the circular economy can be observed. The valuable raw materials are kept in the production cycle instead of landfilling or burning. Wood and wooden products can be efficiently separated in waste management, reused and recycled. The so-called wood waste – old furniture, wooden pallets, window and door frames, demolition wood, used lumber, bark and other wood residues can be reused in particleboard production. Particle board manufacturers in the Czech Republic have adopted progressive waste management and currently use 60% of recycled wood into particle boards. A completed life cycle analysis (LCA) of OSB demonstrates that replacing of 50% of natural fibres with recycled wood has significant environmental benefits. The objective is to push furthermore on effective legislation to promote waste material utilization and thus lead to a more sophisticated waste wood collecting.

Operational Modal Analysis of the „SNP“ Bridge in Bratislava

14.5.2018 | Ing. Michal Venglár, prof. Ing. Milan Sokol, PhD., Ing. Katarína Lamperová, Slovenská technická univerzita v Bratislave, Stavebná fakulta, Katedra stavebnej mechaniky
The article is devoted to extraction of some mode-shapes from measured data during the operational state. The measured bridge is in Bratislava and connects two city districts: The Old Town and the Petrzalka district. The structure is an asymmetric cable-stayed steel bridge with an orthotropic 2-box beam supported in one plane by cables from an inclined pylon. The bridge was measured twice, firstly in 2016 and secondly in 2017. Ambient vibration data were acquired during the measurements. The FEM model has been prepared before the measurements. Some mode-shapes were identified from the data and then compared to the calculated ones.

Environmental benefits of using recycled wood to produce agglomerated materials (Part 2)

14.5.2018 | doc. Ing. Milan Gaff, Ph.D., Ing. Kamil Trgala, Ph.D., Ing. Tereza Adamová, Česká zemědělská univerzita v Praze (ČZU), Fakulta lesnická a dřevařská, katedra dřevěných výrobků a konstrukcí
Wood and the materials on its basis fulfil the requirements of an ever-evolving and accelerating society. In addition to naturally grown wood, wood-based materials are frequently used as a basic material for production of furniture and for building constructions as well. Looking at changes in waste management, a significant shift from the waste to the circular economy can be observed. The valuable raw materials are kept in the production cycle instead of landfilling or burning. Wood and wooden products can be efficiently separated in waste management, reused and recycled. The so-called wood waste – old furniture, wooden pallets, window and door frames, demolition wood, used lumber, bark and other wood residues can be reused in particleboard production. Particle board manufacturers in the Czech Republic have adopted progressive waste management and currently use 60% of recycled wood into particle boards. A completed life cycle analysis (LCA) of OSB demonstrates that replacing of 50% of natural fibres with recycled wood has significant environmental benefits. The objective is to push furthermore on effective legislation to promote waste material utilization and thus lead to a more sophisticated waste wood collecting.
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