THE EFFECT OF MOISTURE ON SIGNIFICANT MECHANICAL CHARACTERISTICS OF MASONRY

2010 ◽  
Vol 2 (3) ◽  
pp. 79-85 ◽  
Author(s):  
Jiri Witzany ◽  
Tomas Cejka ◽  
Radek Zigler
Keyword(s):  
Building Materials ◽  
Mechanical Characteristics ◽  
Laboratory Research ◽  
Masonry Structures ◽  
Historical Structures ◽  
Historical Masonry ◽  
Effect Of Moisture ◽  
Masonry Units ◽  
Physical And Mechanical Characteristics

Experimental and laboratory research into residual physical and mechanical characteristics of historical masonry structures (GAČR 2008; Witzany 2008), in particular the determination of residual strength and modulus of elasticity in compression, included research oriented towards the effect of moisture and porosity on the respective characteristics of masonry units – bricks, sandstone and arenaceous marl. Partial results published in (Witzany et al. 2008) and in this paper testify to the need for further research into the effects of porosity, moisture and chemism on the development of characteristics of building materials applied on historical structures.

Load-Bearing Capacity Determination of Historic Masonry Structures

2014 ◽  
Vol 923 ◽  
pp. 81-84 ◽  
Author(s):  
Jiří Witzany ◽  
Tomáš Čejka ◽  
Radek Zigler
Keyword(s):  
Mechanical Characteristics ◽  
Masonry Wall ◽  
Probabilistic Methods ◽  
Laboratory Research ◽  
Historic Masonry ◽  
Historical Masonry ◽  
Non Destructive ◽  
Physical And Mechanical Characteristics

The experimental, in-situ and laboratory research has manifested a relatively large variance of the physical and mechanical characteristics of historical masonry found e.g. within a masonry wall, a massive masonry pillar etc. Artical presents the evaluation of the experimentally determined physical and mechanical characteristics of masonry members and the binder obtained by sampling specimens and by non-destructive measurements relies on the application of appropriate probabilistic methods.

Determination of Physical and Mechanical Characteristics of Macro Sample of Water Saturated Peat

2018 ◽  
Vol 37 ◽  
pp. 103-111 ◽  
Author(s):  
Aleksandr Vladimirovich Kulikov ◽  
Vyacheslav Viktorovich Vorontsov
Keyword(s):  
Pore Pressure ◽  
Mechanical Characteristics ◽  
Pressure Sensors ◽  
Laboratory Research ◽  
Soil Pressure ◽  
Load Cells ◽  
Water Saturated ◽  
Made In ◽  
Physical And Mechanical Characteristics

The article reports results of laboratory tests of weak water-saturated soils (remoted from day surface) in stress-strain state under influence of compression with double-sided filtration of pore’s water. The authors suggested the upgraded assembly scheme of the soil pressure sensors (load cells). The laboratory research of the water-saturated macro peat sample was made in compression conditions with “ground lock” and modeling of the experiment with Plaxis 2D software system. The unit deformation-pressure graph and excessive pore pressure against time in different steps of load graph were built and based on this findings. Authors made the new experimental device for research of the water saturated peat mechanics properties with excessive pore pressure

Protection of Mediterannean Historical Structures against Earthquakes Using Fragility Curves

2008 ◽  
Vol 56 ◽  
pp. 563-572
Author(s):  
Costas A. Syrmakezis ◽  
M.T. Kosta
Keyword(s):  
Mediterranean Basin ◽  
Fragility Curves ◽  
Masonry Structures ◽  
Earthquake Intensity ◽  
Historical Structures ◽  
Family Of Curves ◽  
Historical Masonry ◽  
Materials Used ◽  
High Seismicity

The post-earthquake rehabilitation and retrofitting of historical structures is an important issue in the entire Mediterranean basin, which is characterized by its richness in historical masonry structures as well as its high seismicity. For the restoration of historical structures and monuments, high demands are raised, due to their great significance as cultural heritage carries. The high importance of these structures, the need for evaluation of their present state and often the determination of the extent and the possible ways of reinforcement, impose the development of a methodology that could offer an estimation of their behaviour, taking into account the uncertainties that are introduced during the analysis. These uncertainties caused by the variety of structural materials used in the same monument, the difficulty of determining their mechanical properties and the random action and intensity of the earthquake phenomenon make essential the presentation of the vulnerability assessment presented in probabilistic terms. This is being accomplished by a methodology which leads to the construction of the fragility curves that can graphically represent the probability of certain damage ranks under the effect of various earthquakes intensities. Through this family of curves, it is possible to investigate the way that each factor affects the vulnerability of the structure, relatively to others. The application of the methodology proposed is illustrated through three typically buildings made of masonry, situated in Crete, Greece and constructed between the 18th and 19th century. Through these case studies the correlation of the earthquake intensity is being shown.

scholarly journals ASSESSMENT OF COMPRESSIVE STRENGTH OF HISTORIC MIXED MASONRY

2015 ◽  
Vol 22 (3) ◽  
pp. 391-400 ◽  
Author(s):  
Jiří WITZANY ◽  
Tomáš ČEJKA ◽  
Miroslav SÝKORA ◽  
Milan HOLICKÝ
Keyword(s):  
Probabilistic Model ◽  
Mechanical Characteristics ◽  
Probabilistic Approach ◽  
Stone Masonry ◽  
Masonry Structures ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive ◽  
Masonry Units ◽  
Physical And Mechanical Characteristics

The majority of load-bearing masonry structures of historic buildings are built of mixed or stone masonry composed of regular or irregular (so-called quarry) masonry units – bricks, sedimentary and metamorphic rock – pos­sessing often very different physical and mechanical characteristics. The identification of residual mechanical properties of stone or mixed masonry of irregular walling units requires the application of a suitable diagnostic method, the as­sessment of the phase of degradation processes and the choice of an appropriate probabilistic model for the strength of mixed masonry. The presented experimental research involves the analysis of the heterogeneity (homogeneity) of mixed masonry of a church from the 17th century. The probabilistic model for masonry strength is developed on the basis of destructive and non-destructive testing of masonry units and mortar. It appears that the probabilistic approach leads to a design value by 75% higher than the deterministic approach.

Study on the Effects of Heat Treatments on the Physical and Mechanical Characteristics of 1.4301 Stainless Steel

2021 ◽  
Vol 42 ◽  
pp. 57-62
Author(s):  
Maria Stoicănescu
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Mechanical Characteristics ◽  
Austenitic Stainless Steels ◽  
Heat Treatments ◽  
Hot Plastic Deformation ◽  
Improved Characteristics ◽  
Physical And Mechanical Characteristics

The 1.4301 stainless steel is part of the category of austenitic stainless steels, steels which do no undergo heat treatments in general, as they are intended for hot plastic deformation in particular. The aim of the research presented in this paper was to obtain significantly improved characteristics of the resistance properties in relation to the values obtained under classical conditions, by applying heat treatments. Samples taken from the delivery state material underwent annealing, quenching and ageing heat treatments. Subsequently, the samples thus treated were subjected to tests enabling the determination of the correlations between the heat treatment parameters, the structure and the properties.

scholarly journals Study of the nature of the dynamic coefficient of internal friction of grainmaterials

2019 ◽  
Vol 135 ◽  
pp. 01102
Author(s):  
Dmitriy Savenkov ◽  
Oleg Kirischiev ◽  
Ylia Kirischieva ◽  
Tatiana Tupolskikh ◽  
Tatiana Maltseva ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Internal Friction ◽  
Agricultural Production ◽  
Mechanical Characteristics ◽  
Dynamic Coefficient ◽  
Bulk Materials ◽  
Dynamic Coefficients ◽  
Internal Friction Coefficient ◽  
Physical And Mechanical Characteristics

The article highlights the issues related to the study of physical and mechanical characteristics of bulk materials, namely internal friction coefficients in static and dynamic modes. An innovative device of the carousel type for determining the frictional characteristics of bulk materials is described, which allows to implement the tasks of practical determination of dynamic coefficients of internal friction. Presented the program, methodology and results of research on the practical study of the internal friction coefficient of typical bulk products of agricultural production in the range of linear velocities of displacement of layers from 0 to 2.79 m/s, the reliability of which is not lower than 0.878.

Determination of the Parameters of the Target Heterogeneous Medium During Centrifugal Arc Dispersion of Hard Alloys

2021 ◽  
pp. 50-57
Author(s):  
K.M. Kolmakov ◽  
A.E. Zverovshchikov ◽  
A.G. Skhirtladze ◽  
A.V. Sokolov
Keyword(s):  
Mechanical Characteristics ◽  
Gaseous Medium ◽  
Heterogeneous Medium ◽  
High Density ◽  
Hard Alloys ◽  
Alloy Particles ◽  
Spheroidal Shape ◽  
Shape Of Particles ◽  
Physical And Mechanical Characteristics

The article considers the ballistic parameters of the trajectories of high-density alloy particles moving in a gaseous medium, accompanied by a phase transition of the of the particle material. A technique has been developed for determining the parameters of the target depending on the physical and mechanical characteristics of the materials of the captured particles and target layers. The possibility of maintaining the spheroidal shape of particles during the electric arc dispersion of high-density alloys has been determined.

scholarly journals Study of reinforced elastomeric bearings for structures in seismic areas

2018 ◽  
Vol 193 ◽  
pp. 03009 ◽  
Author(s):  
Larisa Safina ◽  
Aleksandr Shuvalov ◽  
Mikhail Kovalev
Keyword(s):  
Mechanical Characteristics ◽  
Individual Characteristics ◽  
Seismic Protection ◽  
Power Equipment ◽  
Test Rig ◽  
Elastomeric Bearings ◽  
Full Size ◽  
Metal Support ◽  
Physical And Mechanical Characteristics

The article presents the results of the experimental determination of the physical and mechanical characteristics of rubber-metal vibration-proof supports used in the construction of facilities in the areas of increased seismic hazard. The testing was based on two necessities: to substantiate the possibility of using such a constructive seismic protection solution and to create reliable calculation models of the structures with rubber-metal support. More than thirty samples were tested in the laboratory under various loads and impacts. The elastomers were tested in accordance with the requirements written in EN-1337-3. The experiment was performed on three types of elastomer model samples to determine their vertical and horizontal stiffness, the tensile strength and modulus of elasticity and creep. The work was performed on INSTRON power equipment and a test rig equipped with MTS hydraulic jacks installed in the power frame. The testing results of elastomeric support models were confirmed by the determination of individual characteristics on the full size specimens at the corresponding load. Thus, the test has confirmed and proved the validity of the use of elastomeric bearings for seismic protection of a mall construction.

Two Phase Model of Diffusion in Polycrystalline Material

2014 ◽  
Vol 1040 ◽  
pp. 614-619
Author(s):  
Marija V. Chepak-Gizbrekht ◽  
E.V. Shvagrukova
Keyword(s):  
Mass Transfer ◽  
Grain Boundaries ◽  
Mechanical Characteristics ◽  
Polycrystalline Material ◽  
Approximate Analytical Solution ◽  
Boundary Phase ◽  
New Materials ◽  
Two Phase ◽  
Physical And Mechanical Characteristics

Diffusion research is important for understanding of many processes based on mass transfer. In many respects, diffusion, determines physical and mechanical characteristics for new materials with fine-dispersed matter and a large number of grain boundaries and phases. Models of diffusion along grain boundaries and their modifications are widely known in literature, but they are not always applicable to nanomaterials due to indistinct determination of some notions. At the present paper the model of diffusion is presented, which considers boundaries and area near boundaries as a phase with special properties. Mass transfer between the volume of a grain and a boundary phase is taken into account. The approximate analytical solution of the problem is formulated. In the general case the problem is solved numerically. Non monotonic distributions of concentrations in volume are obtained.

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