11/28/2011

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Wooden Structures The calculation and design elements of wooden structures and buildings. Until recently, the calculation was made of wooden structures on the allowable stress. Under this method, the calculated stress in a wooden element of operating loads compared with the permitted, the latter is obtained by dividing the tensile strength on the safety factor. In this case the tensile strength was taken on the basis of routine laboratory tests on small wood samples. Influence of the duration of the load of wood defects and other factors on the strength of the wooden structures were estimated to be the safety factor, which had different meanings for the lax, compressed and curved wooden elements. This calculation method gives an indication of the wooden structures at the operational load, but did not give a correct idea of the wooden structures in the state close to destruction. The source of the method of allowable stress of a linear relationship between stress and strain are not applicable in practice for many materials, especially wood, even at low voltages. Ignoring the plastic properties of materials, lack of consideration of the actual conditions of the structure under load, the method of calculation of allowable stress, do not give a correct idea of the true margin of safety. As a result of extensive research carried out by Soviet scientists had solved the problem of calculating the wooden structures in engineering limit states. This new method calculation takes into account the effect of various circumstances on the strength of the wooden structure. In the method of limit analysis, in contrast to the method of allowable stress, safety factor is divided into a number of individual coefficients, which take into account the probable change in the load (overload factor n), a possible change in material strength (quality factor k) and the...
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Styling Technology Glass Mosaics Technology laying glass mosaic. From the training base before applying grout. Substrate preparation for laying tile surface should be smooth and clean with no cracks. If the foundation is cracked and it has loose surface then it should be treated accordingly. Otshpaklevat or primed. Caution If your mosaic is made of transparent glass that the base should be white. Quality has a great foundation values for the installation, since the slightest lack of it is visible through the transparent glass mosaic. Preparatory work before laying the glass mosaic. Before starting the work necessary to make a layout on which the surface will be glued material. Horizontal and vertical lines through the level, plumb and line. On them you'll determine the accuracy of the location of the matrix relative to the horizon. Preparation and application of an adhesive solution. For bonding of glass mosaics use a special glue, glue the basic requirements for the following: 1 - it should be suitable for bonding glass mosaic 2 - to be white, gray glue will show through in transparent mosaic tessera. 3 - must fit under the base and the conditions in which the material will be exploited (the street or the interior, in the pool or not, the reason may be cement, plastics, ceramics, wood, metal all this to consider when selecting glue) Getting to the preparation of the adhesive. The proportions for mixing glue looking at the packaging. Amount of new adhesive, you must expect from the accounting of its vitality ( time after which the solution begins to freeze ready-made) and the area in which you can stick the mosaic during its vitality. For gluing the mosaic is recommended to apply adhesive to the area of 1 m2. Apply the adhesive to surface is as follows. First, the smooth side...