CC BY
52
международный научный журнал «символ науки»
№6/2015
issn 2410-700х
ТЕХНИЧЕСКИЕ НАУКИ
UDC 624.071
Mavlonov Ravshanbek Abdujabborovich, Vakkasov Khayrullo Sayfullahanovich
Assistants of department of "Construction of buildings and structures" Namangan Engineering Pedagogical Institute,Namangan city, Uzbekistan
ravshanbek.mavlonov@gmail.com
INFLUENCE OF WIND LOADING
Abstract
Each wind load is determined by a probabilistic-statistical method based on the concept of "equivalent static wind load", on the assumption that structural frames and components/cladding behave elastically in strong wind.
Key words
Wind loading, live loads, wind pressure, wind velocity
Environmental loads are caused by the environment in which the structure is located. For buildings, they are caused by rain, snow, wind, temperature change and earthquake. These are also live loads, but they are the result of the environment. Although they do vary with time, they are not all causing by gravity or operating conditions, as is typical with other live loads.
Wind is a phenomenon of great complexity because of the many flow situations arising from the interaction of wind with structures. Wind is composed of a multitude of eddies of varying sizes and rotational characteristics carried along in a general stream of air moving relative to the earth's surface. These eddies give wind its gusty or turbulent character. The gustiness of strong winds in the lower levels of the atmosphere largely arises from interaction with surface features. The average wind speed over a time period of the order of ten minutes or more, tends to increase with height, while the gustiness tends to decrease with height.
A consequence of turbulence is that dynamic loading on a structure depends on the size ofthe eddies. Large eddies, whose dimensions are comparable with the structure, give rise to well correlated pressures as they envelop the structure. On the other hand, small eddies result in pressures on various parts of a structure that become practically uncorrelated with distance of separation. Eddies generated around a typical structure are shown in Fig. 1. There are several different phenomena giving rise to dynamic response of structures in wind. These include buffeting, vortex shedding, galloping and flutter. Slender structures are likely to be sensitive to dynamic response in line with the wind direction as a consequence of turbulence buffeting. Transverse or cross-wind response is more likely to arise from vortex shedding or galloping but may also result from excitation by turbulence buffeting. Flutter is a coupled motion, often being a combination of bending and torsion, and can result in instability. For building structures flutter and galloping are generally not an issue.
Figure 1: Wind flow around buildings
36
международный научный журнал «символ науки»
№6/2015
issn 2410-700х
An important problem associated with wind induced motion of buildings is concerned with human response to vibration and perception of motion. At this point it will suffice to note that humans are surprisingly sensitive to vibration to the extent that motions may feel uncomfortable even if they correspond to relatively low levels of stress and strain. Therefore, for most tall buildings serviceability considerations govern the design and not strength issues.
Wind represents masses of air moving mainly horizontally (parallel to the ground) from areas of high pressure to ones of low pressure. The main effect of wind is a horizontal loading of buildings (especially high-rise). Wind is air in motion. Structure deflects or stops the wind, converting the wind's kinetic energy into potential energy of pressure, thus create wind loads.
The intensity of the wind pressure depends on:
- shape of structure;
- velocity of air;
- angle of the induce wind;
- stiffness of structure;
- density of air;
Normal amount of wind pressure (O0 determines in the below:
1 2
2
(i)
where:
p - is the air density, which depends on altitude, temperature, latitude and season. The recommended value
for design is 1,25 kg/m3;
l)0 - the value of the wind velocity, is the
characteristic A type at 10 m above ground level, in interval of 10 minutes mean wind velocity. Values of wind velocity are determined for annual probabilities of exceedence, which is equivalent to a mean return period
Fluctuating of 5 years. Figure 2. Variation of wind velocity with height
The mean wind velocity at great heights above the ground is constant and it is called the gradient wind speed. Near the ground the mean wind velocity is decreasing much due to frictional forces caused by the terrain, being equal with zero at the ground level. There is a boundary layer within which the wind speed varies from zero to the gradient wind speed (mean wind velocity increases with height).
Velocity pressure, (Om , evaluated at height z shall be calculated by the following equation: ®m = kC; (2) where: O)0 - normal amount of wind pressure, (kg/m2);
k - velocity pressure exposure coefficient; С - aerodynamic coefficient;
References:
1. Mavlonov R.A., Ergasheva N.E. Strengthening reinforced concrete members // «Символ науки» - 2015. -№3/2015 - С. 22-24. г. Уфа, Россия.
_международный научный журнал «символ науки» №6/2015 issn 2410-700х_
2. Абдурахмонов С.Э., Мавлонов Р.А. Трещины в железобетонных изделиях при изготовлении их в нестационарном климате. // Материалы сборника международной НПК «Наука и образование: проблемы и перспективы». 13 март 2014 г. - С. 197-198. г Уфа, Россия.
3. Мавлонов Р.А., Ортиков И.А. Cold weather masonry construction. // Материалы сборника международной НПК «Перспективы развития науки». 20 март 2014г. - С. 49-51. г Уфа, Россия.
4. Мавлонов Р.А., Ортиков И.А.. Sound-insulating materials. // Материалы сборника международной НПК «Актуальные проблемы научной мысли». 24 апреля 2014г./ - С. 31-33. г Уфа, Россия.
© R.A.Mavlonov, Kh.S.Vakkasov, 2015
UDC 637.525
Syzdykova L. S., candidate of technological science, associate professor laila.ss@mail.ru
Dikhanbayeva F.T., doctor of technological science, professor
Bazylhanova E.Ch, senior lecturer Almaty Technological University Almaty, Republic of Kazakhstan
INCREASING THE BIOLOGICAL VALUE OF DIETARY CUTLETS
Summary
Relevance of work: meat products are the main source of the proteins, necessary for activity of the person. In this article is determined the biological value of the cutlets with dietary properties.
The purpose of this work is development of the production technology of dietary cutlets in branches of public catering and determination of their biological value.
As a result of work dietary cutlets with the increased biological value due to addition of oatmeal are received.
Keywords
Meat, meat semi-finished products, cutlets, oatmeal, power value, nutrition value, technology.
Word cutlet (in french cotelette) formed from the french word cotele - rib or cote - edge. First, with the same name prepared grilled meat of cow, that is a natural cutlet. At the beginning, it was a condition that was cutlet with a bone, because it was helped to consumer for convenient to consume cutlet in his hand. After some time, due to the expansion of the range of cutlery chopping cutlets was extended, and the bone was not considered as an element necessary for this product [1, 2].
Cutlet - a product that is made from meat, fish, poultry, spending through a meat grinder, add the onion, frying, stewing and on water steam. Cutlets are divided for pure without additives, flattened and made from minced meat [3, 4, 5]. Content cutlets prepared from chopped meat shown in the following table (Table 1).
Table 1
Flow chart of meat (chopped) cutlet
Product name Traditional cutlet (norm for one portion of the product, g)
Gross Net
Beef
Wheat bread 14 14
Onions 10 10
Eggs 7-9 7-9
Crackers 8 8
Weight semifinished - 97
Weight fried cutlets - 75
