Deformations of buildings. Deformation of the building Types of deformation and causes of their occurrence

deformation is normal Hm!

> "Company .

> It's also possible that "

ASUS does not believe that you have any problems with your device",

Reassembling the device will slightly reduce this problem."

Bbk

• Gender: Man

I recently purchased a brand new UX305FA. During operation, it turned out that it had “hit a defect” - one of the buttons on the keyboard fell out when pressed at a certain angle. I decided to contact a certified service center in Moscow (TOPAZ-2M). We took the laptop for diagnostics and decided to replace the keyboard completely. When inspecting the laptop after repair, I saw assembly defects: side gaps at the joints, a violation of the geometry of the case (bulge of the keyboard unit and, as a consequence, play of the touchpad, as well as loose fit of the top part when closed). When contacting the service center again, the gaps were corrected, however, the violation of the housing geometry was not corrected. The service center employee reported that such deformation is normal and the defect will be eliminated during operation over time ( Hm!). Everything would be fine, but the play of the touchpad now creates discomfort during operation.

Looking at the photo of the laptop, the official tech. support on the site wrote a strange answer:

> "Company ASUS does not believe that you have any problems with your device.

> Therefore, he does not think that you need to do something with the device.

> You can also contact the ASC and get a conclusion that everything is in order with the device.

> It's also possible that Reassembling the device will slightly reduce this problem."

Those. on the one hand, the existence of a problem is denied: "... ASUS does not believe that you have any problems with your device",

and on the other hand, he admits: “... Reassembling the device will slightly reduce this problem."

Has anyone encountered a similar problem on the UX305FA? What do you advise?

recently, when? If two weeks have passed, go to the independent one and then with a response to the OZPP. Don’t even bother with Rospotrebnadzor. It’s high time to disband this office. The main direction (and the most profitable for them) is food. There was one appeal to them. 4 passed. The answer is crawling on turtles. The second case with a key with a laptop. Died 3 days after the purchase (St. Petersburg). Service workers (I insisted that they be with me) tried everything. Even some super secret programs from asus.zero. so one service technician, the second, stop doing nonsense. It’s still for disassembly. I have no doubt at all that one of these, for disassembly, you got your copy, which was upgraded by some crooked master. It’s easier for the store to do this than to bother with returning it to the supplier .it's up to you.

All structures experience various types of deformation caused by design features, natural conditions and human activity.

Observations of deformations of buildings and structures begin from the moment of their construction and continue during operation. They represent a complex of measuring and descriptive measures to identify the magnitude of deformations and the causes of their occurrence.

Based on the observation results, the correctness of design calculations is verified, and patterns are identified that make it possible to predict the deformation process and timely take measures to eliminate their consequences.

For complex and critical structures, observations begin simultaneously with design. At the future construction site, the influence of natural factors is studied and at the same time a system of support signs is created in order to determine in advance the degree of their stability.

At each stage of construction or operation of a structure, observations of its deformations are carried out at certain intervals. Such observations, carried out according to a calendar plan, are called systematic.

If a factor appears that leads to a sharp change in the normal course of deformation (change in load on the foundation, ambient temperature and the structure itself, groundwater level, earthquake, etc.), urgent observations are performed.

In parallel with the measurement of deformations, to identify the causes of their occurrence, special observations are organized of changes in the condition and temperature of soils and groundwater, the temperature of the body of the structure, meteorological conditions, etc. Changes in the construction load and the load from installed equipment are recorded.

To carry out observations, a special project is drawn up, which generally includes:

terms of reference for the work;

general information about the structure, natural conditions and mode of operation;

layout of conventional and deformation signs;

schematic diagram of observations;

calculation of the required measurement accuracy;

calendar plan (schedule) of observations;

composition of performers, scope of work and estimates.

The main purpose of monitoring the deformations of a complex of structures in the Northern microdistrict of the city of Nakhodka (KPD-80 plant - the main building, a concrete mixing shop, a cement warehouse, a canteen, an administrative and amenity complex, as well as residential buildings) was to obtain information to assess the stability of structures and take timely preventive measures, as well as checking the quality of the adopted construction techniques and the model of piles used for the foundation.

Observation materials were provided by the scientific supervisor L.I. Poltorak.

1. Types of deformation and causes of their occurrence

Due to design features and natural conditions of human activity, structures as a whole and their individual elements experience various types of deformation.

In general, under the term deformation understand the change in shape of the object of observation. In geodetic practice, it is customary to consider deformation as a change in the position of an object relative to some original one.

Under constant pressure from the mass of the structure, the soils at the base of its foundation are gradually compacted (compressed) and displacement occurs in the vertical plane or draft structures. In addition to pressure from its own mass, settlement of a structure can be caused by other reasons: karst and landslide phenomena, changes in groundwater levels, the operation of heavy machinery, traffic, seismic phenomena, etc. When the structure of porous and loose soils changes radically, deformation occurs rapidly over time, called drawdown.

In the case when the soils under the foundation of a structure are compressed unequally or the load on the soil is different, the settlement is uneven. This leads to other types of deformations of structures: horizontal displacements, shifts, distortions, deflections, which can externally manifest themselves in the form of cracks and even faults.

Bias structures in the horizontal plane can be caused by lateral pressure of soil, water, wind, etc.

Tall tower-type structures (chimneys, television towers, etc.) are tested torsion And bend caused by uneven solar heating or wind pressure.

To study deformations in characteristic places of a structure, points are recorded and changes in their spatial position are determined over a selected period of time. In this case, a certain position and time are taken as the initial ones.

To determine absolute or full sediment S points fixed on the structure are periodically determined by their marks H relative to the original reference point, located away from the structure and taken as stationary. Obviously, in order to determine the draft of a point at the current moment in time relative to the beginning of observations, it is necessary to calculate the difference in elevations obtained at these moments, i.e. S=Hcurrent-Hbeginning. Similarly, you can calculate the precipitation for the time between the previous and subsequent periods (cycles) of observations.

Average draft Sav the entire structure or its individual parts is calculated as the arithmetic mean of the sum of the settlements of all n of its points, i.e. Sav=?S/n. Along with the average draft, for completeness of the general characteristics, indicate the greatest Snaib and the smallest Sname settlements of points of structures.

Unevenness precipitation can be determined by the difference in precipitation ?S any two points 1 and 2, i.e. .?S1,2=S2-S1.

Bank And incline structures are defined as the difference in settlement of two points located on opposite edges of the structure, or its parts along the selected axis. The inclination in the direction of the longitudinal axis is called rubble, and in the direction of the transverse axis - skewed. Amount of roll related to distance l between two points 1 and 2 is called relative roll K. It is calculated by the formula K=(S2-S1)/l.

Horizontal offset q a single point of a structure is characterized by the difference in its coordinates xtek, ytek And xbeginning, ybeginning, obtained in the current and initial observation cycles. The position of the coordinate axes, as a rule, coincides with the main axes of the structure. Displacements are generally calculated using the formulas qx=xtek-xstart; qy=ycurrent-ystart. Similarly, you can calculate the offsets between the previous and subsequent observation cycles. Horizontal displacements are also determined along one of the coordinate axes.

Torsion about the vertical axis is typical mainly for tower-type structures. It is defined as a change in the angular position of the radius of a fixed point drawn from the center of the horizontal section under study.

The change in the magnitude of deformation over a selected time interval is characterized by average speed deformation vav. For example, the average settlement rate of the point under study over a period of time t between two cycles i And j measurements will be equal vav=(Sj-Si)/t. There is a distinction between the average monthly speed when t expressed by the number of months, and the annual average, when t- number of years, etc.

All buildings have different sensitivity to precipitation and movement of the foundation soil, which can occur during construction and operation; the degree of this sensitivity is determined mainly by their rigidity.

Depending on the rigidity, all buildings and structures are divided into three main types:

1. absolutely tough
2. having finite stiffness
3. absolutely flexible

Absolutely rigid structures have very high rigidity in the vertical direction. An example of such a structure would be a tower or chimney. Due to their significant rigidity, these structures are not subject to bending or other local deformations and experience settlement as a single mass. For example, the Leaning Tower of Pisa tilts as a single mass (tilt).

Completely flexible structures under the influence of external loads they follow the sediments of the base, while practically no additional forces arise in them. Such structures include, for example, overpasses or ground-based heating mains.

Absolutely flexible and absolutely rigid structures in individual residential construction are extremely rare; in most cases we are dealing with buildings final hardness. Such structures, with the development of uneven settlements or ground movements, receive deformation, expressed in the curvature of individual sections of the buildings. Having finite rigidity, they are able to provide some resistance to uneven settlement, leveling it, as a result of which forces arise in load-bearing walls and walls, which are often not taken into account during design, which can lead to the formation of cracks that disrupt the normal operation of buildings.

The most common deformations of buildings in individual residential construction:

Rice. 1. Deflection

Fig.2. Bending

Rice. 3. Shift.

In turn, buildings of finite rigidity can be divided into two more subtypes:

• conditionally rigid, for which L\H =< 3
• conditionally flexible, for which L\H > 3,

G de L is the length of the longest wall of the building, H is the height of the structural part of the building (usually this is the height of all floors + the height of the foundation, the roof is not taken into account).

Here are two examples of such buildings from our catalog of standard projects:

• Conditionally rigid house according to the project; L=15.5 meters, H= 8.5 meters, ratio L\H=1.8
• Conditionally flexible house according to the project; L=16.5 meters, H= 4.8 meters, ratio L\H=3.4

It is believed that conditionally rigid ones experience deflection (bending) or shear deformations to a lesser extent, but only heel like absolutely rigid ones. In some cases this is true, but in order to finally determine how a building will behave under certain deformations, it is necessary to take into account the materials of the main load-bearing and enclosing structures, the general flexural and shear rigidity of the building, and also calculate the forces arising in the main structures of these buildings.

In most cases, this problem of modeling forces in building structures is solved by reducing the entire building to a certain abstract beam on an elastic foundation with given stiffness indicators. In this case, it is possible to determine the bending moment and shear force in the section of the building. And knowing these force factors, calculate the forces in each structural element that arise during uneven movements of the foundation soil.

For example, VSN 29-85 provides the following formula for calculating forces (bending moment and shear force) depending on the magnitude of frost heaving of the soil:

Rice. 4. Formulas for calculating the bending moment M and shear force F from VSN 29-85.

In this formula:

B, B 1 - coefficients depending on the building design (see VSN 29-85, Fig. 5 and 6);

The stiffness of a building reduced to a simple beam;

Δh fi - difference in heaving deformations of different parts of the building;

L - length of the longest wall of the building

The calculation of forces in various building structures is then carried out using the following formula:

Rice. 5. Formulas for calculating forces in various building structures.

where i, i are the bending and shear stiffness of the section of the element under consideration, respectively;
G - shear modulus, usually taken equal to 0.4E

• the base of the foundation;
• foundation;
• walls;
• reinforced concrete belts;
• reinforced concrete floors

In buildings constructed from rather fragile materials, for example, aerated concrete, the walls have low flexural and shear rigidity, especially in the areas of openings. And walls made of large-sized ceramic stones (“warm ceramics”), which have only tongue-and-groove joints vertically and no vertical adhesive joints, in principle have no shear rigidity. In this case, the main rigidity of the building is largely determined by the other structural elements listed above.

Thus, when solving the problem of ensuring the normal operation of a building in the future, it is necessary to approach its design systematically and take into account:

1. The overall dimensions of the building, in particular the height of its structural part (H) and the length of the longest wall (L), as well as their ratio.
2. The probability of the occurrence of uneven settlements or other movements of the soil, determined by its homogeneity, the value of the elastic modulus and heaving properties.
3. Foundation base rigidity.
4. Foundation rigidity.
5. The rigidity of the walls and the ruggedness of their openings.
6. Floor rigidity.
7. Work of reinforcing belts.

Taking these factors into account makes it possible to understand why it is not very rational to use slab foundations for flat one-story buildings, such as ours or the Z10 project:

Rice. 6. Project K-106-2

Rice. 7. Planning solution for the K-106-2 project.

In this project, the ratio L\H=4.2 when using MZLF, and with a slab foundation L\H will be equal to 5, i.e. the house is very susceptible to deformation and is unable to cope with uneven precipitation and soil movements. Slab foundations do not have the necessary flexural rigidity, and ribbed slabs of the USHP type, having a rib section height of 200-300 mm, also have the necessary shear rigidity.

The situation with a slab foundation can be improved, but it must be taken into account that the performance coefficient of the upper reinforced belt in a one-story building usually does not exceed 20% of the maximum, since it is possible for the belt to slip along the masonry or even tear off. Interfloor reinforced belts work much better, since they experience significant loads from overlying structures, which increase the friction forces at the connection points between the reinforced belt and the wall. For the same reason, U-shaped blocks are preferred for constructing reinforced belts, since they increase the adhesion area of ​​the belt to the wall. In some cases, the operating efficiency of the armored belt increases to 30-35%.

Another option for using a slab foundation for buildings with a ratio L\H > 3 is to increase the rigidity of the base, for example, by installing thick pads of well-compacted crushed stone, but in most cases it looks more rational to use a relatively high MZLF as a foundation.

A ship hull deformation meter refers to a means of measuring position or displacement and can be used when controlling sea and river ships and vessels in order to ensure navigation safety and prevent the ship’s hull from breaking during rough seas or when receiving large loads.

The device provides continuous monitoring of the hull deflection/bending arrows under external influences with high accuracy due to the installation of GNSS antennas on the same line along the ship's hull parallel to its center plane, while the processor determines the deflection/bending arrows as distance of the internal receiving antennas from the line connecting the current positions of the outermost bow and stern antennas.

1 p.f., 2 ill.

The claimed utility model relates to means for measuring position or displacement and can be used, in particular, when controlling sea and river ships and vessels in order to ensure navigation safety and prevent transverse fracture of the ship's hull in rough seas or when receiving large loads.

Devices are known for continuous monitoring of dynamic loads, including stresses and deformations of ship hulls (see US patent 5942750, IPC H01J 5/16, NKI 250/227.14, 356/32, 340/555, US patent 6701260, IPC G01L 1/ 00, NKI 702/43, 702.42, 73.863.636).

These devices use fiber-optic sensors placed at various points in the ship's structure to measure local deformations and stresses in the metal of the ship's hull.

Fiber-optic sensors record tension-compression in local areas of their installation and do not provide sufficient information to assess the condition of the housing, characterized by the magnitude of the deflection/bending arrows of the housing in the vertical plane, for example, under the influence of wave loads.

A known system for determining the relative position of antenna installation points, based on phase measurements in the global navigation satellite system (GNSS) (see US application 2004/0212533, IPC G01S 5/14, NKI 342/357.08, op. 10.28.2004, accepted as prototype).

The system includes one basic receiver with an antenna, several additional receivers with antennas, a communication system and a computer for calculations.

The known system does not solve the problems of monitoring the deflection/bending of a ship's hull, which is an objective characteristic of the measure of hull deformation under the influence of external loads.

The technical problem solved by the claimed device is to provide the possibility of continuous automatic measurement (monitoring) of the values ​​of the arrows of deflection/bending of the ship's hull under the influence of external influences in order to ensure navigation safety.

This problem is solved due to the fact that in a ship hull deformation meter containing global navigation satellite system signal receivers, the receiving antennas of which are fixedly mounted on the ship hull, a data exchange system and a processor, the antennas are placed along the ship hull on the same line from the bow to the stern part parallel to the center plane of the ship, and the processor is configured to calculate the current values ​​of the deflection/inflection arrows at the antenna attachment points as the distance of the internal receiving antennas from the line connecting the current position of the outermost bow and stern antennas.

One of the receivers, the antenna of which is mounted in the extreme bow or stern of the ship's hull, is basic, the rest of the receivers are additional.

The basic receiver operates in base station mode, the additional ones operate in real-time kinematics (RTK) mode with ambiguity resolution of phase measurements in motion (OTF). Data exchange between GNSS receivers, as well as data output from the receivers to the processor, is carried out using a data exchange system.

The accuracy characteristics of the proposed device can be determined from the condition that the root mean square error (RMSE) of measuring a unit difference in the heights of two antennas (h) in RTK mode is 20-30 mm:

Then the SCP of the unit height difference of the line passing through the outer antennas and internal antennas () does not exceed the value:

It is known that for large ships the period of pitching exceeds 10 s, and the frequency of data output by the GNSS receiver reaches values ​​of 20-100 Hz. Thus, it is possible to use the procedure for averaging single values ​​of height differences over an interval of up to 0.5 s, which corresponds to the number N = 10-50 samples according to RTK data. Consequently, the SKP for calculating the average deflection/inflection value amounts to

At N=10 and h =30 mm, the value 15 mm, which is quite acceptable, because deflection/deflection values ​​can exceed 100-300 mm for the hulls of large ships. Consequently, the proposed device achieves the solution to the problem.

The essence of the proposed technical solution is illustrated in Fig. 1 of the drawing; Fig. 2 shows the position of the antennas when the housing is deformed.

The drawing indicates:

1 1 -1 n GNSS signal antenna receiver;

2 1 -2 n GNSS receivers;

3 - data exchange system between receivers and processor;

4 - computer for processing phase measurements from all GNSS receivers;

5 - ship hull in initial and deformed (Fig. 2) states.

The number n of GNSS signal receivers with receiving antennas is determined by the number of points on the ship's hull for which the deflection/inflection boom S 2 -S n-1 is measured.

When the device is operating, GNSS radio signals are received from receiving antennas 1 1 -1 n to the inputs of the corresponding GNSS receivers 2 1 -2 n , and code and phase measurement data are received from GNSS receivers to computer 4, through the data exchange system 3.

In additional receivers, problems are solved in the following sequence:

Differences in phase measurements are formed between the antennas of additional receivers, for example, 2 2 -2 n and the base receiver 2 1 ;

Resolves ambiguity in real-time kinematics (RTK) in motion (OTF) phase measurements;

The current rectangular coordinates of the antennas 1 2 -1 n of additional receivers 1 2 -2 n relative to the antenna 1 1 in a topocentric coordinate system are determined;

Computer 4 solves problems in the following sequence:

The current rectangular coordinates of the receiving antennas 1 2 -1 n are calculated relative to the receiving antenna 1 1 in a topocentric coordinate system;

The current parameters of the line passing through antennas 1 1 and 1 n are calculated;

The values ​​of the deflections/inflections of the ship's hull are calculated as the values ​​of the distance of the antennas 1 2 -1 n-1 relative to the line passing through the antennas 1 1 and 1 n. (S 2 -S n-1).

In the initial position of the antennas (in the absence of deformation of the ship's hull), all antennas are placed on the same straight line, and the value of the deflection/inflection arrow for each receiving antenna will be equal to zero ( i = 0).

During navigation, under the influence of external factors, the ship's hull is deformed and, accordingly, the relative position of the receiving antennas 1 1 -1 n, fixedly attached to the ship's hull, changes (Fig. 2). In this case, the calculated values ​​of the deflection/inflection arrows S obtained in computer 4 for each receiving antenna will not be equal to zero, and comparing them with the maximum permissible values ​​in the computer ROM allows one to assess the degree of safety and prevent the ship from breaking up.

A ship hull deformation meter containing global navigation satellite system signal receivers, the receiving antennas of which are fixedly mounted on the ship hull, a data exchange system and a processor, characterized in that the antennas are placed along the ship hull on the same line from the bow to the stern part, parallel to the centerline plane ship, and the processor is configured to calculate the current values ​​of the deflection/inflection arrows at the antenna attachment points as the distance of the internal receiving antennas from the line connecting the current position of the outermost bow and stern antennas.

The rules of the USSR Register allow deformation of the ship's hull on a large wave with a deflection arrow not exceeding 0.001 of the ship's length. When the main diesel engine is located in the middle part of the vessel, the parts of the hull set together with the machine foundation, the machine frame and the crankshaft will experience bending deformations.
In order for the deformation to be as small as possible, part of the frame set under the machine foundation and the foundation itself are made more rigid. However, this does not completely eliminate deformations of the machine frame. Thus, one of the Doxford diesel engines has a machine frame length exceeding 18 m. When measuring its elastic deformation, the deflection arrow reached 1 mm.
Sometimes significant deformations of machine frames and crankshafts are observed in relatively short diesel engines; Obviously, the reason here is the insufficient rigidity of the set and the machine foundation.
For example, on the motor ship “Port Manchester” with two 14-cylinder V-shaped diesel engines Pilstik (LG = 5660 hp at l = 464 rpm), after 2500 hours of operation, the crankshaft of one of the diesel engines failed. As a result of the examination, it was found that the deflection values ​​of the frame bearing supports under various conditions of the ship’s hull and the diesel engine itself (heated or cold diesel engine, the ship loaded or in ballast) reach 1.8 mm. Such deformations should have led to the crankshaft breaking due to the rapidly developing fatigue process.
There are other data. Measurements of the elastic openings of the crankshaft of the main diesel engine of the motor ship "San Francisco" showed that the amplitude of their vibrations during the course of a loaded ship on a wave reaches 0.3 mm, and the deflection arrow of the ship's hull is 70 mm. It's not that much.
But there are also severe cases. A crankshaft with a diameter of 580 mm in a 6-cylinder Doxford diesel engine is known to break due to the large amplitude of shaft stress fluctuations when the vessel is sailing on a large wave, fully loaded and in ballast. During the investigation of the accident, it was found that the maximum difference in the crankshaft cheek openings reached 0.762 mm.
But in general, failure of the crankshafts of powerful low-speed diesel engines built over the last 15 years is an extremely rare occurrence. During the entire post-war period, there were only two cases of failure of the crankshafts of the main diesel engines on BMP ships.
In addition, in the vast majority of new ships, not to mention tankers, the main diesel engine is located not in the middle of the ship, but in the stern, and the crankshafts, even with strong pitching, do not experience such bending stresses that should be taken into account.
There is no need to present the entire complex of complex stresses that the crankshaft experiences, especially during a strong pitch, especially since the nature and distribution of these stresses depend not so much on the design of the shaft itself, but on the rigidity of its foundation and the frame structure under the foundation, as well as on the nature of the shaft installation. As for the wear rate of bearings, it certainly increases if the crankshaft experiences additional elastic deformation due to insufficient foundation rigidity, but the more the technology for building modern diesel engines improves, the more the wear resistance of the main components of the diesel engine increases.
However, it should be noted that according to studies by Czech specialists, the pressures of the frame bearings of the 6S275IIIPV diesel engine, operating under conditions of crankshaft deformation, differed from the calculated ones by 30-50% in the direction of increase. This was explained by the asymmetrical distribution of pressure fields relative to the longitudinal axis of the bearing.