RU2757181C1 - Shield for protecting structures from seismic impacts - Google Patents

Abstract

FIELD: protection from seismic impacts.

SUBSTANCE: invention relates to protective structures for protecting buildings from seismic impacts. The shield for protecting structures from vertical, horizontal and torsional seismic impacts includes a trench placed around the structure, covered with a damping gasket made of vibration-absorbing material, and the trench is filled with liquid and gas with the possibility of regulating their pressure and the amount of dry friction. The screen in the lower part is provided with an arched wall, which is connected through a hinge and a dry friction system to the inclined walls adjacent to the lower side of the trench, remote from the structure. The movable walls on the inner side have earthquake-dampening shovels, and the surface of the arched wall is ellipsoid and has rubber-metal corrugated elements in the supporting hinge zones.

EFFECT: providing seismic isolation of structures under vertical, torsional and seismic influences, increasing efficiency under horizontal seismic influences.

3 cl, 2 dwg

Description

The invention relates to screens for protecting structures from seismic effects.

The purpose of the work is seismic isolation of structures during vertical, torsional, as well as increasing efficiency during horizontal seismic influences.

The developed screen makes it possible to increase the seismic isolation of structures, both for horizontal and vertical seismic effects.

Known screen (copyright certificate No. 1423694, published 09/15/1988, Bul. No. 34), made in the form of trench 1, located around the structure 2. In trench 1 there are outer 3, inner 4 and lower 5 flat walls adjacent to it a surface remote from a structure to a surface close to a structure and to the bottom. The bottom wall 5 is connected to the outer wall 3 by means of a dry friction system 6 and a cylindrical hinge 7, and rigidly forms a corner wall with the inner wall 4. The trench is filled with liquid 8 and compressed gas 9, the pressure of which is regulated by valves 10. The upper part of the trench is covered with a damping gasket 11. The displacement of the outer and lower walls is prevented with anchoring triangular projections 12 of the sawtooth profile. This invention is the basic analogue.

The disadvantage of this invention is the impossibility of protecting structures from vertical and torsional seismic effects, as well as the ineffectiveness of isolation during horizontal seismic vibrations. ("Filling the trench with liquid or gas contributes to damping torsional vibrations, and torsional moments are transferred to the structure insignificantly", patent SU 1423694, description, column 2, ab. 10-15. ").

The proposed invention sets the task of developing seismic isolation of structures with vertical, torsional, as well as increasing efficiency with horizontal seismic effects. FIG. 1 shows a horizontal seismic shield. FIG. 2 shows a vertical seismic shield. Where: 1 - trench

2 - protected structure

3 - outer wall

4 - inner wall

5 - bottom movable wall

6 - dry friction system

7 - cylindrical hinge

8 - arched wall

9 - liquid and compressed gas

10 - pressure control valves

11 - damping gasket

12 - anchor triangular projections

13 - outer wall

14 - rubber-metal corrugated elements of increased deformability

15 - shovels

The proposed screen for protecting structures from vertical, horizontal and torsional seismic effects is made in the form of a trench 1 located around the protected structure 2. In trench 1 there are external 3, 13, internal 4 and lower 5 walls adjacent, respectively, to its surface, remote from the structure , to the surface close to the structure, as well as the arched wall 8, connected to the movable wall 5. The lower wall 5 and the arched wall 8 are connected to the outer walls 3, 13 by means of a dry friction system 6 and a cylindrical hinge 7, and rigidly with the inner wall 4 , and forms a corner wall with it. The walls 3, 13 have shovels 15 on the inside to extinguish a significant part of the impact energy, especially during torsional vibrations.

Trench 1 is filled with liquid and compressed gas 9, the pressure is regulated by valves 10. The upper part of the trench is covered with a damping gasket 11 made of neoprene. The displacement of the outer and lower walls is prevented by the anchoring triangular projections 12 of the sawtooth profile. The arched wall in the supporting hinge zones has rubber-metal corrugated elements of increased deformability 14.

The screen works as follows:

1. A vertical seismic wave approaching the arched wall (8) is refracted and reflected, and part of it passing through the screen sets the outer walls (3, 13) in motion. Thanks to the cylindrical hinges (7), oscillation of the walls (3, 13) is generated, which, through the dry friction system (6), make a translational-rotary motion. In this case, the liquid and compressed gas (9) in the cavities move up and down, absorbing significant energy (vibrations of the seismic effect). In addition, with the help of the pressure of compressed gas and liquid regulated by a valve (10), as well as a damping pad (11), the trench dampens the rest of the wave energy and ensures the isolation of the structure from vertical seismic effects.

Thus, the intensity of the longitudinal vertical wave is damped by the movement of the outer walls (3, 13) along the dry friction system (6), and the energy of the transverse vertical wave is damped in the trench by the rise of fluid under pressure. The choice of the angle of inclination of the axis of the trench to the vertical depends on the zone of the structure under construction. In the focal zones of the earthquake, the impact has a vertical direction, and the angle of incidence of the wave with the horizontal is Θ → 90 °, and for a structure located far from the focal zones, the angle is Θ-0 °.

In the general case, the value of the angle Θ is determined by the formula

where H _e and H _g are the epicentral and hypocentral distances, respectively, i.e. from the depth of the hearth and its horizontal distance to the structure.

2. A horizontal seismic wave approaching the walls (3, 13) is refracted and reflected, and a part of it passing through the screen leads to movement of the outer walls (3, 13). Thanks to the cylindrical hinges (7), oscillation of the walls (3, 13) is generated, which, through the dry friction system (6), make a translational-rotary motion. In this case, the liquid and compressed gas (9) in the cavities move up and down, absorbing significant vibration energy of the base. Part of the energy of seismic waves is absorbed by the arched wall (8), thanks to the rubber-metal corrugated elements (14). In addition, with the help of the pressure of compressed gas and liquid regulated by a valve (10), as well as a damping pad (11), the trench dampens the rest of the wave energy and ensures the isolation of the structure from horizontal seismic effects.

3. Under torsional influences, a seismic wave approaching the walls (3, 13 and 8) is refracted and reflected, and the part passing through the screen causes the wall to move. The inclined outer walls (3, 13) and the arched wall (8), thanks to the cylindrical hinges (7) and dry friction (6), generate vibration. In this case, the liquid and compressed gas (9) in the cavities make a pivotal movement, absorbing significant vibration energy of the base. In addition, with the help of the pressure of compressed gas and liquid regulated by a valve (10), as well as a damping pad (11) and a dry friction system (6), the trench dampens the rest of the energy and ensures the isolation of the structure from torsional seismic vibrations.

Filling the trench with liquid and gas contributes to damping torsional vibrations, and torsional moments are transferred to the structure only slightly.

The fluid pressure is regulated, which increases the degree of absorption of the seismic impact energy, since part of the vibration energy is spent on the rise of water in the trench during the movement of the outer wall (3, 13) and the arched wall (8), through the dry friction system (6) and the cylindrical hinge ( 7). This compensates for the propagation of longitudinal and transverse waves. During strong and destructive earthquakes, cyclic vibrations of the movable outer walls (3, 13), the arched wall (8) and the dry friction system (6), reduce the loads from seismic shocks. On the inside, the outer walls (3, 13) have shovels (15), which, during torsional vibrations, extinguish a significant part of the energy.

The pressure of the liquid and gas is regulated mainly in three levels, respectively, for 8, 9 and> 9 impact points.

The trench, filled with liquid, is made obliquely, with movable outer walls (3, 13) and a fixed wall (4). An arched wall (8) with a cylindrical hinge (7) and a dry friction system (6), perceives and transmits the oscillatory process to the walls (3, 13) and the movement of fluid up and down, absorbing a significant part of the seismic effects during vertical, horizontal and torsional vibrations ...

With strong vertical seismic effects in the focal zones, the arched wall (8) is made with an ellipsoidal surface, which makes it possible to more effectively influence the movements of the walls (3, 13), the movement of liquid and compressed gas (9) in the trench, increasing the absorbing capacity of the screen. Consider a numerical example:

Let the system be affected by an earthquake of the Spitak type, which happened on December 7, 1988. The average dominant period of the earthquake is 0.6 sec., The duration of the action is 25 sec. Thus, during an earthquake, the system performs 41 oscillation cycles. Average dominant amplitude (0.25-0.3) g. The power plant has P = 30 thousand tons. The filled liquid has a mass of 5000 thousand tons. Each cycle of oscillations consumes 5000 × 0.03 = 0.15 kJ of energy. An earthquake consumes 6,000 kJ of energy.

The energy entering the structure without an earthquake shield is -20,000 kJ, thus, the energy is reduced with a protective shield to 14,000 thousand tons. kJ, in addition, a significant part of the energy is reduced due to dry friction and an arched wall with an ellipsoidal surface, which leads to the reliability of operation of the structure in seismically active regions.

Under torsional impacts, a seismic wave of a Spitak earthquake, advancing to the inclined outer and arched walls, is refracted and reflected, and the part passing through the screen causes the walls to move. The inclined outer walls and the arched wall generate vibrations due to the cylindrical hinges and dry friction. In this case, the liquid in the cavities makes a rotational movement, absorbing 2000 kJ of vibration energy of the base. In addition, using a valve-regulated compressed gas and liquid pressure, as well as a damping pad and a dry friction system, the trench dampens the rest of the energy and ensures the structure is isolated from torsional seismic vibrations.

Thus, the use of this system leads to a significant reduction in the energy of external influences coming to the structure. So, the Screen, characterized in that in order to increase the deformation properties and increase seismic isolation during strong earthquakes, the arched wall in the supporting hinge zones is made with rubber-metal corrugated elements.

A screen characterized in that the pressure of the liquid and gas is regulated in three levels according to the predicted earthquake level for 8, 9 and> 9 point impact.

A screen, characterized in that in order to increase torsional vibrations and increase seismic isolation during strong earthquakes, the movable walls (3, 13) have shovels (15) on the inside, which, during torsional vibrations, extinguish a significant part of the energy.

A screen, characterized in that in order to dampen strong vertical and torsional vibrations, increase the seismic isolation of the building in the focal zones of an earthquake, the arched wall 8 is made with an ellipsoidal surface, which makes it possible to more effectively influence the movements of the walls (3, 13), the movement of liquid and compressed gas in trench, increasing the absorption capacity of the screen.

Claims (3)

1. A screen for protecting structures from vertical, horizontal and torsional seismic effects, including a trench located around the structure, covered with a damping pad made of vibration-absorbing material, and the trench is filled with liquid and gas with the ability to regulate their pressure and the amount of dry friction, characterized in that the screen in the lower part it is equipped with an arched wall, which, through a hinge and a dry friction system, is connected to inclined walls adjacent to the lower side of the trench, remote from the structure, and the movable walls on the inside have earthquake shovels, and the surface of the arched wall is made ellipsoidal and in the supporting hinge zones has rubber-metal corrugated elements. 2. Screen according to claim 1, characterized in that the arched wall in the supporting hinge zones is made with rubber-metal corrugated elements. 3. Screen according to claim 1, characterized in that the arched wall is made with an ellipsoidal surface.

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