RU2758325C1 - Multi-storey earthquake-resistant building - Google Patents

Abstract

FIELD: construction industry.

SUBSTANCE: invention relates to the field of construction, namely to multi-storey buildings erected in seismic areas. This seismic protection design refers to multi-storey earthquake-resistant buildings. A multi-storey earthquake-resistant building with spatially rigid upper floors supported by horizontally flexible pillars of the lower floor with a system of switching connections placed between the ribs of the foundation plate and the structures of the upper part of the underground floor, and the foundation plate is made with ribs on which the pillars of the lower floor are supported, and has overall dimensions in plan exceeding the overall dimensions of the building, and the resulting cantilever parts are loaded with a layer of soil, in addition, the building is equipped with an additional external fence and a damping element, moreover, an additional external fence is installed on the cantilever projections of the foundation plate along the perimeter of the lower underground floor of the building with the formation of a closed cavity filled with liquid and gas with adjustable pressure, and a damping element is placed in the upper part of the cavity between the additional fence and the fence of the lower floor. The system of switching-off connections of the ground part of the building is made combinational in the form of a package of fragile and plastic cable ties having different thresholds of inclusion and destruction.

EFFECT: increase in the stability and reliability of the operation of the building with a wide range of changes in ground vibrations during earthquakes of medium intensity (7-8 points).

1 cl, 6 dwg

Description

This seismic protection design refers to multi-storey earthquake-resistant buildings. The purpose of the work is to increase the stability of the building by limiting its displacements and turns. The upper floors 1 are supported on the horizontally flexible posts 2 of the lower floor 3. The latter is equipped with a system of disconnecting braces 4. The posts 2 are supported on the ribs 6 of the foundation slab 5. A closed cavity 11 is formed above the cantilever projections 7 along the perimeter of the underground floor 3 of the building, which is filled with liquid 12 and gas 13 with adjustable pressure, overloaded with soil 8 and blocked in the upper part of the damping elements 10 (Fig. 1)

The development relates to construction, namely to multi-storey buildings erected in seismic areas.

State of the art.

A complex system of seismic protection of a building or structure is known according to patent No. 2512054 (Application: 2012145680/03, dated 25.10.2012. Published: 10.04.2014 Bull. No. 10), including a seismic-resistant building of a closed type on a spatial foundation platform with a sliding layer at the base, having upper and lower plates, fastened by ribs, characterized in that it additionally contains an automatically controlled fuse system with a seismic protection device, which increases the seismic resistance of the building and ensures its seismic protection in an emergency, the automatically controlled fuse system contains a wired or wireless high-speed connection between the seismic station of observation, located at a remote distance from the building, and a control module located in the building that senses the alarm signal from the seismic station and transmits it to the actuators located in the cavities of the foundation platform, while the actuators are made in the form of pressure cylinders with lubricating fluid and are equipped with locking elements interacting with the control module and responding to the control decision upon receiving an alarm signal from the seismic station by injecting a metered portion of grease into the sliding layer under the foundation platform of the building, the bottom plate of which is equipped with holes or gratings, and the sliding layer, which is a seismic shock absorber, is formed from several layers of a polymer film, the upper of which are made perforated with holes allowing the lubricating liquid to pass inside between the upper layers of the film, and the lower layers are impermeable.

The disadvantage of this analogue is the fact that the platform has a relatively high tensile stiffness in the vertical direction and a low bending stiffness, therefore, such a seismic isolation system protects the building mainly from horizontal components of seismic effects.

Known is a multi-storey earthquake-resistant building (according to the inventor's certificate No. 1310505 A2, publ. 1987.05.15.) And an earthquake-resistant building (according to the author's certificate No. 625012 A1, publ. 1978.09.25) with spatially rigid upper floors supported by flexible ones in the horizontal direction the pillars of the lower floor with a system of disconnecting links and a foundation slab, characterized in that, in order to increase the stability of the building by limiting its displacements and turns, the building is equipped with an additional external fence and a damping element, and an additional external fence is installed on the cantilever protrusions of the foundation slab along the perimeter the lower underground floor of the building with the formation of a closed cavity filled with liquid and gas with controlled pressure, and the damping element is located in the upper part of the cavity between the additional fence and the fence of the lower floor. The technical solution was adopted as a prototype.

The purpose of the development is to increase the seismic resistance of the building with incomplete seismological information.

The technical result consists in increasing the stability and reliability of the building operation with a wide range of changes in ground vibrations during earthquakes of average intensity (7-8 points) due to the fact that the underground part of the building is equipped with an additional system of combinations of fragile and plastic cable ties installed with different switching thresholds and destruction and ensuring self-adjustment of the system due to cascade operation and destruction of reserve elements (cable ties).

Disclosure of the essence of the invention and a brief description of the drawings.

The drawings show schematically a multi-storey earthquake-resistant building.

1 - cable-ties tend to break apart brittle-spasmodically outside the elastic limit

1 '- cable ties tend to deform elastically-plastically

2 - horizontal flexible posts

3 - lower underground floor

4 - fragile cable ties

4 '- plastic guy-ties

5 - foundation slab

6 - ribs on which the racks are supported 2

7 - console protrusions

8 - soil

9 - external fences

10 - damping element

11 - closed cavities

12 - liquid

13 - gas

14 - fence

15 - structures of the upper part of the underground floor

The multi-storey earthquake-resistant building includes a frame-braced space frame, equipped with combination cables-braces 1 and 1 '(Fig. 3, 4), with different mechanical characteristics. Parts of the cables-ties of type 1 tend to brittle-abruptly break outside the elastic limits, and the other - 1 'elastically-plastically deform (Figs. 1, 2). The choice of such a technical solution is due to the fact that brittle-abruptly collapsing elements directly perceive seismic shocks, and plastically deforming elements - seismic shocks.

The load-bearing elements of the above-ground part are additionally supported on the posts 2 of the lower underground floor 3, flexible in the horizontal direction, with an additional system (package) with a combination of fragile and plastic cables-ties 4,4 '(Figs. 3, 4). The foundation slab 5 is made with ribs 6, on which the pillars 2 of the lower floor 3 are supported, and having cantilever protrusions 7 for the dimensions of the building, overloaded with soil 8. The underground part of the building has additional external fences 9 installed on the cantilever protrusions 7 of the foundation slab 5 along the perimeter of the underground floor 3 of the building with the formation of a closed cavity 11 filled with liquid 12 and gas 13 with controlled pressure. A damping element 10 is placed in the upper part of the cavity 11 between the additional fence 9 and the fence 14 of the lower floor 3. A system of disconnecting links 4,4 'is installed between the ribs 6 of the foundation slab 5 and the structures 15 of the upper part of the underground floor.

Implementation of the invention.

The system works as follows:

1) In case of weak earthquakes, the soil 8 above the cantilever protrusions 7 of the foundation slab 5 together with the adjustable pressure inside the cavity 11 limits unacceptable displacements and turns of the building, thereby increasing the absorbing properties of the system and ensuring the seismic resistance of the building.

2) In case of earthquakes of medium intensity, the combined cables-ties 4,4 'are included in the work, which have a lower threshold of operation and destruction than the cables-ties 1,1'. The package of the combination cable-stay system 4,4 'has a variable threshold of actuation and damage. When the damage threshold is reached, part of the cable-ties with a lower damage threshold is destroyed. In further cycles of seismic vibrations, the combination cables are gradually destroyed, which have a higher threshold of operation and destruction (Figs. 3, 4).

Thus, the package of the combination cable-stay system is installed by cascade outputs of reserve elements, providing self-adjustment of the system (survivability of the building), with a wide range of changes in the parameters of seismic effects. The destroyed elements of the basement floor can be quickly restored with little cost.

3) In case of strong and destructive earthquakes, the system of combination cables-ties 1,1 'of the main frame is included in the work (Fig. 4). The package of cable-ties 1,1 ', has higher thresholds of actuation and destruction than the system 4,4'. However, the 1,1 'system is also set by different thresholds of destruction, which ensures the survivability of the building with a wide range of changes in the parameters of the external seismic impact.

Strong and destructive earthquakes are accompanied by intense seismic shocks and tremors. Seismic shocks are characterized by an instantaneous abrupt increase (speed) of the motion transfer function. Seismic shocks are characterized by a change in the force function (acceleration increase).

In case of intense seismic shocks, fragile cables-ties 1 (let's call it type i) are directly triggered and destroyed, while a significant part of the energy of seismic shocks arriving at the building is outflowing.

In the event of intense seismic shocks, elastic-plastic bonds 1 'are directly triggered (we will conventionally call it type j). Areas of flow of plastic bonds are formed, which contributes to the outflow of the energies of seismic shocks coming to the building.

A calculation was made for a 14-storey building equipped with combination cable ties, both above ground and underground parts of the frame (Fig. 3). External seismic impacts were taken as accelerograms of 7-8 magnitude earthquakes. When the combination cable-stay system is triggered and destroyed, seismic loads are significantly reduced. Figures 5, 6 show graphs of changes in the dimensionless coefficient of seismic forces depending on the dimensionless coefficient of periods in the event of the destruction of the combination cable-stay system. As can be seen from the graphs, depending on the degree of destruction of cable-ties, seismic loads are significantly reduced: 20-25% and 30-40%, respectively, in seven and eight point zones.

After an earthquake, broken links can be restored.

During installation, the connections are installed in plastic tubes, have special access areas to the destroyed places, and can be quickly restored without special costs.

Thus, during strong and destructive earthquakes, a cascade destruction of the combination cable ties occurs, a significant part of the seismic effects is absorbed, ensuring the survivability and seismic resistance of the building in a wide range of changes in the parameters of ground vibration.

A multi-storey earthquake-resistant building with spatially rigid upper floors, supported on horizontally flexible posts of the lower floor with a system of disconnecting links and a foundation slab, and the foundation slab is made with ribs on which the posts of the lower floor are supported, and has overall dimensions in plan that exceed the overall dimensions the dimensions of the building, and the resulting cantilever parts are loaded with a layer of soil; in addition, the building is equipped with an additional external fence and a damping element, and the additional external fence is installed on the cantilever protrusions of the foundation slab along the perimeter of the lower underground floor of the building to form a closed cavity filled with liquid and gas with adjustable pressure, and the damping element is located in the upper part of the cavity between an additional fence and a lower floor fence, characterized in that:

1) in order to increase the stability and reliability of the operation of the building with a wide range of changes in ground vibrations during earthquakes of average intensity (7-8 points), the underground part of the building is equipped with an additional system (package) of combinations of fragile and plastic cable ties 4,4 ', and they are installed different thresholds of activation and destruction, which ensures self-adjustment of the system (survivability of the building) due to cascade operation and destruction of reserve elements (cable-ties), and the destruction of fragile ties compensates for the loads from seismic shocks, and plastic ties - loads from seismic shocks;

2) a multi-storey earthquake-resistant building according to claim 1, characterized in that, in order to ensure the stability and reliability of operation by limiting its displacements and turns during strong earthquakes (9 and> 9 points), as well as strong seismic shocks and shocks, each tier of the ground frame equipped with a system of combination cables-ties, which have a higher threshold of operation and destruction under multicyclic impacts.

Claims (2)

1. A multi-storey earthquake-resistant building with spatially rigid upper floors, supported on the horizontally flexible posts of the lower floor with a system of disconnecting links located between the ribs of the foundation slab and the structures of the upper part of the underground floor, and the foundation slab is made with ribs on which the posts of the lower floor, and has overall dimensions in plan that exceed the overall dimensions of the building, and the resulting cantilever parts are loaded with a layer of soil, in addition, the building is equipped with an additional external fence and a damping element, and an additional external fence is installed on the cantilever protrusions of the foundation slab along the perimeter of the lower underground floor of the building with the formation of a closed cavity filled with liquid and gas with controlled pressure, and the damping element is located in the upper part of the cavity between the additional fence and the fence of the lower floor, characterized in that the system of disconnecting earth connections The second part of the building is made in combination in the form of a package of fragile and plastic cables-ties 4, 4 ', having different thresholds of inclusion and destruction. 2. Multi-storey earthquake-resistant building according to claim 1, characterized in that each tier of the ground frame is equipped with a system of combination cables-ties having a higher threshold of operation and destruction under multicyclic impacts than cables-ties 4, 4 'of the underground part of the building.

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