RU2539475C2 - Earthquake-isolating support - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention refers to the construction industry, in particular to supports of earthquake-resistant structures (buildings). An earthquake-isolating support includes a load-carrying element of a column, which is supported through an upper supporting plate from a metal-rubber support (MRS), and the lower supporting plate of MRS is connected by means of anchor bolts to a foundation; MRS is made of elastic rubber sheets (pads) and metal plates, which are alternately laid on each other, and a central core is made in the middle part. In the foundations there are sockets, into which plate-like (cylindrical) elastic elements are inserted in the form of anchor bolts, the tightening value of which is set with the reliability coefficient γ_f, which is by 1.2-1.5 times more than a horizontal component on the support from the design wind load Pw. The lower supporting plate of MRS is supported from an embedded metal plate of the foundation with holes for the movement of the plate-like elastic elements through a sliding pad.

EFFECT: improvement of the earthquake resistance of a building, simplification of a structure, enlargement of an application field of earthquake protection for buildings with different earthquake intensity.

5 cl, 1 tbl, 9 dwg

Description

The invention relates to the field of construction, in particular to the supports of earthquake-resistant structures (buildings).

Known devices for protecting the structure from seismic effects (analogue), including rubber-metal bearings (RMO), made of alternately stacked elastic rubber sheets (gaskets) and metal sheets (accepted application JP 1 No. 23633, E04H 9/02, E04B 1/36, F16F 15/02, 1989). In known devices, the horizontal movement of the structure (building) relative to the foundation occurs due to shear deformation of the elastic rubber sheets.

The disadvantages include the lack of a sufficient restoring force, providing the ability to return the structure (building) to its original position relative to the foundation after their mutual displacement under seismic impact.

The closest solution (prototype) is a seismic isolating support, including the supporting element of the column, which is supported by a rubber-metal support (RMO) through the upper base plate, and the lower base plate of the RMO is connected to the foundation with anchor bolts, the RMO is made of alternately laid on top of each other other elastic rubber sheets (gaskets) and metal sheets, and in the middle part there is a central lead core (Fundamentals of Earthquake engineering. Elnashai, 2008, pp. 355-356, fig. 13.2-13.4).

The disadvantages of the known device include the following:

- the dissipation of the energy of the seismic effect is suppressed only by viscous friction in the nodes of the interaction of the supports, which have different weight characteristics coming from the upper structures of the building. Under seismic effects of different intensities, it may turn out that viscous friction for protection may not be enough, which can lead to the destruction of the building support or its parts;

- in all seismic protection devices of buildings known to the applicant, the main disadvantage is the limited scope of their application, depending on the intensity of the seismic effect (points). These limitations are determined by the magnitude of the residual displacements of the base soil.

Multi-storey buildings have vertical building stiffness compared to horizontal ten times higher, since they are mainly designed to absorb parasitic load from its own weight, which is due to gravitational forces, and payloads. Actual earthquake records also confirm that in most cases (75-95%) the horizontal components of the seismic impact pose the greatest danger.

Experimental data on residual soil displacements Uo (mm), which are related to the intensity of earthquakes I (MSK-64 points) as a function of (Grazer V.M. Seismic data on residual displacements during explosions and earthquakes // DAN. 1989. V.306, No. 4 , p. 822-825)

logU ₀ = -4.6 + 0.78

For example, for intensity I = 9 points:

logU ₀ = -4.6 + 0.78 · 9; logU ₀ = 2.42; U ₀ = 10 ^2.42 = 263 mm.

Summarize the calculations in table 1.

Table 1 Earthquake Points, MSK-64 Ultimate soil displacements U ₀ , mm 6 Uo = 10 ^0.08 1.2 7 Uo = 10 ^0.86 7.24 8 Uo = 10 ^1.64 43.6 9 Uo = 10 ^2.42 263 10 Construction prohibited

The problem solved by the invention is to increase the earthquake resistance of the building, allowing to simplify the design of the seismic isolating support, and at the same time expand the scope of use of seismic protection. In this case, various variants of earthquake energy dissipation are used, built on the principles of viscous and dry friction, as well as elastic elements from flat springs or a combination thereof. All of these seismic isolation elements allow, in their part, to ensure the absorption of seismic energy and thereby to absorb in part a part of the building’s vibrations, while reducing their amplitude, which increases the protective properties of buildings.

The technical result obtained when solving the problem, the achievement of which the claimed invention is directed, and which eliminates the disadvantages inherent in the prototype, is achieved as follows.

A seismic isolating support, including the supporting element of the column, which is supported by a rubber-metal support (RMO) through the upper base plate, and the lower base plate of the RMO is connected to the foundation with anchor bolts, the RMO is made of elastic rubber sheets (gaskets) stacked on top of each other and metal sheets, and in the middle part the central core is arranged, in the foundations there are glasses in which are inserted (Cylindrical elastic elements) in the form of anchor bolts, the tightening value of which is assigned with a coefficient with reliability γ _f , 1.2-1.5 times greater than the horizontal component on the support from the estimated wind load P _w , the lower support plate RMO is supported by a embedded metal foundation plate with holes for moving plate elastic elements through a sliding gasket. Elastic elements in the form of anchor bolts, which take part in achieving movements by the bearing columns of a given value, and contribute to the return of the bearing columns to their original position, the stiffness of the plate elastic elements is assigned from the residual fraction, which is perceived by viscous friction dampers (RMO) by the weight characteristic of the building for each supporting element of the columns.

In an embodiment, the seismic isolating support has an upper, lower plate and a foundation embedded part, which are made in the form of a square, circle, polygon, and the foundation glasses are made in the form of parallelepipeds, cylinders or truncated inverted cones.

, где P_v - вертикальная нагрузка на опору, металлический цилиндрический стакан закреплен через пластину в стаканах фундаментов при помощи цилиндрических упругих элементов в виде анкерных болтов, между металлическим цилиндрическим стаканом и закладной металлической пластиной фундамента устроена скользящая прокладка со своим коэффициентом трения и с коэффициентом надежности γ_f, в 2-5 раза большим, чем горизонтальная составляющая на опору от расчетной ветровой нагрузки P_w.In an embodiment, the seismic insulating support has a bottom support plate RMO, which is inserted into a metal support cylindrical cup with thick-walled sides, and rests on it through a sliding gasket, the coefficient of friction of the gasket material f between the RMO and the bottom of the cylindrical cup is taken as $$f\ge \frac{P_w}{P_{\nu }{\gamma }_f}$$

where P _v is the vertical load on the support, the metal cylindrical cup is fixed through the plate in the foundation cups with the help of cylindrical elastic elements in the form of anchor bolts, a sliding gasket is arranged between the metal cylindrical cup and the embedded metal foundation plate with its friction coefficient and reliability coefficient γ _f , 2-5 times larger than the horizontal component on the support from the estimated wind load P _w .

In an embodiment, the seismic isolating support has foundation glasses and plate elastic elements in the form of anchor bolts that are placed along the perimeter of the support in concentric directions in a checkerboard pattern.

In an embodiment, the seismic insulating support has a central core, which is made of an elastomer reinforced with composites, with the specified elastoplastic properties of the reinforcement material, and their dimensions and spatial orientation along the X, Y, Z axes.

The technical result of the use of the invention is to increase the technical and operational characteristics of the building with a decrease in horizontal seismic load by 2-3 points in a wide spectrum of frequencies, due to energy dissipation, both with the help of viscous and dry friction dampers, and with the help of elastic elements in various combinations . At the same time, the energy of dissipation is 4-10 times higher compared to buildings on ordinary foundations. In addition, the stress concentration problem in the region of kinematic supports is completely removed. At the same time, the design of the seismic isolating support is simplified, and at the same time, the scope of the use of seismic protection for buildings with different earthquake intensities is expanded.

Figure 1 shows a seismic insulating support with square plates of the upper and lower plates, and embedded parts, with parallelepiped cups of the foundation; figure 2 the same is a top view; figure 3 the same is a side view; figure 4 shows a seismic isolating support with round plates of the upper and lower plates, and embedded parts, the foundation glasses are made in the form of truncated inverted cones; figure 5 the same is a top view; in Fig.6 the same is a side view; Fig. 7 shows a seismic isolating support inserted into a metal supporting cylindrical cup, which is fixed in conical cups using elastic plate elements in the form of anchor bolts; in Fig.8 the same is a top view; in Fig.9 section 1-1 in Fig. 8.

A seismic isolating support, including the supporting element of the column 1, which, through the upper base plate 2, is supported by a rubber-metal support 4 (PMO), and the lower support plate PMO 3 is connected to the foundation using anchor bolts 11. RMO is made of alternately stacked elastic rubber sheets 6 (gaskets) and metal sheets 7, and the central core is arranged in the middle part 8. Cups 10 are arranged in the foundations, into which cylindrical elastic elements 11 are inserted in the form of anchor bolts, the tightening value of which is assigned with a reliability coefficient γ _f , 1.2-1.5 times greater than the horizontal component on the support from the estimated wind load P _w . The lower base plate 3 of the PMO is supported by the embedded metal plate of the foundation 12 through the sliding gasket 13. Elastic elements in the form of anchor bolts 11, which take part in the achievement of displacements by the supporting columns 2 of a given size, and contribute to the return of the supporting columns 2 to their original position, rigidity elastic supports is assigned from the residual fraction, which is perceived by viscous friction dampers 4 (RMO) according to the weight characteristic of the building for each supporting element of the columns 1.

In an embodiment, the seismic isolating support has an upper 2, lower 3 plate, and a foundation embedded part 12, which are made in the form of a square, circle, polygon, and the foundation glasses 10 are made in the form of parallelepipeds, cylinders, or truncated inverted cones.

, где P_v - вертикальная нагрузка на опору, металлический цилиндрический стакан 14 закреплен через пластину 17 в стаканах фундаментов 10 при помощи упругих пластинчатых элементов 11 в виде анкерных болтов, между металлическим цилиндрическим стаканом 14 и закладной металлической пластиной 12 фундамента устроена скользящая прокладка 13 со своим коэффициентом трения и с коэффициентом надежности γ_f, в 2-5 раза большим, чем горизонтальная составляющая на опору от расчетной ветровой нагрузки Pw.In an embodiment, the seismic insulating support has a bottom support plate RMO, which is inserted into the metal support cylindrical cup 14 with thick-walled sides 15, and rests on it through the sliding gasket 16, the coefficient of friction of the gasket material f between the RMO and the bottom of the cylindrical cup is taken as $$f\ge \frac{P_w}{P_{\nu }{\gamma }_f}$$

where P _v is the vertical load on the support, the metal cylindrical cup 14 is fixed through the plate 17 in the cups of the foundations 10 using elastic plate elements 11 in the form of anchor bolts, a sliding gasket 13 is arranged between the metal cylindrical cup 14 and the embedded metal plate 12 of the foundation coefficient of friction and with a reliability coefficient γ _f , 2-5 times greater than the horizontal component on the support from the estimated wind load Pw.

In an embodiment, the seismic isolating support has foundation glasses 10 and lamellar (cylindrical) elastic elements 11 in the form of anchor bolts that are placed along the perimeter of the support in concentric directions in a checkerboard pattern.

In an embodiment, the seismic insulating support has a central core 18, which is made of an elastomer reinforced with composites, with the specified elastoplastic properties of the reinforcement material, and their dimensions and spatial orientation along the X, Y, Z axes.

A seismic isolating support works as follows.

When seismic impact due to the inertial forces of the column, 1 due to the flexibility of the RMO begins to move by the magnitude of the bending of the RMO (Fig.1-6). In this case, the lower plate, depending on the magnitude of the horizontal seismic force P _s (at a low value), remains stationary. If the horizontal seismic force P _sx , or P _sy (where the index x, y denotes the direction along the coordinates in the X, Y plane) exceeds the braking force of friction of the material of the sliding pad 13 between the lower support plate 3 and the embedded foundation 12, then the free sliding of the lower plate begins 3 on the gasket 13 on the mortgage 12. The free sliding of the lower plate 3 will be prevented by the bending stiffness of the plate, (cylindrical) springs 11 in the form of anchor bolts. The return of the support to its original position will be facilitated by the bending stiffness of the leaf (cylindrical) springs 11, and the shear stiffness of the PMO 4.

At maximum seismic load, the support will move by an amount equal to half the side of the square (a / 2) or ... (d / 2) with a round or conical glass, and due to the deviation (shift) from the vertical by δ.

U = a _c / 2 + δ with a square in terms of glass U ― d _c.ph / 2 + δ with a round glass top

U≤U ₀ ,

where a _c and d _{c · f} is the side of the square, or the diameter of the foundation glass.

Thus, it is possible to achieve the maximum deviation U _{0 of the} seismic isolating support for a given ballistic design of the designed building. Moreover, in the supporting element of the column, the bending moments from the seismic effect will be negligible, and are mainly due to the inertial forces of friction. The dissipation of the energy of seismic effects in the proposed embodiment (Fig.1-6) consists of three components:

due to the visco-elastic friction of the RMO 4;

due to dry friction of the sliding strip 13;

due to the elastic elements of leaf (cylindrical) springs 11 in the form of anchor bolts.

Thus, the functionality of using a seismic isolating support at different earthquake intensities is expanding. Moreover, due to the inclusion in the work of additional dry friction bonds 13 and elastic elements of leaf (cylindrical) springs 11, the load on the RMO is reduced and the reliability of the building's seismic protection is increased.

, где P_v - вертикальная нагрузка на опору, P_w - горизонтальная составляющая расчетной ветровой нагрузки на колонну, γ_f - коэффициент надежности, принимаемый равным 1,2-1,5, для того, чтобы опора была неподвижной от расчетной ветровой нагрузки. Если, горизонтальная сейсмическая сила P_sx или P_sy (где индекс x, y обозначает направление по координатам в плоскости X, У) превысит тормозящую силу трения, материала скользящей прокладки 16 между нижней опорной пластиной 3 и дном металлического цилиндрического стакана 14, (которая в 1,2-1,5 раза больше горизонтальной составляющей ветровой нагрузки), тогда начинается скольжение нижней опорной пластины 3 по дну стакана.In an embodiment of the seismic isolating support, when the lower base plate 3 of the PMO is inserted into the metal supporting cylindrical glass 14 with thick sides 15, the following occurs with seismic action. Under seismic action due to inertial forces, the column 1 due to the flexibility of the RMO begins to move by the amount of bending (shift) of the RMO (Fig.7-9). In this case, the lower plate, depending on the magnitude of the horizontal seismic force P _s (at a low value), remains stationary. If the horizontal seismic force P _sx or P _Psy (where the index x, y denotes the direction along the coordinates in the X, Y plane) exceeds the braking force of friction of the material of the sliding pad 16 between the lower support plate 3 and the bottom of the metal cylindrical cup 14, then the free sliding of the lower plate 3 on the gasket 16 lying on the bottom of the glass 17. The support remains stationary until the seismic force P _sx , or P _sy exceeds the friction force of the gasket material between the PMO and the bottom of the cylindrical glass. The coefficient of friction of the gasket material f between RMO and the bottom of the cylindrical glass is taken as $$f\ge \frac{P_w}{P_{\nu }{\gamma }_f}$$

where P _v is the vertical load on the support, P _w is the horizontal component of the estimated wind load on the column, γ _f is the reliability coefficient, taken equal to 1.2-1.5, so that the support is stationary from the estimated wind load. If, the horizontal seismic force P _sx or P _sy (where the index x, y denotes the direction along the coordinates in the X, Y plane) exceeds the braking force of friction, the material of the sliding pad 16 between the lower support plate 3 and the bottom of the metal cylindrical cup 14, (which 1.2-1.5 times the horizontal component of the wind load), then the sliding of the lower base plate 3 along the bottom of the glass begins.

With a higher seismic intensity, the bottom plate 3 of the PMO support abuts against the thick sides 15 of the cup 14. Friction forces that act on the sliding pad 13 between the embedded plate of the foundations 12 and the plate of the cup 17 begin to prevent further displacement of the support. The friction coefficient of the sliding pad 13 is assigned from the reliability coefficient γ _f , 2-5 times greater than the horizontal component on the support from the estimated wind load P _w . With an even greater seismic force, in addition to the dampers described above, lamellar (cylindrical) elastic elements of the springs 11 begin to work.

At maximum seismic load, the support will move by an amount equal to

U = d _c.ph. / 2 + (d _m.st -d _RMO ) / 2 + δ≤U ₀ ,

where and d _{c · f} is the diameter of the foundation glass, d _mst is the diameter of the metal foundation glass, d _PMO is the diameter of the bottom plate of the PMO, 8 is the deviation (shift) of the RMO from the vertical.

The dissipation of the energy of seismic effects, in the proposed embodiment (Fig.7-9) consists of four components:

- due to the visco-elastic friction of the PMO 4;

- due to dry friction of the sliding strip 16 (with its friction coefficient);

- due to dry friction of the sliding strip 13 (with its friction coefficient);

- due to the elastic elements of leaf (cylindrical) springs 11 in the form of anchor bolts.

Thus, the functionality of using a seismic isolating support at different earthquake intensities is expanding. Moreover, due to the inclusion of additional dry friction bonds 13 and 16 and elastic elements of leaf (cylindrical) springs 11, the load on the RMO is reduced and the reliability of the building's seismic protection is increased.

In an embodiment of a seismic isolating support with a central core 18, which is made of an elastomer reinforced with composites, the device operates as follows. In layers with rubber sheets 6 during plastic deformation, an elastomer reinforced with composites is introduced. In this case, elastoplastic work is performed, which absorbs part of the energy of the earthquake.

The dissipation of energy of seismic effects in the proposed embodiment consists of five components:

- due to the visco-elastic friction of the PMO 4;

- due to dry friction of the sliding strip 16 (with its friction coefficient);

- due to dry friction of the sliding strip 13 (with its friction coefficient);

- due to the elastic elements of leaf (cylindrical) springs 11 in the form of anchor bolts;

- due to viscous friction during the introduction of the elastomer between the steel sheets 7 in the layers with rubber 6.

Thus, due to the particular design of seismic protection of the structure, the invention allows the creation of a unified support for an earthquake-resistant structure with a sufficiently large bearing capacity, minimizing the horizontal load, the structure to be protected, reliable operation during operation under seismic conditions, and simplifying the structure of the structure support. Along with this, the invention allows to create a fairly compact support structure, which is completely mounted on the construction site of the protected structure (building). Such a design of seismic isolation can significantly reduce the amount of installation and construction work, reduce their complexity and, therefore, reduce the time and cost of construction of the structure as a whole. In addition, the invention provides the possibility of creating a modular seismic protection system, easily modified depending on the specific parameters of the structure (building) and the intensity of the seismic impact. Moreover, the invention provides the adaptability of the support to structures with various overall mass indicators, which expands its operational capabilities and increases unification.

Claims (5)

1. A seismic isolating support, including the supporting element of the column, which is supported by a rubber-metal support (RMO) through the upper base plate, and the lower base plate of the RMO is connected to the foundation with anchor bolts, the RMO is made of elastic rubber sheets (gaskets) laid alternately on top of each other. and metal sheets, and in the middle part a central core is arranged, characterized in that glasses are arranged in the foundations in which lamellar (cylindrical) elastic elements are inserted in the form of anchor bolts, ratio, which is assigned a reliability coefficient γ _f, 1.2-1.5 times larger than the horizontal component on the support from the estimated wind load P _w, lower support plate rests on the RMS embedded metal foundation plate with holes for the elastic elements move the plate through the sliding gasket. 2. The seismic isolating support according to claim 1, characterized in that the upper, lower plate and embedded part of the foundation is made in the form of a square, circle, polygon, and the glasses of the foundations are made in the form of parallelepipeds, cylinders or truncated inverted cones. 3. The seismic isolating support according to claims 1 and 2, characterized in that the lower support plate of the PMO is inserted into the metal support cylindrical cup with thick-walled sides and rests on it through a sliding gasket, the coefficient of friction of the gasket material f between the RMO and the bottom of the cylindrical cup is taken as

where P _v is the vertical load on the support, the metal cylindrical cup is fixed through the plate in the foundation cups using plate (cylindrical) elastic elements in the form of anchor bolts, a sliding gasket is arranged between the metal cylindrical cup and the embedded metal foundation plate with its friction coefficient and the reliability coefficient γ _f , 2-5 times greater than the horizontal component on the support from the estimated wind load P _w . 4. A seismic isolating support according to claims 1 to 3, characterized in that the foundation glasses and (cylindrical) elastic elements in the form of anchor bolts are placed along the perimeter of the support in concentric directions in a checkerboard pattern. 5. A seismic isolating support according to claims 1 to 4, characterized in that the central core is made of an elastomer reinforced with composites with the specified elastoplastic properties of the reinforcement material and their dimensions and spatial orientation.

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