KR101121133B1 - Hybrid bearing using lead-tin alloy - Google Patents

Abstract

The present invention relates to a hybrid seismic isolator using a lead-tin alloy, and lead and tin having different properties as energy absorbers so as to more precisely and easily control the yield strength and energy absorption capacity according to the design conditions, but these By using lead and tin in a uniformly mixed alloy form, the problem caused by the contact of lead and tin can be solved even though the material is a different material having different stiffness.

The present invention for this purpose is made of an elastic body made of rubber, a flange installed on each of the upper and lower portions of the elastic body for coupling to the structure, the core is planted through the elastic body in the vertical direction to absorb vibration energy, The core is made of a lead-tin alloy prepared by melting lead and tin, respectively, and mixing them in a predetermined ratio.

Isolation Device, Lead, Tin, Sheath

Description

Hybrid Isolation Device Using Lead-Tin Alloy {HYBRID BEARING USING LEAD-TIN ALLOY}

The present invention relates to a seismic isolator, and in particular, lead and tin having different properties as energy absorbers to adjust the yield strength and energy absorption capacity more precisely and easily according to the design conditions, but these lead and tin uniformly The present invention relates to a hybrid seismic isolator using a lead-tin alloy, which is suitable for solving a problem caused by the contact between lead and tin, despite being different in stiffness by using a mixed alloy form.

In general, a seismic isolator is installed between an upper structure such as a bridge deck and a lower structure such as a pier supporting the same to secure energy with vertically sufficient rigidity while horizontally providing energy with sufficient deformation capacity and energy dissipation capacity. Will be absorbed.

Such a base isolation device has traditionally consisted of an elastic body obtained by alternately stacking a plurality of rubber plates and steel sheets, and a flange for installing the elastic body on a foundation or a structure.

However, in recent years, in order to further reduce the degree of deformation while further improving the energy absorption capacity of the base isolation device, a technique using high purity lead as a vibration energy absorber has been used.

1 is a longitudinal sectional view for explaining the base isolation device according to the prior art using the lead.

As shown, the seismic isolator according to the related art has an elastic body 10 formed by alternately stacking a plurality of rubbers 11 and a steel sheet 12, and a flange for fixing the elastic body 10 to a foundation or a structure ( In addition to the traditional configuration consisting of 20 and 30, a core 40 made of lead is placed in the center of the elastic body 10.

As described above, the seismic isolator in which the lead core 40 is implanted in the conventional elastic body 10 easily yields to the pier's creep characteristics for a load that gradually acts over a long period of time such as a temperature load, thereby reducing the temperature load to the piers. It has an effect of improving stability by resisting with great rigidity against loads acting for a short period such as wind load and braking load of a vehicle. In addition, it surrenders to larger loads exceeding wind loads such as earthquake loads to achieve long periods by the elastic body 10 to reduce the induction of seismic forces, while suppressing displacement by absorbing the vibration energy of the bridge deck as nonlinear behavior of lead. It was.

Thus, although the seismic isolator using lead has superior performance compared to the conventional seismic isolator which relies on the elastic body 10, the elastic body 10 is relatively increased because the installation area of the lead is increased to increase the resistance by the lead in the region with strong wind load. The lack of restoring force caused by this problem caused the insufficiency of the seismic isolation device using lead in some cases.

In addition, despite the yield strength and energy absorption ability by lead, there are still limitations in reducing the displacement of the bridge deck during the earthquake, which is still unsatisfactory in terms of maintenance problems such as collision with adjacent bridges and the use of small expansion joints.

In addition, the conventional seismic isolator using lead is inevitable to excessive use of lead, a harmful substance, there is a concern of environmental destruction. As a result, the handling of lead became a problem during manufacturing, and in the future, when dismantling the structure, it became a problem in the disposal method of the seismic isolation device using lead. Therefore, it is urgent to develop a seismic isolation device having the same performance or higher performance while minimizing the use of lead.

Meanwhile, the seismic isolator according to the prior art has a deformation portion 40a protruding from the outer circumferential surface while the lead core 40 pushes the rubber 11 positioned between the steel sheets 12 relatively, as can be seen in the detailed description of the drawing. ) Is lost and its original form is lost. In addition, the core 40 has many scratches on the outer circumferential surface due to direct contact with the steel sheet 12 having a relatively high rigidity for a long time. If the core 40, which absorbs vibration energy, does not preserve the original shape designed for optimal performance, and is deformed or damaged, the seismic isolator does not provide optimal seismic performance during an earthquake. Will be carried.

Accordingly, the present invention has been proposed to solve the conventional problems as described above, the object of the present invention is to use a mixture of lead and tin of different materials as an energy absorber, but the contact of lead and tin having different stiffness The present invention provides a hydride isolating device using a lead-tin alloy without problems.

In order to achieve the above object, a hybrid base isolator using a lead-tin alloy according to the technical idea of the present invention includes an elastic body including rubber; Flanges respectively installed on the upper and lower portions of the elastic body for coupling with the structure; The core is formed by penetrating the elastic body in the vertical direction to absorb the vibration energy, wherein the core is made of a lead-tin alloy prepared by melting lead and tin, respectively, and then mixing them uniformly. It features.

Here, the core may be characterized in that the tin is contained in a component ratio of 2 to 40% by weight.

In addition, a protective tube surrounding the outer circumferential surface of the core may be further installed between the elastic body and the core.

In addition, the protective tube may be made of a material having a greater compressive strength than the core.

Also. Male threads are formed on the outer circumferential surfaces of the upper and lower ends of the protective tube, and the flange may have a female thread formed to be coupled to the male screw of the protective tube.

Hybrid seismic isolator using a lead-tin alloy according to the present invention by using a lead-tin alloy prepared by melting lead and tin, respectively, and then uniformly mixed, damage and gaps due to direct contact of lead and tin of different materials It can completely solve the problem that the seismic performance is degraded due to the occurrence.

In addition, the present invention can be easily used to adjust the yield strength and energy absorbing capacity according to the design conditions according to the structure while having a superior yield strength and energy absorbing capacity than the lead-based seismic isolator by using a mixture of lead and tin.

In addition, the present invention can reduce the displacement of the bridge top plate or upper structure during the earthquake, compared to the conventional lead seismic isolation device can solve the problem of collision with the adjacent bridge or structure, it is possible to use a smaller bridge expansion joint device It is advantageous in terms of maintenance.

In addition, the present invention can reduce the environmental problems due to excessive use of lead.

In addition, the present invention is provided with a protective tube between the core and the elastic body to protect the core from contact and deformation and damage by the elastic steel sheet having a relatively strong rigidity. This can prevent the problem that the seismic performance is degraded due to the deformation and damage of the core.

In addition, the present invention helps to improve the ability to respond to the negative reaction force because the protective tube is connected to the flange located in the upper and lower by the screw coupling stably.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Example]

The present invention is a seismic isolation using only one of these alone by the composition of tin, which is a material having a damping force and yield load of 1.7 times compared to the lead used as an energy absorbing material in order to increase the yield strength and energy absorption capacity It is possible to obtain the effect that cannot be achieved in the device, that is, the yield strength and energy absorption capacity required according to the structure can be precisely adjusted to the design value. In addition, the environmental problems caused by excessive use of lead can be largely solved.

However, the present invention is not limited to this, and furthermore, lead and tin, which are heterogeneous materials having different characteristics, are prepared by melting the lead and tin, respectively, and manufacturing the core in the form of a lead-tin alloy prepared by melting and uniformly mixing the lead and tin. It is possible to completely eliminate the damage and crevice phenomenon at the interface caused by the direct contact can achieve the optimal seismic performance.

Hereinafter, the configuration of a hybrid base isolation device using a lead-tin alloy according to the present invention will be described.

Figure 2 is an external perspective view of the present invention, Figure 3 is a partial cross-sectional view for explaining the configuration of the present invention, Figure 4 is a longitudinal cross-sectional view of the present invention, Figure 5 is a cross-sectional view of the present invention, Figure 6 is lead and tin The relationship between the horizontal load and the horizontal displacement to compare and explain the yield strength of.

As shown, the present invention comprises an elastic body 110, a flange (120a, 120b), a core 130 for absorbing vibration energy, and a protective tube 140.

Here, the core 130 according to the present invention was able to adjust the yield strength and energy absorption capacity by adjusting the content ratio of lead and tin having different damping and yield stress according to the design value according to the structure. However, instead of simply forming a combination of a specific type of lead and tin cores, the core of a cylindrical shape is formed by using a lead-tin alloy prepared by melting lead and tin, respectively, and uniformly mixing them with each other. 130).

As such, when using lead-tin alloy manufactured by melting lead and tin to provide a core 130 and then mixing them at a predetermined ratio, a problem arises at the interface where lead and tin having different characteristics directly contact each other. You do not have to worry about them.

If lead and tin are each made of a specific type of partial core and the total core is prepared in such a way that they are combined, they must be tightly sealed so that there is no gap in the lead-tin contact area to ensure proper seismic performance. Therefore, the processing and assembly process for the precise combination of lead and tin in a specific form had to be difficult. Moreover, even if the lead and tin are intimately adhered to initially, the weaker stiffness will be damaged over time due to the contact of lead with different stiffness. In addition, due to the difference in deformation or behavior due to load and temperature change, it is inevitable that the contact between the lead and tin interfaces cannot be maintained and a gap is generated. Therefore, it was virtually impossible to achieve optimal seismic performance as originally intended by combining partially formed lead and tin cores.

However, since the core 130 according to the present invention is in the form of an alloy prepared by uniformly mixing lead and tin in a required ratio, the interface between direct contact between lead and tin is completely removed.

As such, when the core 130 is made of a lead-tin alloy, the yielding strength and energy absorption capacity of the lead 130 can be basically secured as compared with the core 130 of the lead material. Yield strength and energy absorption capacity can be adjusted more precisely by appropriately changing the ratio of lead and tin depending on the design conditions of the structure. This is described below.

That is, FIG. 6 shows the horizontal hysteresis characteristics when comparing the case where the core 130 having a diameter of 900 mm with only the lead material is installed in the seismic isolator and the case where the tin 130 is replaced with the tin material under the same conditions. According to FIG. 6, when the core 130 is formed only of tin material, the capacity to withstand horizontal loads is about 1.7 times higher than the case where the core 130 is formed only of the lead material in the base isolation device. You can check it. This is due to the fact that tin has greater capacity in damping and yield stress than lead.

Therefore, the seismic isolator of the present invention is higher in the yield strength and energy absorption capacity of the vibration energy than the case of using only lead alone by using a tin-tin alloy to form the core 130 alone and using only tin alone. It has the ability in the lower midrange rather than the case. However, the middle area is the area which is currently impossible to protect with a seismic device based on the lead core, and is a blind area that is difficult to protect even if lead is replaced with tin. However, the present invention can secure the yield strength and energy absorption capacity to protect the range of the intermediate region that is difficult to protect by using only one of lead or tin alone by adjusting the composition ratio of lead and tin according to the design conditions. It is. Therefore, in the case where the present invention is installed on the bridge, for example, in the region where the wind load is strong enough that the lead seismic isolator can not afford, the stronger the strength of the wind load, the higher the component ratio of tin, and the weaker the strength of the wind load, the lead component ratio Can increase. Similarly, for earthquakes, the composition ratio of lead and tin may be adjusted appropriately according to design values that take into account the expected seismic strength in a particular region.

For reference, it can be seen from the table below that tin is superior in mechanical properties to lead. In addition, tin is known to have properties equal to or higher than lead in ductility, repeatability, recrystallization at room temperature, etc., and is suitable for use as a heterogeneous energy absorber together with lead.

Item lead Remark Characteristic strength (MPa) 12.9 19.2 Shear stiffness (GPa) 17.6 51.9 Elastic Strain (× 10 ^-4 ) 7.33 3.70

However, in the case of increasing the composition ratio of tin in the core 130, although there is a positive aspect of increasing the damping force and the constant stability, the increase in the residual strain and the cost increase due to the lack of the restoring force caused by the action of the elastic body 110 There are also negative aspects, so it is very important to determine the amount of tin. This will be described with reference to Table 1 and FIGS. 7A to 7C.

Remark
Ingredient ratio The diameter of the core 130 is 1/3 of the elastic body 110 The diameter of the core 130 is 1/4 of the elastic body 110 Diameter of core 130 is 1/5 of elastic body 110 Damping Force (KN) Resilience (KN) Damping Force (KN) Resilience (KN) Damping Force (KN) Resilience (KN) 2% 879 1971 662 2071 527 2171 3% 894 1957 673 2057 537 2157 5% 927 1928 694 2028 557 2128 10% 1006 1856 759 1956 609 2056 20% 1166 1711 885 1811 721 1911 30% 1329 1567 1028 1567 842 1767 40% 1496 1422 1198 1422 972 1622 50% 1598 1278 1354 1278 1105 1478 60% 1758 1133 1436 1133 1244 1333 70% 1921 989 1556 989 1391 1189 80% 2088 844 1674 844 1544 1044 90% 2151 700 1788 700 1673 900 100% 2210 555 1898 555 1802 755

      First, the results of experiments based on the case where the diameter of the core 130 is 1/3 of the diameter of the elastic body 110 are shown. As shown in Table 1 and FIG. 7A, the composition ratio of tin to the entire core 130 is 40. When the weight percentage is exceeded, the restoring force falls short of the damping force. Therefore, when the diameter of the core 130 is 1/3 of the diameter of the elastic body 110, it can be seen that the component ratio of tin to the entire core 130 is preferably set in the range of 2 to 40 wt%.

Looking at the results of the experiment based on the case where the diameter of the core 130 is 1/4 of the diameter of the elastic body 110, the content ratio of tin to the entire core 130 is 50% by weight, as shown in Table 1 and FIG. 7B. At over, the restoring force fell short of the damping force. Therefore, when the diameter of the core 130 is 1/4 of the diameter of the elastic body 110, it can be seen that the component ratio of tin to the entire core 130 is preferably set in the range of 2 to 50 wt%.

Looking at the results of the experiment based on the case that the diameter of the core 130 is 1/5 of the diameter of the elastic body 110, as shown in Table 1 and FIG. 7C, the component ratio of tin to the entire core 130 is 70% by weight. At over, the restoring force fell short of the damping force. Therefore, it can be seen that when the diameter of the core 130 is 1/5 of the diameter of the elastic body 110, the component ratio of tin to the entire core 130 is preferably set in the range of 2 to 70 wt%.

In consideration of the foregoing, it can be seen that when the component ratio of tin to the entire core 130 is 2 to 40% by weight, it can be used universally. Such a composition ratio of tin can be said to be a range in which the burden of cost increase due to the use of expensive tin is relatively low from an economic point of view.

As such, the seismic isolator of the present invention should carefully determine the content ratio of lead and tin in consideration of the damping force of the core 130 made of lead-tin alloy and the restoring force of the elastic body 110.

The elastic body 110 has a lower damping force or yield stress than the core 130 made of an alloy of lead and tin, but reduces the seismic input acceleration and achieves a long period of inherent period, thereby primarily protecting the structure from the destructive force of the earthquake. Do it. To this end, the elastic body 110 alternately stacks the rubber 111 and the steel plate 112 in the vertical direction. In addition, the outer surface is coated with rubber 114 to prevent corrosion of the steel sheet 112. On the other hand, between the elastic body 110 and the flange (120a, 120b) is connected to the connecting steel plates 113a, 113b connecting them.

The flanges 120a and 120b serve to couple the elastic body 110 to structures such as bridges, buildings, and large tanks. To this end, the flanges (120a, 120b) is usually made of a metallic plate and is connected to the upper and lower portions of the elastic body 110 by connecting steel plates (113a, 113b), respectively. The flanges 120a and 120b include a plurality of bolt holes 123 and bolts 125 for coupling with the connecting steel plates 113a and 113b and the elastic body 110, and a plurality of circumferential portions for coupling to the structure. The fastening through hole 121 is provided.

The protective tube 140 isolates the core 130 from the elastic body 110 to prevent the core 130 made of lead-tin alloy from being damaged due to the relatively rigid rigid steel sheet 112. It plays a role. To this end, the protective tube 140 is installed in the form of a circular tube wrapped close to the outer peripheral surface of the core 130 between the elastic body 110 and the core 130. The protective tube 140 should be made of a material having a greater rigidity (compressive strength) than the core 130 made of lead-tin alloy. When the protective tube 140 is provided, the core 130 having a cylindrical shape, which is a core element used as an energy absorber, can fully exhibit its original function without being deformed or damaged by the steel plate 112. However, if the protective tube 140 is not provided, while the core 130 pushes the rubber 111 and is pushed between the elastic body 110 and the steel plate 112, the shape of the outer circumferential surface is deformed, while the outer circumferential surface is relatively rigid. The sharp edges of the 112 and a lot of scratches while prolonged contact. As a result, the core 130, which is designed to exert optimal performance in a circular state, does not exhibit optimal performance, resulting in a reduction in the seismic isolation performance of the seismic isolator when an earthquake occurs.

In addition, male threads 141 are formed on the outer circumferential surfaces of the upper and lower ends of the protective tube 140 to be screwed corresponding to the female threads 127 formed on the flanges 120a and 120b. As such, when the upper end and the lower end of the protective tube 140 are stably screwed with the flanges 120a and 120b, the upper structure and the lower end of the protective pipe 140 are largely suppressed from the tendency of the upper structure to be lifted or detached by the negative reaction, thereby contributing to preventing the harmful effects due to the negative reaction. do. As described above, since the protective tube 140 provided in the present invention has a capability of responding to the negative reaction force, a part for responding to the negative reaction force may be replaced in a place where the negative reaction force is relatively weak. On the other hand, where the negative reaction force is relatively strong, it contributes to mitigating the design conditions of the components provided to cope with the negative reaction force.

Although preferred embodiments of the present invention have been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

1 is a longitudinal sectional view for explaining the base isolation device according to the prior art using lead.

Figure 2 is an external perspective view of the present invention.

Figure 3 is a partial cross-sectional view for explaining the configuration of the present invention.

4 is a longitudinal sectional view of the present invention;

5 is a cross-sectional view of the present invention.

6 is a horizontal load and horizontal displacement relationship diagram for comparing and explaining the yield strength of lead and tin.

7A to 7C are correlation diagrams showing the relationship between the damping force and the restoring force according to the change in the composition ratio of tin;

* Description of the symbols for the main parts of the drawings *

110: elastomer 111,114: rubber

112: steel plate 120a, 120b: flange

130: lead-tin alloy core 140: protective tube

Claims (5)

An elastic body including rubber; Flanges respectively installed on the upper and lower portions of the elastic body for coupling with the structure; Is made of a core that penetrates the elastic body in the vertical direction to absorb the vibration energy, The core is made of a lead-tin alloy prepared by melting lead and tin, respectively, and mixing them in a predetermined ratio. The elastic body and the core is made of a material having a greater compressive strength than the core wraps around the outer circumference of the core and completely isolated between the elastic body and the core without gaps, the male thread formed on the flange is formed with a male screw on the outer peripheral surface Hybrid seismic isolator using a lead-tin alloy, characterized in that the protective tube is provided to be screwed correspondingly. The method of claim 1, The core is a hybrid isolation device using a lead-tin alloy, characterized in that the tin is contained in a component ratio of 2 to 40% by weight. delete delete delete

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