WO2013141210A1

WO2013141210A1 - Seismic tie for boiler damping and earthquake-resistant boiler structure body using same

Info

Publication number: WO2013141210A1
Application number: PCT/JP2013/057679
Authority: WO
Inventors: 清相田; 幸太郎河村; 泰治築地; 佑一樋吉
Original assignee: バブコック日立株式会社
Priority date: 2012-03-23
Filing date: 2013-03-18
Publication date: 2013-09-26
Also published as: JP5843732B2; CL2014002507A1; JP2013224730A

Abstract

Provided is a seismic tie for increasing the vibration-absorbing performance of a boiler body and reducing the seismic load acting on a support structure. A seismic tie disposed between the support structure comprising a plurality of pillars and joists and a boiler body suspended from an upper joist has a hinge joint structure comprising an elastic-member link and an elasto-plastic member pin (16). The pin (16) has a circular-sectioned bearing section (16C) in the center, and a pin spindle-shaped cut-processed section (16B) comprising: a web section (16W), in which a spindle-shaped pin, the diameter of which becomes gradually smaller toward the hinge joint area, is partially cut-processed; and a flange section (16F) existing at the outer edge of the web section. The web section (16W) is configured such that both side sections are cut into a plate shape in the axial direction of the pin, and the ratio of the sectional area of the flange section to the sectional area of the web section in a section perpendicular to the pin axis direction is 1.3 to 1.7.

Description

Seismic tie for boiler vibration control and boiler seismic structure using the same

The present invention mainly relates to a seismic structure of a large boiler for a thermal power plant, and more particularly to a seismic tie which is a vibration absorber installed in the boiler.

Large boilers mainly used in thermal power plants usually suspend the boiler body from the upper part of a support frame composed of a combination of steel columns arranged in the vertical direction and main beams arranged in the vertical direction. It is a lowered structure.

A description will be given of a seismic structure of a boiler that has been conventionally employed and also relates to an embodiment of the present invention, with reference to FIGS. FIG. 15 is a side view of the boiler seismic structure, FIG. 16 is a schematic diagram showing the layout of the main piping that is piped between the boiler body, the boiler building, the turbine building, the boiler building and the turbine building, and FIG. 17 is each layer of the support frame. FIG. 18 is a perspective view showing the structure of a conventional seismic tie, FIG. 19 is a diagram showing the structure of a spindle-type pin in the conventional seismic tie, and FIG. 20 is a seismic tie. It is a figure explaining the principle of the energy absorption by a tie.

For example, as shown in FIG. 15, the support frame 7 is composed of a combination of a plurality of steel columns 1 arranged in the vertical direction and a plurality of main beams 2 arranged in the vertical direction. Since the boiler body 4 is thermally stretched in the vertical direction during operation, the boiler body 4 is suspended from the upper portion of the support frame 7 by suspension bolts 3 so as not to restrain this thermal elongation.

Here, the main beam 2 means a seismic beam arranged in the horizontal direction. The main beam 2 (hereinafter also referred to as a beam or a steel beam) is arranged in a plurality of stages along the height direction from the ground 32. In order from the bottom, the uppermost part for hanging the boiler body 4 with the first layer from the foundation part of the support frame 7 to the lowermost main beam 2 and the second layer from the lowermost main beam 2 to the next main beam 2 A plurality of layer structures are formed up to the main beam 2, and up to the seventh layer is formed in the example of FIG.

17 (1) is a cross-sectional view as viewed from FIG. 15A-A, FIG. 17 (2) is a cross-sectional view as viewed from FIG. 15B-B, FIG. 17 (3) is a cross-sectional view as viewed from FIG. 17 (5) is a cross-sectional view from FIG. 15E-E, FIG. 17 (6) is a cross-sectional view from FIG. 15F-F, and FIG. 17 (7) is a cross-sectional view from FIG. It is sectional drawing seen from.

15 and 17, a seismic tie 6 is provided between the boiler body 4 and the support frame 7 in order to absorb the vibration energy of both during the earthquake. Specifically, as shown in FIG. 15, seismic ties 6 are respectively installed on the upper part of the first layer, the upper part of the second layer, the upper part of the fourth layer, the upper part of the fifth layer, and the upper part of the sixth layer. Yes. In this example, as shown in FIG. 17, a total of 14 seismic ties 6 are used.

FIG. 18 is a perspective view showing the structure of a seismic tie applied to a boiler seismic structure related to the prior art. An example of the structure of the seismic tie 6 having the spindle type pin 6B shown in FIG. 18 is disclosed in, for example, Patent Document 1 below.

The seismic tie 6 is connected to the boiler body 4 and the support frame 7 through a pressure bearing 6C. The seismic tie 6 is configured by hinge-joining a spindle type pin 6B (soft steel material) and a link 6A (rigid steel material). According to this Patent Document 1, the steady-state structure spanned between the boiler body and the supporting steel frame is composed of two parallel links and a pin material coupled to the link. In addition, it is disclosed that a spindle shape is formed in which the pin diameter is gradually reduced from the central portion toward both ends (see FIGS. 18 and 19).

FIG. 19 shows the structure of the spindle-type pin 6B and the bearing portion 6C in the seismic tie 6 disclosed in Patent Document 1. 19 (1) is a front view of the spindle-type pin 6B and the bearing section 6C, FIG. 19 (2) is a cross-sectional view taken along line CC in FIG. 19 (1), and FIG. 19 (3) is FIG. 19 (1) D. It is sectional drawing on the -D line.

The pin 6B has a so-called spindle type (rugby ball type) in which the cross section becomes smaller in the axial direction from the bearing portion 6C. As for the cross-sectional shape, the cross section of the bearing section 6C (CC cross section) and the cross section of the other part (DD cross section) are circular.

FIG. 20 is a diagram for explaining the principle of energy absorption by the seismic tie related to the prior art and the present invention. The relationship between the reaction force Fi of the seismic tie and the displacement δi in the conventional structure of the spindle type pin shown in FIG. This is indicated by the solid line in FIG. The area surrounded by the solid line corresponds to the vibration energy absorption amount. In FIG. 20, a solid line passing through the origin of coordinates is a line for explaining the first gradient described later.

In the case of a boiler structure, the relative displacement between the boiler body and the support frame becomes a displacement δi that acts on the seismic tie, and this action generates a reaction force Fi on the seismic tie. In order to prevent damage to the piping during an earthquake, it is necessary to suppress the seismic tie displacement δi in the actual machine to a maximum value (maximum displacement δi, max = 15 cm in FIG. 20) or less.

Japanese Patent No. 2572403

Here, the principle of energy absorption by seismic tie will be described with reference to FIG. The maximum value of the vibration energy absorption amount is shown in FIG. 20 under the condition that the maximum displacement (δi, max = 15 cm) and the maximum reaction force Fi, max in the conventional structure of the spindle type pin shown in FIG. It is a rectangular area indicated by a dotted line (denoted as a target in FIG. 20).

It is desirable to have a structure that expands the vibration absorption energy area by the conventional structure of the spindle type pin indicated by the solid line so as to be as close as possible to this rectangular area. In order to increase the energy absorption performance from the conventional structure, the first gradient of the pin material in the seismic tie shown in FIG. 20 (the gradient when the pin material in the seismic tie is elastic) is increased, and the second gradient (the seismic tie). It is necessary to reduce the gradient when the pin material is plastic (the pin material 6 has elastic-plastic characteristics).

In order to increase the first gradient described above, it is necessary to increase the second moment of section as compared with the conventional structure. To reduce the second gradient, it is necessary to widen the plastic stress area and level the stress distribution. is there.

As described above, when the diameter of the pin member 6 in the conventional structure is increased so as to increase the moment of inertia of the cross section, the cross sectional area is increased and the plastic stress area is reduced, which does not lead to an increase in energy absorption. On the contrary, if the seismic tie diameter is reduced in order to widen the plastic stress area, the secondary moment of the cross section is reduced, which does not lead to an increase in energy absorption. Thus, since there is a reciprocal relationship between increasing the moment of inertia of the cross section and expanding the plastic stress area, it has been a very difficult task to find a structure in which both are compatible.

In other words, when the diameter of the pin material in the seismic tie is increased, the second moment of the cross section is increased, and the reaction force against the displacement is increased due to the rise in the first gradient, resulting in an increase in energy absorption. The difference in height distribution becomes large, the stress distribution is not leveled, the plastic stress area is reduced, and the second gradient is increased, so that energy absorption is not increased (see the explanation of FIGS. 12 and 13 described later).

In order to solve the above-mentioned problems, the present invention increases the vibration energy absorption performance of the boiler body by using a seismic tie that achieves both an increase in the secondary moment of section and an expansion of the plastic stress area. The objective is to provide a boiler seismic structure that reduces the seismic load acting on the frame.

In addition, an object of the present invention is to provide a sikumi tie that increases the vibration energy absorption performance at the time of an earthquake and minimizes damage to equipment such as piping in consideration of the speed of restoration work after the earthquake. And a boiler damping structure that reduces a seismic load acting on a boiler building that is a support frame of the boiler body. As a result, the vibration energy absorption performance during an earthquake can be increased by seismic ties, so there is no need to increase the rigidity of the support frame as in the past, and in the case of a new boiler, it is used for the boiler building that is the support frame Steel weight can be reduced. In the case of an existing boiler, it is possible to provide a boiler seismic structure with improved seismic resistance.

In order to solve the above problems, the first means of the present invention is:
A support frame composed of a plurality of steel columns and steel beams and a boiler body supported by being suspended from the steel beam above the support frame are connected, and the relative displacement during the earthquake between the support frame and the boiler body is used. It is intended for seismic ties that absorb the vibration energy of earthquakes.

The seismic tie includes a link material that is an elastic member and a pin material that is an elastic-plastic member in a direction perpendicular to the link material, and a structure in which both ends of the link material and the pin material are hinged to each other. Have
The pin member has a bearing portion having a circular cross-sectional shape at the axial center of the pin member, and has a substantially spindle shape in which the outer diameter gradually decreases from the bearing portion toward the hinge coupling portion. Have
The bearing portion of the pin material is connected to the support frame and the boiler body,
The substantially spindle shape is characterized by a structure formed by a web portion and a flange portion installed on the outer edge side of the web portion.

According to a second means of the present invention, in the first means,
The substantially spindle shape is a structure formed by a web plate and a flange plate installed on the outer edge side of the web plate,
The web plate has a shape in which both sides of the web plate are symmetrically arranged in the axial direction of the pin material around the axis of the pin material,
The ratio of the cross-sectional area of the flange plate to the cross-sectional area of the web plate is 1.3 to 1.7 in the cross section in the axial direction of the pin material and the direction perpendicular to the axis of the pin material. To do.

A third means of the present invention is the first or second means,
The cross-sectional shape of both sides is made symmetrical with respect to the axis of the pin material on which the reaction force to the bearing portion of the seismic tie with respect to the relative displacement at the time of the earthquake is applied.

In order to solve the above-mentioned problem, the fourth means of the present invention is:
A support frame comprising a plurality of steel columns and steel beams and having a plurality of layered structures, a boiler body supported by being suspended from a steel beam above the support frame, and connecting the support frame and the boiler body In a boiler seismic structure with seismic ties,
The seismic tie is a seismic tie of any one of the first to third means,
The seismic tie is provided at least in a layer corresponding to the position of the center of gravity of the boiler seismic structure.

In order to solve the above-mentioned problem, the fifth means of the present invention is:
A support frame comprising a plurality of steel columns and steel beams and having a plurality of layer structures, a boiler having a furnace, a side wall portion and a rear wall portion, and supported by being suspended from a steel beam above the support frame In a boiler seismic structure with a main body and a seismic tie connecting the support frame and the boiler body,
The seismic tie is a seismic tie of any one of the first to third means,
In the layer of the support frame having the furnace and the rear wall part, the seismic tie is installed between the furnace and the support frame and between the rear wall part and the support frame. To do.

According to the present invention, the pin structure having the spindle-shaped cutting portion in the seismic tie is configured by the web portion and the flange portion, and the cross-sectional area of the flange portion is appropriately set by setting the cross-sectional area of the flange portion with respect to the cross-sectional area of the web portion. The seismic tie absorbs the vibration energy of the boiler body by the seismic tie, and the seismic load acting on the support frame can be reduced by coexisting the increase of the next moment and the expansion of the plastic stress area.

Also, by reducing the seismic load, the weight of the support frame can be reduced in the case of a new boiler, and the earthquake resistance can be improved in the case of an existing boiler.

It is a front view which shows the structure of the pin material in the seismic tie which concerns on embodiment of this invention. It is a perspective view which shows the structure of the pin material in the seismic tie which concerns on this embodiment. It is the side view and top view which show the other structure of the pin material in the seismic tie which concerns on this embodiment. It is a figure which shows the web board which shows the other structure of the pin material in the seismic tie which concerns on this embodiment, a flange board, a fixed board, and a bearing part part. It is a figure which shows the cross-sectional shape of a pin axis | shaft perpendicular | vertical direction in each site | part of the pin axis direction in the pin material shown in FIG. FIG. 4 is a view showing a cross-sectional shape in a direction perpendicular to the pin axis at each part (EE cut to JJ cut part) in the pin axis direction in another structure of the pin member shown in FIG. 3; It is a figure which shows the cross-sectional shape of the pin-axis perpendicular | vertical direction in the pin material regarding this embodiment, and its dimensional relationship. It is a figure which shows the relationship between the vibration energy absorption amount of the seismic tie which concerns on this embodiment, and the ratio of the flange part cross-sectional area with respect to the web part cross-sectional area of a pin material. It is a figure which shows the 1/4 division | segmentation model of the finite element analysis model of the seismic tie which concerns on this embodiment. It is a figure showing the boundary condition of the 1/4 division | segmentation model of the finite element analysis model of the seismic tie which concerns on this embodiment. It is a figure which shows the load displacement curve which is an analysis result of the finite element analysis model of the seismic tie which concerns on this embodiment. It is a figure which shows the stress distribution in the maximum reaction force point in the load displacement curve which is an analysis result of the finite element analysis model of the seismic tie regarding a prior art. It is a figure which shows the stress distribution in the maximum reaction force point in the load displacement curve which is an analysis result of the finite element analysis model of the seismic tie which concerns on this embodiment. It is a figure showing by the distribution of the height direction of a boiler support frame about the horizontal seismic load at the time of applying the seismic tie which concerns on this embodiment to a boiler main body, compared with a prior art. It is a side view of the boiler seismic structure provided with the boiler main body, the column and main beam of the support frame, and the seismic tie. It is the schematic which shows the arrangement | positioning relationship of the main piping arrange | positioned between a boiler main body, a boiler building, a turbine building, a boiler building, and a turbine building. It is a figure which shows the arrangement | positioning relationship of the seismic tie in each layer of a support frame. It is a perspective view which shows the whole structure of the seismic tie applied to the boiler earthquake proof structure of a prior art. It is a figure which shows the structure of the spindle-type pin and bearing part in the seismic tie of a prior art. It is a figure explaining the principle of energy absorption by seismic tie.

The seismic tie according to the embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 15 and 18, a plurality of seismic ties 6 according to the present embodiment are installed between the boiler body 4 and a support frame (also referred to as a boiler building) 7. 5 absorbs the seismic energy generated by 5 and controls the boiler body 4 and the supporting frame 7.

Here, for the seismic tie 6 according to the present embodiment, the boiler building 7 composed of the steel column 1 and the steel beam 2, the boiler body 4 suspended from the boiler building 7, and the boiler body 4 to the turbine building 30 are arranged. In view of the overall structure including the installed main pipe 24, the necessity of seismic tie as an earthquake response will be explained.

FIG. 16 shows the boiler body 4 including the furnace 20, the side wall portion 21, the rear wall portion 22, and the penthouse portion 23, the boiler building 7 that is a support frame, the turbine building 30, and the boiler building 7 and the turbine building 30. It is the schematic which shows the whole structure of the main piping 24 arrange | positioned. FIGS. 15 to 18 and 20 are diagrams showing configurations for explaining the conventional technique, but are fundamental techniques applied also in the present embodiment.

In FIG. 16, a large boiler used in a thermal power plant is a boiler building 7 (also referred to as a support frame 7) that has a steel structure in which the boiler body is usually composed of a combination of a plurality of steel columns 1 and steel beams 2. ) Is suspended from the uppermost steel beam 2.

The boiler body has a casing structure surrounded by a heat transfer wall (also referred to as a peripheral wall), and burns by supplying combustion air together with fuel such as fossil fuel by a burner provided on the heat transfer wall. A furnace 20 that is communicated with the upper portion of the furnace 20 and provided in a horizontal direction, a flow path (also referred to as a side wall 21) through which combustion exhaust gas generated by combustion flows, and a combustion exhaust gas that is provided in communication with the flow path Consists of a flow path (also referred to as rear wall portion 22) that flows downward.

A suspended superheater or reheater is provided in the combustion exhaust gas flow path at the upper part of the furnace 20, and a high-temperature combustion exhaust gas from the furnace 20, for example, about 1400 ° C to 1500 ° C, a superheater, and reheat Heat exchange is performed with water vapor or water flowing through the inside of the vessel and the peripheral wall. Also in the side wall 21, the combustion exhaust gas exchanges heat with water vapor or water flowing inside the peripheral wall, and becomes a combustion exhaust gas of about 1000 ° C. to 1100 ° C., for example, and flows into the rear wall portion 22.

In the rear wall portion 22, a horizontal type superheater, a reheater, and a economizer are provided in the combustion exhaust gas flow path, and the flue gas from the side wall portion 21 is superheater, reheater, and economizer. Heat exchange is performed between water vapor or water flowing through the inside of the vessel and the peripheral wall, and the combustion exhaust gas becomes, for example, about 300 ° C. to 400 ° C.

At the uppermost portion of the boiler body 4 (see FIG. 15), there is a penthouse portion 23 that is insulated from the furnace 20, the side wall portion 21 and the rear wall portion 22 by a ceiling wall and a seal structure. A container header is provided. Steam heated to a high temperature by the superheater or the reheater is connected to the main header via the header in the penthouse section 23. The turbine building 30 is provided separately from the boiler building 7.

Further, an exhaust gas duct is provided in communication with the outside of the boiler building 7 from below or behind the rear wall portion 22. Environmental devices such as a denitration device, a dust removal device and a desulfurization device, and a heat exchanger are provided in the exhaust gas duct path. After the combustion exhaust gas from the rear wall portion 22 reaches about 50 ° C. at the desulfurization device outlet, Eventually released from the chimney to the atmosphere.

In addition, although not shown in FIG. 16, the main water supply pipe that supplies water to the boiler body 4 and the like are connected to the vicinity of the turbine building 30 from the boiler body 4 through the boiler building 7. The main steam pipe and the reheat steam pipe are spring hangers provided in the boiler building 7, the turbine building 30, and the steel structure between them in the path from the boiler body to the turbine building 30 via the boiler building 7. It is hung on the support support, so that it can cope with the thermal expansion of the piping in each structure. Further, the exhaust gas duct is provided with an expansion structure at the exit from the boiler building 7 or the like, so that it can cope with the thermal expansion of the boiler body.

These pipes and ducts are designed to be compatible with at least the thermal expansion of the boiler body 4 (see FIG. 15), but there is a limit to the response to an earthquake with a large amplitude. In particular, the relative displacement between the boiler body 4 and the boiler building 7 is limited between the boiler body 4 and the boiler building 7 in order to prevent interference between the boiler body 4 and the boiler building 7 during an earthquake. When the displacement exceeding 1 is generated, the main pipe 24 and the like are damaged, so that it takes a long time to recover after the earthquake.

Therefore, a seismic tie 6 is used between the boiler body 4 and the boiler building 7 to absorb vibration energy by plastic deformation in addition to elastic deformation.

FIG. 15 shows a side view for explaining the boiler seismic structure. In FIG. 15, a boiler body 4 is suspended in a boiler building 7 which is a support frame composed of a steel beam 2 and a steel column 1. Here, among the steel column 1 and the steel beam 2, the important components of the boiler seismic structure are particularly referred to as the main steel column 1 and the main steel beam 2.

The boiler body 4 is suspended and supported by the uppermost main steel beam 2a via the suspension bolts 3, and is thermally stretched in the vertical direction downward from the suspension support portion during operation. Although not shown, a slide or an expansion allowance is provided so that an arbitrary position of the suspension support portion is set as a reference point for moving in the horizontal direction, and horizontal movement is possible.

Here, the main steel beam 2 is arranged in a horizontal direction in the boiler building and constitutes an important component of the boiler seismic structure, and a plurality of main steel beams 2 are horizontally arranged in the height direction from the ground (also referred to as a foundation) 32. Arranged in the direction. The boiler seismic structure is referred to as the first layer from the base to the bottom main steel beam 2 from the bottom, and the second layer from the bottom main steel beam 2 to the next main steel beam 2, A plurality of layer structures are formed up to the main steel beam 2 from which the main body 4 is suspended. In the example of FIG. 15, a boiler seismic structure composed of the first layer to the seventh layer is formed.

In the boiler building 7, which is a boiler seismic structure composed of a plurality of layers, the main body 4 and the main body 4 are connected to the main body 4 in a plurality of layers to absorb the vibration energy of the main body 4 during an earthquake. A seismic tie 6 is provided as a structure. One seismic tie 6 is normally connected to the main steel column 1, but can be connected to the main steel beam 2 if the rigidity is high. In addition, the other of the seismic ties 6 is usually provided with a structure that restrains a peripheral wall called a back step so as to surround the furnace of the boiler body 4 (see FIG. 18), and is connected via the back step.

In FIG. 15, one seismic tie 6 is connected to the main steel column 1 at the same height as the main steel beam 2, and the other is connected to a backsteer (not shown). It is connected to. As described above, the reason why the seismic tie 6 is connected to the main steel column 1 at the same level as the main steel beam 2 is that the rigidity on the boiler building side is the highest because both are provided. by.

Further, in FIG. 15, the seismic tie 6 is installed at the upper part of the first layer, the upper part of the second layer, the upper part of the fourth layer, the upper part of the fifth layer, and the upper part of the sixth layer. FIG. 17 is a plan view of the arrangement of seismic ties 6 in FIG. A total of 14 seismic ties 6 are arranged in the BB to GG cross sections shown in FIGS. 10 on the furnace side and 4 on the rear wall side. The angle of attachment of each seismic tie 6 to the steel column 1 is, for example, 30 ° to 45 ° (the angle at which the long seismic tie 6 shown in FIG. 17 abuts the steel column 1). It corresponds to any displacement direction on the plane. In addition, it has a structure that can cope with thermal expansion (up and down movement) of the boiler body. Thus, the seismic energy due to the seismic load 5 is absorbed by the seismic tie 6 to control the boiler structure of the boiler body 4 and the boiler building 7.

FIG. 18 shows a conventional example of seismic tie 6. According to this, seismic tie 6 consists of two rigid steel materials such as a steel plate as a set and welded at one end in the length direction. Between the two steel members in the vertical direction on the upper and lower ends of the link member 6A and the one in the upper and lower ends of the link member 6A. It is composed of two spindle-type soft steel materials (referred to as pin material 6B) that are inserted and arranged, and both ends of the pin material 6B and both ends of the link material 6A are hinged by small-diameter round steel (pins). is doing.

In addition, a connection member is provided for each of the support portions 6C provided at the center of the two pin members 6B, one of which is connected to the steel column 1 of the support frame 7 via the support portion 6C, and the other is connected to the back support. It is connected. That is, the seismic tie 6 is configured by hinge-connecting a pin 6B (relatively flexible steel material) and a link 6A (rigid steel material) with a pin (see Patent Document 1 described above).

FIG. 19 shows the pin material 6B used in the seismic tie having the conventional structure described in FIG. This pin material 6B has a so-called spindle type (rugby ball type) in which the cross section becomes smaller as it is separated from the pressure bearing portion 6C provided in the central portion in the axial direction of the pin material in the axial direction. The cross section (CC cross section) of the bearing section 6C and the cross section of other portions (DD cross section) are concentric circles.

The relationship between the seismic tie reaction force Fi and displacement δi in this conventional structure is shown by the solid line in FIG. The rhombus area surrounded by the solid line corresponds to the amount of vibration energy absorbed during an earthquake.

Next, the case of the boiler seismic structure in the embodiment of the present invention will be described. The relative displacement between the boiler body 4 and the boiler building 7 becomes a displacement δi acting on the seismic tie, and a reaction force Fi is generated on the seismic tie due to this displacement.

In order to prevent damage to the main pipe 24 shown in FIG. 16 during an earthquake, it is necessary to suppress the seismic tie displacement δi in the actual machine to a maximum value (also referred to as the maximum displacement) or less.

That is, the maximum displacement is the maximum relative displacement that displaces within a range in which the main pipe 24 or the like is not damaged. When the boiler body 4 and the boiler building 7 are relatively displaced by vibration during an earthquake, the main displacement is the same as the boiler body 4. The piping 24 is arbitrarily set in consideration of the relative displacement that exceeds the displacement absorption amount by the spring hanger or the like on the boiler building 7 side and does not interfere with the boiler building 7.

Here, assuming that the maximum displacement δi, max is 15 cm, the principle of vibration energy absorption during an earthquake by seismic tie will be described with reference to FIG.

The solid line in FIG. 20 shows the state of the reaction force that acts on the displacement of the seismic tie during an earthquake. It is at the origin before the start of displacement and increases to the right according to the displacement on the right side. This gradient is referred to as a first gradient, and the reaction force increases due to elastic deformation. As the displacement progresses, the elastic deformation changes to plastic deformation, and the gradient from this is called the second gradient. This second gradient continues until the displacement reaches the maximum displacement (15 cm).

Next, when the displacement changes direction from right to left, the direction of the reaction force is reversed, and the elastic deformation causes the plastic deformation at a position where it continuously moves backward from the maximum displacement in parallel with the first gradient and does not return to the origin. The process proceeds until the maximum displacement (−15 cm) is reached in parallel with the second gradient with respect to the displacement on the left side.

Further, when the displacement changes direction from left to right, the direction of the reaction force is reversed, that is, the same as the first direction, and progresses until it changes to plastic deformation in parallel with the first gradient by elastic deformation. It will go up to the maximum displacement (15 cm) with a gradient.

Thus, since there is a reciprocal relationship between increasing the moment of inertia of the cross section and expanding the plastic stress area, finding a structure that achieves both is accompanied by a very difficult problem. In order to solve such a problem, the embodiment of the present invention provides the above-described compatible structure, which will be described below.

The seismic tie 6 according to the present embodiment is connected to the boiler body 4 and the support frame 7 via a pressure bearing 6C (see FIG. 18), and is relative to the support frame 7 and the boiler body 4 at the time of an earthquake. It is made of steel that absorbs vibration energy using displacement.

The seismic tie 6 has a specific structure in which two links 6A that are two elastic members are provided in the horizontal direction with respect to the direction in which the relative displacement occurs, and two in the direction perpendicular to the direction in which the relative displacement occurs. The pin 6B, which is an elastic-plastic member, is provided, and the link 6A and the end of the pin 6B are hinged.

The feature of the present invention is that, in general, the pin material 16 in the seismic tie 6 has a specific structure shown in FIGS. 1 to 7 described below.

Here, the pin material 16 relating to the present embodiment has a circular cross-sectional shape of the pin bearing portion 16C provided at the center in the axial direction. This is because the seismic tie 6 is connected to the boiler body 4 and the support frame 7 so as to be freely rotatable when the boiler body 4 is thermally expanded. The diameter of the pin bearing portion 16C of the pin material 16 is about 1.5 times the upper limit of the spindle type bearing portion 6C shown in FIG.

Further, the pin member 16 relating to the present embodiment shown in FIGS. 1 and 2 is in the axial direction as shown in FIGS. 1, 2, 5, and 7 with respect to the spindle-shaped pin 6B shown in FIG. In this structure, the both sides are partially cut (turned through) with the axis as a symmetric center line to form the web portion 16W, and the flange portions 16F are formed on both ends of the web portion 16W. . Fi shown in FIG. 1 indicates an axis on which the reaction force of the seismic tie 6 acts.

Here, the direction of the reaction force to the pin support portion 16C of the seismic tie 6 attached to the boiler body 4 and the support frame 7 shown in FIG. 18 is the reaction force of the pin spindle-shaped cutting portion 16B shown in FIG. The pin 16B having the structure shown in FIGS. 1 and 2 is attached to the link 6A so as to be an axis on which Fi acts, that is, so that the flat processed surface of the cutting portion 16B is symmetrical with the reaction force Fi interposed therebetween. Install and install.

FIG. 5 (1) is a cross-sectional view taken along the line EE of FIG. 1, showing the cross-sectional shape of the bearing portion 16C. 5 (2) is a cross-sectional view taken along line FF in FIG. 1, FIG. 5 (3) is a cross-sectional view taken along line GG in FIG. 1, and FIG. 5 (4) is taken along line HH in FIG. The cross-sectional view shows the cross-sectional shape of the pin spindle-shaped cutting portion 16B.

As shown in FIGS. 5 (1) to (4), the cross-sectional shape of each part is vertically symmetric about the axis 1001 on which the reaction force Fi of the seismic tie acts.

2, 5, and 7, as a configuration example of the present embodiment, the plate thickness tw of the cross-sectional shape of the web portion 16 </ b> W of the pin material 16 is a constant thickness in the axial direction of the pin spindle-shaped cutting portion 16 </ b> B. The dimension tF of the flange portion 16F in the direction perpendicular to the pin axis is also a fixed length in the pin axis direction.

Further, as shown in FIG. 7, the pin spindle-shaped cutting portion 16B according to this embodiment is characterized by a web portion 16W (a plate-like body) having a constant thickness tw in the cross-sectional shape of the pin spindle-shaped cutting portion 16B. In addition, the width direction dimension (the dimension in the left-right direction in the example shown in FIG. 7) decreases as the distance from the pin bearing part 16C increases, and the flange part in which spindle pins remain at both ends of the web part 16W 16F.

Further, the ratio of the cross-sectional area (AF) of the flange portion 16F to the cross-sectional area (Aw) of the web portion 16W (AF / Aw) is 1.3 to 1.7 (the technical significance of the cross-sectional area ratio is shown in FIG. 5). (Which will be described later in the description).

The structure of the pin 16B having the cut shape and the cross-sectional area ratio of the spindle type pin described above is an optimal cross-sectional shape obtained by the present inventor through a parameter survey.

FIG. 7 shows the parameters of the cross-sectional shape of the pin spindle-shaped cutting portion 16B according to this embodiment. These parameters are the area AF of the cross-section flange portion 16F and the area Aw of the cross-section web portion 16W shown in the following equation.

A F = 1/2 × r ² × θ−r ² × cos (θ / 2) × sin (θ / 2) (1)
Aw = tw × H (2)
FIG. 7 (2) shows a portion in the vicinity of the area AF of the flange portion shown in FIG. 7 (1).
With reference to FIG. 7 (2), the area A F of the flange portion shown in Expression (1) will be described below.

In the formula (1), 1/2 × r ² × θ is a fan-shaped area Az, and r ² × cos (θ / 2) × sin (θ / 2) is a triangular area AT. The area AF of the flange portion is obtained by subtracting the triangular area AT from the fan-shaped area Az.
Here, the radius r, the web portion height H, and the angle θ are obtained by using the diameter D and the flange portion thickness tF. R = D / 2 (3)
H = r-tF (4)
θ = 2 × cos ⁻¹ (H / r) (5)
Here, as a parameter, the ratio of the flange area AF to the web area Aw (AF / Aw) is a parameter, and the result of a parameter survey of AF / Aw useful for increasing the vibration energy absorption amount of the present embodiment with respect to the conventional structure shown in FIG. Is shown in FIG. As shown in FIG. 8, the region where the vibrational energy absorption amount with respect to the conventional structure increases rapidly is a region where AF / Aw is 1.3 to 1.7.

As described above, the pin material structure that increases the amount of energy absorption, as shown in FIGS. 2 and 7, corresponds to the cross-sectional area (Aw) of the web section 16W having a cut cross-sectional shape on both sides in the pin axial direction of the spindle type pin. It can be seen that the ratio (AF / Aw) of the cross-sectional area (AF) of the flange portion 16F is 1.3 to 1.7.

Next, another structure of the pin material in the seismic tie according to the embodiment of the present invention will be described below with reference to FIGS. 3, 4, and 6. The seismic tie according to the present embodiment and the boiler seismic structure using the same have the following characteristics.
(1) In order to make the seismic tie free to rotate during the thermal expansion of the boiler, the cross-sectional shape of the pressure bearing portion provided at the axial center point of the pin material is circular.
(2) The diameter of the bearing portion of the pin material is 1.5 times or less than that of the conventional structure due to geometric restrictions on the attachment of the seismic tie.
(3) The cross-sectional shape of the pin material other than the bearing portion is I-shaped, and the ratio of the area of the flange portion to the area of the I-shaped web portion is 1.3 to 1.7.

The cross-sectional shape having the characteristics (1) to (3) above is the optimal cross-sectional shape obtained by the inventors through a parameter survey (repetition of numerical analysis by changing parameters).

FIG. 7 shows the parameters of the cross-sectional shape of the pin material. These parameters are the area A F of the cross-section flange portion and the area Aw of the web portion shown in the following equation.
A F = 1/2 × r ² × θ−r ² × cos (θ / 2) × sin (θ / 2) (6)
Aw = tw × H (7)
Here, the radius r, the web portion height H, and the angle θ are obtained by using the diameter D and the flange portion thickness tF. R = D / 2 (8)
H = r-tF (9)
θ = 2 × cos ⁻¹ (H / r) (10)
Here, as a parameter, the ratio of the flange area AF to the web area Aw (AF / Aw) is a parameter, and the result of a parameter survey of AF / Aw useful for increasing the vibration energy absorption amount of the present embodiment with respect to the conventional structure shown in FIG. Is shown in FIG.

As shown in FIG. 8, it can be seen that the conventional region where the amount of vibration energy absorption increases is the region where A F / A w is 1.3 to 1.7. As described above, it can be seen that the ratio of the area of the flange portion to the area of the I-shaped web portion in the pin structure that increases vibration energy absorption is 1.3 to 1.7.

FIG. 3 is a view showing another structure of the pin material in the seismic tie according to the present embodiment, FIG. 3 (1) is a side view of the pin structure, and FIG. 3 (2) is a plan view of the pin structure.

As shown in FIG. 3 and FIG. 6, the structure of the pin material according to this embodiment is as follows. The web plate 2001, the flange plate 2002, the plate 2003 for fixing these plates, and the bearing part component 2004 are assembled into a spindle type. This is a welded structure.

The web plate 2001, the flange plate 2002, the fixed plate 2003, and the bearing part component 2004 are shown in FIGS. 4 (1) to 4 (6), respectively. 4 (1) is a plan view of the web plate 2001, FIG. 4 (2) is a plan view of the flange plate 2002, FIG. 4 (3) is a side view of the flange plate 2002, and FIG. 4 (4) is a cross section of the fixed plate 2003. 4 and FIG. 4 (5) are side views of the fixing plate 2003, and FIG. 4 (6) is a partial plan view of the bearing section component 2004.

FIG. 6 (1) is a cross-sectional view taken along line EE in FIG. 3 (1), and shows the cross-sectional shape of the bearing portion 16C. FIG. 6 (2) is a cross-sectional view taken along line FF in FIG. 3 (1), and shows a cross-sectional shape of the spindle portion support 16B. 6 (3) is a cross-sectional view taken along the line II of FIG. 3 (1), and FIG. 6 (4) is a cross-sectional view taken along the line JJ of FIG. 3 (1).

As shown in FIGS. 6 (1) to (4), the cross-sectional shape of each part is bilaterally symmetric about the axis on which the reaction force Fi of the seismic tie acts.

The shaft on which the seismic tie reaction force Fi described in FIG. 3 (1), FIG. 6 (1), and FIG. 6 (2) is applied, and the direction of the reaction force Fi shown in FIG. Are supported on the seismic tie 6 shown in FIG.

Next, the result of evaluating the vibration energy absorption amount of the seismic tie according to the embodiment of the present invention by the finite element analysis will be described with reference to FIGS. FIG. 9 is a diagram showing a quarter division model of the seismic tie finite element analysis model according to the present embodiment, and FIG. 10 is a quarter division model of the seismic tie finite element analysis model according to the present embodiment. It is a figure showing the boundary conditions.

As shown in FIG. 9, the finite element analysis model (FEM model) of the

pins

6B and 16B is a model in which the pin materials are divided into 1/4 in consideration of the symmetry of the shape of the

pins

6B and 16B. FIG. 10 shows the boundary conditions of these models, and the finite element analysis was performed with the completely fixed point in FIG. 10 as the reaction force detection point and the displacement input point repeatedly applied with the displacement shown in FIG.

The load displacement curve obtained as a result of the implementation is shown in FIG. As shown in FIG. 11, the vibration energy absorption area surrounded by the load displacement curve (dotted line) 102 of the seismic tie according to the present embodiment as compared with the vibration energy absorption area surrounded by the load displacement curve (solid line) 101 of the conventional structure. It can be seen that is increasing. The stress distribution (Mises stress distribution) at the maximum reaction force point in this load displacement curve is shown in FIGS.

When paying attention to the stress distribution in the conventional structure shown in FIG. 12, a low stress portion appears in the central axis portion of the pin 6B, and a high stress portion appears on the outer edge side of the pin 6B, and the difference between the stresses is large. On the other hand, paying attention to the stress distribution according to the present embodiment shown in FIG. 13, a high stress portion appears on the outer edge side of the pin 16B, and a middle stress portion appears on the central axis portion of the pin 16B, and the difference between these stresses is It can be seen that the stress distribution of the pin 16B is leveled.

In FIG. 12, in the illustrated example, there are high stresses at the upper and lower outer edge portions of the pin 6 </ b> B, and there is a low stress portion in the form of a belt at the central shaft portion. In FIG. 13, in the illustrated example, a portion with high stress appears in a bowl shape from the outer edge side of the pin 16 </ b> B toward the central axis, and a moderate level of stress appears at the central axial portion. As described above, the small stress difference (leveling of the stress distribution) in the seismic tie having the pins 16B according to the present embodiment leads to a reduction in the second gradient (gradient during plasticity) of the seismic tie (FIG. 20). See description).

FIG. 14 shows a lateral load during an earthquake when the seismic tie according to the present embodiment is applied to the boiler body 4. Lateral load (layer shear force) at the time of earthquake of the support frame 7 on which the seismic tie adopting the pin 16B having the spindle-shaped cutting portion (configuration including the web portion 16W and the flange portion 16F) shown in this embodiment is installed. ) Is reduced as compared with the conventional structure using the spindle type pin 6B shown in FIG. If the amount of vibration energy absorbed by the seismic tie is increased, the lateral load during the earthquake of the support frame 7 can be reduced, which leads to a reduction in the weight of the support frame and an improvement in earthquake resistance.

The attachment direction of the boiler body of the seismic tie and the steel column is shown in FIG. 18 in which the link material is provided parallel to the height direction, and the pin material is provided in the vertical direction, that is, the axial direction of the steel column. The pin is connected to both ends by pins, and the supporting members of the pin material connected to the boiler body and the support member connected to the steel column are shown as being rotatably mounted around the axis of the pin material. In order to secure the rigidity at the bearing section of the material, if the structure is to absorb the displacement such as the slide structure when the boiler body is thermally expanded with respect to the steel column, the direction rotated 90 degrees It does not matter if

FIG. 15 shows a side view of a boiler seismic structure using a seismic tie according to the present embodiment. In FIG. 15, a portion 8 surrounded by a dotted line indicates a layer corresponding to the position of the center of gravity of the boiler seismic structure composed of the boiler body 4 and the support frame 7. By providing the seismic tie 6 according to the present embodiment in the equivalent layer 8 at the center of gravity, a boiler structure with improved earthquake resistance can be obtained.

Further, in FIGS. 15 and 16, for the layer in which the boiler body has the furnace 20 and the rear wall portion 22, the seismic tie 6 according to the present embodiment is provided between the furnace 20 and the support frame 7, and By providing both between the rear wall part 22 and the support frame 7, it can be set as the boiler structure which improved earthquake resistance.

1 Column of support frame (steel column)
2 Supporting frame beam (steel beam)
3 Suspension bolt 4 Boiler body 5 Seismic load 6 Seismic tie 6A Link (link material)
6B Spindle type pin 6C Bearing section 7 Support frame (boiler building)
8 Layer corresponding to the position of the center of gravity of the boiler seismic structure 9 Bottom part of the vertical part of the boiler 16 Pin material 16B Spindle-shaped cutting part of the pin material 16C Pin bearing part 16D Pin connection part with the link 16F Pin part flange part 16W Pin Material web part 20 Furnace 21 Side wall part 22 Rear part wall part 23 Penthouse part 24 Main piping 30 Turbine building 32 Ground 102 Load displacement curve according to the present embodiment 201 Hopper part 1001 Shaft 2001 on which seismic tie reaction force Fi acts 2001 Web plate 2002 Flange plate 2003 Fixed plate 2004 Bearing part component

Claims

A support frame composed of a plurality of steel columns and steel beams and a boiler body supported by being suspended from the steel beam above the support frame are connected, and the relative displacement during the earthquake between the support frame and the boiler body is used. In seismic ties that absorb the vibration energy of earthquakes,
The seismic tie includes a link material that is an elastic member and a pin material that is an elastic-plastic member in a direction perpendicular to the link material, and has a structure in which both ends of the link material and the pin material are hinged to each other. And
The pin member has a bearing portion having a circular cross-sectional shape at the axial center of the pin member, and has a substantially spindle shape in which the outer diameter gradually decreases from the bearing portion toward the hinge coupling portion. Have
The bearing portion of the pin material is connected to the support frame and the boiler body,
The substantially spindle shape has a structure formed by a web portion and a flange portion installed on the outer edge side of the web portion.
In the seismic tie according to claim 1,
The substantially spindle shape is a structure formed by a web plate and a flange plate installed on the outer edge side of the web plate,
The web plate has a shape in which both sides of the web plate are symmetrically arranged in the axial direction of the pin material around the axis of the pin material,
The ratio of the cross-sectional area of the flange plate to the cross-sectional area of the web plate is 1.3 to 1.7 in the cross section in the axial direction of the pin material and the direction perpendicular to the axis of the pin material. Seismic Thailand to do.
In the seismic tie according to claim 1 or 2,
A seismic tie characterized in that the cross-sectional shape of both sides is symmetrical with respect to the axis of the pin material on which the reaction force of the seismic tie to the bearing section against relative displacement during an earthquake acts.
A support frame comprising a plurality of steel columns and steel beams and having a plurality of layered structures, a boiler body supported by being suspended from a steel beam above the support frame, and connecting the support frame and the boiler body In a boiler seismic structure with seismic ties,
The seismic tie is the seismic tie according to any one of claims 1 to 3,
A boiler seismic structure characterized in that the seismic tie is provided at least in a layer corresponding to the position of the center of gravity of the boiler seismic structure.
A support frame comprising a plurality of steel columns and steel beams and having a plurality of layer structures, a boiler having a furnace, a side wall portion and a rear wall portion, and supported by being suspended from a steel beam above the support frame In a boiler seismic structure with a main body and a seismic tie connecting the support frame and the boiler body,
The seismic tie is the seismic tie according to any one of claims 1 to 3,
In the layer of the support frame having the furnace and the rear wall part, the seismic tie is installed between the furnace and the support frame and between the rear wall part and the support frame. Boiler seismic structure.