JP5659703B2 - Elastic-plastic brace anti-seismic structure - Google Patents

Description

  The present invention relates to an elastic-plastic brace seismic isolation structure.

  In general, various types of earthquake-proof structures have been proposed in order to reduce damage to structures caused by earthquakes.

  For example, a boiler used in a thermal power plant is supported by being suspended from a support frame (fixed member) in order to release the thermal expansion of the furnace wall of the boiler body (structure to be seismically isolated) composed of water pipes. In such a suspended boiler that suspends and supports a heavy heavy boiler body, the boiler body and the support frame move differently when an earthquake occurs. Seismic measures against vibration are required.

  For this reason, conventionally, the displacement caused by the thermal expansion of the boiler is allowed without being restricted, the displacement caused by the shaking at the time of the earthquake is restricted, and the anti-sway device part is plastically deformed against a large earthquake. Measures have been taken to absorb seismic energy and reduce the impact on support frames and foundations. As a seismic-proof structure of this type of suspended boiler, a tie plate sandwiched from the front and back of the vibration direction of the boiler body is arranged on the support steel frame, and the tie plate and the boiler body are connected by a plurality of elastic-plastic elements. There is something like that (see Patent Document 1).

  Although it is not a suspended boiler, the frame support structure in the exhaust heat recovery boiler is composed of an outer support bracket fixed to the backstay and an inner support bracket fixed to the inner truss, each of which is expanded by thermal expansion. The sliding support bracket having a sliding outer surface and a sliding inner surface in the direction and fitted so that the sliding outer surface and the sliding inner surface are in contact with each other, so as to reduce the deformation of the backstay due to the difference in thermal expansion Some have done.

JP 05-322104 A

  However, in a configuration in which a tie plate is disposed on a supporting steel frame as in Patent Document 1 and the tie plate and the boiler body are connected by a plurality of elastic plastic elements, an elastic-plastic member is provided with respect to the swing direction of the boiler body. It is necessary to have a large number of elastic-plastic members in order to prevent a large earthquake force, and because the elastic-plastic members have a complicated shape There is a problem that the processing work is difficult, the processing man-hours, the work time for installation increase, and the cost increases.

  Moreover, in the frame support structure in the exhaust heat recovery boiler as described above, the earthquake is not taken into consideration, so that when the earthquake occurs, the sliding outer surface of the outer support bracket and the sliding inner surface of the inner support bracket are separated from each other. When the contact is made again, a large impact force is generated, and there is a possibility that an excessive load is applied to the mounting portion of the outer support bracket with respect to the backstay and the mounting portion of the inner support bracket with respect to the internal truss.

  In view of such circumstances, the present invention can absorb a seismic force reliably while allowing a displacement due to the thermal expansion of a structure with a small and simple structure, and a large impact force is generated when an earthquake occurs. It is an object of the present invention to provide an elastic-plastic brace seismic isolation structure that can prevent an excessive load from being applied to a connecting member.

The present invention includes a connecting member disposed so as to surround either one of a fixing member or a structure-side holding member that supports a load caused by an earthquake of a structure;
There are elastic plastic braces arranged at line-symmetric positions via the connecting member, each end fixed to the connecting member, and each other end fixed to either the fixing member or the structure side holding member. And
The transmission of the load caused by the earthquake transmitted from the structure-side holding member to the fixing member via the connecting member by the elastic-plastic braces arranged in line symmetry is the compression of one elastic-plastic brace and the tension of the other elastic-plastic brace. Is an elastoplastic brace anti-seismic structure configured to be performed simultaneously,
A gap between either the fixing member or the structure-side holding member and the connecting member is filled between one of the fixing member or the structure-side holding member and the connecting member, and thermal expansion of the structure is performed. Interposing a guide means for guiding relative movement in the axial direction of the fixing member involved ,
The guide means is an elastic-plastic brace anti-seismic structure characterized by comprising a guide roller that can roll around a roller shaft extending in a direction perpendicular to the axial direction of the fixed member .

  According to the above means, the following operation can be obtained.

When the structure is thermally expanded and moves relatively in the axial direction of the fixed member at normal times when no earthquake occurs, the relative movement between the structure-side holding member and the fixed member is perpendicular to the axial direction of the fixed member. The structure is allowed to thermally expand because it is guided by guide means composed of a guide roller that can roll around a roller shaft extending to the center .

  On the other hand, when an earthquake occurs and the fixing member and the structure-side holding member move relative to each other in the horizontal direction, the load of the structure is transmitted to the fixing member via the connecting member and the elastic-plastic brace. Transmission is transmitted simultaneously by an elastic-plastic brace arranged in line symmetry so that when one elastic-plastic brace receives a tensile load, the other elastic-plastic brace receives a compressive load. The tensile load is repeatedly applied, and the elastoplastic brace extends and deforms or buckles, thereby preventing the earthquake.

  Here, if no guide means is provided, a gap is provided between one of the fixing member or the structure-side holding member and the connecting member in order to allow thermal expansion of the structure. Since either the fixing member or the structure-side holding member and the connecting member are in contact with each other and a large impact force is generated, an excessive load may be applied to the connecting member. A guide means is interposed between either the fixing member or the structure-side holding member and the connecting member, and the gap is filled, so that a large impact force is not generated even in the event of an earthquake. There is no worry of overloading the members.

  According to the elastic-plastic brace seismic isolation structure of the present invention, a small and simple structure can absorb a seismic force while allowing displacement due to thermal expansion of the structure, and a large impact force is generated when an earthquake occurs. And the outstanding effect that it can prevent that an excessive load is applied to a connection member can be show | played.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole schematic block diagram which shows the Example of the elastic-plastic brace seismic-proof structure of this invention applied to the earthquake-proof of the boiler main body of a suspension type boiler as a structure. It is a plane sectional view showing the example of the elastic-plastic brace seismic isolation structure of the present invention, and is a view corresponding to II-II in FIG. It is a sectional side view which shows the Example of the elastic-plastic brace seismic isolation structure of this invention, Comprising: (a) is a III-III arrow equivalent view of FIG. 2, (b) is a figure which shows the state which the structure thermally expanded. is there. It is a perspective view which shows the guide means in the Example of the elastic-plastic brace anti-seismic structure of this invention. (A) is a perspective view which shows the state which assembles an elastic-plastic brace, (b) is a perspective view of the assembled elastic-plastic brace, (c) is Vc-Vc sectional drawing of FIG.5 (b). It is a side view which shows the detailed structure of an elastic-plastic brace. It is a plane sectional view which shows the reference example of the elastic-plastic brace seismic-proof structure of this invention, Comprising: It is the II-II arrow equivalent view of FIG. It is a sectional side view which shows the reference example of the elastic-plastic brace seismic-proof structure of this invention, Comprising: (a) is a VIII-VIII arrow equivalent figure of FIG. 7, (b) is a figure which shows the state which the structure expanded thermally. is there.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 6 show an embodiment of the elastoplastic brace seismic isolation structure of the present invention applied to the seismic isolation of a boiler body of a suspended boiler as a structure. Is suspended by a boiler frame 2 as a fixing member for supporting a load caused by the earthquake, and the boiler frame 2 includes a plurality of frame steel columns 3 standing so as to surround the boiler body 1 and the frame steel frame. It is formed with high strength by the horizontal steel frame 4 extending in the horizontal direction connecting the columns 3.

  The boiler body 1 is integrally provided with a boiler steel column 5 as a structure-side holding member, and a connecting member 6 is disposed so as to surround the boiler steel column 5, and the boiler steel column 5 is interposed via the connecting member 6. An elastic-plastic brace 10 is arranged at a line-symmetrical position about the vertical axis O of the above-mentioned, one end of each elastic-plastic brace 10 is fixed to the connecting member 6, and the other end of each elastic-plastic brace 10 is used as the fixing member. The transmission of the load due to the earthquake transmitted from the boiler steel column 5 to the frame steel column 3 via the connecting member 6 by the elastic-plastic braces 10 fixed to the frame steel column 3 of the boiler frame 2 of the above-described line symmetry, The elasto-plastic brace 10 is compressed and the other elasto-plastic brace 10 is pulled simultaneously.

  As shown in FIGS. 5A, 5B, 5C, and 6, the elastoplastic brace 10 includes a load receiving portion 11 made of a low yield point steel material having a cross-shaped cross-section, An end member 12 which is formed by welding a width and thickness of each fin larger than that of the load receiving portion 11 and is welded and fixed to one end of the load receiving portion 11 and is fixed to the other end of the load receiving portion 11 by welding. It has a core member 14 composed of an end member 13.

  Further, as shown in FIGS. 5A to 5C, angle steel (L) having a width equal to the width of each fin of the end members 12 and 13 is formed at the four corners of the core member 14. The buckling prevention material 15 which consists of a character-shaped cross section is arrange | positioned, and this buckling prevention material 15 has the length which straddles a part of the said end member 12 and the end member 13. As shown in FIG. Spacers 16 having a thickness equivalent to the fins of the end members 12 and 13 are arranged outside the fins of the load receiving portion 11, and the end members are supported by the buckling prevention member 15. 12 and 13 are sandwiched between the spacer 16 and tightened with an assembly bolt / nut 17 (high-strength bolt / nut) as a fastening member, so that the load receiving portion 11, the end members 12, 13 and the spacer 16 are connected. It is designed to be assembled together. Further, a long hole 18 is formed at a position where one end of the buckling prevention member 15 is attached to a part of the end member 12 by an assembly bolt and nut 17.

  Therefore, when the assembly bolts and nuts 17 are tightened in a state in which a part of the end members 12 and 13 and the spacer 16 are sandwiched by the buckling prevention member 15, as shown in FIG. Since a gap S is formed between the receiving portion 11 and the buckling prevention member 15, when a tensile or compressive load acts between the end members 12 and 13, the load receiving portion 11 is Tensile deformation or compression deformation is performed. At this time, the buckling prevention material 15 allows a change in the length of the load receiving portion 11 due to the long hole 18, and the buckling prevention material 15 against the load that the load receiving portion 11 is to buckle. I try to resist.

  In addition, a short connecting piece 19 made of general steel having the same cross-sectional shape as the end member 12 is disposed on the end surface in the extending direction of the one end member 12 as shown in FIGS. The connecting piece 19 is detachably attached to the end member 12 by a connecting plate 20 and an assembly bolt / nut 17 arranged so as to sandwich each fin.

  The tip of the connecting piece 19 attached to one end of the elastoplastic brace 10 is fixed to the frame steel column 3 by welding, and the tip of the other end member 13 of the elastoplastic brace 10 is connected to the end. The member 6 is fixed to a slide plate 21 described later by welding.

  On the other hand, as shown in FIG. 2, the connecting member 6 includes a slide plate 21 having a width larger than the front-rear width of the boiler steel column 5 (the vertical width in FIG. 2). As shown in FIG. 6, the parts are detachably fastened by upper and lower fastening bolts 22 and nuts 23, and there is a gap between the slide plate 21 and the boiler steel column 5. The nut 23 is tightened so as to be formed.

  And between the said boiler steel column 5 and the slide plate 21 of the connection member 6, the clearance gap between this boiler steel column 5 and the slide plate 21 of the connection member 6 is filled, and the thermal expansion of the boiler main body 1 as said structure is carried out. The guide means 24 which guides the relative movement to the axial direction of the frame steel column 3 accompanying this is interposed.

  In the case of the present embodiment, the guide means 24 has a base plate 25 that extends in the vertical direction and projects from the base plate 25 to the side as shown in FIGS. 2, 3 (a), 3 (b), and 4. The bracket 26 is disposed at a required interval as described above, and the guide roller is rotatable about a roller shaft 27 extending in a direction perpendicular to the axial direction of the frame steel column 3 so as to be spanned between the brackets 26. 28, and the base plate 25 is attached to the boiler steel column 5 by welding.

  In the example shown in FIGS. 3 (a), 3 (b), and 4, the guide roller 28 is arranged in seven upper and lower stages. The number of stages depends on the amount of thermal expansion of the boiler body 1. In addition, the guide roller 28 in each stage may be arranged so as to be divided into a plurality of parts in the axial direction.

  Next, the operation of the above embodiment will be described.

  When the boiler body 1 as a structure thermally expands and moves relative to the axial direction of the frame steel column 3 of the boiler frame 2 as a fixed member at a normal time when no earthquake occurs, the boiler as a structure-side holding member The relative movement between the steel column 5 and the frame steel column 3 is such that the guide roller 28 of the guide means 24 rolls around the roller shaft 27 with respect to the slide plate 21 of the connecting member 6 from the state shown in FIG. As a result, the guide is smoothly guided as shown in FIG. 3B, so that thermal expansion of the boiler body 1 as a structure is allowed.

  On the other hand, when an earthquake occurs and the frame steel column 3 of the boiler frame 2 as the fixing member and the boiler steel column 5 as the structure-side holding member relatively move in the horizontal direction, the boiler body as the structure 1 is transmitted to the frame steel column 3 via the connecting member 6 and the elastoplastic brace 10, and the transmission of the load at this time is performed by the elastoplastic brace 10 arranged in line symmetry. Is subjected to a compressive load at the same time so that the other elastic-plastic brace 10 receives a compressive load, and the compressive load and the tensile load act repeatedly on the elastic-plastic brace 10, and the elastic-plastic brace 10 extends and deforms. Alternatively, seismic isolation is performed by buckling deformation. Incidentally, in the above, the axisymmetric elastoplastic brace 10 that receives the tensile load and the compressive load at the same time is more resistant to the extension due to the tensile load than the load resistance 11 of the low yield point steel material buckled by the compressive load. Is larger, and the vibration of the boiler body 1 can be effectively damped by a large load resistance obtained by adding the buckling strength to the extension strength. As described above, since the proof strength is increased by simultaneously receiving the tensile load and the compressive load with the axisymmetric elastic-plastic brace 10, the elastic-plastic brace 10 can be made small in size with a reduced cross-sectional dimension.

  Here, if the guide means 24 is not provided, a gap is left between the boiler steel column 5 and the connecting member 6 in order to allow thermal expansion of the boiler body 1 as the structure. Since there is a need, the boiler steel column 5 and the connecting member 6 come into contact with each other, a large impact force may be generated, and an excessive load may be applied to the connecting member 6, but the boiler steel column 5 and the connecting member Since the guide means 24 is interposed between them and the gap is filled by the guide roller 28 of the guide means 24, a large impact force is not generated even in the event of an earthquake, and the connecting member 6 is excessively large. There is no need to worry about heavy loads.

  Thus, the connecting member 6 can absorb the seismic force reliably while allowing the displacement due to the thermal expansion of the boiler body 1 as a structure with a small and simple structure, and generates a large impact force when the earthquake occurs. It is possible to prevent an excessive load from being applied.

  FIG. 7, FIG. 8 (a) and FIG. 8 (b) are reference examples of the elastic-plastic brace seismic-proof structure of the present invention. In the figure, the same reference numerals as those in FIGS. Although the basic configuration is the same as that shown in FIGS. 1 to 6, the features of this reference example are as shown in FIGS. 7, 8 (a) and 8 (b). A guide frame 29 having a C-shaped cross section and a guide path 29a extending in the vertical direction on the inner surface side is attached as a connecting member on both left and right side surfaces of the boiler steel column 5, and at one end of the elastoplastic brace 10, The guide means 24 is configured by attaching a slide piece 30 fitted to the guide frame 29 so as to be slidable in the vertical direction along the guide path 29a.

  Next, the operation of the reference example will be described.

  When the boiler body 1 as a structure thermally expands and moves relative to the axial direction of the frame steel column 3 of the boiler frame 2 as a fixed member at a normal time when no earthquake occurs, the boiler as a structure-side holding member The relative movement between the steel column 5 and the frame steel column 3 is such that the guide frame 29 of the guide means 24 slides with respect to the slide piece 30 attached to one end of the elastic-plastic brace 10 from the state shown in FIG. Thus, as shown in FIG. 8 (b), it is guided smoothly, so that thermal expansion of the boiler body 1 as a structure is allowed.

  On the other hand, when an earthquake occurs and the frame steel column 3 of the boiler frame 2 as the fixing member and the boiler steel column 5 as the structure-side holding member relatively move in the horizontal direction, the boiler body as the structure 1 is transmitted to the frame steel column 3 via a guide frame 29 as a connecting member and an elastoplastic brace 10 having a slide piece 30 attached to one end. The transmission of the load at this time is arranged line-symmetrically. When one elastic-plastic brace 10 receives a tensile load, the other elastic-plastic brace 10 is simultaneously transmitted so that the other elastic-plastic brace 10 receives a compressive load. The elastic-plastic brace 10 is repeatedly subjected to a compressive load and a tensile load. As a result, the elastoplastic brace 10 extends and deforms or buckles, so that the vibration is prevented. Incidentally, in the above, the axisymmetric elastoplastic brace 10 that receives the tensile load and the compressive load at the same time is more resistant to the extension due to the tensile load than the load resistance 11 of the low yield point steel material buckled by the compressive load. Is larger, and the vibration of the boiler body 1 can be effectively damped by a large load resistance obtained by adding the buckling strength to the extension strength. As described above, since the proof strength is increased by simultaneously receiving the tensile load and the compressive load with the axisymmetric elastic-plastic brace 10, the elastic-plastic brace 10 can be made small in size with a reduced cross-sectional dimension.

  Here, a guide means 24 is interposed between the boiler steel column 5 and the elastoplastic brace 10, and the gap between the guide frame 29 and the slide piece 30 of the guide means 24 can be set small. Even when an earthquake occurs, it is possible to suppress the impact force, and there is no fear that an excessive load is applied to the guide frame 29 as a connecting member.

  Thus, also in the reference examples shown in FIGS. 7, 8A and 8B, the seismic force while allowing displacement due to the thermal expansion of the boiler body 1 as a structure with a small and simple structure. Can be reliably absorbed, and it is possible to prevent an excessive load from being applied to the guide frame 29 as a connecting member due to the generation of a large impact force when an earthquake occurs.

  The elastic-plastic brace seismic isolation structure of the present invention is not limited to the above-described embodiment, and the positions of the steel frame column of the boiler frame as a fixing member and the boiler steel column as a structure-side holding member Replacing the relationship, arranging a connecting member on the side of the fixing member, and being applicable to the type of fixing the other end of the elastic-plastic brace whose one end is fixed to the connecting member to the structure-side holding member, etc. In addition, it goes without saying that various changes can be made without departing from the scope of the present invention.

1 Boiler body (structure)
2 Boiler frame (fixed member)
3 Frame steel column (fixing member)
5 Boiler steel column (structure-side holding member)
6 connecting member 10 elastic-plastic brace 11 load receiving portion 15 buckling prevention material 17 assembly bolt / nut 19 connecting piece 20 connecting plate 21 slide plate 22 fastening bolt 23 nut 24 guide means 25 base plate 26 bracket 27 roller shaft 28 guide roller O axis

Claims (1)

A connecting member arranged to surround one of the fixing member or the structure-side holding member that supports the load caused by the earthquake of the structure;
There are elastic plastic braces arranged at line-symmetric positions via the connecting member, each end fixed to the connecting member, and each other end fixed to either the fixing member or the structure side holding member. And
The transmission of the load caused by the earthquake transmitted from the structure-side holding member to the fixing member via the connecting member by the elastic-plastic braces arranged in line symmetry is the compression of one elastic-plastic brace and the tension of the other elastic-plastic brace. Is an elastoplastic brace anti-seismic structure configured to be performed simultaneously,
A gap between either the fixing member or the structure-side holding member and the connecting member is filled between one of the fixing member or the structure-side holding member and the connecting member, and thermal expansion of the structure is performed. Interposing a guide means for guiding relative movement in the axial direction of the fixing member involved ,
An elastic-plastic brace anti-seismic structure characterized in that the guide means is constituted by a guide roller which can roll around a roller shaft extending in a direction perpendicular to the axial direction of the fixed member .

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