Instructions for using the components
By employing switchable load-bearing members, the method addresses the time-consuming nature of traditional earthquake restoration, achieving rapid performance recovery and minimizing further damage.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- OHBAYASHI GUMI LTD
- Filing Date
- 2022-06-10
- Publication Date
- 2026-05-15
AI Technical Summary
Existing methods for restoring buildings damaged by earthquakes are time-consuming, leading to prolonged non-use of the structure.
A method involving load-bearing members that can be switched between operational and non-operational states to rapidly restore structural performance by altering their load transmission status.
Enables rapid restoration of structural performance, reducing downtime and preventing further damage from subsequent earthquakes.
Smart Images
Figure 0007859212000001 
Figure 0007859212000002 
Figure 0007859212000003
Abstract
Description
Technical Field
[0001] The present invention relates to a method of using members installed in a structure.
Background Art
[0002] When a building is damaged by an earthquake, it is common to restore and improve its performance by repair and reinforcement in order to ensure safety against aftershocks and future earthquakes (Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Non-Patent Documents
[0004]
Non-Patent Document 1
Non-Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0005] In the structure described in Patent Document 1, since it takes a long time for the design and construction planning and implementation, the building cannot be used for a long time.
Means for Solving the Problems
[0006] In one aspect, the present invention provides a method for using a member that is performed on a structure comprising a structure and a load-bearing member attached to the structure and capable of bearing at least a portion of the load acting on the structure, the method comprising a step of changing the state of the load-bearing member installed on the structure to either an operational state in which load is transmitted to the structure or a non-operational state in which load is not transmitted to the structure. [Effects of the Invention]
[0007] According to the present invention, a method for rapidly restoring structural performance can be provided. [Brief explanation of the drawing]
[0008] [Figure 1] This diagram illustrates a performance-recovery structure, showing (a) the structure before damage occurs and (b) the structure after damage occurs. [Figure 2] (a) Front view of the performance recovery structure of the first embodiment when the excess member is in a non-operating state, (b) Front view when the excess member is in a non-operating state, (c) Enlarged view of section IIc with the splice plate omitted, and (d) Enlarged view of section IIc with the splice plate present. [Figure 3] (a) a front view of the performance recovery structure of the second embodiment when the excess capacity member is in a non-operating state, and (b) a front view of the performance recovery structure when the excess capacity member is in an operating state. [Figure 4] (a) Front view of the modified performance recovery structure when the excess capacity member is in a non-operating state, and (b) Front view of the excess capacity member when it is in an operating state. [Figure 5] (a) Front view of the modified performance recovery structure when the excess capacity member is in a non-operating state, and (b) Front view of the excess capacity member when it is in an operating state. [Figure 6] This flowchart shows the procedure for changing the state of excess capacity members in a performance recovery structure. [Figure 7]This diagram illustrates the analysis procedure, showing (a) the analysis model for the first earthquake, (b) the analysis model for the second earthquake, and (c) the state of the analysis model after the second earthquake analysis. [Figure 8] This diagram illustrates the relationship between the plasticity ratio and the seismic performance reduction coefficient used in the analysis model. [Figure 9] This graph shows (a) the maximum response inter-story drift angle for each layer during the first earthquake and (b) the maximum response inter-story drift angle for each layer during the second earthquake in the analysis model. [Figure 10] This graph shows the maximum response inter-story drift angle (the maximum value among all layers) in the analysis model. [Modes for carrying out the invention]
[0009] <First Embodiment> A performance-recovering structure 1 according to one embodiment of the present invention will be described with reference to the figures. As shown in Figures 1 and 2, the performance-recovering structure 1 comprises a structure 2 and a surplus member 3 installed on the structure 2.
[0010] Structure 2 has a rigid frame structure, and as shown in Figure 1, it is constructed by assembling horizontally extending beams 21 and vertically extending columns 22 in a rectangular shape and then rigidly connecting them to each other. Gusset plates 23 for fixing the load-bearing members 3 are fixed to a part of the joint between the beams 21 and columns 22. The gusset plates 23 are arranged to face each other on the diagonal of the rectangular frame made up of the beams 21 and columns 22.
[0011] The gusset plate 23 is a flat steel member and has multiple bolt holes 23A formed therein. The multiple bolt holes 23A are formed to be aligned diagonally across the rectangular frame formed by the beams 21 and columns 22 (Figure 2). In addition, as shown in Figures 2(c) and (d), the gusset plate 23 has bolt holes 23B that are different from the bolt holes 23A.
[0012] The bolt hole 23B is formed at a location away from the bolt hole 23A. Specifically, in the gusset plate 23 fixed to the lower part of the beam 21, the bolt hole 23B is located below the bolt hole 23A. Also, in the gusset plate 23 fixed to the upper part of the beam 21, the bolt hole 23B is located above the bolt hole 23A.
[0013] As shown in FIGS. 1 and 2, the surplus member 3 is a member installed with respect to the structure 2. The surplus member 3 includes two members 31, 32, and splice plates 33, 34, 35 in which a plurality of bolt holes are formed.
[0014] The members 31 and 32 are members having substantially the same shape, and are formed of, for example, section steel such as H-shaped steel or angle steel. In this embodiment, H-shaped steel is used.
[0015] The member 31 has end portions 311, 312, and the member 32 has end portions 321, 322. The members 31 and 32 can function as an integrated brace by joining the end portion 311 and the end portion 321.
[0016] A plurality of bolt holes are formed in each of the end portions 311, 321. By joining the end portions 311, 321 via the splice plate 33, the surplus member 3 can be made into an integrated member.
[0017] A plurality of bolt holes are formed at a plurality of locations in each of the end portions 312, 322. The end portions 312, 322 are joined to the gusset plate 23 via the splice plates 34, 35, respectively.
[0018] The splice plates 33, 34, 35 each include a plurality of bolt holes and are flat steel materials bolted to the target members. The splice plate 33 is bolted to the end portions 311, 321 and has a function of joining the end portions 311, 321. In FIG. 2, at least three splice plates 33 join the flanges and webs of the end portions 311, 321.
[0019] The splice plate 34 has the function of joining the gusset plate 23 and the end portion 312 by being bolted to them. The splice plate 34 also has the function of joining the gusset plate 23 and the end portion 322 by being bolted to them.
[0020] [Operating state and non-operating state] The load-bearing member 3 can be in two states relative to the structure 2: a non-operating state (Figure 1(a), Figure 2(a)) and an operating state (Figure 1(b), Figure 2(b)). The non-operating state refers to a state in which no load is transmitted between the structure 2 and the load-bearing member 3, while the operating state refers to a state in which load is transmitted between the structure 2 and the load-bearing member 3.
[0021] In the non-operational state, the splice plate 33 is removed, as shown in Figure 2(a). Therefore, members 31 and 32 are installed on the structure 2 in a separated state. In the non-operational state, the ends 312 and 322 are bolted to the splice plates 34 and 35, respectively. The splice plates 34 and 35 are also bolted to the gusset plate 23 by passing one bolt through each of the bolt holes 23B and 23A, respectively (Figure 2(d)). In this way, members 31 and 32 are fixed to the structure 2 so as to extend in the vertical direction.
[0022] As shown in Figure 1(a)(i), the reserve member 3 in the non-operating state does not apply a member load regardless of the deformation of the structure 2.
[0023] In the operating state, the excess force member 3 is formed by joining members 31 and 32 via a splice plate 33, as shown in Figure 2(b). Furthermore, the splice plates 34 and 35 are bolted to the ends 312 and 322 and the gusset plate 23.
[0024] Furthermore, the excess force member 3 in the operating state is joined to the gusset plate 23 via splice plates 34 and 35. More specifically, bolts are passed through the bolt holes of the end parts 312 and 322 and the splice plates 34 and 35 to fasten them together, and bolts are also passed through the bolt holes 23A and the splice plates 34 and 35 to fasten them together. In this way, as shown in Figure 2(b), the end parts 312 and 322 are joined to the structure 2.
[0025] In the operational state, the reserve member 3 is joined to the structure 2, and as shown in Figure 1(b)(i), a member load acts on the reserve member 3 in accordance with the deformation of the structure 2. This also restores the performance of the performance-recovering structure 1. The degree of performance recovery of the performance-recovering structure 1 varies depending on the situation, but it can be made almost the same as the performance before the occurrence of an external force such as an earthquake, or it may be restored to a level midway between the performance before and after the occurrence of the external force. In some cases, the performance may even be improved compared to before the occurrence of the external force.
[0026] The reserve member 3 is, in principle, kept in a non-operational state when there is no damage to the structure 2 or when the damage to the structure 2 is below a predetermined permissible limit. On the other hand, if the damage to the structure 2 exceeds the permissible limit, the reserve member 3 is changed to an operational state.
[0027] <Second Embodiment> In the first embodiment, the excess force member 3 was configured to be separable into two members, but in the second embodiment, the excess force member 13 may be configured as a single member, as shown below.
[0028] In the following description, the same reference numerals and names will be used for components similar to those in the first embodiment, and their descriptions will be omitted.
[0029] As shown in Figure 3, the excess support member 13 is formed from a single steel section and can be installed on the structure 2 as a brace.
[0030] Multiple bolt holes are formed at the ends 131 and 132 of the excess member 13. The ends 131 and 132 can be joined to the gusset plate 23 via splice plates 34 and 35, respectively.
[0031] The reserve member 13, like the reserve member 3, can be in two states: an operating state and a non-operating state.
[0032] In the non-operational state, one of the ends 131 and 132 is joined to the gusset plate 23 via splice plates 34 and 35, but the other is not joined to the gusset plate 23. Figure 3(a) shows the state in which the connection of end 132 is detached. In the non-operational state, since one end is not joined, load transmission between the structure 2 and the load-bearing member 13 is impossible (Figure 1(a)).
[0033] In operation, the ends 131 and 132 are joined to the gusset plate 23 via splice plates 34 and 35 (Figure 3(b)). This allows for load transfer between the structure 2 and the load-bearing member 13 (Figure 1(b)).
[0034] <Variation> Furthermore, the surplus members 3 and 13 can also be installed on the structure 2 after its completion.
[0035] In this case, as shown in Figures 4 and 5, one possible example is to fix a rectangular steel frame 4 to the beam 21 and column 22. Specifically, the frame 4 is formed from four rectangular steel sections, with their ends rigidly connected to each other.
[0036] Two gusset plates 23 are fixed to the two corners of the frame 4 so as to face each other along a single diagonal line. The configuration of the gusset plates 23 is the same as that in the first and second embodiments.
[0037] The outer periphery of frame 4 is fixed to beams 21 and columns 22. Therefore, frame 4 can deform to follow the movements of beams 21 and columns 22.
[0038] In the modified configuration, the excess load members 3 and 13 can be in two states, an operational state and a non-operational state, by attaching and detaching the splice plates 33, 34, and 35, similar to the first and second embodiments (Figures 4 and 5). In the operational state, the excess load members 3 and 13 function as braces that receive load transmission from the structure 2.
[0039] <Evaluation Procedure> If damage occurs to structure 2 due to an external force such as an earthquake, the first step is to evaluate the amount of damage to the building. Based on the evaluation results, all or part of the reserve members 3 are changed from a non-operational state to an operational state. This will be explained below using the flowchart in Figure 6.
[0040] When an external force occurs (S1), the extent of damage to structure 2 is evaluated (S2). If the damage is below the permissible limit (S3: YES), the reserve members 3 and 13 remain in a non-operational state (S7).
[0041] If the damage exceeds the permissible limit (S3:NO), in step S5, the reserve members 3 and 13 are changed from a non-operational state to an operational state. If multiple reserve members 3 and 13 are installed in structure 2, the appropriate reserve member 3 or 13 is selected and activated according to the location and extent of the damage. Therefore, it is possible that only one reserve member 3 or 13 is activated, or that all installed reserve members 3 and 13 are activated.
[0042] Here, the allowable amount may represent the amount of damage that can be tolerated in a single member, or the amount of damage that can be tolerated in a single layer. It may also represent the allowable amount of damage to the entire structure 2. It may also represent the number of damaged locations in structure 2. Furthermore, the allowable amount may be set by considering a combination of these factors. In this way, the allowable amount can be set appropriately according to the structure and performance of the performance-recovery structure 1 or structure 2.
[0043] <Analysis> The purpose of this study was to evaluate the performance of performance-recovering structure 1, and its behavior was analyzed. The analysis method and results are described below.
[0044] [Analysis conditions] The analysis was performed as shown in (1) to (4) below.
[0045] (1) Three types of building models, 5F, 5B, and 5R, were set as building models as shown in (a) to (c) below. As shown in Figure 7, building models 5F, 5B, and 5R are all reinforced concrete frame structures with 5 stories and 3 spans. Building model 5F is a structure without braces, while building model 5B is a model in which steel braces (shown as thick lines in Figure 7) are installed on each story of building model 5F. On the other hand, building model 5R is a model equipped with steel braces corresponding to the reserve members 3 and 13. Depending on the damage that occurred in building model 5R during the first earthquake, these steel braces are set to an operational state. (a) Reinforced concrete frame structure (building model 5F) (b) Reinforced concrete frame + steel bracing (Building model 5B) (c) Performance recovery structural model (RC frame + steel braces on specific floors activated after the first earthquake; building model 5R)
[0046] (2) Assuming the first earthquake, the same seismic waves were input to each of the building models 5F, 5B, and 5R, and seismic response analysis was performed. Note that in building model 5R, which is a performance-recovery structure, the reserve member 3 is in a non-operating state, so building model 5R in this analysis exhibits the same behavior as building model 5F, which is a pure reinforced concrete frame structure.
[0047] (3) Based on the damage that occurred in each model obtained from the seismic response analysis results, the performance of the constituent members was reduced in each of the building models 5F, 5B, and 5R, as shown in (i) to (ii) below. (i) From the maximum plasticity ratio of each member in the first seismic response analysis and the predetermined relationship between the plasticity ratio μ and the seismic performance reduction coefficient η, the seismic performance reduction coefficient η for each member constituting each building model 5F, 5B, and 5R was determined. Here, the seismic performance reduction coefficient η is a value that represents the ratio of the seismic performance after the disaster to the seismic performance when the building was newly constructed, and the relationship between the plasticity ratio μ and the seismic performance reduction coefficient η was determined as shown in Figure 8(1) with reference to Non-Patent Literature 1. (ii) Based on Non-Patent Document 4, the energy absorption amount was reduced by η times by multiplying the rigidity and load-bearing capacity of each member, and these models were used for the damaged building models 5F, 5B, and 5R (Figure 8(2)). Although Non-Patent Documents 1 and 2 are for reinforced concrete buildings, the same evaluation method was used for steel braces in this study.
[0048] (4) The same seismic waves as the first earthquake were input to each damaged building model, and seismic response analysis (assuming a second earthquake) was performed. In building model 5R, the braces of the layers that showed a large response (damage) in the analysis results for the first earthquake were set to the operational state.
[0049] The input seismic waves for both the first and second earthquakes were artificial seismic waves that conformed to the response spectrum of Type 2 ground as defined in Ministry of Construction Notification No. 1457, and the phase was set to random phase. The input magnification was set to 0.8 times.
[0050] [Analysis results] Figure 9(a) shows the maximum response inter-story drift angles for each layer during the first earthquake, based on the analysis results described above.
[0051] In all building models, the response is larger on the lower floors. Furthermore, in building models 5F and 5R, the overall response is larger compared to building model 5B.
[0052] In this study, in building model 5R, after the first earthquake, the braces on floors 1-4 were activated, excluding floor 5 which had the smallest response (Figure 7(b)).
[0053] Figure 9(b) shows the maximum response inter-story drift angle for each floor during the second earthquake, and Figure 10 shows the maximum response inter-story drift angle within the building (the maximum value among all floors).
[0054] In building models 5F and 5B, the deformation of the lower floors is large, and the response is greater in the second earthquake than in the first earthquake. On the other hand, in building model 5R, the deformation of each floor is uniform. Therefore, the maximum response inter-story drift angle of building model 5R in response to the second earthquake is about the same as in the first earthquake, and the response is smaller than that of building models 5F and 5B.
[0055] The results above demonstrate that in building model 5R, which features a performance-recovering structure, activating a portion of the steel braces (corresponding to the reserve members 3 and 13) after an earthquake has the effect of suppressing the response to subsequent earthquakes.
[0056] <Other variations> The structure of structure 2 in this embodiment is an example, and may have a structure or shape other than a rigid frame structure.
[0057] It should be noted that the criteria for changing the operating state of the reserve members 3 and 13 in the present invention are not limited to the method in the above embodiment (operating the reserve members of all layers except the layer with the smallest response). For example, if damage occurs, all reserve members 3 and 13 of all layers, including the layer with the smallest response, may be put into an operating state.
[0058] The method for evaluating damage is not limited to the above embodiment. For example, sensors for measuring acceleration, velocity, etc., may be attached to the structure 2, and if seismic waves exceeding a preset threshold for acceleration or velocity are detected, it may be evaluated that damage exceeding the allowable limit has occurred in the structure 2, and the reserve members 3 and 13 may be set to an operational state.
[0059] Alternatively, sensors such as strain gauges may be attached to the beams 21 and columns 22, and the damage to the structure 2 may be evaluated from the measured strain to determine whether the reserve members 3 and 13 are operational or non-operational. Furthermore, the damage evaluation may be performed visually.
[0060] The reserve members 3 and 13 do not have to be braces. For example, various reinforcing members such as chin braces and studs may be used as reserve members. In addition, multiple types of reserve members may be installed in the structure 2, not just one type. Furthermore, members with vibration damping properties, such as viscous dampers, viscoelastic dampers, and friction dampers, may also be used as reserve members.
[0061] The bolt holes 23B may be used to join the retaining member 13. Therefore, in the non-operating state, either end 131 or 132 of the retaining member 13 may be separated from the gusset plate 23.
[0062] The arrangement of the excess members 3 and 13 in each of the above embodiments and modifications is just an example. Matters such as which structural surface to install them on, which layer to install them on, and how many locations to install them in, will be determined appropriately according to the structure and performance of the structure 2.
[0063] <Effects> The following embodiments are shown in the above-described examples and modifications.
[0064] (Aspect 1) In the performance recovery type structure 1 of the above embodiment, reserve members 3 and 13 capable of bearing at least a portion of the load acting on the structure 2 are installed on the structure 2. A change step (S5, S7) is performed to change the reserve members 3 and 13 installed on the structure 2 to either an operating state in which load is transmitted to the structure 2 or a non-operating state in which load is not transmitted to the structure.
[0065] In the above configuration, depending on the degree of damage to structure 2, the reserve members 3 and 13 are activated, allowing for prompt reinforcement of structure 2. As shown in Figure 1(b)(i), the load-deformation performance of the performance-recovering structure 1 is restored when the reserve members 3 and 13 are activated. Even if external forces such as earthquakes occur repeatedly in a short period of time, the increase in damage to structure 2 is reduced or prevented. Furthermore, unlike when braces are installed from the time of completion of structure 2, damage to the braces when external forces occur is prevented. Therefore, the performance-recovering structure 1 can maintain high performance even when external forces occur multiple times.
[0066] (Aspect 2) In Aspect 1, the method further includes an evaluation step (S2) for evaluating damage to the structure 2, and in the modification steps (S5, S7), depending on the evaluation results in the evaluation step, the excess load members 3, 13 are set to either an operational state in which load is transmitted to the structure 2, or a non-operational state in which load is not transmitted to the structure.
[0067] By activating the reserve members 3 and 13 according to the extent of the damage, the building's response to subsequent external forces such as earthquakes can be made uniform, thereby suppressing damage to the entire building.
[0068] (Aspect 3) In Aspect 2, if the damage to structure 2 exceeds the permissible limit during the evaluation process, the reserve members 3 and 13 are set to an operational state during the modification process. Also, if the damage to structure 2 is below the permissible limit during the evaluation process, the reserve members 3 and 13 installed on structure 2 are set to a non-operational state during the modification process.
[0069] In the above configuration, the operational and non-operational states of the reserve members 3 and 13 are determined by comparing the damage occurring to structure 2 with the allowable limit. Appropriately, the increase in damage to structure 2 is reduced or prevented.
[0070] (Aspect 4) In Aspect 2 or 3, multiple surplus members 3, 13 are installed in the structure 2, and it is determined which surplus members 3, 13 are in an operational or non-operational state according to the evaluation results in the evaluation process.
[0071] In the above configuration, it is possible to appropriately determine whether multiple reserve members 3 and 13 are in an operational state or a non-operational state. This appropriately reduces or prevents an increase in damage to the structure 2.
[0072] (Aspect 5) In any of aspects 1 to 4, the excess members 3 and 13 are divisible into multiple members, and in the non-operating state, the excess members 3 and 13 are divided and joined to the structure 2. In the operating state, the excess members 3 and 13 are integrated and joined to the structure 2.
[0073] In the above configuration, the unused surplus members 3 and 13 can be compactly stored. Therefore, the surplus members 3 and 13 can be installed without interfering with the use or habitability of the structure 2.
[0074] (Aspect 6) In any of aspects 1 to 5, the structure 2 is provided with a gusset plate 23 (corresponding to a support part) that supports the excess force members 3 and 13. The gusset plate 23 supports the excess force members 3 and 13 so that they can move between a position in which the excess force members 3 and 13 are in a non-operational state and a position in which the excess force members 3 and 13 are in an operational state.
[0075] In the above configuration, since the structure 2 can movably support the reserve members 3 and 13, the reserve members 3 and 13 can be easily moved and quickly brought into an operational state. [Explanation of Symbols]
[0076] 1 Performance recovery type structure 2 structures 23 Gusset Plate 3.13 Reserve members 4 frames
Claims
1. A method to be performed on a structure comprising a structure and a load-bearing member attached to the structure and capable of bearing at least a portion of the load acting on the structure, The process includes changing the state of the excess load member installed in the structure to either an operational state in which load is transmitted between it and the structure, or a non-operational state in which load is not transmitted between it and the structure, even during an earthquake. Instructions for using the components.
2. A method to be performed on a structure comprising a structure and a load-bearing member attached to the structure and capable of bearing at least a portion of the load acting on the structure, A process of changing the state of the excess load member installed in the structure to either an operating state in which load is transmitted between it and the structure, or a non-operating state in which load is not transmitted between it and the structure. The process includes an evaluation step for evaluating the damage to the aforementioned structure, In the modification step, the excess member is set to either the operating state or the non-operating state, according to the evaluation results in the evaluation step. Instructions for using the components.
3. If the damage to the structure exceeds the allowable limit in the evaluation step, the excess member is set to the operating state in the modification step. If the damage to the structure in the evaluation step is less than or equal to the allowable amount, the reserve member is set to the non-operational state in the modification step. The method of using the member according to claim 2.
4. Multiple of the aforementioned extra-force members are installed in the structure. Depending on the evaluation results in the evaluation step, it is determined which of the excess capacity members will be in the operating state or the non-operating state. The method of using the member according to claim 2 or 3.
5. The aforementioned excess force member can be divided into multiple members, In the aforementioned non-operational state, the excess member is divided and joined to the structure. In the aforementioned operating state, the excess force member is integrated and joined to the structure. The method of using the member according to claim 1 or 2.
6. The structure includes a support portion that supports the excess force member, The support portion supports the excess force member so that it can move between a position in which the excess force member is in a non-operating state and a position in which the excess force member is in an operating state. The method of using the member according to claim 1 or 2.