Earthquake-resistant steel frame shelter

Abstract

The present invention provides an earthquake-resistant steel frame shelter for installation inside existing wooden houses and the like, which can be installed quickly with simple on-site work and has relatively low installation costs. It also provides an earthquake-resistant steel frame shelter that, even with a simple structure consisting only of steel, is designed so that the bottom surface does not distort under load from above, and has a structure that prevents tripping or falling when entering or exiting. [Solution] The present invention provides an earthquake-resistant steel frame shelter comprising an assembled rectangular metal frame, four or more columns, four or more beams connecting the tops of the columns, and four or more base plates connecting the bottoms of the columns, wherein at least four of the base plates are positioned such that one end overlaps the bottom of the columns and the other end abuts against the side of another base plate.

Description

Technical Field

[0001] The present invention relates to a seismic steel frame shelter for evacuation during an earthquake, and particularly to a seismic steel frame shelter installed indoors in an existing wooden house or the like.

Background Art

[0002] <Background etc.>

[0003] When an earthquake occurs while one is inside a house, it is not uncommon for it to be difficult to immediately evacuate outdoors before the building collapses. This tendency is particularly prominent in households with elderly people, infants, disabled persons, etc. For these reasons, it is said that the number of people who die due to the collapse of buildings after an earthquake, including those caused by aftershocks, is quite large. For example, in the Noto Peninsula offshore earthquake that occurred in January 2024, it was reported that the number of deaths due to building collapses accounted for approximately 80% of the deaths whose causes had been determined (refer to the article "NHK NEWSWEB" dated March 13, 2024).

[0004] In such a situation, the recognition of the importance of a seismic steel frame shelter (hereinafter sometimes simply referred to as "shelter") installed indoors in an existing wooden house or the like, which is particularly at high risk of building collapse due to an earthquake, is increasing. A seismic steel frame shelter is a steel frame structure having a seismic structure, and has a plurality of columns, a beam connecting the upper parts thereof, and a base plate connecting the bottom parts. For example, if this is installed indoors on the first floor of a house and one takes shelter inside it when an earthquake occurs, even if the house collapses before one can evacuate outdoors, it is expected that the safety of the bodies of those who have taken shelter inside can be ensured without the shelter being crushed.

[0005] Of course, making the house itself earthquake-resistant would reduce the likelihood of it collapsing, so that would be preferable. However, this would require large-scale construction work, which would be time-consuming and costly. In contrast, an earthquake-resistant steel-frame shelter installed inside an existing wooden house can be made with a simpler structure, allowing for quicker installation with less work compared to making the house itself earthquake-resistant, and at a relatively lower cost.

[0006] The above explains the background to the growing awareness of the importance of earthquake-resistant steel-frame shelters installed inside existing houses. <Conventional Technology> Earthquake-resistant steel-frame shelters have a simple structure, basically consisting of multiple columns, beams connecting their upper parts, and base plates connecting the bottom. Therefore, if a house collapses and the upper floors fall onto the shelter, placing a large load on it, uneven forces are applied to the four corners of the bottom surface, causing the bottom surface to warp and all or part of the columns to detach from the bottom surface. In such cases, the entire shelter collapses, and the people inside cannot be protected. To prevent this, earthquake-resistant steel-frame shelters have been devised that are less prone to warping of the bottom surface even under heavy loads, and therefore less likely to collapse.

[0007] For example, Patent Document 1 describes an earthquake-resistant steel frame shelter with a steel frame assembly structure that is installed inside an existing house, and is designed to prevent distortion of the bottom surface even when a large load is applied from above.

[0008] Figure 17 is a schematic diagram illustrating the configuration of a conventional earthquake-resistant steel frame shelter, showing an overview of the shelter configuration described in Patent Document 1. It should be noted that this figure is merely a schematic diagram and does not represent all the configurations described in Patent Document 1, nor does it faithfully reflect the shape described in that document.

[0009] As shown in the figure, the shelter 1700 has steel frames 1701 that form the four sides of the base inside the house, a plurality of steel columns 1702 connected to the steel frames, and steel beams 1703 arranged to connect the upper parts of the steel columns. Furthermore, surrounded by the steel frames that form the four sides of the base, there is a grid-like arrangement of steel frames 1704 (only some are labeled to avoid complexity), and panel-like members (hereinafter simply referred to as "panels") 1705 (only one part is labeled to avoid complexity) are fixed to the inside of the grid. In this way, the earthquake-resistant steel frame shelter described in Patent Document 1 prevents distortion of the base by assembling the steel frames that form the base in a grid and fixing panels in the space within each grid.

[0010] Furthermore, in the earthquake-resistant steel frame shelter described in Patent Document 1, the bottom surface consists of a grid-like arrangement of steel frames and panels, on which a floor made of flooring boards or tatami mats is placed. In addition, the sides and ceiling are also fitted with the same type of exterior walls and ceilings as a normal room on the inside (indoor side) of the walls and ceiling made of steel frames and panels. Thus, the earthquake-resistant steel frame shelter described in Patent Document 1 is designed to be used with the same interior finishes as a normal room, in addition to its steel frame structure.

[0011] Furthermore, in the earthquake-resistant steel frame shelter described in Patent Document 1, the aforementioned grid-like steel frame is fixed to the sides of the steel frame that constitutes the four sides of the base by bolts or welding, and the panels are also fixed to the sides of the grid-like steel frame by bolts or welding. Consequently, the steel frame that constitutes the four sides of the base inevitably has to have a certain thickness (height).

[0012] Non-patent document 1 also describes an earthquake-resistant shelter with a steel frame assembly structure that is installed inside an existing house and has a structure that is generally similar to the shelter in patent document 1.

[0013] Figure 18 is a schematic diagram illustrating the configuration of a conventional earthquake-resistant steel frame shelter, showing an overview of the shelter configuration described in Non-Patent Document 1. However, like Figure 17 mentioned above, this figure is merely a schematic diagram and does not represent all the configurations described in Non-Patent Document 1, nor does it faithfully reflect the shape described in that document.

[0014] As shown in the figure, the earthquake-resistant steel shelter 1800 of Non-Patent Document 1 also has basically the same configuration as the shelter described in Patent Document 1, and has a steel beam assembly 1803 consisting of four steel frames 1801 that make up the bottom surface, four steel columns 1802 connected to the four corners, and four beams positioned at the upper ends of the steel columns (each part is labeled with a reference numeral only once to avoid complexity). Furthermore, a ceiling section 1804 made of multiple steel plates is positioned above the steel beam assembly. Although not shown in the figure, the underside of the ceiling section is reinforced by arranging two steel plates in a grid pattern. These steel beam assembly, ceiling section, and grid-like steel plates are fixed to each other with bolts 1805, etc.

[0015] In the shelter described in Non-Patent Document 1, unlike the configuration in Patent Document 1, a configuration to prevent distortion of the bottom surface is provided in which multiple wire-like X-shaped place anchors 1806 (two on each diagonal in the example shown in the figure, for a total of four) are arranged on each diagonal of the bottom surface. These X-shaped place anchors are arranged so that their ends are bonded to the inner sides of the steel frames that make up the four sides of the bottom surface.

[0016] The earthquake-resistant steel-frame shelter described in Non-Patent Literature 1 is also designed to be used with an interior similar to that of a normal room, after the steel frame is assembled as the main construction work, by placing flooring made of floorboards or tatami mats on top of the base made of steel frame and bracing anchors as the overall construction work.

[0017] Furthermore, in the shelter described in Non-Patent Document 1, as mentioned above, the X-shaped place anchors are arranged by adhering them to the inner sides of the steel frames that make up the four sides of the base. Therefore, similar to the shelter described in Patent Document 1, the steel frames that make up the four sides of the base inevitably have to have a certain thickness (height). [Prior art documents] [Patent Documents]

[0018] [Patent Document 1] Japanese Patent Application Publication No. 9-165936 [Non-patent literature]

[0019] [Non-Patent Document 1] Earthquake-resistant steel frame shelter "mamoru-kun" (URL: https: / / www.mamoru-kun.jp / ) [Overview of the project] [Problems that the invention aims to solve]

[0020] As mentioned above, earthquake-resistant steel frame shelters installed inside existing houses are designed with a simple structure, offering the advantage of being able to be installed quickly and with simpler work compared to making the house itself earthquake-resistant. Therefore, it is desirable that earthquake-resistant steel frame shelters can be completed by even laypeople with no construction experience through simple on-site work. However, conventional earthquake-resistant steel frame shelters, including those described in Patent Document 1 and Non-Patent Document 1, are designed to be used after interior work such as flooring and walls are completed in addition to the steel frame assembly. Such interior work requires specialized skills, and consequently, it takes more time and costs more.

[0021] Furthermore, in order to be able to install a seismic-resistant steel-frame shelter at a low cost with a short working time, it is desirable that the structure be as simple as possible with as few component parts as possible and easy to assemble. An ideal configuration is one in which only a total of 12 steel frames, namely, four base plates, four columns, and four beams that form the frame of the bottom surface, are joined together. This makes it possible to realize a structure in which the bottom surface does not distort under a large load from above when the building collapses, and it is desirable that it can be used in the state of only the steel frame without interior finishing. However, conventionally, such a structure has not existed, including those described in Patent Document 1 and Non-Patent Document 1.

[0022] Furthermore, considering use by the elderly, the physically handicapped, etc., when entering and leaving the shelter installed in the room, it is desirable that the structure be such that one does not trip or fall over due to steps between the inside and outside of the shelter or members provided at the entrance and exit. However, the shelters described in Patent Document 1 and Non-Patent Document 1 probably have lattice-shaped steel frames or wire-shaped X-type place anchors arranged at the bottom of the steel frame structure. Therefore, when using the shelter, it is necessary to provide an interior finish such as a floor board or tatami mat at a position one step higher than outside the shelter so as to cover these. For this reason, there was a risk of tripping or falling over due to the step when entering and leaving the shelter. Also, even assuming a case where it is used with only the steel frame structure without interior finishing, since the steel frames that necessarily form the four sides of the bottom surface inevitably have a certain thickness (height) as described above, it is considered that there was also a risk of tripping or falling over on the steel frame when entering and leaving. In addition, conventionally, there has not been a shelter that does not risk tripping or falling over when entering and leaving.

[0023] The present invention is made in view of the problems described above. That is, the problem to be solved by the present invention is a seismic steel frame shelter installed indoors in an existing wooden house or the like, which can be completed only by a simple steel frame work on site without interior finishing, can be installed in a short time and at a relatively low installation cost, and has a structure consisting only of steel frames of columns, beams and base plates, and is configured so that the bottom surface is not distorted by the load from above, and also has a configuration that can prevent tripping or falling when entering or exiting. The object is to provide a seismic steel frame shelter with such a configuration.

Means for Solving the Problems

[0024] In order to solve the above problems, a first invention of the present invention is an assembled rectangular parallelepiped metal frame body, which consists of four or more columns, four or more beams connecting the tops of these columns, and four or more base plates connecting the bottoms of these columns. At least four base plates are configured such that at the bottom of the column, one end overlaps the bottom and the other end abuts against the side surface of another base plate. A seismic steel frame shelter is provided.

[0025] Further, a second invention of the present invention provides a seismic steel frame shelter in which, based on the first invention, the column is a steel material having a substantially square cross-section.

[0026] Further, a third invention of the present invention provides a seismic steel frame shelter in which, based on the first or second invention, the beam is a steel material having a substantially square cross-section.

[0027] Further, a fourth invention of the present invention provides a seismic steel frame shelter in which, based on the first or second invention, the base plate is fixed to the column by being screwed to a metal fold welded to the lower side surface of the column.

[0028] Further, a fifth invention of the present invention provides a seismic steel frame shelter in which, based on the first or second invention, the base plate has a thickness of 3 mm or more and 8 mm or less.

Effects of the Invention

[0029] The present invention provides an earthquake-resistant steel frame shelter that can be installed inside an existing wooden house or the like, which can be completed with simple on-site steel frame assembly work without interior finishing, can be installed in a short time, and has relatively low installation costs. Furthermore, even though it is a structure consisting only of steel frames consisting of columns, beams, and base plates, it is configured so that the bottom surface does not distort under load from above, and it is also configured to prevent tripping or falling when entering or exiting. [Brief explanation of the drawing]

[0030] [Figure 1] Perspective view showing an example of the configuration of the earthquake-resistant steel frame shelter of Embodiment 1. [Figure 2] A diagram showing an example of beam arrangement in the earthquake-resistant steel frame shelter of Embodiment 1. [Figure 3] A diagram showing an example of beam arrangement in the earthquake-resistant steel frame shelter of Embodiment 1. [Figure 4] A diagram showing an example of the shape and dimensions of each beam in Embodiment 1. [Figure 5] A diagram showing how to arrange the base plates in an earthquake-resistant steel frame shelter. [Figure 6] This figure shows an example of the cross-sectional shape of a column in the earthquake-resistant steel frame shelter of Embodiment 2. [Figure 7] A diagram showing an example of the configuration of an earthquake-resistant steel frame shelter in Embodiment 4. [Figure 8] A diagram illustrating the results of a load-bearing test on an earthquake-resistant steel frame shelter according to the present invention. [Figure 9] A diagram illustrating the results of a load-bearing test on an earthquake-resistant steel frame shelter according to the present invention. [Figure 10] A diagram illustrating the results of a load-bearing test on an earthquake-resistant steel frame shelter according to the present invention. [Figure 11] A diagram illustrating the results of a load-bearing test on an earthquake-resistant steel frame shelter according to the present invention. [Figure 12]A diagram illustrating the results of a load-bearing test on an earthquake-resistant steel frame shelter according to the present invention. [Figure 13] A diagram illustrating an example of an assembly method for an earthquake-resistant steel frame shelter according to the present invention. [Figure 14] A diagram illustrating an example of an assembly method for an earthquake-resistant steel frame shelter according to the present invention. [Figure 15] A diagram illustrating an example of an assembly method for an earthquake-resistant steel frame shelter according to the present invention. [Figure 16] A diagram illustrating an example of an assembly method for an earthquake-resistant steel frame shelter according to the present invention. [Figure 17] Schematic diagram illustrating the configuration of a conventional earthquake-resistant steel frame shelter. [Figure 18] Schematic diagram illustrating the configuration of a conventional earthquake-resistant steel frame shelter. [Figure 19] A photograph documenting a scene from the actual exam. [Figure 20] A photograph showing an example of an earthquake-resistant steel frame shelter according to the present invention actually installed inside a house. [Figure 21] A photograph showing an example of an earthquake-resistant steel frame shelter according to the present invention actually installed inside a house. [Figure 22] A photograph showing an example of an earthquake-resistant steel frame shelter according to the present invention actually installed inside a house. [Figure 23] A photograph showing an example of an earthquake-resistant steel frame shelter according to the present invention actually installed inside a house. [Figure 24] A photograph showing an example of an earthquake-resistant steel frame shelter according to the present invention actually installed inside a house. [Figure 25] Plan view illustrating the arrangement of the base plate in Embodiment 1. [Explanation of symbols]

[0031] 0100 Earthquake-resistant steel frame shelter 0101, 0102, 0103, 0104 pillars 0111, 0112, 0113, 0114 Beam 0121, 0122, 0123, 0124 Base plate 0215a, 0215b Beams connecting two opposing beams 0216 A beam that diagonally connects two beams that are touching at a right angle. 0341 L-shaped reinforcing bracket 0411a Screw holes for fastening L-shaped reinforcing brackets 0521a One end of the base plate 0521b Other end of the base plate 0731, 0732 Kinori [Modes for carrying out the invention]

[0032] The embodiments of each invention will be described below. However, the present invention is not limited in any way to these embodiments, and can be implemented in various forms without departing from its essence. The relationship between the embodiments and claims is as follows: Embodiment 1 mainly relates to claims 1 and 5, etc. Embodiment 2 mainly relates to claim 2, etc. Embodiment 3 mainly relates to claim 3, etc. Embodiment 4 mainly relates to claim 4, etc. However, the present invention is not limited in any way to these embodiments, and can be implemented in various forms without departing from its essence. <Embodiment 1>

[0033] Embodiment 1 mainly relates to claims 1, 5, and the like. <Embodiment 1: Overview>

[0034] The earthquake-resistant steel frame shelter of Embodiment 1 consists of a modular rectangular metal frame, and its characteristic feature is that each base plate constituting the metal frame is configured such that one end overlaps the bottom of the column and the other end abuts against the side of another base plate, so as to prevent distortion of the bottom by evenly receiving the load from above. Furthermore, since it can be used as just the metal frame, even laypeople who are not building professionals can install it in a short time with simple work on site, and the installation cost can be kept relatively low. In addition, since the base plates are made of thin plate-like members, it is possible to prevent tripping or falling when entering or exiting. <Embodiment 1: Configuration>

[0035] (Embodiment 1: Configuration: General)

[0036] The earthquake-resistant steel frame shelter of this embodiment is a modular rectangular metal frame consisting of four or more columns, four or more beams connecting the tops of these columns, and four or more base plates connecting the bottoms of these columns. From the viewpoint of being able to install it in a short time with the simplest possible work and keeping costs low, it is most preferable to have four columns, four beams, and four base plates.

[0037] Figure 1 is a perspective view showing an example of the configuration of an earthquake-resistant steel shelter according to Embodiment 1. This earthquake-resistant steel shelter 0100 is an example in which there are four columns, four beams, and four base plates. That is, this earthquake-resistant steel shelter consists of four columns 0101, 0102, 0103, and 0104, four beams 0111, 0112, 0113, and 0114 that connect the tops of these columns, and four base plates 0121, 0122, 0123, and 0124 that connect the bottoms of these columns. Note that this figure shows each of these members in perspective (therefore, for example, the joint between beam 0111 and beam 0114, which is covered by the L-shaped metal fitting 0141 described later, is visible).

[0038] (Embodiment 1: Composition: Materials)

[0039] The columns, beams, and base plates are made of iron. Iron here includes alloys of iron and other metals. Specifically, materials such as steel and stainless steel are desirable, as it is desirable that they have enough strength to withstand the load even if a house or room collapses and places a load on them. Furthermore, since the earthquake-resistant steel frame shelter of this embodiment is completed only by the steel frame consisting of these columns, beams, and base plates and their connecting members (bolts, nuts, etc.), if the connecting members are made of iron, the entire earthquake-resistant steel frame shelter will be made of iron.

[0040] (Embodiment 1: Configuration: Shape and Dimensions)

[0041] The assembled earthquake-resistant steel frame shelter has a rectangular (including cubic) shape. In particular, the earthquake-resistant steel frame shelter according to the present invention is composed solely of steel frames and, unlike conventional shelters, does not require interior finishes such as floors and walls. In other words, the shelter according to the present invention has a shape that assumes the use of the original room's floors and walls when installed and used in a room.

[0042] The specific shape and dimensions will be appropriately designed according to the shape and dimensions of the room in which it will be installed. For example, assuming installation inside a Japanese house, it could be (1) a roughly cubic shape of about 2.3m long x 2.3m wide x 2.1m high, or (2) a rectangular prism shape of about 3.2m long x 2.5m wide x 2.2m high. Figure 1 shows an example with a roughly cubic shape.

[0043] For example, if the former ((1) in the previous paragraph) is installed in a 4.5 tatami mat room (approximately 2.7m long x 2.7m wide x 2.2m high), or if the latter ((2) in the previous paragraph) is installed in a 6 tatami mat room (approximately 3.6m long x 2.7m wide x 2.2m high), they will fit almost perfectly into the respective rooms (hereinafter, for convenience, the former will be referred to as the "4.5 tatami mat type" and the latter as the "6 tatami mat type"). In this case, the floor, walls, ceiling, etc., of the original room can be used as they are. In other words, the shelter according to the present invention makes it possible to use the room in almost the same condition as before the shelter was installed, while being inside the shelter in daily life. For this reason, it is conceivable to use the inside of the shelter as a daily living space, and in that case, instead of hastily evacuating into the shelter after an earthquake occurs, if an earthquake occurs while you are going about your daily life inside the shelter, there is a high probability that you will be safe even if the building collapses by remaining inside the shelter.

[0044] Furthermore, if the type of shelter described above is installed in a larger room, it will likely be placed in a corner of the room, which would relatively increase the probability of being outside the shelter in the event of an earthquake. However, even in that case, it would still be possible to evacuate into the shelter immediately after the earthquake, so safety can still be easily ensured by evacuating into the shelter before the building collapses.

[0045] Furthermore, power outages often occur immediately after an earthquake. In particular, if a power outage occurs at night, the room becomes completely dark, making it easy to trip or fall over even small steps. In this regard, the earthquake-resistant steel frame shelter according to the present invention is composed only of a steel frame and does not have a separate floor for the shelter on top of the original room's floor, as described in Patent Document 1 and Non-Patent Document 1. Moreover, the thickness of the base plate separating the floors of the room inside and outside the shelter is thin (preferably 3 mm to 8 mm as described later). For this reason, there is less risk of tripping or falling even in the dark, and it is easy to move safely into the shelter.

[0046] (Embodiment 1: Configuration: Column)

[0047] The columns are installed in a manner that four or more are erected between the base plate and the beams. If there are four columns, they are installed at the four corners of the earthquake-resistant steel shelter. If more columns are installed, they are also installed between the base plate and beams on the four sides of the bottom surface other than the four corners to reinforce the structure of the earthquake-resistant steel shelter. However, from the perspective of using the room in which the shelter is installed on a daily basis, it is preferable to have only four columns at the four corners, as this allows for wider use of the walls and easier access to and from the shelter.

[0048] (Embodiment 1: Configuration: Column: Shape and Dimensions)

[0049] Each column is a slender, rod-shaped member. There are no particular limitations on the shape of the horizontal cross-section of the column (the horizontal cross-section when installed), but it is preferable that it be rectangular (including square) in terms of ease of joining with the base plate and beams. The column may be solid or hollow. Hollow columns will be described later in another embodiment (see Embodiment 2).

[0050] As for the specific dimensions and shape of the column, for example, it could have a square cross-section with sides of 100 mm and a length of approximately 2000 to 2100 mm.

[0051] Furthermore, in order to support the beams connecting the tops of the columns from below at the connection points, it is desirable that reinforcing brackets be provided on the upper parts of the two sides of the column that face the sides of adjacent columns. In the example in Figure 1, for example, in order to support the two beams 0112 and 0113 connected to the top of column 0103 from below, L-shaped angle bracket-shaped reinforcing brackets 0133a and 0133b are provided on the upper parts of the two sides 0103a and 0103b of the column that face the sides of adjacent columns 0102 and 0104. The same applies to the other three columns. It is desirable that these reinforcing brackets be welded to the columns before shipment from the factory in order to make on-site work easier.

[0052] (Embodiment 1: Configuration: Beam)

[0053] Four or more beams are installed at the top of the columns. If there are four beams, they are installed connecting the tops of the columns located at the four corners of the earthquake-resistant steel shelter. If more beams are installed, the structure of the earthquake-resistant steel shelter is reinforced by connecting two opposing beams or diagonally connecting perpendicular beams.

[0054] Figure 2 shows an example of beam arrangement in the earthquake-resistant steel frame shelter of Embodiment 1, and illustrates an example where more than four beams are arranged. Similar to Figure 1, this figure also shows each member, such as beams, in perspective.

[0055] The shelter in the figure is a 4.5 tatami mat type, similar to the one shown in Figure 1. However, while Figure 1 only shows four beams connecting the tops of the four corner pillars, Figure 2 shows, in addition to the four beams 0211-0214 connecting the tops of the four corner pillars, beams 0215a and 0215b connecting two opposing beams 0214 and 0212 are positioned on top of the aforementioned two opposing beams 0214 and 0212.

[0056] In the example shown in the figure, a beam 0216, consisting of two thin plates, diagonally connects two beams 0214 and 0211 that are perpendicular to each other, sandwiching the perpendicular beams from above and below. Similarly, beams (with reference numerals omitted to avoid complexity) are arranged in the same configuration diagonally between the other three pairs of perpendicularly connected beams. The two perpendicularly connected beams 0214 and 0211 are connected to each other by screwing in L-shaped reinforcing brackets 0241.

[0057] Figure 3, similar to Figure 2, shows an example of beam arrangement in the earthquake-resistant steel shelter of Embodiment 1, and is an enlarged view of the area roughly enclosed by the dashed circle 0200a in Figure 2. The figure shows that beam 0315a, which connects two opposing beams (beam 0314 and beam 0312 (corresponding to beam 0212 in Figure 2)) that connect the tops of the four corner columns, is screwed onto beam 0314 with bolts and nuts. It also shows that beam 0316, made of two thin plates, is positioned to diagonally connect two beams 0314 and 0311 that are touching at right angles, sandwiching the perpendicular beams from above and below. Furthermore, it shows that the two beams 0314 and 0311 that are touching at right angles are connected to each other by screwing in L-shaped reinforcing brackets 0341.

[0058] (Embodiment 1: Configuration: Beam: Shape and Dimensions)

[0059] Of the beams, the four beams connecting the columns at the four corners are, for example, slender, rod-shaped members with a rectangular (including square) cross-section.

[0060] Figure 4 shows an example of the shape and dimensions of each beam in Embodiment 1. Figure 4(a) is a perspective view of beam 0411. The holes 0411a provided near both ends are screw holes for fastening L-shaped reinforcing brackets. Figure 4(b) shows the shape of the beam in a plan view. As shown in this figure, it is desirable that the shape of beam 0411 be a trapezoidal column shape with a trapezoidal top surface having a base angle θ of 45 degrees. (c) is a cross-sectional view of line AA in (b), and in this example the cross-sectional shape is a hollow square.

[0061] As mentioned above, it is desirable that the top surface of the beam be trapezoidal with a base angle of 45 degrees. This is because a method called miter joint allows the slanted ends of two beams positioned at right angles to fit together perfectly on top of the column. With this configuration, the load applied to each beam is evenly distributed to the columns at both ends, making it less likely for the beams to fall off, thus contributing to maintaining the necessary structural strength of the earthquake-resistant steel shelter.

[0062] For example, in a 4.5 tatami mat room, the beams could have a square cross-section with sides of 100 mm, as shown in Figure 4(c), with a length of 2200 mm at the bottom base L1 and 2000 mm at the top base L2, as shown in Figure 4(b). For a 6 tatami mat room, the beams connecting the columns at the four corners, specifically the longer beams, could have a square cross-section with sides of 100 mm, with a trapezoidal bottom base L1 of 3100 mm and an upper base L2 of 2900 mm. The shorter beams could have a square cross-section with sides of 100 mm, with a trapezoidal bottom base L1 of 2400 mm and an upper base L2 of 2200 mm.

[0063] Furthermore, beams 0215a and 0215b, positioned between opposing beams as shown in Figure 2, are slender, rod-shaped members with a rectangular (including square) cross-section, similar to the beams connecting the columns at the four corners. Their dimensions are approximately the same as those of the parallel beams connecting the columns at the four corners. In addition, the pair of beams 0216, positioned diagonally between two beams that are perpendicular to each other, are trapezoidal columns with identical shapes and dimensions, each with a thickness of 6 mm. Their specific shapes and lengths are appropriately designed according to their mounting positions. In the example in Figure 2, they are trapezoids with a base angle of 45 degrees, a lower base length of 850 mm, and an upper base length of 710 mm.

[0064] Of the beams described above, the rod-shaped beams may be solid or hollow. Hollow beams will be described later in another embodiment (see Embodiment 3).

[0065] (Embodiment 1: Configuration: Base plate)

[0066] Four or more base plates are installed at the bottom of the columns. If there are four, they are installed connecting the columns at the four corners of the earthquake-resistant steel shelter. If more base plates are installed, the structure of the earthquake-resistant steel shelter is reinforced by connecting two opposing base plates or diagonally connecting perpendicular base plates. However, from the perspective of allowing the room floor to be used as much as possible in its original state, it is preferable to install only four base plates connecting the four corners.

[0067] (Embodiment 1: Configuration: Base plate: Shape and dimensions)

[0068] The base plate is a plate-shaped component placed on the bottom surface of an earthquake-resistant steel-frame shelter. The purpose of using only the base plate as a component to fix the space between the four corner columns is to prevent tripping or falling when entering or exiting the shelter. The thickness of the base plate is preferably between 3 mm and 10 mm, and more preferably around 6 mm. A thickness exceeding 10 mm is undesirable as it makes it easy for people to trip or fall when entering or exiting the shelter, while a thickness of less than 3 mm is also undesirable as it makes it difficult to firmly support the superstructure, including the columns, and makes the shelter prone to collapse.

[0069] Furthermore, the overall dimensions, including the thickness of each base plate, could be such that, for example, the aforementioned 4.5 tatami mat type earthquake-resistant steel frame shelter has a rectangular cross-section of 6 mm x 150 mm and a length of 2200 mm. For a 6 tatami mat type, it could have a rectangular cross-section of 6 mm x 150 mm and a length of 3100 mm (for the long side) and 2400 mm (for the short side).

[0070] (Embodiment 1: Configuration: Base plate: Arrangement method)

[0071] The base plate is positioned at the bottom of the column such that one end overlaps the bottom and the other end abuts against the side of another base plate. The earthquake-resistant steel shelter shown in Figure 1 above is an example of a base plate arranged in this manner.

[0072] Figure 5 shows how the base plates are arranged in the earthquake-resistant steel frame shelter of Embodiment 1, and is an enlarged view of both ends of the base plate shown in Figure 1. Of these, (a) is an enlarged view of one end of Figure 1 (roughly enclosed by the dashed circle 0121a), showing that one end 0521a of the base plate 0521 (roughly the shaded area) overlaps with the bottom of the column 0501, in other words, it is positioned in contact with the underside of the column. (b) is an enlarged view of the other end of Figure 1 (roughly enclosed by the dashed circle 0121b), showing that the other end 0521b of the base plate 0521 (roughly the shaded area) is positioned abutting against the side of another adjacent base plate 0524. Note that the diagram shows only the base plate and column, omitting the illustration of the connecting hardware, in order to visually clearly show the state in which the base plate is positioned with one end overlapping the bottom of the column and the other end abutting against the side of another base plate. In actual assembly, as shown in Figure 1, these base plates and columns will be joined via base plate-column connectors.

[0073] "The state in which one end of the base plate overlaps the bottom of the column" typically refers to a state in which the entire bottom surface of the column rests on one end of a single base plate. Figure 5 shows this case. Figure 25 is a plan view illustrating the arrangement of the base plates in this embodiment, and Figure 25(a) shows a state in which the entire bottom surface of the column 2501 rests on one end 2521a (roughly the area indicated by the diagonal lines) of a single base plate 2521, similar to Figure 5.

[0074] The significance of positioning the pillars so that their entire base rests on the base plate is that, in the case of heavy shelters (for example, the 4.5 tatami mat type mentioned above has a total weight of approximately 340 kilograms), the pillars do not come into direct contact with the floor of the room where the shelter is installed, thereby reducing the likelihood of the pillars damaging or denting the floor. In particular, when the pillars are hollow (Figure 25 is an example of this), the area of ​​the pillar's mounting surface is even smaller than when it is solid, so if the pillars were to come into direct contact with the floor of the room, the risk of the pillars denting the floor would be even greater.

[0075] From this perspective, it is not essential that the entire bottom surface of the column rests on one end of a single base plate; the entire bottom surface of the column may rest across two adjacent base plates without any gaps. Figure 25(b) shows an example of such a case, where the entire bottom surface of the column 2501 rests across two adjacent base plates 2521 and 2524 without any gaps. In this case, one end 2521a of base plate 2521 (roughly the area indicated by the diagonal lines) overlaps the bottom of the column 2501, and this end, along with the other end of base plate 2524 which is adjacent to the end of base plate 2521 without any gaps, is configured to overlap the bottom of the column 2501 in such a way that they equally bear the weight of the superstructure including the column that rests on the bottom surface of the column. Viewing this as a single base plate configuration, the base plate is configured such that, at the bottom of the column, one end overlaps the bottom surface of the column in such a way that it equally supports the weight of the superstructure including the column, together with the other end of another base plate that is adjacent to it without any gaps, and the other end overlaps the bottom surface of the column in such a way that it equally supports the weight of the superstructure including the column, adjacent to one end of yet another base plate that is separate from the aforementioned base plate, also adjacent to it without any gaps. Furthermore, this configuration in which "the other end is adjacent to one end of another base plate without any gaps" can be seen as one form of the configuration in which "the other end is positioned abutting against the side surface of another adjacent base plate," and therefore such a configuration is also included in the configuration of the first invention (the invention according to claim 1).

[0076] Furthermore, although not shown in the diagram, the configuration is similar to the above, where the entire bottom surface of the column rests on two adjacent base plates without any gaps. However, a configuration in which one end of one base plate and the other end of the other base plate divide the bottom of the column unequally rather than equally is also included in the configuration of the first invention (the invention according to claim 1). For example, this would be the case if one end is a convex arc shape and the other end, which is in contact with it without any gaps, is a concave arc shape.

[0077] Regarding the specific fasteners for connecting the base plate and the columns, if the base plate and columns are not securely joined, the columns will easily detach from the base plate, even without considering the distortion of the bottom surface formed by the base plate, and the object will be destroyed. Therefore, a fastener that can securely join the base plate and columns is required. An example of such a fastener is a metal bracket. Details of the metal bracket will be described later in another embodiment (see Embodiment 4).

[0078] The purpose of arranging the base plate so that one end overlaps the bottom of the column and the other end abuts against the side of another base plate is to make the base less prone to distortion by assembling the base plates that make up the base surface in a rotationally symmetrical shape (1, 2, or 3 rotational symmetry if the base surface is square, and 2 rotational symmetry, i.e., point symmetry, if the base surface is rectangular), so that the load is evenly distributed to the four corners of the base surface.

[0079] (Embodiment 1: Structure: Significance)

[0080] With this configuration, even if the structure consists only of 12 steel beams forming a framework of columns, base plates, and beams, without the need to assemble steel frames in a grid or arrange panels as in conventional shelters, it is possible to provide an earthquake-resistant steel shelter that is less prone to distortion and destruction at the bottom when a large load is applied from above.

[0081] (Embodiment 1: Configuration: Summary of Load-Bearing Test Results)

[0082] Load-bearing tests were conducted using the aforementioned 4.5-tatami mat type prototype. The results confirmed that the earthquake-resistant steel frame shelter could maintain its original shape without being destroyed up to 10 tons, regardless of whether the load was applied from above or at an angle. Details of these test results will be described later as <Experimental Example>.

[0083] It's difficult to say exactly how much load would be placed on a first-floor room if a second-floor room fell from a house, as it depends on the condition of the room, but generally it's around 200-300 kg / m².2 It is said to be around that size. In that case, the 4.5 tatami mat type shelter of this embodiment (floor area approximately 5.3 m²) 2 The load on the shelter when a second-floor room falls onto it is approximately 1.1 to 1.6 tons. Therefore, the ability to withstand the above-mentioned 10-ton load is sufficient to withstand the load that would be exerted if a second-floor room of a house were to fall.

[0084] (Embodiment 1: Configuration: Ease of assembly)

[0085] The earthquake-resistant steel frame shelter of this embodiment, with its simple structure consisting only of steel frames as described above, can be easily assembled and installed in a short time by even laypeople who are not building professionals, through simple on-site work. The ease of assembly of the earthquake-resistant steel frame shelter of this embodiment will be explained in detail below.

[0086] For joining steel frames, it is possible to use well-known and simple methods. For example, a method can be used in which bolt holes provided near the ends of each column, base plate, and beam are aligned and joined using bolts, nuts, etc.

[0087] In addition, reinforcing members may be joined. For example, as described later (see Embodiment 5), it is conceivable to join the columns and base plates using metal brackets. Even in this case, if, for example, bolt holes are provided in the reinforcing members and aligned with bolt holes provided near the ends of each base plate and column, and joined using bolts, nuts, etc., it will still be easy for laypeople to assemble and install the structure in a short time with simple work on site. Furthermore, to enable assembly in an even shorter time and with simpler work, it is even more desirable to weld the reinforcing members to the columns, etc., in advance before shipment from the factory. Similarly, the joint between columns and beams can also be reinforced using metal brackets, etc., and in this case as well, joining or welding using bolts, nuts, etc., as in the case of columns and base plates described above, is conceivable.

[0088] When a prototype of a 6-tatami mat type shelter, configured in this way, was assembled multiple times by 3-4 people with no architectural experience, it was possible to assemble it in about 15-20 minutes each time.

[0089] Furthermore, because it is easy to assemble using such a simple method, it is also easy to disassemble. Therefore, it is possible to disassemble an earthquake-resistant steel-frame shelter installed in one room, move it to another room, and then reassemble and use it there. Similarly, in the case of moving, it is possible to disassemble it, transport it to the new location, and reassemble and use it there. <Embodiment 1: Effects>

[0090] The invention of this embodiment provides an earthquake-resistant steel frame shelter that can be installed inside an existing wooden house or the like, which can be completed with only simple steel frame assembly work on site without interior finishing, can be installed in a short time and at a relatively low cost, and even though it is a structure consisting only of steel frames consisting of columns, beams and base plates, it is configured so that the bottom surface does not distort under load from above, and it is also configured to prevent tripping or falling when entering or exiting. <Embodiment 2>

[0091] Embodiment 2 mainly relates to claim 2, etc. <Embodiment 2: Overview>

[0092] The earthquake-resistant steel frame shelter of Embodiment 2 is based on the earthquake-resistant steel frame shelter of Embodiment 1, and is further characterized in that the columns are made of steel with a roughly square cross-section. <Embodiment 2: Configuration: General>

[0093] The configuration of the earthquake-resistant steel shelter in this embodiment is basically the same as that of the earthquake-resistant steel shelter in Embodiment 1. However, the columns in the earthquake-resistant steel shelter in this embodiment are steel materials with a roughly square cross-section. "Steel materials with a roughly square cross-section" means that the steel material is hollow and has a roughly square cross-section. <Embodiment 2: Configuration: Shape and Dimensions>

[0094] Figure 6 shows an example of the cross-sectional shape of a column in the earthquake-resistant steel frame shelter of Embodiment 2. In the example shown, column 0601 of this embodiment is a hollow steel material with a square cross-section. Preferred dimensions of the cross-section are, for example, a side length (L) of the square steel material forming the cross-section being 90 mm or more and 110 mm or less, and a thickness (D) of the steel material being 3.0 mm or more and 3.5 mm or less, and particularly preferred is a side length (L) of the square steel material forming the cross-section being 100 mm and a thickness (D) of the steel material being 3.2 mm. <Embodiment 2: Configuration: Purpose>

[0095] The purpose of making the columns hollow is to make the work easier by reducing the weight compared to using solid steel materials, and to keep costs down. <Embodiment 2: Composition: Materials>

[0096] The material used for the column is one that can maintain the required strength even when hollow, and steel is preferably used. <Embodiment 2: Effects>

[0097] This invention makes it easier to work by making the column hollow and thus lighter, and also makes it possible to keep costs lower compared to using solid steel materials. <Embodiment 3>

[0098] Embodiment 3 mainly relates to claim 3, etc. <Embodiment 3: Overview>

[0099] The earthquake-resistant steel frame shelter of Embodiment 3 is based on the earthquake-resistant steel frame shelter of Embodiment 1 or Embodiment 2, and is further characterized in that the beams are steel materials with a roughly square cross-section. <Embodiment 3: Configuration: General>

[0100] The configuration of the earthquake-resistant steel shelter in this embodiment is basically the same as that of the earthquake-resistant steel shelter in Embodiment 1 or Embodiment 2. However, the beams in the earthquake-resistant steel shelter in this embodiment are steel members with a roughly square cross-section. <Embodiment 3: Configuration: Shape and Dimensions>

[0101] Although not shown in the diagram, an example of the beam shape in the earthquake-resistant steel shelter of Embodiment 3 is a hollow steel material with a square cross-section, similar to the column described in Embodiment 2, and the cross-section is approximately rectangular. For example, the dimensions of the cross-section could be such that the length of one side of the square steel material forming the cross-section is 100 mm and the thickness of the steel material is 3.2 mm. <Embodiment 3: Configuration: Purpose / Materials>

[0102] The purpose of making the beam hollow is the same as described for the column in Embodiment 2. The material for the beam is also the same. <Embodiment 3: Effects>

[0103] This invention makes it easier to work by making the beam hollow and thus lighter, and also makes it possible to keep costs lower compared to using solid steel materials. <Embodiment 4>

[0104] Embodiment 4 mainly relates to claim 4, etc. <Embodiment 4: Overview>

[0105] The earthquake-resistant steel frame shelter of Embodiment 4 is based on the earthquake-resistant steel frame shelter of Embodiment 1 or Embodiment 2, and is further characterized in that the base plate is fixed to the column by being screwed to a metal bracket welded to the lower side of the column. <Embodiment 4: Configuration>

[0106] The configuration of the earthquake-resistant steel frame shelter in this embodiment is basically the same as the configuration of the earthquake-resistant steel frame shelter in Embodiment 1 or Embodiment 2. However, in the earthquake-resistant steel frame shelter of Embodiment 4, the base plate is fixed to the column by being screwed to a metal bracket welded to the lower side surface of the column.

[0107] Figure 7 shows an example of the configuration of an earthquake-resistant steel frame shelter in Embodiment 4. This figure, like Figure 1, is shown in perspective. As shown in the figure, in this embodiment, the base plates 0722 and 0723 located at one corner of the earthquake-resistant steel frame shelter are fixed to the column 0703 by screws to metal brackets 0731 and 0732 welded to the lower side surface of the column 0703, respectively. In other words, the metal brackets in this embodiment are configured so that the vertical surface is welded to the column in advance, and the horizontal surface is fixed to the base plate by screws during on-site work. Although not shown, the other three corners are configured in the same way.

[0108] (Embodiment 4: Composition: Metal folding)

[0109] In this embodiment, the metal bracket refers to a fastener having a shape formed by bending a plate-shaped metal fitting into an L-shape. The material used may include steel or stainless steel. To facilitate on-site work, it is desirable to weld the metal bracket to the column before it leaves the factory.

[0110] The preferred dimensions for the metal bracket are: length (L) 100 mm to 140 mm, width (W) 80 mm to 120 mm, height (H) 100 mm to 140 mm, and thickness (D) 4 mm to 8 mm. The one shown in Figure 7 is a particularly preferred example, with a length (L) of 120 mm, width (W) of 100 mm, height (H) of 120 mm, and thickness (D) of 6 mm. <Embodiment 4: Effects>

[0111] This embodiment of the invention allows for a secure connection between the base plate and the columns, thus providing an earthquake-resistant steel-frame shelter that is not susceptible to damage due to the columns easily detaching from the base plate. Furthermore, welding the metal brackets to the columns before factory shipment simplifies on-site work. <Example of experiment>

[0112] A load-bearing test was conducted on the earthquake-resistant steel frame shelter according to the present invention, and it was confirmed that it can withstand stresses up to 10 tons, as described above. The details of this test are described below.

[0113] The shelter used in this test is an earthquake-resistant steel frame shelter described in Embodiment 1, which is an "assembly-type rectangular metal frame consisting of four or more columns, four or more beams connecting the tops of these columns, and four or more base plates connecting the bottoms of these columns, wherein at least four of the base plates are arranged so that one end overlaps the bottom of the columns and the other end abuts against the side of another base plate." More specifically, it has the same shape and dimensions as the 4.5 tatami mat type shown in Figure 2. That is, in addition to the 12 steel frames that form the basic framework, it is equipped with two reinforcing members that span between a pair of opposing beams and reinforcing members that diagonally connect beams that are adjacent at right angles. In particular, it is characterized by the arrangement of the four base plates as described above, so that each base plate receives the load from above evenly, and so as not to collapse due to uneven loads causing the columns to detach. Thus, the shelter used in this test differs from the shelter according to the first invention (the invention described in claim 1) in that it has two reinforcing members spanning between a pair of opposing beams and reinforcing members diagonally connecting beams that are perpendicular to each other. However, since the load applied from above is transmitted to the base plate via four columns provided at the four corners, and the configuration of these columns is the same, the force applied to the base plate is equivalent. Therefore, this test is equivalent to that of the earthquake-resistant steel frame shelter according to the first invention.

[0114] The most important objective of this test is to confirm that, by incorporating a configuration with a distinctive arrangement of base plates as described above, even if the bottom consists only of four base plates, that is, without the need for reinforcement such as assembling a grid of steel frames on the bottom surface and fitting in panel-shaped members or placing X-shaped place anchors diagonally across the bottom surface, as is done with conventional shelters, it can withstand sufficient loads.

[0115] In this test, we first set a constant value as the material constant for the steel used in the earthquake-resistant steel frame shelter, and then performed computer simulations to calculate the stress values ​​generated in each part as a result of applying a 10-ton load.

[0116] Table 1 shows the values ​​of the material constants set. The values ​​of the material constants set here are those commonly found in commercially available steel materials intended for use as materials for the earthquake-resistant steel frame shelter according to the present invention. [Table 1]

[0117] Of these, Young's modulus indicates the inherent hardness of a material, showing the degree to which it deforms when a load is applied, and Poisson's ratio indicates the ratio of strain (expansion and contraction) that occurs when a load is applied to a material. In addition, the coefficient of linear expansion indicates how much a material expands or contracts in response to temperature changes. In this test, as described below, five different cases were set for how the load is applied (location and direction of application), and for each of these, computer simulations were performed to determine the value of the stress generated in each part using the above material properties. As a result, it was found that in all cases, the earthquake-resistant steel shelter according to the present invention could withstand a load of 10 tons.

[0118] Figures 8 to 12 illustrate the results of load-bearing tests (computer simulations) on the earthquake-resistant steel shelter according to the present invention. For each of the five cases, the figures show the stress values ​​generated in each part of the earthquake-resistant steel shelter when a 10-ton load is applied to the shelter from directly above (Figures 8 to 11) or from diagonally above (Figure 12). In each figure, (a) shows how the load is applied to the earthquake-resistant steel shelter, with arrows indicating the location and direction of the load. (b) and (c) show the stress values ​​generated in each part of the shelter as a result. (b) shows the displacement (unit: mm), which is the strain width of each part, and (c) shows the pressure applied to each part (unit: MPa). The maximum and minimum values ​​of the generated stress are also shown for (b) and (c), respectively. Please note that these diagrams are merely conceptual diagrams and do not necessarily correspond to the actual shape (specifically, the width of the base plate is depicted as being the same as the width of the column, which differs from Figure 2, which depicts the shape to match the actual form).

[0119] Please note that Figures 8 through 12 are shown in grayscale due to the constraints of the application format, but color drawings will be submitted separately in a written statement as reference drawings.

[0120] In Figure 8, as shown in (a), a load is applied evenly from directly above to the entire ceiling surface enclosed by four beams. The stresses generated in each part of the shelter at this time are as follows. First, looking at the displacement of each part in (b), the maximum displacement is shown in the central part of the two reinforcing members that span between a pair of opposing beams located near the center of the ceiling surface, but the value was less than 9 mm. On the other hand, it was less than 1 mm near the columns and the base. Next, looking at the pressure generated in each part in (c), the maximum pressure is again shown near the center of the ceiling surface, but the value was less than 120 MPa, and it was less than 30 MPa near the columns and the base. Thus, in terms of both displacement and pressure, it was shown that the stress at the base was generated almost evenly, to the extent that the base surface did not deform. As a result, it was shown that the earthquake-resistant steel shelter would not be destroyed in this test.

[0121] Next, in Figure 9, as shown in (a), a load is applied from directly above to the central portion of two reinforcing members spanning a pair of opposing beams. The stress generated in each part of the shelter at this time is as follows. First, looking at the displacement of each part in (b), the maximum value is shown in the central portion of the two reinforcing members, but the value is less than 17 mm. On the other hand, it was less than 1.7 mm near the columns and the base. Also, looking at the pressure on each part in (c), the maximum pressure is again shown in the central portion of the two reinforcing members, but the value is less than 300 MPa, and it was less than 30 MPa near the columns and the base.

[0122] Next, in Figure 10, as shown in (a), a load is applied from directly above to the central part of each of the opposing beams. The stress generated in each part of the shelter at this time is as follows. First, looking at the displacement of each part in (b), the maximum value is shown in the central part of each of the opposing beams, but the value is less than 14 mm. On the other hand, it was less than 1.7 mm near the columns and the base. Also, looking at the pressure generated in each part in (c), the maximum pressure is again shown in the central part of each of the opposing beams, but the value is less than 300 MPa, and it was less than 30 MPa near the columns and the base.

[0123] Furthermore, as shown in Figure 11 (a), a load is applied from directly above to the entire structure of two reinforcing members spanning a pair of opposing beams. The distribution of the load at each part of the shelter at this time is as follows: First, looking at the displacement at each part in (b), the maximum value is shown in the central part of the two reinforcing members, but the value is less than 20 mm. On the other hand, it is less than 2 mm near the columns and the base. Also, looking at the pressure generated at each part in (c), the maximum pressure is shown near the center of each of the opposing beams and in the central part of the two reinforcing members, but the value is less than 240 MPa, and it is less than 30 MPa near the columns and the base.

[0124] Thus, in all cases from Figures 9 to 11, as in Figure 8, it was shown that, regardless of the amount of displacement or pressure, the stress at the bottom was generated almost uniformly, to the extent that the bottom surface did not deform. As a result, it was shown that the earthquake-resistant steel shelter would not be destroyed in this test.

[0125] Figure 12 shows that a load is applied to one of the beams from above at a 45-degree angle, as shown in (a). The stresses generated in each part of the shelter at this time are as follows. First, looking at the displacement of each part in (b), the maximum value is shown across almost the entire ceiling surface of the earthquake-resistant steel shelter, but all of these values ​​were less than 11 mm. On the other hand, the displacement near the bottom and base of the column was less than 1.1 mm. Note that the upper part of (b) is a side view, and the lower part is a perspective view. Furthermore, looking at the pressure generated in each part in (c) (showing only the part close to where the load was applied), the pressure near the maximum value is shown at the bottom of the column on the same side as the central part of the beam where the load was applied, but the value was less than 120 MPa, and less than 30 MPa near the base. As a result, it was shown that the earthquake-resistant steel shelter would not be destroyed in this test as well.

[0126] Next, using an actual earthquake-resistant steel frame shelter, we conducted a verification test to see if the shelter could withstand a 10-ton load for each of the five cases used in the computer simulation described above. The earthquake-resistant steel frame shelter used in this test was also a 4.5 tatami mat type with the configuration shown in Figure 2, and the force applied to the base plate was equivalent to that of an earthquake-resistant steel frame shelter with the configuration of the first invention (the invention described in claim 1). Furthermore, the material constant values ​​of the steel material of the earthquake-resistant steel frame shelter used in this test are shown in Table 2, and are almost the same as the material constant values ​​used in the simulation. Therefore, this verification test is equivalent to that of an earthquake-resistant steel frame shelter according to the first invention. [Table 2]

[0127] As a result, in none of the cases was the earthquake-resistant steel frame shelter actually destroyed. Through these tests, it was demonstrated that the earthquake-resistant steel frame shelter according to the present invention can withstand a load of 10 tons.

[0128] Figure 19, for reference, is a photograph documenting a scene from this test, showing that the earthquake-resistant steel frame shelter does not collapse even when a 10-ton load is applied from above.

[0129] As explained above, it has been confirmed that the earthquake-resistant steel frame shelter according to the present invention will not be destroyed even when a load of 10 tons is applied from directly above or diagonally above. Based on these test results, it can be evaluated that the earthquake-resistant steel frame shelter according to the present invention has sufficient performance to withstand the load that would be applied if a second-floor room of a house were to fall. <Example of how to assemble an earthquake-resistant steel-frame shelter>

[0130] Here, an example of the assembly method for the earthquake-resistant steel frame shelter according to the present invention will be explained using Figures 13 to 16. The earthquake-resistant steel frame shelter used in these figures has the same structure as the one shown in Figure 2.

[0131] (1) First, as shown in Figure 13(a), four base plates 1321, 1322, 1323, and 1324 are arranged in a square shape on the horizontal floor of the room. Figure 13(b) is an enlarged view of one end (the joint with base plate 1324) and the other end (the joint with base plate 1322) of base plate 1321. As shown in (b), one end of base plate 1321 is in contact with the front surface 1324a of the adjacent base plate 1324, and the other end is positioned so that the front surface 1321a is in contact with the side surface near one end of the adjacent base plate 1322. The same applies to the other base plates. The arrangement here is simply by placing them side by side; no fixing such as screws is performed. Note that screw holes 1321b are drilled near both ends of the base plates for attaching the columns to the base plates, as described next. The same applies to the other base plates.

[0132] One base plate (one example of dimensions is 0.6cm x 15cm x 210cm = 1890cm) 3 The mass of the object is approximately 15.8 kg (the specific gravity of steel is 7.85), so it is not impossible for one person to perform this task, and it is a task that can be easily done by two or three people.

[0133] (2) Next, as shown in Figure 14(a), the column 1404 is attached to the base plate 1424. Specifically, the column is attached to one end of the base plate with screws. To facilitate this attachment, metal brackets 1431 are pre-welded to the lower side of the column. Then, these metal brackets and the base plate are screwed together using bolts or the like. The other three columns are erected on the base plate in the same manner by screwing them in. In addition, metal brackets 1441 are attached to the sides of the columns to facilitate the attachment of the beams described next. The order in which the columns are attached does not matter. Figure 14(b) shows the state after all four columns have been attached using the same procedure.

[0134] This work can be done manually using only a wrench. One column (example dimensions: a square-shaped column with a thickness of 0.3 cm, a cross-section of 10 cm x 10 cm, a length of 200 cm, volume excluding the cavity = 1880 cm³) 3 Since the mass of the base plate is almost the same as that of the base plate, this task can also be performed by 1 to 3 people.

[0135] (3) Next, as shown in Figure 15(a), a beam 1514 is attached to connect the tops of adjacent columns 1501 and 1504. The tops of other adjacent columns are connected in the same manner with beams. At that time, as shown in Figure 15(b), the columns and beams are fastened together using bolts or the like with metal brackets 1541 that are pre-welded to columns 1501 (not shown) and 1504, and the beams are fastened together using bolts or the like with L-shaped reinforcing brackets 1551. These operations can also be performed manually using only a wrench.

[0136] (4) Furthermore, when increasing the number of beams for reinforcement, for example, as shown in Figure 16(a), beams 1615a and 1615b are placed to connect two opposing beams 1611 and 1613 that connect the four corners, and then, as shown in Figure 16(b), beams 1616 made of two thin plates are placed to diagonally connect two beams that are adjacent at a right angle. These can also be installed manually using only a wrench.

[0137] As described above, the entire structure can be assembled by 1 to 3 people using only simple tools. Based on our testing, the assembly time is approximately 20 minutes for two people without architectural expertise.

[0138] To disassemble it, simply follow the reverse procedure described above. This is a simple, manual process that can be completed quickly, just like the assembly process. <Examples of earthquake-resistant steel frame shelter installations>

[0139] Figures 20 to 24 are photographs showing an example of the earthquake-resistant steel frame shelter according to the present invention actually installed inside a house, showing a 4.5 tatami mat type shelter installed in a Western-style room of about 16 tatami mats in size.

[0140] Figure 20 shows an overview of the entire installed earthquake-resistant steel frame shelter. Figure 21 shows the shelter from a different angle. As these figures show, the shelter is basically composed only of a steel frame and does not require the addition of interior finishes such as flooring, as conventional earthquake-resistant steel frame shelters do. Instead, the room in which it is installed is used in the same state as before the shelter was installed. For example, the floor uses the existing floor of the room, so items inside and outside the shelter are placed on the same floor (for example, the table inside the shelter and the sofa outside the shelter are on the same floor as shown in Figure 20). Also, since there are no obstructions on the four sides other than the four pillars, movement inside and outside the shelter (for example, moving between the sofa and table shown in Figure 20) is extremely easy. Furthermore, since the walls also use the existing walls of the room, it is possible to directly view, for example, the wall-mounted TV monitor and paintings shown in Figure 20, or the wall-mounted clock shown in Figure 21, from inside the shelter. In short, the room in which the shelter is installed can be used in almost the same manner as before the shelter was installed. Furthermore, as mentioned above, movement inside and outside the shelter is extremely easy, so even if you are outside the shelter (for example, on a sofa) when an earthquake occurs, it is easy to immediately take refuge inside the shelter.

[0141] Furthermore, one of the advantages of having a room with a shelter in almost the same condition as before the installation is that, in the event of an earthquake, it is easy to move immediately from an adjacent room to the room with the shelter and then take refuge inside the shelter. For example, in Figure 20 mentioned above, the kitchen of the adjacent room is visible in the back left, and it can be seen that even if you were in the kitchen when the earthquake occurred, you could take refuge in the shelter very easily.

[0142] Figure 22 is an enlarged view of the lower part of column 2201 and the two base plates 2224 and 2221 connected thereto. These column and base plates are firmly fixed together by metal brackets 2231 and 2232 that are pre-welded to the column. At this time, one end of base plate 2224 (generally indicated by arrow 2224a) overlaps the bottom of column 2201. The other end of base plate 2224 (not shown) is positioned abutting against the side of another base plate (not shown) (similar to how the other end of base plate 2221 (generally indicated by arrow 2221b) is positioned abutting against the side of base plate 2224 in the same figure). As already mentioned, with this configuration, each base plate is able to prevent distortion at the bottom by having all four base plates evenly receive the load from above, and this is the most important feature of the present invention.

[0143] Furthermore, the diagram shows that the base plates 2224 and 2221 are extremely thin (6mm in this example photo), and this photo also demonstrates that there is little risk of tripping or falling, even in the dark, making it easy to move safely into the shelter.

[0144] On the other hand, Figure 23 is an enlarged view of the upper part of column 2303 and the two beams 2314 and 2311 connected thereto. In addition, a thin plate beam 2316 is installed on the upper surface of these two beams, diagonally connecting the two beams as a reinforcing member. Furthermore, as shown in Figure 24, two beams are also placed between a pair of opposing beams 2414 and 2412 as reinforcing members. These seismic-resistant steel frame shelters according to the present invention, whether of the 4.5 tatami mat type or the 6 tatami mat type, are designed to be almost touching the ceiling when installed in the interior of a Japanese house, regardless of the size of the room. This state is also shown in Figure 24. In this case, these reinforcing members also serve to prevent objects falling from the upper floor from falling into the shelter, without compromising the advantage of the present invention, which is that it can be easily assembled with a small number of parts.

Claims

1. It is an assembly-type rectangular metal frame, consisting of four or more columns, four or more beams connecting the tops of these columns, and four or more base plates connecting the bottoms of these columns. An earthquake-resistant steel frame shelter comprising at least four base plates, arranged such that one end overlaps the bottom of the column and the other end abuts against the side of another base plate.

2. The earthquake-resistant steel shelter according to claim 1, wherein the column is a steel material with a roughly square cross-section.

3. The earthquake-resistant steel shelter according to claim 1 or claim 2, wherein the beam is a steel material with a roughly square cross-section.

4. The earthquake-resistant steel frame shelter according to claim 1 or claim 2, wherein the base plate is fixed to the column by being screwed to a metal bracket welded to the lower side of the column.

5. The earthquake-resistant steel frame shelter according to claim 1 or claim 2, wherein the base plate has a thickness of 3 mm or more and 8 mm or less.

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