JP2021188301A - Reuse method of structure - Google Patents

Abstract

To provide a reuse method of a structure capable of reusing almost all existing members when a temporary large space structure constructed in an exhibition or the like is scaled-down and reused.SOLUTION: A roof frame 2b of a scale-reduced building 1a has a similar shape of a roof frame size ratio A1/A (=B1/B) to a roof frame 2 of an original building 1, and coincides with a truss beam size ratio d/D. As shown in Fig. 5, one end or both ends of respective truss members 10, 11, 12, 13 after reduction in scale (hatched portions in Fig. 5 (a)) are cut off so as to correspond to a ratio S1/S of a dimension between truss upper chord nodes, and the truss is reassembled into a truss having a similar shape dimension as shown in Fig. 5 (b).SELECTED DRAWING: Figure 5

Description

The present invention relates to a method for reusing a structure when a roof frame of a large space structure such as a large-scale exhibition hall constructed at an exposition or the like and used only for a short period of time is reduced in scale and reused.

Conventionally, for example, a large-scale exhibition hall constructed at an exposition may be constructed as a temporary building for short-term use, and in that case, it is designed on the premise that the frame members will be reused after dismantling. It was sometimes constructed.

There is no problem if it is reused as the exact same building, but for example, in the building 1 shown in FIG. 1, the roof frame 2 (plan dimension AxB, beam frame D flat plate) of the truss structure is scaled down and shown in the figure. As shown in 2, when reusing as a scaled-down building 1a, only the central part frame 2a (plan dimension A ₁ x B ₁ , beam frame D flat plate) of the roof frame 2 is left, and other parts are left. If the frame part is omitted, even if the ratio of the plane dimensions is A ₁ / A = B ₁ / B, the frame after reuse (central frame 2a) is similar to the original frame (roof frame 2). Therefore, the strength of the recycled member is not always sufficient because the stress distribution changes completely.

That is, it is not always possible to reuse existing members as they are, and it is necessary to study the strength of the members and to design and manufacture new members if the strength is insufficient.

For example, Patent Document 1 or Patent Document 2 is a prior art related to the reuse of a structure. In Patent Document 1, a ramen structure using a strong shaft of H-shaped steel in the span direction, a ramen structure using a weak shaft of H-shaped steel in the girder direction, and a seismic column using H-shaped steel as a strong shaft are combined. , A method for constructing a steel-framed building structure in which a three-dimensional structure having a certain size is used as an independent unit block is disclosed. According to this construction method, the block can be continuously expanded or contracted in the girder direction and the stretch direction.

That is, even in an existing building, the number of the blocks can be reduced or increased so as to have a required scale. However, if the scale (building area) increases or decreases, the number of pillars will only increase or decrease in proportion, so the space structure without pillars, such as a large-scale exhibition hall constructed at an exposition, will be scaled down and reused. Not applicable if you try.

In Patent Document 2, as a roof frame suitable for a roof having a relatively large span such as a competition facility or an event facility, a tension beam whose lower chord is a tension material and a tension beam whose upper chord is a tension material are orthogonal to each other, and a bundle material is provided at the intersection thereof. A tension beam structure in which prestress is introduced into the tension material is disclosed on the basis of constructing a cross beam by interposing the roof. Since the joint between each of these members is a simple pin joint, it is easy to assemble and disassemble the frame, and each member can be highly reused.

The invention of Patent Document 2 belongs to the field of roof frames of large space structures, which is the subject of the present invention, but when reusing an existing roof frame, the shape and dimensions of the chord beam, which is a cross beam, are reused as they are. Therefore, it is impossible to reduce the scale of the roof frame (shortening the chord beam) after reuse. Therefore, it cannot be applied when the scale is reduced and reused as assumed by the present invention.

Japanese Unexamined Patent Publication No. 2006-46023 Patent No. 3918715

According to the present invention, when a roof frame of a large space structure such as a large-scale exhibition hall constructed at an exposition or the like, which is used only for a short period of time, is reduced in scale and reused, the size remains unchanged in almost all cases. It provides a method for reusing a structure in which existing members can be reused.

The means of the present invention for solving the above-mentioned problems is that when the frame of a structure such as an exhibition hall is reused, the frame shape dimension after the scale reduction is similar to the original frame, and the original frame is configured. It is characterized in that one end or a part of both ends of the member before the scale reduction is cut so that the internode length after the scale reduction of each member becomes a length corresponding to the ratio of the similar figures. It is a method of reusing a structure.

Further, when the roof frame of a structure such as an exhibition hall is reused, the shape and dimensions of the roof frame after the scale reduction are similar to those of the original roof frame, and after the scale of each member constituting the original roof frame is reduced. Reuse of the structure, characterized in that one end or a part of both ends of the member before the scale reduction is cut so that the inter-node length of the member is adjusted to the ratio of the similar shape. The method.

Further, in the present invention, for example, in a frame structure in which the roof frame is a multi-layer or single-layer truss structure and includes a member twisted around the axis, the internode length of the member is the above-mentioned. One end or a part of both ends of the twisted member before the scale reduction is cut off so that the length matches the ratio of the similar shape, and the length is matched to the shape of the roof frame after the scale reduction. The method for reusing the structure is characterized in that the twisted member after the scale is reduced in size so as to have a twist angle, and additional twist is applied around the axis thereof.

Since the present invention is the above means, when the roof frame of a structure such as an exhibition hall is reused, if the frame shape dimension after the scale reduction is similar to the original frame, the frame can be constructed. All the constituent members become shorter according to the similarity ratio, but the rigidity ratio of each member remains the same, so that the stress distribution state does not change even if the stress value changes. Moreover, since the load effect acting on the frame is reduced by the scale reduction, the stress value becomes small, so that the strength of the members has a larger margin than in the original frame. That is, since the same member can be reused only by shortening the member length (that is, the member cross-sectional size remains the same), there is no need to design and manufacture the member again.

Further, regarding the joint portion of the node where the members are connected to each other, if the original joining method is bolt joining, a bolt hole is provided so that the cut end portion of the member matches the node joint member of the node. Once processed, it can be reused as it is.

但し、ｗ：鉛直等分布荷重、L：梁の長さ（支点間寸法）
Ｅ：ヤング係数、I：梁の断面二次モーメント The relationship between member dimensions (length, cross section) and stress and deformation will be described. For example, as a very simple example (see FIGS. 7A and 7B), the maximum bending moment M and the maximum deflection due to the vertically evenly distributed load w per unit length loaded on one simple beam G. δ is as follows.

However, w: vertical evenly distributed load, L: beam length (dimension between fulcrums)
E: Young's modulus, I: Moment of inertia of area of beam

As can be seen from the above (Equation 1) and (Equation 2), the bending moment M acting on the member (simple beam G) is proportional to the square of the length L, and the deflection δ is proportional to the fourth power of the length L. ..

Here, assuming that the simple beam G is a truss beam T (see FIG. 8) having the following cross-sectional performance, the bending strength M ₁ and the deflection δ _{1 of the truss beam T 1} after being reduced in a similar manner. Describe the impact.

但し、Ｆ：材料強度

（トラス梁Ｔ₁）
相似比率をα（＜1.0）として（式３）、（式４）のｊ、Lをαｊ、αLに置換えて、断面係数Ｚ₁＝（a・ｊ）・α、 断面二次モーメントＩ₁＝（a・ｊ²/2）・α²

(Truss beam T)
Section modulus Z = a · j, the geometrical moment of inertia I = a · j ^2/2
However, a: Cross-sectional area of the chord material on one side (same for the upper and lower chord materials)
j: Dimensions between the centers of gravity of the upper and lower chords

However, F: material strength

(Truss beam T ₁ )
With the similarity ratio as α (<1.0), replace j and L in (Equation 3) and (Equation 4) with αj and αL, and the _{moment of inertia of area Z 1} = (a · j) · α, moment of inertia of area I ₁ = ^{(a · j 2/2)} · α 2

As can be seen from the comparison between (Equation 3) and (Equation 4) and (Equation 5) and (Equation 6), (Equation 3) and (Equation 4) and (Equation 5) and (Equation 6) are (Equation 6). Since the equations 5) and (6) are the same except that the similarity ratio α and the square of the similarity ratio α are multiplied, the truss beam T ₁ has the original bending strength M as compared with the truss beam T. ₀ drops to alpha times the original moment of inertia of I, that is, the deflection [delta] ₀ is reduced to alpha ^2-fold.

On the other hand, when the member (truss beam) length L becomes α times, as described above, the bending moment M decreases in proportion to the square of the length L and becomes ^{α 2 times.} If the shape and dimensions are similar to the original after the scale is reduced as it is, and the length L of the truss beam and the dimension j between the center of gravity of the upper and lower chords are 50% (= α), the bending strength is α times. Since the bending moment M that acts is reduced by α ² times, the margin of bending momentum of the truss beam after scale reduction becomes α / α ² = 2.0 times. In addition, the deflection is ^{greatly improved with α 2} = 0.25 times.

The above is the case of a simple beam, but as a more complicated case, for example, a cylindrical three-dimensional truss frame as shown in FIG. 9 is similar to the side lengths A and B and the beam length D while keeping the member cross-sectional size as it is. It will be verified when it is reduced to 2/3 and the reduced frame is as shown in FIG. The symbols and design conditions in these figures are as follows.

(Common) △ mark: fulcrum, arrow: fulcrum movable direction (Fig. 9 to Fig. 12: original frame) Zhangma A x girder line B: 60m x 60m, truss formation D: 3m, upper and lower chord material: H-300x150x6.5x9 And (partly) H-294x200x8x12, truss material: φ-139x4.5 and (only near the fulcrum) φ-165.2x5 or φ-190.7x5.3, fixed load (vertical equal distribution): 1907N / m ²

(Figs. 13 to 16: Reduced frame) Zhangma A ₁ x girder line B ₁ : 40m x 40m, truss length d: 2m, upper and lower chord materials: H-300x150x6.5x9 and (partially) H-294x200x8x12, lattice material : Φ-139x4.5 and (only near the fulcrum) φ-165.2x5 or φ-190.7x5.3, fixed load: 2293 N / m ²
Since the reduced frame is similar to the original frame, the arrangement of each member is naturally the same.

但し、C₁、C_2、C₂ ^’：係数（無次元）、p₀：鉛直等分布の単位荷重（kN/m²）、
L：辺長（ｍ）、E：ヤング係数（kN/m²）、ｔ：版厚（ｍ）、
I：版の断面二次モーメント（ｍ⁴/ｍ）
即ち、最大曲げモーメントは長さの２乗に比例し、最大たわみは長さの４乗に比例しかつ版の断面二次モーメントに反比例する。 Here, the relationship between stress / deformation and frame dimensions in the above-mentioned plate-shaped frame will be described by analogy with a square flat plate of a continuum such as a concrete slab. _{It is known that the maximum bending moment M s} and the maximum deflection δ _{s in} the case of simple four-sided support (similar to the fulcrum condition of the three-dimensional truss frame) occur in the center of the plate and are as follows.

However, C ₁ , C _2, C ₂ ^' : Coefficient (dimensionless), p ₀ : Vertical equal distribution unit load (kN / m ² ),
L: Side length (m), E: Young's modulus (kN / m ² ), t: Plate thickness (m),
I: Moment of inertia of area of plate (m ⁴ / m)
That is, the maximum bending moment is proportional to the square of the length, and the maximum deflection is proportional to the fourth power of the length and inversely proportional to the moment of inertia of area of the plate.

但し、ｓ：１台のトラス梁の支配幅（ｍ）
となる。 Since the case of the above equation continuum, when fit to the space truss Frame as described above is not a continuum, already described so on, moment of inertia of I ₁ of the truss beam one at a · j ^2/2 Considering that the moment of inertia of area I in (Equation 8) is a value per unit width of the plate, if the dominant width of one truss beam is s, I = I ₁ / s can be set. Therefore, (Equation 8) is

However, s: the dominant width (m) of one truss beam
Will be.

最大たわみは、（式９）のL、ｊ、ｓをそれぞれαL、αｊ、αｓと置いて、

となる。 Next, when the length is reduced by α times in a similar manner, it becomes as follows.
For the maximum bending moment, set L in (Equation 7) as αL.

For the maximum deflection, place L, j, and s in (Equation 9) as αL, αj, and αs, respectively.

Will be.

As can be seen from the comparison between (Equation 7) and (Equation 9) and (Equation 10) and (Equation 11), (Equation 7) and (Equation 9) and (Equation 10) and (Equation 11) are (Equation 11). Since it is the same in 10) and (Equation 11) except that the square of the similarity ratio α and the cube of the similarity ratio α are multiplied, the reduced frame of the similarity ratio α has the maximum bending moment compared to the original frame. It can be seen that is α ² times and the maximum deflection is α ^{3 times.}

In the three-dimensional truss frame of the example, since α = 2/3, the maximum bending moment corresponds to (2/3) ² = 0.444 times, and the maximum deflection ^{corresponds to (2/3) 3} = 0.296 times. However, as can be seen from (Equation 10) and (Equation 11), these are _{proportional to the vertically evenly distributed load p 0} per unit area, so correction is required when the vertically equally distributed load p _{0 changes.}

As an example, the results of three-dimensional stress analysis under a fixed (vertical) load in the cylindrical three-dimensional truss frame of FIGS. 9 and 13 are shown in FIGS. 10 to 12 and 14 to 16, respectively. In each figure, FIGS. 10 and 14 show the axial force of the upper chord material, FIGS. 11 and 15 show the axial force of the lower chord material, and FIGS. 12 and 16 show the axial force of the lattice material. The tensile force is the force and no hatching. The large numbers in each figure are the maximum tensile and compressive axial force values (kN).

The maximum value of the axial force is as shown in Fig. 10 upper chord material (tension 272.0 kN, compression 730.9 kN), Fig. 11 lower chord material (tension 444.9 kN, compression 490.5 kN), and Fig. 12 lattice material (tension 272.0 kN, compression 730.9 kN) in the frame of Fig. 9, which is the original frame. The tension is 185.5kN and the compression is 223.6kN). On the other hand, in the frame of Fig. 13 after reduction, Fig. 14 upper chord material (tension 140.4kN, compression 381.5kN), Fig. 15 lower chord material (tension 235.4kN, compression 259.1kN), Fig. 16 lattice material (tension 95.9kN, compression 117.1). kN).

Comparing FIGS. 10 to 12 with FIGS. 14 to 16, each maximum axial force generating member is at the same position, and FIGS. 14 to 14 with respect to FIGS. 10 to 12 of the maximum axial force values of tension and compression. The ratios in FIG. 16 are FIG. 10, FIG. 14 upper chord material (tension 0.517, compression 0.522), FIG. 11, FIG. 15 lower chord material (tension 0.529, compression 0.528), FIG. 12, FIG. 16 lattice material (tension 0.517, compression 0.524). It has become.

Let us compare the above results with the results estimated from (Equation 10) and (Equation 11). Since the chord material axial force N of the truss beam has a relationship of N = M / truss (D = 3 m, d = 2 m), the relationship of (Equation 10) and (Equation 11) is directly applied to the chord material axial force. Also applies.

Therefore, here, a comparison is made with the chord material axial force of the analysis result. Chords axial force in the case of FIGS. 13 to 16 similar ratio alpha 2/3 reduction Frames of to the original Frames of 9 to 12 is the alpha ² = ^{(2/3) 2} times greater than (Equation 10) be. However, since the cross-sectional size of the truss member remains the same, the ratio of the weight w per unit area of the reduced frame of FIG. 13 to the original frame of FIG. 9 is corrected in consideration of the fact that it is 2239/1907 = 1.20 times heavier. Then, the equivalent magnification β of the chord material axial force ^{becomes β = (2/3) 2} x 1.2 = 0.533 times.

As described above, the ratio of the maximum member axial force to FIGS. 10 to 12 based on the analysis result is 0.52 to 0.53 times, which is in good agreement with β. That is, even in the case of the three-dimensional truss frame as shown in FIG. 9, according to the method of reducing the frame in a similar manner, the stress distribution state is almost unchanged and the absolute value of the stress becomes smaller according to the similarity ratio. The yield strength of each member is uniformly increased compared to the case of the original frame.

Regarding the deformation analysis results (not shown), the maximum deflection occurred at the central node, the original frame in FIG. 9 was 9.8 cm, and the reduced frame in FIG. 13 was 3.4 cm, so the ratio is 3.4 / 9.8 = 0.347. On the other hand, if α ³ of (Equation 11) is corrected by the ratio of weight w per unit area (= 1.2), the equivalent magnification β of the maximum deflection is β = (2/3) ³ x 1.2 = 0.356 times. So it's almost the same.

From the above, when the roof frame of a structure is reduced and reused in a similar manner, there is no damage even if the same member is reused only by shortening the member length (that is, the member cross-sectional size remains the same). As long as it can be said that there is no structural problem with stress and deformation.

In a roof frame such as the large-scale exhibition hall, the bending moment that most affects the magnitude of stress generated in the members constituting the roof frame is mainly generated by a vertical load, so the scale of the structure is reduced to a similar shape. The above effects can be expected most in the roof frame of the large-scale exhibition hall or the like.

Since the present invention is based on the above means, the following effects can be obtained. According to the method of reusing the roof frame of a structure such as an exhibition hall so that the frame shape and dimensions after the scale reduction are similar to the original roof frame.
(1) The strength of the members that make up the roof frame after scale reduction will have a greater margin than in the case of the original roof frame, so the length of the members should be shortened according to the ratio of the similar figures. Therefore, almost all of the same member can be reused while keeping the member cross-sectional size as it is.

(2) Therefore, there is no need to design and manufacture the members again.
(3) By shortening the original roof frame members, almost all the members can be reused as they are, which greatly contributes to the effective use of resources.

An example of the original roof frame consisting of a truss structure is shown, (a) is a roof frame frame view, and (b) is a cross-sectional view of (a). An example of the case where the scale is reduced while leaving the central part of the roof frame in FIG. 1 is shown. be. In the first embodiment of the present invention, (a) is a roof frame frame plan after the roof frame of FIG. 1 is scaled down to a similar figure, and (b) is a cross-sectional view of Ha-ha in (a). be. In the second embodiment of the present invention, when the roof is cylindrical, the roof frame is reduced in scale as in FIG. 3, and is a view corresponding to the cross-sectional view of the roof in FIG. 3 (a). (The roof frame plan is omitted). In the embodiment of the present invention, it is a figure explaining the method of reducing the shape dimension of a truss into a similar figure, (a) shows the original truss, and (b) shows the truss after reduction. FIG. 4 is an enlarged plan view of the P part of the roof frame 2c near the ridge (corresponding to the P part of FIG. 3A), and the positional relationship between the upper chord member 10 and the lower chord member 11 of the truss near the ridge. It is a figure explaining. FIGS. (A) and (b) are diagrams illustrating the effects of the member dimensions L on the bending moment M and the deflection δ, respectively, using the simple beam G as an example. It is a figure which shows the shape dimension when the simple beam G of FIG. 7 is a truss beam T. It is an example of a three-dimensional truss frame, and shows the frame structure. FIG. 9 is a three-dimensional stress analysis result under a fixed (vertical) load of the three-dimensional truss frame shown in FIG. 9, and shows an axial force diagram of the upper chord member. FIG. 9 is a three-dimensional stress analysis result under a fixed (vertical) load of the three-dimensional truss frame shown in FIG. 9, and shows an axial force diagram of the lower chord member. FIG. 9 is a three-dimensional stress analysis result under a fixed (vertical) load of the three-dimensional truss frame shown in FIG. 9, and shows an axial force diagram of the lattice material. This is a case where the three-dimensional truss frame of FIG. 9 is reduced to 2/3 in a similar manner, and the reduced three-dimensional truss frame is shown. FIG. 13 is a three-dimensional stress analysis result under a fixed (vertical) load of the three-dimensional truss frame shown in FIG. 13, and shows an axial force diagram of the upper chord member. FIG. 13 is a three-dimensional stress analysis result under a fixed (vertical) load of the three-dimensional truss frame shown in FIG. 13, and shows an axial force diagram of the lower chord member. FIG. 13 is a three-dimensional stress analysis result under a fixed (vertical) load of the three-dimensional truss frame shown in FIG. 13, and shows an axial force diagram of the lattice material. It is a frame structure showing a circular dome by a ball joint type three-dimensional truss, FIG. (A) is a perspective view of the prototype, and FIG. be. FIGS. (A) to (d) are diagrams illustrating a procedure for reducing the scale of a prototype of a ball joint type three-dimensional truss unit frame in a similar manner.

The first embodiment of the present invention will be described with reference to FIGS. 3 to 5. FIG. 3 shows a case where the roof frame 2 of the original building 1 shown in FIG. 1 is similarly reduced in scale to become the roof frame 2b of the building 1a. The roof shape is planographic, and the roof frame 2b is similar to the roof frame 2. Since the roof structure dimensional ratio A ₁ / A (= B ₁ / B) and the truss formation size ratio d / D match, the lengths of all the members of the roof structure 2b are shortened in accordance with the similarity ratio.

FIG. 4 is a cross-sectional frame diagram of the roof frame 2c after the scale is reduced in the same manner as in FIG. 3 when the roof shape is cylindrical (corresponding to the ha-ha cross-sectional arrow view in FIG. 3).

A method of shortening each member 10, 11, 12, and 13 after reduction will be described. As shown in FIG. 5, one end or a part of both ends of each of the original members 10, 11, 12, and 13 (diagonal line in FIG. 5A) so as to correspond to _{the ratio S 1} / S of the dimension between the upper chord nodes of the truss. Part) is excised and reassembled into a truss with similar figures and dimensions as shown in FIG. 5 (b).

A new bolt hole (not shown) for joining to each node joint J is formed at the cut side end of each member 10, 11, 12, and 13 after reduction. At this time, since the node joints J, J, ... Are reused as they are, for example, in the case of the upper chord material 10, the dimension e from the truss upper chord node to the node joint J edge does not change. It is necessary to take this into consideration when determining the dimensions of the upper chord member 10 after reduction.

Further, since the shape and dimensions of the reduced truss are similar to those of the original truss, the inclination angle θ of the lattice material 12 is the same.

As described above, the present invention is a method in which the roof frame 2 is reduced to a similar shape and reused. Therefore, by shortening the length of the members constituting the roof frame, the cross-sectional size of the members remains almost the same. It becomes possible to reuse the members of.

FIG. 6 is a roof frame of a truss structure according to a second embodiment of the present invention, in which the upper chord member and the lower chord member are not parallel (in a twisted positional relationship), and a partial truss plan and a cross-sectional axis are shown. It is a group drawing. Corresponds to the P part (near the ridge part) of FIGS. 3 (a) and 4 (a).

Such a multi-layer truss structure in which the upper chord material and the lower chord material are not parallel is known, for example, in Japanese Patent No. 6450707, and the upper chord material and the lower chord material are characterized by being twisted around the member axis, respectively. Is. There is also a single-layer truss structure composed of a member twisted around a member axis instead of a plurality of layers, which is known, for example, in Japanese Patent No. 3418660.

The second embodiment of the present invention is for a roof frame having a multi-layer truss structure or a single-layer truss structure having a member (string material) twisted around the member axis.

In a roof frame with a multi-layer (or single-layer) truss structure whose roof shape is cylindrical or has a two-way curvature, the upper chord material and the lower chord material are not parallel (in the case of a multi-layer truss) and they are as shown in FIG. The member may be constructed by twisting around the axis.

The chord material 10 or 11 is the same as in Example 1 up to the point where one end or both ends of each member of the truss is cut off and shortened so that the shape and dimensions of the original roof frame are reduced to a similar shape. Is twisted around its axis, so if the length is shortened, the twist angle per unit length will be the same, but the twist angle at the end of the member will be smaller than at the original material length. As shown in FIG. 5 (b), when joining with the node joining portion J that is reused as it is, the joining surfaces of the two do not match, and a skin gap is generated.

In order to avoid this, it is necessary to add additional twist around the axis of the chord member 10 or 11 so that the twist angle of the member end matches the shape and dimension of the roof frame after the scale reduction.

As described above, in the second embodiment, one end or both ends of the members 10, 11, 12, and 13 before the scale reduction is performed so that the length between the nodes of the members is adjusted to the ratio of similar figures. The part is cut and drilled, and the axis circumference is about the shortened chord material 10 or 11 so that the twist angle of the member end matches the shape of the roof frame after scale reduction. It is a method of reusing a structure, which is characterized by adding an additional twist to the roof.

17 and 18 are a third embodiment of the present invention, wherein a roof frame (circular dome is exemplified) composed of a ball joint type three-dimensional truss in which a steel pipe member is joined to a steel ball at a node with a single bolt. ) Is an explanatory diagram when the scale is reduced in a similar manner and reused.

As shown in FIGS. 18 (a) to 18 (d), the roof frame of this three-dimensional truss is mainly an aggregate of square pyramids composed of eight steel pipe members, and is reduced in scale. When reusing, as shown in the figure, each member is cut so that the length between the nodes matches the ratio of similar figures, and the end hardware having a screw hole at the end of the member on the cut side. Is newly welded, and each steel pipe may be reassembled using a new bolt screwed into the screw hole of the metal end and the screw hole of the original steel ball.

Therefore, the only materials that are discarded during reuse are the cut-out portion of the member and the bolt that has been removed, and the new members are only the newly welded end hardware and bolts. Since the member size and bolt size remain the same, the steel ball can be reused as it is.

The above has described the reuse method of reducing the scale of the roof frame in a similar manner, but these are not limited to the roof frame, but are similar to the frame of a general structure (for example, a factory or a warehouse). The same applies when the scale is reduced to and reused.

That is, the frame shape dimension after the scale reduction is similar to the original frame, and the internode length after the scale reduction of the members constituting the original frame is the length that matches the ratio of the similar shape. Therefore, according to the method in which one end or a part of both ends of the member before the scale reduction is cut off, the stress distribution state is almost unchanged and the absolute value of the stress becomes smaller according to the similarity ratio. It is a verification of stress and deformation of the three-dimensional truss frame in the example that the yield strength of each member is uniformly increased as compared with the case of the original structure and the maximum deformation is also significantly reduced according to the similarity ratio. It is also clear from. Therefore, the present invention is not limited to the roof frame.

The present invention is a reuse method capable of reusing almost all existing members, especially when a temporary large space structure constructed at an exposition or the like and used only for a short period of time is reduced in scale and reused. , Contributes greatly to the effective use of resources.

1: Original building 1a: Building after scale reduction 2: Original roof frame 2a, 2b, 2c: Roof frame after scale reduction 10: Upper chord material 11: Lower chord material 12: Lattice material 13: Bundle material A, A ₁ , B, B ₁ : Roof frame dimensions D, d: Truss construction dimensions G: Beam L: Member (beam) length (dimension between beam fulcrum)
M: Bending moment δ: Deflection S: Dimension between the upper chord nodes of the truss in the original roof frame S ₁ : Dimension between the upper chord nodes of the truss in the roof frame after scale reduction e: Dimension from the truss node to the edge of the node joint θ : Tilt angle of truss material

Claims (3)

When the frame of the structure is reused, the frame shape dimensions after the scale reduction are similar to the original frame, and the internode length after the scale reduction of each member constituting the original frame is similar to the original frame. A method for reusing a structure, characterized in that one end or a part of both ends of each member before scale reduction is cut so as to have a length that matches the ratio of shapes. When reusing a roof frame of a structure, the roof frame shape dimensions after scale reduction are similar to the original roof frame, and the length between nodes after scale reduction of each member constituting the original roof frame. However, a method for reusing a structure, characterized in that one end or a part of both ends of each member before the scale reduction is cut so as to have a length corresponding to the ratio of the similar shape. In the frame of a structure including a member twisted around the axis core, the length before the scale reduction is made so that the length between the nodes of the twisted member becomes a length corresponding to the ratio of the similar figures. One end or a part of both ends of the twisted member is excised, and the twisted member after the scale is reduced so that the twist angle matches the shape of the frame of the structure after the scale is reduced. The method for reusing a structure according to claim 1 or 2, wherein an additional twist is applied around the axis.

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