JP7849691B2 - Installation structure and construction method for additional reinforcing frame framework. - Google Patents

Description

This invention relates to a mounting structure for an additional reinforcing frame structure, and more specifically, to a mounting structure for an additional reinforcing frame structure and a method for constructing it, which integrates a seismic reinforcement frame surface to which braces can be attached with an existing frame surface on the common corridor side of an RC (reinforced concrete) or SRC (steel-reinforced concrete) apartment building.

In reinforced concrete (RC) or steel-reinforced concrete (SRC) apartment buildings, seismic walls are formed in the span direction, i.e., the shorter side direction, while a rigid frame structure is adopted in the girder direction to ensure openings such as entrances and windows. When applying seismic reinforcement to such existing buildings, a proposed structure for integrating the seismic reinforcement structure with the existing structural surface on the common corridor side extending in the girder direction is described, for example, in Patent Document 1.

As shown in Figure 10, the seismic reinforcement structure 44 is installed separately from the existing structure 33 via a reinforcing slab 55R (see the lower half of Figure 10) integrated with the underside of the common corridor BB, and a right-angle beam 66 (see the upper half of Figure 10) installed at approximately the same level at the unit boundary on that floor. Therefore, it is installed on the outside of the common corridor BB. As a result, the seismic reinforcement structure 44 is not subject to the constraints of providing openings such as entrances and windows. Therefore, as shown in Figure 11, although the bracing members 64 and gusset plates 65 act as a screen, making the common corridor BB space dim and reducing visibility while walking, there is the advantage of increased freedom in attaching braces to the seismic reinforcement structure 44 (for example, freedom in selecting brace types).

If the existing structural surface 33 (see Figure 10) is made of reinforced concrete (RC) or steel-reinforced concrete (SRC), then the seismic reinforcement structural surface 44 will also be made of RC or SRC (see, for example, Patent Document 2), and consequently, the orthogonal beam 66 (see the upper half of Figure 10) will also be made of RC or SRC.

If the orthogonal beam 66 is constructed of reinforced concrete (RC) or steel-reinforced concrete (SRC), the base end 66b and the tip end 66e require high anchorage for the reinforcing bars 67 embedded in the orthogonal beam 66 (see the upper half of Figure 10) when integrating with the existing structural plane 33 or the seismic reinforcement structural plane 44. Of course, high anchorage is also required for the shear reinforcement bars 67S embedded in the reinforcing slab 55R (see the lower half of Figure 10) formed beneath the common corridor BB. Incidentally, the upper 69 in Figure 10 is a post-installed anchor for integrating the floor slab 55 and the orthogonal beam 66, and the lower 69 in Figure 10 is a post-installed anchor for integrating the floor slab 55 and the reinforcing slab 55R (for comparison purposes, Figure 10 depicts the vertical planes of the orthogonal beam 66 and the reinforcing slab 55R as being on the same vertical plane).

To enhance the anchoring effect, both ends of the reinforcing (main) bars 67 of the orthogonal beam 66 must be significantly embedded in or bent into the existing structural plane 33 or the seismic reinforcement structural plane 44, as shown in Figure 12, which is an enlarged view of only the orthogonal beam 66. This necessitates a modification that increases the volume of the connection point with the existing structural plane 33. Furthermore, the connection point with the seismic reinforcement structural plane 44 will also involve a significant increase in volume, making the temporary removal of the handrail fence 68 (see also Figure 10) or the fence parapet of the common corridor BB unavoidable. This will inevitably result in either prohibiting passage or, even if passage is permitted, causing a sense of insecurity underfoot. Ultimately, a considerable number of residents will be forced to vacate their homes during the construction.

Japanese Patent Publication No. 2012-1922 Japanese Patent Publication No. 2015-196942

Despite the disadvantages and inconveniences described above, the introduction of orthogonal beams is essential for seismic reinforcement. Orthogonal beams are primarily installed at the partition points between units in the common corridor BB, but this also involves construction work to integrate them with the floor slab 55 that forms the common corridor BB. To withstand the bending forces acting on the orthogonal beams, the second moment of area and section modulus must be large, and a sufficiently large cross-sectional area is particularly required in the direction perpendicular to the plane of the paper.

By the way, when installing an additional reinforced frame structure made of reinforced concrete or steel-reinforced concrete, if you compare the reinforcing slab 55R (see the lower half of the slab in Figure 10), which is installed between the partitions to reinforce the floor slab 55 and share the horizontal force, with the orthogonal beam 66 (see the upper part of Figure 10) installed at the partitions, the latter, which is deliberately drawn superimposed, is bulkier, and the difference in its vertical dimensions is immediately obvious (the upper 31 in Figure 10 indicates the lower edge of the orthogonal beam 66, while the lower dashed line 31 in Figure 10 indicates the hypothetical lower edge of the orthogonal beam 66. On the other hand, the upper dashed line 32 in Figure 10 represents the hypothetical lower edge of the reinforcing slab 55R). When moving through the corridor after completion, even if the reinforcing slab 55R installed between the partitions is not a concern, one needs to pay attention to what is overhead due to the orthogonal beam 66 installed at each partition, making the use of the common corridor BB inconvenient. This leads to a significant decrease in livability.

This invention has been made in view of the above circumstances, and its purpose is to provide a structural frame structure and construction method for an additional reinforcing frame that allows for reinforcement work without the need to remove corridor fences or parapets, enables continued occupancy during construction, provides a compact orthogonal beam that does not obstruct overhead after completion, ensures safe passage, and enables miniaturization of the orthogonal beam and seismic reinforcement structure, thereby reducing the amount of construction work.

The features of the present invention are, as shown in Figure 1, in an additional reinforcing frame structure for an RC or SRC apartment building where the short side direction is a seismic wall and the girder direction is a rigid frame structure, and an additional reinforcing frame structure for which a seismic reinforcement surface 44 to which braces can be attached is integrated with an existing structural surface 33 on the common corridor BB side extending in the girder direction of the existing building 1AA,
From the intersection of the existing columns 33C and existing beams 33B of the existing structural plane 33, a steel orthogonal beam 56, which is an asymmetrical deformed welded H-shaped steel beam 56H extending perpendicular to the girder direction of the existing building 1AA, is positioned with its flange portion 56f along the inclined lower surface 5u of the floor slab 55 forming the common corridor BB.
As shown in Figure 2, a headed stud 7 is welded to the web portion 56w of the deformed welded H-beam 56H, projecting horizontally toward the space beneath the floor slab 55.
The base end 56b of the deformed welded H-beam 56H is integrated with the existing column 33C of the existing structural plane 33, while the tip end 56e is integrated with the reinforcing column 44C of the seismic reinforcement structural plane 44.
The seismic reinforcement structure 44 is a steel frame structure,
The space 8 enclosed by the existing column 33C, existing beam 33B, steel reinforcing column 44C, steel reinforcing beam 44B, deformed welded H-shaped steel 56H, another adjacent deformed welded H-shaped steel 56H, and the lower inclined surface 55u of the floor slab 55 is made into an additional slab equipped with shear reinforcement bars 9R (see Figure 3).

As shown in Figure 2, the base end 56b of the deformed welded H-beam 56H is integrated with the existing column 33C by adhesive anchor bolts 11, while the tip end 56e is integrated with the reinforcing column 44C by friction bonding through a splice plate 13 and high-strength bolts 6 fastened to a vertical bracket 12 attached to the reinforcing column 44C.

As shown in Figure 9, when PC panels 18 are attached to the outer surfaces of existing columns 33C and existing beams 33B in an apartment building, the additional slab 84, which is at approximately the same level as the orthogonal beam 56 at the unit boundary, is integrated with the existing structural surface 33 via an indirect joint 20 that includes the head 19h of a thick-walled steel pipe shackle 19, which has a leg portion 19f that penetrates the PC panel 18 and is embedded and fixed in the existing beam 33B.

As shown in Figures 5 and 6, the brace that can be attached to the additional reinforcing frame 44 is a cross brace mechanism 25 (see Figure 6) made of two half-width flat steel plates fitted into the space 34 (see Figure 5) surrounded by the reinforcing column 44C and the reinforcing beam 44B.

In the invention of the method for constructing the additional reinforcement frame frame structure described above, a bottom plate formwork 26 (see Figure 2) is placed on the surface corresponding to the bottom of the surrounding space 8, and a high-flow, non-shrinkage, high-strength mortar 28 or high-flow, non-shrinkage, high-strength concrete is injected into the surrounding space 8 through injection holes 27 that penetrate the floor slab 55 vertically, until it flows out through air vent holes 29 that penetrate the floor slab 55, thereby forming the additional slab 84.

According to this invention, since the seismic reinforcement structure is made of steel, the orthogonal beams can also be made of steel for ease of connection. Because the orthogonal beams are asymmetrical, deformed welded H-beams, the flange portion can easily be aligned with the inclined surface of the floor slab forming the common corridor. Furthermore, because they are made of steel, the asymmetry allows for greater freedom in shape selection, eliminating the need to increase the second moment of area and section modulus to the extent of RC or SRC orthogonal beams. Therefore, the need to be careful not to bump one's head while walking in the corridor is minimized, and a compact, unobtrusive orthogonal beam can be realized.

Avoiding the use of reinforced concrete (RC) or steel-reinforced concrete (SRC) for orthogonal beams promotes a lower building volume, eliminating concerns about residents' safety while walking, avoiding the need to remove fences that would force temporary relocation, and allowing residents to continue living in the building during construction.

Since the base of the orthogonal beam and the existing structural plane are integrated using adhesive anchor bolts, the construction is simplified compared to cases where reinforcing bars are used with high anchorage in mind. On the other hand, the tip of the orthogonal beam is integrated with the reinforcing column by fastening high-strength bolts via splice plates to vertical brackets attached to the reinforcing column, thus enabling a highly stable friction joint configuration.

Even in the case of apartment buildings where precast concrete panels (PC panels) are attached to the outer surfaces of existing columns and beams, an indirect joint can be formed, including the head of a thick-walled steel pipe shackle with legs that penetrate the PC panels and are embedded and fixed into the existing beams. By integrating through this indirect joint, the additional slab can have a highly stable support structure on the existing structural surface.

By using a brace mechanism consisting of two half-width flat steel plates fitted into the space enclosed by the reinforcing columns and beams, which can be attached to the additional reinforcing frame, it is possible to achieve a significantly improved view from the common corridor while maintaining mechanically equivalent functionality to a double-width brace that obstructs the view.

Even in the above-described additional reinforcement frame structure, an additional slab can be formed by placing a formwork bottom plate on the surface corresponding to the bottom of the surrounding space and injecting high-flow, non-shrinkage, high-strength mortar or high-flow, non-shrinkage, high-strength concrete into the surrounding space through injection holes that penetrate the floor slab vertically, until it flows out through air vent holes that penetrate the floor slab. After the additional slab has cured and solidified, only the formwork bottom plate needs to be removed, as the surrounding steel members act as formwork, significantly reducing the effort required for formwork removal.

An overall view of one embodiment of the mounting structure for the additional reinforcing frame structure according to the present invention. Enlarged view of a right-angle beam made of deformed welded H-shaped steel with asymmetrical top and bottom. An overhead view of the orthogonal beams and the added slab. Diagram illustrating the stresses on orthogonal beams caused by horizontal forces acting on the floor slab and extension slab. Side view of a cross brace mechanism made of two half-width flat steel plates joined together. Front view of a cross brace mechanism made of two half-width flat steel plates joined together. A conceptual diagram showing how the view is improved by applying an additional reinforcing frame structure with a cross bracing mechanism made of two half-width flat steel plates joined together. An overhead view of a reinforced slab in which thick-walled steel pipe shears have been introduced by attaching PC panels to the seismic reinforcement structure. Enlarged structural diagram of an extension slab to which thick-walled steel pipe shears are applied. A diagram showing the layout of a corridor when the orthogonal beams are made of reinforced concrete (RC) or steel-reinforced concrete (SRC). A conceptual diagram illustrating the poor visibility when a cross-bracing mechanism using a single, full-width flat steel plate is applied to a seismic reinforcement structure. Enlarged view of the internal structure of a right-angle beam when constructed of reinforced concrete (RC) or steel-reinforced concrete (SRC).

The following describes in detail the mounting structure for the additional reinforcing frame frame and its construction method according to the present invention, based on the drawings illustrating embodiments. This invention relates to a mounting structure for an additional reinforcing frame frame in a reinforced concrete (RC) or steel-reinforced concrete (SRC) apartment building where the short-side direction is a seismic wall and the girder direction is a rigid frame structure. As shown in Figure 1, this structure integrates a seismic reinforcing frame surface, to which braces (not shown) can be attached, with the existing frame surface on the side of the common corridor extending in the girder direction of the existing building.

The additional reinforcing frame structure is positioned on the outside of the common corridor, allowing for the installation of seismic braces without affecting openings such as entrances and windows. This minimizes the size of the necessary orthogonal beams, ensuring safe passage through the corridor during construction. Furthermore, it eliminates the need for temporary removal and reinstallation of corridor handrails, enabling continued occupancy during construction. The seismic reinforcement structure 44 can accommodate various brace configurations, including X-shaped, V-shaped, and K-shaped braces, and, in particular, an innovative narrow X-shaped brace (which will be discussed in more detail later) that does not obstruct the view.

The narrow X-shaped brace in question is the cross brace mechanism 25 made of two laminated flat steel plates (see Figures 5 and 6) proposed by the inventor in Japanese Patent Application No. 2021-69387, and will be explained later with examples of its adoption.

As shown in Figure 1, a steel orthogonal beam 56, which is an asymmetrical deformed welded H-shaped steel beam 56H extending perpendicularly to the existing building 1AA, is installed from the intersection of the existing column 33C and existing beam 33B of the existing structural plane 33, with its upper flange portion 56f aligned with the lower inclined surface 55u of the floor slab 55 forming the common corridor BB shown in Figure 2. The intersection of the existing column 33C and existing beam 33B of the existing structural plane 33 refers to the height level of the existing beam 33B at the existing column 33C that forms the partition between units on the common corridor BB side, and the orthogonal beam means that it extends horizontally perpendicularly to the girder direction of the existing building 1AA.

This welded H-beam 56H is not a roll-formed H-beam, which is created by passing a billet through multiple rolling rolls on a rolling line to gradually deform it into an H-shape. Instead, it is a steel frame obtained by cutting and deforming flat steel into the desired shape in a metal fabrication plant, and then welding it into an H-shape. Therefore, it is a steel material whose shape and dimensions can be freely selected, without being constrained by JIS standards such as roll-formed steel. Consequently, it can be asymmetrical, meaning the cross-sectional shape and dimensions are not necessarily standardized, and the flange can be angled or bent instead of flat. Of course, the web can also be easily shaped to match the non-flat flange.

A headed stud 7 (see also Figure 3) is welded to the web portion 56w of this deformed welded H-beam 56H, projecting horizontally toward the space beneath the floor slab 55, ensuring a secure connection with the additional slab 84 described later. Note that in deformed welded H-beams (not shown) located at the outermost ends of a building where the floor slab 55 is not present on both sides (top and bottom in Figure 3), the headed stud is welded to only one side of the web portion.

Returning to Figure 2, the base end 56b of the deformed welded H-beam 56H is integrated with the existing column 33C of the existing structural plane 33, while the tip 56e is integrated with the reinforcing column 44C of the seismic reinforcement structural plane 44. Incidentally, the existing column 33C of the existing structural plane 33 extends vertically, and the existing beam 33B is located between the existing column 33C, transmitting the force supporting the floor on each floor to the existing column 33C. The reinforcing column 44C of the seismic reinforcement structural plane 44 also extends vertically across floors via flange joints (not shown), and the reinforcing beam 44B is located between the reinforcing column 44C, connected via flange joints 30 (see Figure 3), etc., and transmitting the force supporting the load on each floor to the reinforcing column 44C. In other words, all vertical loads acting on the seismic reinforcement structure 44 are indirectly transmitted via the reinforcing columns 44C to a newly constructed foundation (not shown) directly beneath them, or to the foundation directly beneath the existing columns 33C, through members not shown.

Incidentally, the base end 56b of the deformed welded H-beam 56H is integrated with the existing column 33C by adhesive anchor bolts 11 (see Figure 2), while the tip 56e is integrated with the reinforcing column 44C by a friction joint using high-strength bolts 6 fastened via a splice plate 13 to a vertical bracket 12 attached to the reinforcing column 44C. Note that 12A is a backup stiffener.

The existing beam 33B is integrated with the existing column 33C using reinforced concrete (RC) or steel-reinforced concrete (SRC) construction, while the reinforcing beam 44B is welded to the reinforcing column 44C. As can be seen from this, the seismic reinforcement structure 44 is pre-assembled in sub-assembly at the construction site or elsewhere, and then lifted up using a crane or similar method.

Once the above steel frame assembly is complete, an additional slab (horizontal diaphragm) 84 (see Figure 3) integrated with the orthogonal beam 56 is formed beneath the floor slab to increase the floor slab's resistance to horizontal forces while also achieving high rigidity for the orthogonal beam 56. Then, a bottom plate formwork 26 (see Figure 2) is placed on the surface that corresponds to the bottom of the space 8 surrounded by the existing columns 33C, existing beams 33B, reinforcing columns 44C, reinforcing beams 44B, deformed welded H-shaped steel 56H, and other adjacent deformed welded H-shaped steel 56H, and is supported by scaffolding, etc. Shear reinforcement bars 9R and spiral hoops 85 (see Figure 3) are placed in space 8. Once the space for the additional slab 84 is formed, high-flow, non-shrinkage, high-strength mortar (for example, 40 N/ ^mm² or more) 28 or high-flow, non-shrinkage, high-strength concrete (see Japanese Patent Application Publication No. 2003-89563) is injected into the surrounding space 8 from injection holes 27 (see Figure 2) that penetrate the floor slab 55 vertically, until it flows out through air vent holes 29 that penetrate the floor slab 55, thereby forming the additional slab 84. It should be noted that the existing columns 33C, existing beams 33B, reinforcing columns 44C, reinforcing beams 44B, deformed welded H-shaped steel 56H, and other adjacent deformed welded H-shaped steel 56H serve as formwork for pouring the high-flow, non-shrinkage concrete, and it is understood that there is no need to install or remove formwork other than the bottom plate 26.

With this configuration, since the seismic reinforcement structure 44 is made of steel, the orthogonal beam 56 can also be made of steel as described above for ease of connection. Because the orthogonal beam is a deformed welded H-beam 56H with an asymmetrical top and bottom, the upper flange portion 56f can easily be aligned with the lower inclined surface 55u of the floor slab 55 forming the common corridor BB. Because it is made of steel, there is a high degree of freedom in shape selection due to the asymmetrical design, and it is not necessary to make the second moment of area and section modulus as large as those of orthogonal beams made of reinforced concrete (RC) or steel-reinforced concrete (SRC). Therefore, the need to take precautions against bumping one's head when passing through the corridor is minimized, and a compact orthogonal beam that does not obstruct the view from the front is realized.

Since the orthogonal beams are made of steel, integration of the base end 56b and tip end 56e of the orthogonal beams with the existing structural surface 33 or the steel-framed seismic reinforcement structural surface 44 becomes easy, promoting weight reduction and shortening of construction time for the seismic reinforcement structural surface 44.

A headed stud 7 is welded to the web portion 56w of the deformed welded H-beam 56H, projecting horizontally toward the space beneath the floor slab 55. This ensures a rigid connection between the deformed welded H-beam 56H and the additional slab 84, and contributes to the compact design of the deformed welded H-beam 56H.

Avoiding the use of reinforced concrete (RC) or steel-reinforced concrete (SRC) for the orthogonal beam 56 promotes a lower volume, eliminating concerns about residents' mobility and the need to remove fences that would force temporary relocation, thus allowing residents to continue living in the building during construction. Since the base end 56b of the orthogonal beam and the existing structural plane 33 are integrated by adhesive anchor bolts 11, the construction is simplified compared to cases where reinforcing bars are used with high anchorage in mind. On the other hand, the tip end 56e of the orthogonal beam is integrated with the reinforcing column 44C by high-strength bolt fastening via a splice plate 13 to a vertical bracket 12 attached to the reinforcing column 44C, thus enabling a highly stable friction joint configuration.

Even in the above-described additional reinforcement frame structure, an additional slab 84 can be formed by placing a formwork bottom plate 26 on the surface corresponding to the bottom of the surrounding space 8 and injecting high-flow, non-shrinking, high-strength mortar 28 into the surrounding space 8 through injection holes 27 that penetrate the floor slab 55 vertically. After the additional slab 84 has cured and solidified, only the formwork bottom plate 26 needs to be removed, as the surrounding steel members act as formwork, greatly reducing the effort required to remove the formwork.

Incidentally, as shown in Figure 4, when a horizontal force 11A acts on the floor slab 55 due to an earthquake or the like, a moment 11M is generated. To counteract this moment 11M, a force 11a is generated in the orthogonal beam 56, creating a moment. Since the adjacent slab to the right also generates a similar force 11b in the opposite direction on the orthogonal beam 56, these forces cancel each other out, and ultimately, no large force acts on the orthogonal beam. This behavior also applies to orthogonal beams in reinforced concrete structures, but only when there are slabs on both sides. If there is only a slab on one side, it is unavoidable that a large force acts on the orthogonal beam in the longitudinal direction. The orthogonal beam needs to withstand this force 11a, and countermeasures are necessary for orthogonal beams in reinforced concrete structures. On the other hand, it is quite easy to give the deformed welded H-beam 56H sufficient resistance. To put it simply, it can withstand the force even if it is made to the same specifications as an H-beam orthogonal beam with slabs on both sides, and the commonality of materials used can also be realized.

Incidentally, the brace that can be attached to the additional reinforcing frame 44 is a cross brace mechanism 25 (see Japanese Patent Application No. 2021-69387) made of two half-width flat steel plates fitted into the space 34 perpendicular to the plane of the paper, surrounded by the reinforcing column 44C and reinforcing beam 44B shown in Figure 5. An example is a type attached to the weak axis of the reinforcing column 44C, which will be briefly described below.

Referring to Figure 6, four flat steel plates 1a, 1b, 1c, and 1d, all of the same length and thickness, are arranged in a vertical plane close to each other. A wide end plate 2, which is the same thickness as the flat steel plate 1, is joined to both ends of the flat steel plate 1 by butt welding 3, with a narrow end equal to the width of the flat steel plate. The first flat steel plate 1a intersects with the second flat steel plate 1b without making contact in an X shape, and the third flat steel plate 1c, positioned in the same orientation as the first flat steel plate 1a, intersects with the fourth flat steel plate 1d, positioned in the same orientation as the second flat steel plate 1b, without making contact in an X shape. The two gusset plates 4A and 4B have a thickness less than or equal to that of flat steel and are welded to the diagonal corners of the structural plane. The first flat steel 1a and the third flat steel 1c sandwich the first gusset plate 4A and the second gusset plate 4B and are rigidly fixed and integrated between the end plates _2a1 , _2c1 , _2a2 , _2c2 with high-strength bolts 6, thus forming the first brace body 5A made of double flat steel. The other gusset plates 4C and 4D also have a thickness less than or equal to that of flat steel and are welded to the other diagonal corners of the structural plane. The second flat steel 1b and the fourth flat steel 1d sandwich the third gusset plate 4C and the fourth gusset plate 4D and are rigidly fixed and integrated between the end plates _2b1 , _2d1 , _2b2 , _2d2 with high-strength bolts 6, thus forming the second brace body 5B made of double flat steel. Furthermore, the first brace member 5A and the second brace member 5B form a cross brace body 10 made of two flat steel plates joined together, without a gusset plate being provided at the intersection of the two brace members.

If the brace that can be attached to the additional reinforcing frame 44 is configured as a cross-bracing mechanism 25 of two half-width flat steel plates fitted into the space 34 surrounded by the reinforcing column 44C and reinforcing beam 44B, it is mechanically equivalent to a double-width brace that obstructs the view (see Figure 11), while significantly improving the view from the common corridor and eliminating the feeling of confinement (see Figure 7).

Incidentally, in apartment buildings, as shown in Figure 8, when PC panels (precast concrete panels) 18 are attached to the outer surfaces of existing columns 33C and existing beams 33B, the additional slab 84 shown in Figure 9, which is at approximately the same level as the orthogonal beam 56 at the unit boundary, is integrated with the existing structure, i.e., the existing structural plane 33, via an indirect joint 20 that includes the head 19h of a thick-walled steel pipe shackle 19, which has a leg portion 19f fixed to the existing beam 33B by penetrating the PC panel 18 with an oversized hole 13a designed to prevent load transmission. Note that 86 is a headed stud, and 36 is mortar filled between the reinforcing steel frame 35 and the existing structure 33.

As a result, it becomes easy to install the reinforced steel frame 35 perpendicular to the reinforced steel frame in the RC and SRC structures. This allows the thick-walled steel pipe key to achieve significantly greater bending and shear rigidity than conventional steel bars used as anchors, in addition to a larger concrete bearing area. Large shear forces acting on the indirect joint from the structure can be reliably transmitted to the reinforced steel frame. Therefore, the number of materials used for reinforcement is drastically reduced, and the resulting savings in construction volume and time are remarkable. Of course, construction can also be expedited.

1AA: Existing building, BB: Common corridor, 1: Flat steel, 1a: First flat steel, 1b: Second flat steel, 1c: Third flat steel, 1d: Fourth flat steel, 2, 2a ₁ , 2a _{2, 2b 1 ,} 2b ₂ , 2C ₁ , 2C ₂ , 2d ₁ , 2d ₂ : End plate, 3: Butt weld, 4: Gusset plate, 4A: First gusset plate, 4B: Second gusset plate, 4C: Third gusset plate, 4D: Fourth gusset plate, 5: Brace body, 5A: First brace body, 5B: Second brace body, 6: High-strength bolt, 7: Headed stud, 8: Enclosed space, 9R: Shear reinforcement, 10: Cross brace body, 11: Adhesive anchor bolt, 12: Bracket, 13: Splice plate, 13a: Hole,
18: PC panel (precast concrete panel), 19: Thick-walled steel pipe shackle, 19f: Leg section, 19h: Head section, 25: Cross brace mechanism of two half-width flat steel plates joined together, 18: PC panel, 19: Thick-walled steel pipe, 19: Thick-walled steel pipe shackle, 19f: Leg section, 19h: Head section, 20: Indirect joint section, 21: Bracket, 22: Splice plate, 23: High-strength bolt, 25: Cross brace mechanism of two half-width flat steel plates joined together, 26: Bottom plate formwork, 27: Injection hole, 28: High-flow, non-shrinkage, high-strength mortar, etc., 29 : Air vent hole, 33: Existing structural surface, 33C: Existing column, 33B: Existing beam, 34: Surrounding space, 35: Reinforcement steel frame, 36: Mortar, 44: Seismic reinforcement structural surface, 44B: Reinforcement beam, 44C: Reinforcement column, 55: Floor slab, 55R: Reinforcement slab, 55u: Lower inclined surface, 56: Steel right-angle beam, 56H: Asymmetrical deformed welded H-beam, 56f: Flange section, 56w: Web section, 56b: Base end, 56e: Protruding end, 84: Additional slab (horizontal diaphragm), 85: Spiral hoop, 86: Headed stud,

Claims (5)

In a reinforced concrete (RC) or steel-reinforced concrete (SRC) apartment building, where the short side is a shear wall and the girder direction is a rigid frame structure, an additional reinforcing frame structure is attached to an existing structural surface on the common corridor side extending in the girder direction of the existing building, to which a brace can be attached.
From the intersection of the existing columns and beams of the existing structural plane, a steel orthogonal beam, which is an asymmetrical deformed welded steel section extending perpendicular to the existing building with its flange portion aligned along the inclined lower surface of the floor slab forming the common corridor, is positioned.
A headed stud is welded to the web portion of the deformed welded steel section, projecting horizontally toward the space beneath the floor slab.
The base end of the deformed welded steel section is integrated with the existing column of the existing structural plane, while the tip end is integrated with the reinforcing column of the seismic reinforcement structural plane.
The seismic reinforcement structure is made of steel.
An additional reinforced frame structure is characterized in that the space surrounded by the existing columns, existing beams, reinforcing columns, reinforcing beams, deformed welded steel sections, other adjacent deformed welded steel sections, and the inclined lower surface of the floor slab is an additional slab equipped with shear reinforcement bars. The base end of the deformed welded steel section is integrated with the existing column by adhesive anchor bolts, while the tip end is integrated with the reinforcing column by friction bonding via a splice plate and high-strength bolts to a vertical bracket attached to the reinforcing column, as described in claim 1. In the case where PC panels are attached to the outer surfaces of existing columns and beams in an apartment building, the additional slab, which is at approximately the same level as the orthogonal beam at the partition between units, is integrated with the existing structural surface via an indirect joint that includes the head of a thick-walled steel pipe shackle having legs that penetrate the PC panel and are embedded and fixed in the existing beam, as described in claim 1.
The brace that can be attached to the aforementioned additional reinforcing frame is a cross brace mechanism of two half-width flat steel plates fitted into the space surrounded by the reinforcing column and reinforcing beam, as described in claim 1, for the additional reinforcing frame frame mounting structure. A method for constructing a structural surface structure to which an additional reinforcing frame structure is attached, characterized in that a bottom plate formwork is placed on the surface that is at the bottom of the surrounding space, and an additional slab is formed by injecting high-flow, non-shrinkage, high-strength mortar or high-flow, non-shrinkage, high-strength concrete into the surrounding space through injection holes that penetrate the floor slab vertically until it flows out through air vent holes that penetrate the floor slab.