JP2017057568A - External reinforcing frame for existing building, unit body structure thereof, and construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of an external reinforcing frame of an existing building, shorten the construction period, and reduce the construction cost. SOLUTION: This is a steel frame unit structure 10 for forming an external steel frame reinforcing frame by assembling along an outer wall of an existing building having a veranda slab. The unit structure 10 is formed by joining the column members 10a in the vertical direction and transmitting the vertical force to the foundation, and a beam extending from the column member 10a to the building side through the lower side of the veranda slab 40 and joining with the skeleton of the building A. It has a member 10c. [Selection diagram] FIG. 6A

Description

The present invention relates to an external reinforcement frame for retrofitting seismic reinforcement of an existing building of a reinforced concrete frame having a veranda slab projecting from a building, a unit structure and a construction method thereof, and in particular, a heavy joint between a building frame and a reinforcement frame. The present invention relates to a reinforcing frame that is joined with a light steel beam member instead of a slab.

Reinforced frames that reinforce existing buildings of reinforced concrete frames from the outside for seismic reinforcement are divided into two types depending on the mounting position of the reinforcing frame to the building frame: a column internal / beam external type and a complete external type. Separately (see Non-Patent Document 1). Moreover, as a reinforcement frame, as described in Patent Documents 1 to 3, a structure in which a reinforcement brace or a reinforcement rib is provided inside a rectangular steel frame is known.

No. 7-26520 JP-A-9-67939 Japanese Patent Laid-Open No. 9-317198

"External seismic retrofitting manual for existing reinforced concrete buildings-Reinforcement with framed steel braces-" Japan Architecture Disaster Prevention Association, September 2002, pp. 44-46

The column-attached / beam-external type has the advantage that the reinforcing frame does not protrude significantly outside the building, but may not be able to be constructed depending on the size and shape of the columns and beams. On the other hand, the completely external type has the advantage that it can be constructed freely regardless of the size and shape of the pillars and beams, but on the other hand, it is difficult to join the reinforcing frame to the building frame, and the construction period is generally long. Construction costs also tend to be high.

Conventionally, it is general that the completely external reinforcing frame 100 shown in FIG. 10 is joined to the frame of the building A by the joining slab 120 (see, for example, Japanese Patent Application Laid-Open No. 2005-155139 for “joining slab”). . This joint slab 120 is configured by constructing a formwork on the lower side of a cantilever slab 110 of a veranda protruding from a building A and then placing concrete.

In order to place the joining slab 120 later, a mold is constructed below the veranda slab 110, and an injection hose is inserted into a through-hole drilled in the veranda slab 110 above the mold to solidify the mold. Fill with mortar (non-shrink mortar) as material. However, slab joining has the following problems.
(1) Since the weight of the joining slab is large, the weight of the building frame is greatly increased.
(2) Since the entire reinforcement frame is heavy due to the weight of the joint slab, it is necessary to add a pile foundation that can withstand this heavy weight separately from the existing pile foundation. When it is impossible to add pile foundations, it is necessary to give up the seismic reinforcement itself.
(3) The construction period becomes longer due to the extension of pile foundations and the construction of joint slabs, making home construction difficult and construction costs increasing.

Accordingly, an object of the present invention is to reduce the weight of an external reinforcement frame, eliminate the need for additional pile foundations, shorten the construction period, reduce the construction cost, and facilitate home construction.

In order to solve the above-described problems, a steel unit structure according to the present invention is a steel frame for constituting an external steel frame reinforcing frame by assembling along an outer wall of an existing building of a reinforced concrete frame having a veranda slab projecting from a building. The unit structure is formed by joining a vertical member on the outside of the veranda slab and assembling and transmitting a vertical force as a basis, and passing from the pillar member to the lower side of the veranda slab. It has a beam member that protrudes toward the existing building and has a tip part that can be joined to the frame of the existing building.

Further, the steel frame reinforcing frame according to the present invention includes the steel frame unit structure intermittently arranged in accordance with the span between the columns of the existing building, and is assembled upward along the outer wall of the building outside the veranda slab of the building to sandwich the span between the columns. The adjacent unit structures are connected in the horizontal direction by inter-unit connecting members, and the beam member protruding from the column member of the unit structure is joined to the building frame through the lower side of the veranda slab.

Further, the method for constructing a steel frame reinforcing frame according to the present invention includes a step of intermittently arranging the steel frame unit structure in accordance with a span between columns of an existing building, and assembling upward along the outer wall of the building outside the veranda slab of the building, A step of horizontally connecting adjacent unit structures with an inter-unit connecting member across an inter-span; a step of joining a beam member projecting from a column member of the unit structure to a building frame through the underside of the veranda slab; and It has the process of joining the said connection member between units to the housing of a building.

The steel structure unit structure of the present invention is made of steel frame, and the tip of the beam member projecting from the column member of the unit structure toward the building side is joined to the building frame, so when using a joining slab as in the past The weight of the entire reinforced frame can be reduced by this weight reduction, reducing the construction period and reducing the construction cost by reducing or eliminating the need for additional pile foundations that support the reinforced frame, It is possible to facilitate home construction.

It is a perspective view of a unit structure concerning an embodiment of the present invention. It is a 3rd page figure of the unit structure concerning an embodiment of the present invention, (a) is an elevation view, (b) is a right side view, (c) is a top view. It is an elevational view showing the first stage of the assembly process of the unit structure. It is an elevational view showing the second stage of the assembly process of the unit structure. It is an elevational view showing a third stage of the assembly process of the unit structure. It is an elevational view showing the fourth stage of the assembly process of the unit structure. It is an elevational view showing the fifth stage of the assembly process of the unit structure. It is a side view of the state which assembled the unit structure to the last stage. It is an elevation view which shows the state which assembles a unit structure using a crane. It is a top view which shows the state which hangs a unit structure to the building side using a crane. It is a side view which shows the state which hangs a unit structure to the building side using a crane. FIG. 6B is an enlarged view around the beam member of FIG. 6A. It is a top view which shows the junction part of a unit structure and a building frame. (A) is a VIII-VIII arrow directional cross-sectional view of FIG. 7, (b) is a top view of (a). It is the IX-IX arrow directional cross-sectional view of FIG. It is a side view which shows the reinforcement frame by the conventional joining slab.

Hereinafter, the steel structure unit structure which concerns on embodiment of this invention, the steel structure reinforcement frame using the said unit structure, and its construction method are demonstrated.

(Steel structure unit structure)
FIG. 1 and FIG. 2 schematically show a steel structure unit structure 10 according to an embodiment of the present invention, and this unit structure 10 is constructed integrally by welding a plurality of H-shaped steels at a factory. . The unit structure 10 includes a pair of left and right column members 10a, a first connection member 10b that connects the height direction intermediate portions of the pair of column members 10a in the horizontal direction, and a height direction intermediate portion of the pair of column members 10a. Each has a pair of beam members 10c projecting to one side (building side) in the horizontal direction, and a second connecting member 10d that connects the tip portions of the pair of beam members 10c to each other in the horizontal direction.

The unit structure 10 has an H shape as shown in FIG. 2A in a front view, and a T shape as shown in FIG. 2B in a side view. The unit structure 10 has a horizontally long rectangular frame shape as shown in FIG.

Both end portions of the first connecting member 10b and the second connecting member 10d protrude in the left-right direction with a predetermined length as shown in FIG. 2C, and the end portions of the inter-unit connecting members 31, 32 described later are bolted to the protruding portions. It is configured to be connectable. A plurality of studs 51 protruding in the horizontal direction are provided on the outer side surfaces of the H-shaped steel webs of the second connecting member 10d and the second inter-unit connecting member 32 as shown in FIGS. Fixed at intervals.

A suspension fitting 20 protruding in the projecting direction (building side) of the beam member 10c is welded to the upper ends of the pair of column members 10a. As shown in FIGS. 3A to 3E, the hanging bracket 20 is for hanging a wire rope R3 suspended from the suspension beam B. The unit structure 10 is suspended from the suspension beam B using the suspension bracket 20, In this suspended state, the crane C is operated to move the unit structure 10 to a predetermined height on the target floor.

A vertical first gusset plate 11 is welded to the upper surface of the intermediate portion of the first connecting member 10b. A vertical second gusset plate 12 is welded to a corner where the column member 10a and the first connecting member 10b intersect. A horizontal third gusset plate 13 is welded to a corner where the column member 10a and the beam member 10c intersect. A horizontal fourth gusset plate 14 is welded to the inner side surface of the intermediate portion of the second connecting member 10d.

An inclined brace 15 is disposed between the third gusset plate 13 and the fourth gusset plate 14. A vertical brace 16 is disposed between the fourth gusset plate 14 and the central portion of the first connecting member 10b. The inclined brace 15 and the vertical brace 16 can be bolted or welded by post-installation after assembling the unit structure 10.

By post-installing the inclined braces 15 and the vertical braces 16, the weight of the unit structure 10 when the crane is lifted is reduced, and the position of the center of gravity of the unit structure 10 in the suspended position is made as close as possible to the column member 10a. be able to. Thereby, the overhang length of the beam member 10c can be minimized while avoiding interference between the wire ropes R1 to R3 extending upward from the hanging metal fitting 20 and the veranda slab 40. The shortening of the beam member 10c is effective in reducing the weight of the reinforcing frame and reducing the member cost, and further leads to an improvement in the strength of the reinforcing frame.

(Steel frame reinforcement and its construction method)
The unit structure 10 is configured as described above, and the unit structure 10 finished in the factory is transported to the construction site by a truck. Then, the steel structure reinforcement frame S is constructed by lifting the unit structures 10 one by one with the crane C and building them up step by step along the outer wall of the existing building A of the reinforced concrete structure as shown in FIGS. 3A to 3E.

The reinforced frame S is partially constructed on the wall surface of the frame that requires reinforcement, and the weight of the frame is significantly reduced compared to the conventional reinforced slab frame. Accordingly, the vertical force of the reinforcing frame S can be supported by the pile foundation PF of the existing building A as shown in FIG. 4 without adding a pile foundation for supporting the reinforcing frame S to the ground G. Hereinafter, the construction method of the steel structure reinforcement frame S is demonstrated in order.

First, the first-stage reinforcing frame S1 is constructed as the lowest level of the reinforcing frame S. The first-stage reinforcing frame S1 has a height corresponding to the height of the first floor portion, and is constructed directly on the pile foundation PF. Then, the unit structure 10 of the second-stage reinforcing frame S2 is assembled on the first-stage reinforcing frame S1.

The unit structures 10 are lifted one by one by the crane C and placed on the first-stage reinforcing frame S1. For work by the crane C, the suspension beam B is horizontally suspended from the hook F attached to the lower end of the wire rope R1 of the crane C via the wire rope R2. Then, the lower end portion of the wire rope R <b> 3 lowered in parallel from both ends of the suspension beam B is hung on the suspension fitting 20 of the unit structure 10.

In accordance with the assembly height of the reinforcing frame S, a scaffold FL for connecting the unit structures 10 is assembled outside the reinforcing frame S, that is, on the front side of the reinforcing frame S in FIGS. 3A to 3E. The scaffolding FL is connected to the building A or veranda slab 40 with a plurality of wall-connecting materials to prevent toppling.

After assembling the second-stage reinforcing frame S2, as shown in FIG. 3B, an inclined brace 33 is disposed between the first-stage reinforcing frame S1 and the second-stage reinforcing frame S2. The lower end of the inclined brace 33 is bolted to the upper surface of the center portion between the spans of the first stage reinforcing frame S1, and the upper end of the inclined brace 33 is bolted to the second gusset plate 12 of the unit structure 10 of the second stage reinforcing frame S2. Link.

Above the second-stage reinforcing frame S2, the unit structures 10 having the same structure are sequentially assembled to extend the reinforcing frame S upward. As shown in FIG. 4, since the uppermost eighth-stage reinforcing frame S8 has a half-story height, the upper half of the column member 10a of the unit structure 10 is used.

When the unit structure 10 is assembled, as shown in FIGS. 6A and 6B, which will be described later, the unit structure 10 is brought close to the tip of the veranda slab 40 and is intermittently arranged according to the span of the outer wall of the building. Then, the unit structures 10 adjacent to each other on the left and right with the inter-column span interposed are bolt-connected by the first inter-unit connecting member 31 and the second inter-unit connecting member 32 as shown in FIG. 3B.

These inter-unit connecting members 31 and 32 are also suspended by the crane C and disposed between the unit structures 10 and delivered to a hanging jig to be aligned with the unit structure 10. The inter-unit connecting members 31 and 32 connect the unit structures 10 to each other and can correct a dimensional error between the unit structures 10 by correcting the position of the bolt connection.

Further, the unit structures 10 adjacent to each other in the vertical direction are connected by an inclined brace 33. Further, the first inter-unit connecting members 31 that are vertically adjacent to each other are also connected by the same inclined brace 33. These inclined braces 33 are also suspended by the crane C, arranged at predetermined positions, and delivered to a suspension jig to be aligned with the unit structure 10. The inclined brace 33 is a bolt connection, and a dimensional error between the unit structures 10 can be absorbed by correcting the position of the bolt connection.

FIG. 3C shows a state in which the second-stage reinforcing frame S2 is assembled on the first-stage reinforcing frame S1. Thereafter, the unit structure 10 is assembled in the same procedure until the final eighth-stage reinforcing frame S8 shown in FIG. 3D shows the arrangement of the unit structures 10 of the third-stage reinforcing frame S3, and FIG. 3E shows the arrangement of the unit structures 10 of the fourth-stage reinforcing frame S4. In these reinforcing frames S3 and S4, the unit structure 10 is similarly lifted by a crane and arranged every other span.

(Horizontal suspension of the unit structure)
FIGS. 5A to 6B show a state where the tip of the beam member 10c of the unit structure 10 is hung horizontally below the veranda slab 40. FIG. The unit structure 10 suspended horizontally by the suspension beam B as shown in FIG. 5A is moved to a predetermined height on the target floor so as not to interfere with the veranda slab 40 as shown in FIG. 6A. Thereafter, the crane C is operated to horizontally move the unit structure 10 toward the building in the direction of the arrow, and the tip of the beam member 10c is inserted below the veranda slab 40 as shown in FIG. 6B.

On the other hand, a pitty frame 41 is installed on the veranda slab 40 in advance, and a level adjustment jack 42 is adjusted to a low position on the pitty frame 41 and installed as a pair on the left and right. Further, a ruler angle 43 for adjusting the entrance / exit is fixed with an anchor at a position corresponding to the pair of level adjustment jacks 42 below the distal end portion of the veranda slab 40.

Then, the tip of the beam member 10c of the unit structure 10 suspended horizontally is moved to the level adjustment jack 42 adjusted to a low position, and the flange portion of the column member 10a of the unit structure 10 is attached to the tip of the ruler angle 43. Make contact. In this state, the tip of the beam member 10c is temporarily placed on the level adjustment jack 42.

Thereafter, the left and right level adjustment jacks 42 are respectively adjusted to rise, and the vertical gap H between the beam member 10c and the veranda slab 40 is adjusted to 150 mm, for example. Thus, the horizontal direction and the vertical direction of the unit structure 10 with respect to the building A are positioned. During the positioning operation, the crane C is operated as necessary to finely adjust the height position of the unit structure 10.

With the unit structure 10 positioned in this manner, the lower ends of the pair of left and right column members 10a are respectively bolted to the upper ends of the pair of left and right column members 10a of the lower unit structure 10. Further, the unit structures 10 that are vertically adjacent to each other are connected by the inclined brace 33. Further, the first inter-unit connecting members 31 that are vertically adjacent to each other are also connected by the same inclined brace 33. The scaffolding FL on which the worker W rides is assembled to a height that allows this connection work.

(Join between reinforced frame and building frame)
As shown in FIGS. 7 to 9, the second connecting member 10 d and the second inter-unit connecting member 32 of the unit structure 10 are connected to the building frame each time each of the two-stage reinforcing frames S <b> 2. The beam member 45 is joined. For this joining, post-construction anchors 50 are installed horizontally at equal intervals in the left-right direction on the beam member 45 of the building frame. As a pre-process for installing the post-construction anchor 50, first, a hole having a predetermined diameter and a predetermined depth is formed in the beam member 45 by a drilling drill. Then, a post-construction anchor fixing adhesive is inserted and filled into the hole. Then, the post-construction anchor 50 is fixed to the beam member 45 with an adhesive by rotating and inserting the post-construction anchor 50 into the hole. The post-construction anchor 50 is arranged so that the stud 51 attached to the H-shaped steel web of the second connecting member 10d and the second inter-unit connecting member 32 is sandwiched between the post-construction anchors 50.

Then, the mold frames 52 and 53 are constructed above and below the second connecting member 10 d and the second inter-unit connecting member 32, and the spiral muscles 54 are inserted inside the mold frames 52 and 53. In this state, non-shrink mortar 55 as a solidifying material is injected into the molds 52 and 53.

This mortar injection can be performed from above the upper mold 52 or from below the lower mold 53. In the case of filling from above the upper formwork, a hole 56 for mortar filling is formed in the veranda slab 40 by a drill or a vertical gap H between the beam member 10c and the veranda slab 40 is used for filling the mortar. A hose 57 is introduced.

When mortar injection is performed from below the lower mold 53, a hole is formed in the mold 53 and an injection hose 57 for filling mortar is connected to the hole. In this case, since the mortar liquid level rises gently in the mold, the mortar filling efficiency can be increased. In addition, the lower half flange of the H-shaped steel of the second connecting member 10d is partially cut away in order to insert a bolt rotating jig used for connecting the second inter-unit connecting member 32. .

The reinforcing frame S constructed by the plurality of unit structures 10 as described above is joined to the building frame. Since the reinforcing frame S does not use a joining slab, the weight can be significantly reduced as compared with the conventional structure. For this reason, it is also possible to reduce or eliminate the need for newly placing a pile foundation that supports the reinforcing frame S, and to support the vertical force of the reinforcing frame S by the pile foundation PF of the existing building.

(Summary)
As mentioned above, although embodiment of this invention was described, this invention can be variously deformed without being limited to the said embodiment. For example, in the above-described embodiment, the unit structures 10 are intermittently arranged according to the span between columns of the existing building. However, depending on the state of the building to be reinforced, the unit structures 10 may be arranged continuously instead of intermittently. In addition, the unit structure 10 may basically have a column member 10a and a beam member 10c, and is not limited to the structure shown in the above-described embodiment.

10: Steel frame unit structure 10a: Column member 10b: First connecting member 10c: Beam member 10d: Second connecting member 11: First gusset plate 12: Second gusset plate 13: Third gusset plate 14: Fourth gusset plate 15: Inclined brace 16: Vertical brace 20: Hanging bracket 31: First unit connecting member 32: Second unit connecting member 33: Inclined brace 40: Veranda slab 41: Piti frame 42: Level adjustment jack 43: Ruler angle 45 : Beam member of building frame 50: Post-construction anchor 51: Stud 52: Upper formwork 53: Lower formwork 54: Spiral muscle 55: Non-shrink mortar 56: Hole 57: Injection hose 100: Reinforcement frame 110: Cantilever slab 110: Veranda slab 120: Joint slab A: Building B: Hanging beam C: Crane F: Hook FL: Scaffolding H: Vertical gap PF: Pile foundation R1-R3: Wire rope S: Steel frame reinforcing frame S1: First stage reinforcing frame S2: Second stage reinforcing frame S3: Third stage reinforcing frame S4: Fourth stage reinforced frame S5: Fourth stage reinforced frame S6: Fourth stage reinforced frame S7: Fourth stage reinforced frame S8: Eighth stage reinforced frame W: Worker

Claims (10)

A steel structure unit structure for constructing an external steel frame reinforcement frame by assembling along the outer wall of an existing building of a reinforced concrete frame structure having a veranda slab protruding from the building, the unit structure is
A pillar member that is joined to the outside of the veranda slab in the vertical direction and assembled to transmit the vertical force as a basis;
A beam member projecting from the pillar member to the existing building side through the lower side of the veranda slab, and having a tip part that can be joined to the frame of the existing building;
A steel unit structure for building reinforcement characterized by comprising: The steel structure unit structure is
A pair of left and right column members;
A first connecting member that connects the pair of column members in a horizontal direction;
A pair of beam members that project from the middle in the height direction of the pair of column members toward the existing building side and whose front ends can be joined to the existing building;
A second connecting member for horizontally connecting the tip portions of the pair of beam members;
The steel structure unit structure according to claim 1, comprising:   The steel frame unit structure according to claim 1 or 2, wherein a suspension fitting for hanging a wire rope is provided in a projecting direction of the beam member at an upper end portion of the pair of column members.   The steel unit structure according to any one of claims 1 to 3 is intermittently arranged in accordance with a span between columns of an existing building, and is assembled upward along the outer wall of the building outside the veranda slab of the building, with the span between columns sandwiched therebetween. A steel structure characterized in that adjacent unit structures are connected in a horizontal direction by inter-unit connecting members, and a beam member protruding from a column member of the unit structure is joined to a building frame through the lower side of the veranda slab. Reinforced frame.   5. The steel frame reinforcing frame according to claim 4, wherein a column member of the steel frame unit structure is connected to a pile foundation of a building. The inter-unit connecting member is
A first inter-unit connecting member that connects the ends of the first connecting members in a horizontal direction;
A second inter-unit connecting member that connects the end portions of the second connecting member in a horizontal direction;
The steel frame reinforcing frame according to claim 4, comprising:   The steel structure reinforcing frame according to claim 6, wherein the second connecting member and the second inter-unit connecting member are respectively joined to a frame of an existing building.   The second connecting member and the second inter-unit connecting member are made of H-shaped steel with a horizontal flange, and anchors are installed on the building frame toward the H-shaped steel web. The steel frame reinforcing frame according to claim 7, wherein a stud is fixed, a spiral line is inserted, a formwork is constructed vertically, and mortar is injected into the formwork and joined. A step of intermittently arranging the steel structure unit structure according to any one of claims 1 to 3 in accordance with an inter-column span of an existing building and assembling it upward along the outer wall of the building outside the veranda slab of the building,
A step of connecting horizontally between adjacent unit structures across the span between the columns with inter-unit connecting members;
A steel structure reinforcement comprising: a step of joining a beam member projecting from a column member of a unit structure to a building frame through a lower side of the veranda slab; and a step of joining the inter-unit connecting member to a building frame. Construction method of the frame. Fixing a ruler angle to the tip of the veranda slab,
Installing a frame scaffold on the veranda slab and placing a level adjustment jack on the framework scaffold;
A step of suspending a beam member of the unit structure below the veranda in a state where the steel unit structure of any one of claims 1 to 3 is suspended by a wire rope of a crane;
A step of bringing the column member of the unit structure in a state suspended by a wire rope into contact with the ruler angle;
Placing the tip of the beam member suspended by a wire rope on the level adjustment jack;
Adjusting the level adjustment jack to form a predetermined vertical gap between the beam member and the veranda slab;
The construction method of the steel frame reinforcement frame of Claim 9 characterized by the above-mentioned.