JP2012140818A - Earthquake strengthening structure for existing reinforced concrete apartment house - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the earthquake resistance of an existing medium low apartment house, while actualizing a barrier-free environment by installing an elevator installation in an earthquake strengthening structure.SOLUTION: On the outside corridor side of the existing reinforced concrete apartment house 1 having an outside corridor 6 extended in the ridge direction, a core wall 15 is constructed at a predetermined space for storing the elevator installation 5 in an inside space. A roof section of the apartment house 1 and a top slab of the core wall 15 are integrally connected to each other via a connection girder 20 to construct an earthquake-proof frame 10 which improves the earthquake protection of the existing apartment house 1.

Description

  The present invention relates to a seismic reinforcement structure of an existing reinforced concrete apartment house, and improves the earthquake resistance of an existing medium- and low-rise apartment house, and can be realized by installing an elevator facility in the earthquake-proof reinforcement structure and making it barrier-free. The present invention relates to a seismic reinforcement structure for existing reinforced concrete apartment buildings.

In the 1950s and 1940s, a number of five-story low- and high-rise apartments were built throughout the country by the Housing and Urban Development Corporation (current UR City Organization), local governments, and private construction companies.
Most of these mid- and low-rise apartments do not have elevators despite the aging of residents.

  Moreover, since these apartment houses are designed in accordance with the design standards of the time, they do not satisfy the current seismic design standards. In addition, many years have passed since the building was built, and there are many cases where it is necessary to determine whether to reinforce an existing building or replace it with a new building.

  In that judgment, in the case of rebuilding, since the new building is built on the ruined site, the degree of freedom and safety of the new building is high, but the period between the request for resident relocation, the dismantling of the existing building, and the completion The total cost, such as arrangements for temporary housing and construction costs, will be considerably high. In the conventional seismic reinforcement of existing buildings, external reinforcement of reinforcing members such as steel braces is common. However, in this type of seismic reinforcement work, all the reinforcement members are connected to the existing building by post-construction anchors, so noise, vibration, and dust are generated, and temporary relocation during construction is forced. In addition, the construction period is generally longer.

  Furthermore, it is anticipated that both the exclusive and shared parts will be narrowed and the usability will deteriorate due to the reinforcing members added to the inside or the outer shell of the existing building. When these reinforcement measures are applied to the entire building, the period is shorter than in the case of new construction, but temporary relocation may be required. As a concrete concept, for example, the renaissance plan by the UR City Organization has been proposed, but the existing building's rehabilitation method has been proposed to improve the life function of the existing building. The construction cost is said to be 80 to 90% at the time of rebuilding.

  In addition to repairs to ensure seismic resistance of existing buildings, as a challenge to improve the living environment, requests for repairs related to barrier-free, such as installing elevators and eliminating stepped parts, taking into account the convenience of elderly residents There is also.

  In response to these problems, for example, the invention of Patent Document 1 has been proposed as a reconstruction method for an existing building for the purpose of simultaneously achieving seismic resistance of the existing building and achieving barrier-free. In Patent Literature 1, an outer corridor is newly provided on the staircase side of the staircase type apartment house, and an elevator is newly provided in the staircase after the stairs are removed, thereby realizing barrier-free of the existing middle-rise housing. In addition, by constructing a grid-like outer frame on the entire surface of the existing staircase, the outer frame bears the seismic force acting on the existing house. As a result, the staircase-type apartment house can be made barrier-free and seismic strengthened at the same time, and it is possible to carry out the renovation work required for an old building at low cost. It is also proposed to provide more seismic reinforcement by installing an outer frame on the veranda side of the staircase type apartment house as necessary.

  However, the renovation work in Patent Document 1 requires a full refurbishment work, such as remodeling an existing staircase to make it an outer corridor type dwelling unit, or breaking a staircase in the staircase to make an elevator shaft. Moreover, since the arrangement of the entrances of each dwelling unit is changed, there is a problem that these constructions cannot be performed unless the resident is moved for a certain period.

  On the other hand, the applicant has proposed a seismic reinforcement structure that eliminates the above-described construction problems and efficiently raises the earthquake resistance of an existing building, called a plate-shaped apartment (Patent Document 2). . In this seismic retrofit structure, seismic retrofit is performed in the direction of girder by newly installing reinforcement frames on both sides of the existing building. The reinforcement frame is composed of one new column erected on the outside of the existing outer peripheral column on the wife side of the existing building, a new beam erected between the new column and the existing outer peripheral column, and a new column. And a seismic damper installed in the form of braces between the existing outer peripheral column and the new column.

JP 2004-124527 A JP 2004-176460 A

  In the seismic reinforcement structure disclosed in Patent Document 2, a new pillar is constructed at a predetermined distance from the existing building on both ends of the existing building, and this new pillar is integrated with the existing building with a beam and a member for connecting horizontal braces. However, it is impossible to install an elevator facility or the like for barrier-free construction. In addition, because it is a construction on the wife side of the building, there is little impact on the resident's life, but it is necessary to install a connecting member at the column beam joint position on each floor of the outer column, so Since the dwelling units at both ends are greatly affected by construction, it is necessary to move residents during the construction period.

  By the way, as shown in the mechanical model diagram shown in FIG. 5B for both Patent Documents 1 and 2, the rigidity at each floor of the existing building is compared with the state of the existing existing building (FIG. 5A). To improve earthquake resistance. On the other hand, the inventor aims to solve the above problems and to improve the earthquake resistance of existing buildings and realize a seismic reinforcement structure that can be barrier-free by a different concept from the conventional seismic structure design. It was. Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, and in existing buildings consisting of various apartment housing types, the seismic performance is improved by a new seismic reinforcement type without disturbing the daily living environment of residents. It is to provide an anti-seismic reinforcement structure for existing reinforced concrete apartment buildings that can improve the environment and install new living environment improvement equipment such as elevators.

  In order to achieve the above-mentioned object, the seismic reinforcement structure for an existing reinforced concrete apartment building of the present invention has an independent seismic structure equipped with an elevator facility, and the seismic structure and the top of the existing building have high rigidity. By connecting so as to have, it is intended to improve the earthquake resistance of existing buildings during an earthquake. Specifically, it has the following configuration.

  The seismic reinforcement structure of an existing reinforced concrete apartment house according to the present invention is an earthquake proof reinforcement structure added to an existing reinforced concrete apartment house, and is placed on one side of the apartment house with a predetermined distance on the underground support structure. A seismic frame comprising a core wall having a top slab, which is erected and accommodates elevator equipment in an internal space, and a connecting member that connects the core wall to the apartment house, the connecting member having the core wall Only the top is structurally connected to the roof of the apartment house, and the seismic frame is fixedly held on the apartment house.

  As another aspect of the invention, there is a seismic reinforcement structure added to an existing reinforced concrete apartment house in which the outer corridor extends in the direction of the beam, and a predetermined distance is taken on the outer corridor side of the apartment house. A seismic frame that is erected on an underground support structure and includes a connecting member for connecting an elevator installation in an internal space and having a top slab connected to the apartment house, the connecting member including the core wall; Only the top of the housing is connected to the roof of the apartment house, and the seismic frame is fixedly held on the apartment house.

  It is preferable that the connecting member has an integral structure of a beam and a slab of a reinforced concrete structure that connects the roof of the apartment house and the top slab of the core wall.

  It is preferable that the beam and the slab are fixed to the roof surface by a post-installed anchor at a portion installed on the roof surface of the apartment house.

  It is preferable that a passage floor is installed between the elevator stop floor provided in the core wall and the apartment house through an expansion joint.

  The seismic frame includes a core wall having no elevator equipment in addition to a core wall containing elevator equipment in the internal space, and the tops of the plurality of core walls are structurally connected to the roof of the apartment house. It is preferable.

  According to the present invention, it is possible to improve the seismic performance of an existing building without changing the environment of daily life in an existing building by temporary transfer, etc., and to improve the living environment by making an elevator etc., barrier-free. There is an effect.

The top view of the existing apartment house which provided the earthquake-resistant frame as embodiment of the earthquake-proof reinforcement structure of the existing reinforced concrete apartment house of this invention. The front view which showed the central core wall as a seismic frame. The side view which showed the connection state of the earthquake-resistant frame shown in FIG. 1, and the existing apartment house. The partial enlarged view which showed the connection structure in the upper end of an earthquake-resistant frame (central core wall) and the existing apartment house. The comparison figure of resistance moment distribution to the seismic force in a dynamic model.

  The technical point of the present invention is that a seismic reinforcing structure having an elevator shaft inside is erected along an existing building, and only the top of the seismic reinforcing structure is connected to the existing building 1 to perform seismic reinforcement. It is a feature (see FIG. 5C). Hereinafter, the following embodiment will be described with reference to the accompanying drawings as a mode for carrying out the seismic reinforcement structure of an existing reinforced concrete apartment house of the present invention.

  The existing building 1 to be subjected to seismic reinforcement of the present embodiment has no elevator equipment shown in the building plan view (floor beam plan view) in FIG. 1 and the building side view (reinforcement axis diagram) in FIG. It is a plate-shaped apartment house where the entrance (not shown) of the dwelling unit faces the straight outer corridor. 1 to 4 show a structural example of the seismic reinforcement structure of the present invention applied to the existing building 1 (hereinafter, the reference numeral 10 is attached, but is synonymous with the seismic frame). FIG. 3 is a front view (axial view) of the central core wall 15 as a main structural member of the seismic frame 10, and FIGS. 4A and 4B are diagrams in which the top of the central core wall 15 is connected to the existing building 1 with a connecting girder 20. It is explanatory drawing which showed the state.

  As shown in the plan view of the building in FIG. 1, the seismic frame 10 added to the existing building 1 is a center erected at a predetermined distance (about 3 m) from the outer corridor 6 extending in the longitudinal direction of the building. The core wall 15, the underground support structure 11 that supports the central core wall 15, the top of the central core wall 15 and the existing building 1 are connected, and the central core wall 15 functions as a seismic reinforcement structure for the existing building 1. And a connecting girder 20. The central core wall 15 is used as an elevator shaft as in the first embodiment, and an elevator facility is installed in the internal space. As an incidental structure, on the elevator floor (in this embodiment, each floor is stopped), the elevator hall 7 on each floor, and the passage floor 40 that allows the elevator hall 7 and the outer corridor 6 of the existing building 1 to move. Is laid. In addition, the central core wall has a point where the seismic frame is erected almost at the center of the existing building, which is the target of seismic reinforcement in the form of a plate, and the wall space of the frame structure consisting of a column beam structure. It is a term used in the present specification to refer to a structure incorporating a seismic wall.

  The structure of each member mentioned above and the earthquake-resistant frame 10 comprised from these members is demonstrated with reference to an accompanying drawing.

  As shown in FIGS. 2 and 3, the underground support structure 11 is constructed in the ground at a position away from the outer edge of the underground foundation structure of the target existing building 1 by a predetermined distance. In the present embodiment, as shown in FIG. 2 (b), the foundation structure includes an underground beam 12 constructed in a square shape in plan view so as to support the entire plane of the central core wall 15, It is composed of a foundation pile P that is placed so as to support the corners of the underground beam 12 and a connecting beam 13 that connects the underground beam 12 arranged in parallel to the beam direction. The lower end of the central core wall 15 is arranged to be rigidly connected to the upper surface side of the underground beam 12, and the central core wall 15 is integrally supported by the underground support structure 11. As the type of pile foundation, it is preferable to select a pile type by a construction method that minimizes the influence on the existing building 1 during pile construction. Embedded precast concrete piles and steel pipe piles are preferable from the viewpoint of construction space and construction period, but cast-in-place concrete piles can be adopted if a site where construction is possible is secured. In addition, when the existing building 1 is a low-rise building or when the supporting ground is good, a direct foundation structure may be used.

  The configuration of the central core wall 15 will be described. As shown in FIG. 1, the central core wall 15 of the present embodiment is a plane in which two core walls that are substantially U-shaped in plan view are arranged so that the openings 15 a serving as the entrances and exits of the elevator facility are opposed to each other. It consists of a shape. Further, as shown in FIG. 1, the height is set higher than the rooftop height of the existing building 1 by an overhead required by the installed elevator equipment 5. The central core wall 15 functions as a main structural member of the seismic frame 10, but as shown in FIG. 2A, the central core wall 15 itself is joined to the pillar 16 as a through pillar and the pillar 16 on each floor. It is designed as a reinforced concrete self-supporting structure having high rigidity, which is composed of a beam 17, a column 16, and a seismic wall 18 that fills a space partitioned by the beam 17.

  In the present embodiment, the pillars 16, the beams 17, and the earthquake-resistant walls 18 of the central core wall 15 are constructed of cast-in-place concrete. The column beam connection portion is a column penetration type in which the beam 17 is bonded to the column 16 from the side at each floor level. In addition, the wall space surrounded by the four sides of the pillar 16 and the beam 17 is constructed with a seismic wall 18 having a predetermined reinforcement arrangement, and the central core wall 15 as a whole has improved horizontal resistance during an earthquake. It is a structure. The central core wall 15 may be constructed as a pre-cast concrete product unit for each floor or a plurality of floors as a factory, and may be constructed as a self-supporting structure in which they are stacked and connected upward by a mechanical joint (not shown).

  The planar dimension and shape of one central core wall 15 are preferably determined according to the degree of seismic reinforcement required for the existing building 1 and the standard of the elevator equipment 5 to be installed. Needless to say, a predetermined number of core walls having an equivalent structure other than the central core wall can be arranged depending on the length of the existing building 1 in the longitudinal direction in consideration of the balance in the seismic structure.

  The connection structure between the seismic frame and the existing building 1 will be described with reference to FIGS. The technical feature of this embodiment is that the structural connection between the existing building 1 and the central core wall 15 as an earthquake-resistant frame is only the top of the building. In the case of the present embodiment, the central core wall 15 is installed only on one side (exterior corridor side) of the existing building 1, and therefore when the seismic force is applied in the direction of girder, the central core wall 15 connected to the existing building is provided. Eccentric stress is generated in. At that time, the shearing force in the transverse direction generated in the central core wall 15 is borne by the seismic wall 18 and the top slab 19 of each floor. Further, the connecting girder 20 bears the axial force, bending moment, and shear force generated in the central core wall 15 as an eccentric stress with respect to the existing building. The plane area of the central core wall 15 and the cross-section of the connecting girder 20 are set according to the generated external force (assumed seismic force), so that the seismic frame (central core wall) as a reinforcing frame can be installed on the existing building 1 Optimal reinforcement effect can be expected.

  As shown in FIG. 4A, the central core wall 15 is designed to be higher than the existing building 1 by the overhead of the elevator equipment 5 installed on the elevator shaft. The top of the central core wall 15 is covered with a top slab 19, and a connecting slab 21 is installed between the central core wall 15 side and the existing building 1. As shown in the figure, the connecting slab 21 is installed so that the end portion is placed on the roof surface 1a of the existing building 1, so that there is a step between the top slab 19 and the connecting slab 21. Has occurred. As described above, the slab thickness and bar arrangement of the two slabs 19 and 21 are appropriately designed so that the shearing force in the direction of the crossing acting on the existing building 1 can be transmitted to the central core wall 15 side. .

  The structure of the connection slab 21 and the connecting large beam 20 connected to the connection slab 21 will be described with reference to FIGS. As shown in FIG. 4A, the connecting slab 21 is constructed so as to project from the wall surface near the top of the central core wall 15 toward the existing building 1, and the front end portion 21 a is the roof of the existing building 1. It is supported so that it may be mounted by the predetermined | prescribed hanging width at the edge part of the upper surface 1a. A predetermined number of post-construction anchors 22 (see FIG. 4C) are arranged in a row on the slab support portion on the existing building 1 side. The placement range of the post-construction anchor 22 can be set to the full width of the slab support portion or a part thereof by design. As a result, the end of the connecting slab 21 is integrally fixed and supported on the existing building 1 by the post-construction anchor 22. Further, since the connecting beam 20 is structurally and integrally joined to the side surface of the connecting slab 21, the connecting slab 21 is in a four-sided fixed state.

  As shown in FIGS. 4B and 4C, one of the connecting girder 20 is fixed to the roof of the existing building 1 over a predetermined range, and the other protruding from the existing building 1 is the side surface of the connecting slab 21. In addition, the central core wall 15 and the wall surface of the central core wall 15 are structurally and integrally connected. In other words, in addition to the reinforcing bars for the beam structure, fixing bars necessary for joining the connecting slab 21 and the wall surface of the central core wall 15 are arranged in the beam. On the other hand, the fixing part in a state of being placed on the roof surface 1a of the existing building 1 is a part that transmits the bending moment, axial force, and shear generated on the central core wall 15 side during an earthquake or the like to the existing building 1 side. . Therefore, in the present embodiment, the length L (FIG. 4A) of the fixing portion is the same as that of the predetermined number of post-installed anchors 23 (for example, deformed bar D16) arranged on the roof surface 1a of the existing building 1. It is set to a length that can transmit the applied force to the existing building 1 side.

  Between the central core wall 15 of each floor and the outer corridor 6 of the existing building 1, a passage floor 40 is constructed as shown in FIG. This passage floor 40 serves as a bridge for residents who use the elevator equipment 5 installed in the central core wall 15 to go back and forth between the outer corridor 6 and the elevator hall 7 (FIG. 1) on each floor of the existing building 1. Fulfill. In order to structurally separate the passage floor 40 from the existing building 1, an expansion joint 41 is interposed between the passage floor 40 of each floor and the central core wall 15. Thereby, at the time of an earthquake, the shaking of the central core wall 15 having a different vibration mode and the shaking of the existing building 1 do not interfere with each other, and a connected state only at the top of the existing building 1 and the central core wall 15 is ensured. The passage floor 40 is provided with a handrail wall of the outer corridor 6 and a handrail (not shown) continuous through an expansion joint (not shown).

  In consideration of the balance of the change in rigidity in the height direction of the central core wall 15, it is preferable to equip the machine room-less type elevator 5 without an incidental facility such as a machine room.

  The central core wall 15 described above is constructed as a reinforced concrete self-supporting structure, and the top portion thereof is structurally connected to the existing building 1 by two connecting beams 20 so that the seismic reinforcement structure of the existing building 1 is provided. As a role. Therefore, it is important to design each member of the central core wall 15 in consideration of the degree of seismic reinforcement required by the existing building 1. For example, as shown in FIG. 5C, depending on the rigidity of the reinforcing frame, it has been confirmed that different stress distributions are shown in the simulation of the mechanical model. It is preferable to perform an appropriate seismic design and set an appropriate reinforcing frame. At that time, when it is necessary to provide seismic reinforcement more than the above-described configuration, the connecting slab 21 is provided with a reinforcing beam parallel to the beam row direction, or the number of the connecting large beams 20 is increased so that the center as an earthquake-resistant frame is provided. It is also preferable to enhance the integration of the core wall 15 and the existing building 1.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope indicated in each claim. In other words, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Existing building 5 Elevator 10 Seismic frame 11 Underground support structure 12 Underground beam 13 Connection beam 15 Central core wall 16 (Central core wall) Column 17 (Central core wall) Beam 18 (Central core wall) Earthquake resistant wall 19 Top slab 20 Connecting beam 21 Connecting slabs 22, 23 Anchor 40 Passage floor

Claims (6)

  It is a seismic reinforcement structure added to an existing reinforced concrete apartment house, and is erected on an underground support structure at a predetermined distance on one side of the apartment house, and accommodates elevator equipment in the internal space. An earthquake-resistant frame comprising a core wall having a top slab and a connecting member for connecting the core wall to the apartment house, wherein only the top of the core wall is structurally structured on the roof of the apartment house. A seismic reinforcement structure for an existing reinforced concrete apartment house, characterized in that the earthquake-resistant frame is fixedly held in the apartment house by being connected to the housing.   A seismic reinforcement structure added to an existing reinforced concrete apartment house with an outer corridor extending in the direction of the beam, standing on the underground support structure at a predetermined distance on the outer corridor side of the apartment house A seismic frame comprising a connecting member for connecting a core wall having a top slab and accommodating an elevator facility in the interior space to the apartment house, wherein only the top of the core wall is connected to the apartment house by the connecting member. A seismic reinforcement structure for an existing reinforced concrete apartment house, wherein the earthquake resistant frame is fixedly held on the apartment house by being connected to the rooftop of the house.   The said connection member consists of a monolithic structure of the beam and slab of the reinforced concrete structure which connects between the roof top of the said housing complex, and the top slab of the said core wall, The Claim 1 or Claim 2 characterized by the above-mentioned. Seismic reinforcement structure for existing reinforced concrete apartment buildings.   The seismic reinforcement structure for an existing reinforced concrete apartment building according to claim 3, wherein the beam and the slab are fixed on the roof top surface by post-installed anchors.   The passage floor is erected between the elevator stop floor provided in the core wall and the apartment house through an expansion joint. Seismic reinforcement structure for existing reinforced concrete apartment houses.   The seismic frame includes a core wall having no elevator equipment in addition to a core wall containing elevator equipment in the internal space, and the tops of the plurality of core walls are structurally connected to the roof of the apartment house. The seismic reinforcement structure for an existing reinforced concrete apartment house according to any one of claims 1 to 3, wherein

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