JP2015113589A - Ps post-introduction method of rc building and structure thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for imparting prestress endurable up to seismic intensity 7, by increasing an aseismatic performance by compensating for strength by the imparted prestress, when an unassumed giant earthquake in design as an RC building is caused.SOLUTION: The method is provided for introducing the prestress into a building structure for constructing a plurality of floors by a column and a beam from a foundation made of RC, and a sheath 6 for inserting a tension material 9 in advance into a required place of a footing 3, the column 5 and the beam 8 of the respective floors, is buried and constructed as an RC structure up to the uppermost floor, nd afterwards, is tensioned and fixed by inserting the tension material 9 into the sheath 6, and the prestress is introduced into the whole building structure mase of RC up to the column and the beam from the foundation, so that the building structure designed as the RC structure is largely improved in the whole aseismatic performance. An always load and a medium-small earthquake are coped with a reinforcement of the designed RC structure, so as to be endurable against the gant earthquake unassumed in by the design.

Description

  The present invention relates to a method for introducing prestress (PS) into a reinforced concrete structure (RC structure) and a structure obtained by the method.

  Needless to say, in apartment houses such as apartments and condominiums, it is not necessary to skip the spans of the columns in consideration of the habitability. Buildings with a ramen structure consisting of wooden pillars and beams are common, and most are built.

  The prestressed concrete structure (PC structure) is pre-stressed (PS) on the cross section of the concrete member so that it can resist the load assumed in advance. Yes, it has strong earthquake resistance against earthquakes. Furthermore, the pre-stress (PS) force is an internal force that exists in the member in advance and always acts in a direction perpendicular to the cross section. It becomes a force that resists when the building is about to deform due to work, an earthquake, etc., trying to return the deformed building like a pendulum, that is, a force to return to the original, this is prestress ( This is the effect of restoring force by PS). This effect is a seismic control action and effect due to prestress, and cannot be obtained with an RC structure or a steel structure.

        None (There is no literature that added PS to RC structure)

  By the way, the current seismic design standard has allowed a structural body to be damaged at a seismic intensity of about 5 or higher, and has allowed a collapse if it is designed to ensure life safety. There were reports that RC buildings collapsed or were greatly deformed and damaged during a huge earthquake exceeding seismic intensity 6 and that there were many damages that could not be repaired with residual deformation remaining after the earthquake.

  The present invention applies prestress (PS) to an RC building designed as usual, and is used as an RC building at the time of constant load. In the event of an earthquake, if an earthquake that is larger than expected occurs in the design of an RC building, an RC building that can withstand a seismic intensity of 7 by increasing the seismic performance by supplementing the strength with the applied pre-stress. It is intended to provide a method for providing the prestress easily and rationally.

  As a concrete means for achieving the above object, the first invention according to the present invention is a method of introducing prestress into a building structure constructed with a plurality of floors with columns and beams from an RC foundation. The foundation is constructed by embedding a sheath for inserting a tension material in advance at the required portions of the foundation and the pillars and beams of each floor, and constructing it as an RC structure up to the top floor, and then inserting the tension material into the sheath and fixing the tension. The present invention provides a post-PS introduction method for an RC building characterized by introducing pre-stress into the entire building structure having an RC structure from a pillar to a beam.

  In the first aspect of the invention, the sheath is arranged continuously from the foundation to the top floor in the column, and continuously arranged from the foundation to the outer peripheral column surface over the entire span between the columns in the column; and the required intermediate of the building structure A pair of unboxing anchors are formed in each of the column pillars and the required intermediate span beam, and the sheath is unboxed from the foundation to the unboxing anchorage in the pillar, from the unboxing anchorage to the top floor, and in the beam It includes disposing from the fixing unit to both outer peripheral column surfaces, overlapping the box unfixing unit, inserting the tension material, and applying prestress.

  A second invention according to the present invention is a building in which pre-stress is introduced to a building structure constructed with a plurality of floors from a RC foundation to a pillar and a beam, and the foundation and the pillars and beams on each floor are required. The building which makes RC construction from the foundation to the pillar and the beam by burying the sheath which inserts the tension material in the place beforehand and constructing as RC construction up to the top floor, inserting the tension material into the sheath of the construction and fixing the tension. The present invention provides an RC building structure having PS introduced, which is characterized by introducing prestress to the entire structure.

According to the post-PS introduction method for an RC building according to the present invention, after a building and an RC building are constructed and the entire building structure is completed, a PC steel material as a tension material is embedded in the column and the beam in advance. The building structure designed as an RC structure is greatly improved in the overall seismic performance by being inserted into the structure and fixing the tension material and introducing prestress into the entire RC structure building. Responding with the designed RC reinforcing bars during normal loads and small and medium-sized earthquakes, RC buildings with a seismic intensity of about 5 are compensated for by the prestress that has been introduced to compensate for a larger earthquake than expected It has an excellent effect of being able to withstand a huge earthquake up to 7.
In addition, the restoring force of the installed PS can significantly reduce the shaking at the time of the earthquake, and the building returns to its original state after the earthquake. can get.

  Also, according to the RC building structure according to the present invention, since it is designed as a conventional RC structure, it can be constructed at a low cost and a long period of time usually passes until the entire RC building is completed. Since the age of the steel is long, it is ensured that sufficient concrete strength is achieved, and the progress of the drying shrinkage of the concrete is almost completed, so that the high-strength concrete required for a normal PC structure is not used. What is necessary is just to use the cheap ordinary concrete used for RC building. Moreover, the prestress (PS) introduced has various excellent effects that the loss due to drying shrinkage of concrete can be greatly reduced.

It is the RC building which concerns on the 1st Embodiment of this invention, Comprising: It is the side view which abbreviate | omitted and showed a part of RC building before providing PS. It is the RC building which concerns on the same embodiment, Comprising: It is the top view which showed only the principal part of RC structure before providing PS. It is RC structure building which concerns on the embodiment, Comprising: It is the side view which showed schematically the state which provides PS. It is RC building which concerns on the embodiment, Comprising: It is the top view which showed schematically the state which provides PS. It is RC building based on the 2nd Embodiment of this invention, Comprising: It is the side view which abbreviate | omitted and showed the state which provides PS. It is RC building based on the embodiment, Comprising: It is a top view of only the principal part which showed the state which provides PS roughly. It is RC structure building which concerns on the 3rd Embodiment of this invention, Comprising: It is the side view which abbreviate | omitted and showed the state which provides PS. It is RC building based on the embodiment, Comprising: It is a top view of only the principal part which showed the state which provides PS roughly. It is the Example of the pillar structure applicable to the 1st-3rd embodiment of this invention, Comprising: It is the side view which showed schematically the state which provides PS. Similarly, it is an example of a beam structure applicable to the first to third embodiments, and is a side view schematically showing a state in which PS is applied. It is the beam structure of the Example, Comprising: It is a top view of only the principal part which showed the state which provides PS roughly.

  The present invention will be described in detail based on a plurality of illustrated embodiments. In the first embodiment shown in FIGS. 1 to 4, the RC building 1 is constructed in the order of a conventional foundation, column, and beam. For example, on a pile foundation 2 formed by driving into the ground at a required interval, a formwork is assembled and a required reinforcing bar is arranged inside, and concrete is cast to construct a footing 3 and each footing 3 The underground beam 4 that connects the two and the pillar 5 are constructed above the footing 3. When forming the concrete members to be constructed, that is, when the footing 3, the underground beam 4 and the column 5 are formed, a plurality of sheaths 6 for inserting tension members are disposed in advance, so that the inside of the concrete member A sheath 6 is embedded at a required position.

  The sheath 6 disposed in the underground beam 4 is linear in a state of being continuous from the footing 3 on one side to the footing 3 on the other side so as to penetrate through the inside of the footing 3 and the underground beam 4. And a fixing portion 7 formed of a steel pipe sleeve for fixing and fixing the tension material on the outer side surface of the footing 3 positioned at each side end portion.

  Further, the sheath 6 disposed in each column 5 is disposed in a straight line from the footing 3 to the upper end of the column 5 on the uppermost floor so as to penetrate the inside thereof, and the tension material is disposed at the uppermost end. A fixing portion 7 formed of a steel tube sleeve for fixing the tension is provided, and in the footing 3 on the lower end side, means for fixing the lower end of the tension material is provided.

  Further, as for the connecting portion between the beam 8 and the column 5 at each level, as in the case of the underground beam 4, the sheath 6 arranged inside the beam 8 is connected to the other side from the column 5 on the other side. Up to the side pillars 5 are arranged in a straight line so as to pass through the insides of the pillars 5 and the beams 8, and tension tension is fixed on the outer side surfaces of the pillars 5 on both side end faces. The fixing unit 7 can be provided.

In this case, for the beams 4 and 8, two sheaths 6 are disposed horizontally along the cross-sectional centroid of the beam, and for the column 5, four sheaths 6 are provided as the column cross-sectional centroid. In other words, it is preferable that the tension material centroids are arranged so that PS is introduced in the axial direction of the column beam without being eccentric with the cross-sectional centroid of the column beam.
For the beams 4 and 8, the sheath 6 may be arranged in two stages symmetrically with respect to the cross-sectional centroid in the beam forming direction.

In this manner, the RC building 1 is constructed by a cast-in-place concrete or precast concrete method with the sheath 6 embedded in the footing 3, the underground beam 4, the column 5, and the beam 8 at each level on the foundation. After the construction, the tension members 9 are inserted into the respective sheaths 6 and the tension members 9 are tension-fixed by using fixing devices installed at the fixing portions at the end portions of the tension materials 9 and prestressed in the axial direction of the concrete members. Is applied to the sheath 6 by high-pressure injection of the grout 10. As a result, prestress is introduced to the entire RC building 1.
In addition, by arranging the centroids of the tension members to be aligned with the cross-sectional centroid of the column beam member, only the axial force is introduced into the member cross-section, so the cross-section of the member designed as RC is complicated due to eccentricity. Since no stress is generated, the design can be easily confirmed.

  In this case, the tension material 9 is inserted into the sheath 6 from the lateral direction with respect to the beam, and the tension is fixed using a fixing tool installed on the fixing portion 7 at the end of the tension material 9 on the side of the footing 3 at the end. Then, after prestress is applied in the axial direction between the underground beam 4 and the beam 8 that are concrete members, the grout 10 is injected at a high pressure to fill the sheath 6. In this way, prestress is applied in the axial direction of the underground beams 4 and 8 which are concrete members. In addition, the column 5 is provided on the sheath 6 after the tension material 9 is inserted into the sheath 6 from the uppermost end and the distal end of the tension material 9 reaches the distal end of the sheath 6 embedded in the footing 3. After the grout 10 is hardened by filling the sheath 6 with high pressure using the injection hole 13 and the discharge hole (exhaust hole) 11 formed by the hose, the fixing unit 7 at the uppermost end is filled. Thus, the upper end portion of the tension member 9 is tension-fixed and prestress is applied to the column 5 which is a concrete member of the RC member. In short, since fixing is performed by the adhesive force of the grout without using a normal fixing tool in the footing, the construction can be performed very easily and at low cost.

  When the tension member 9 is fixed to the RC building 1 constructed, the tension is fixed in the order from the underground beam 4 on the lower floor to the beam 8 side of the upper building. After the tension work of the material 9 is finished, the tension fixing work of the tension material 9 to the pillar 5 is performed. The reason is that since the building is constructed from the lower layer side, the concrete member on the lower layer side is sufficiently cured and hardened over time, so even if prestress is introduced, deformation due to drying shrinkage does not occur Because.

The second embodiment shown in FIGS. 5 and 6 will be described. In the RC building 1 according to this embodiment, the arrangement of the sheath and the tension material for the column 5 is different from that of the first embodiment, and the other components are substantially the same. A detailed description is omitted with reference numerals.
That is, the lower end portions of the four sheaths 6 with respect to the pillars 5 are opened to the box opening recesses 12 provided on the side surfaces of the footings 3 and the upper end portions are continuously extended to the upper ends of the pillars 5 on the uppermost floor so as to extend linearly. And a fixing portion 7 for fixing the tension material 9 in tension at the uppermost end. The box opening recess 12 serves as a storage space for a fixing tool such as an anchor head, and thus can be substantially referred to as a box fixing section 7.

  Then, as in the first embodiment, the tension fixing work is performed from the underground beam 4 on the lower floor and the beam 8 side of the upper building, and after the tension work of the tension member 9 of the beam 8 is finished, the column 5 The tension fixing work of the tension material 9 is performed. The reason is that since the building is constructed from the lower layer side, the concrete member on the lower layer side is sufficiently cured and hardened over time, so that no trouble occurs even if prestress is introduced. In this way, prestress is applied in the axial direction of the concrete member, and as a result, prestress is introduced to the entire RC building 1. However, without being limited to this order, the tension fixing work is first performed on the pillar 5 by the entire construction process, and then the tension fixing is performed in the order from the beam 4 on the lower floor to the beam 8 on the upper floor. May be.

A third embodiment shown in FIGS. 7 and 8 will be described. Also in this embodiment, the RC building 1 constructed is different from the first embodiment only in the arrangement configuration of the sheath and the tension material with respect to the pillar 5, and the other components are substantially the same. Therefore, the same reference numerals are assigned and detailed description is omitted.
That is, the lower end portions of the four sheaths 6 with respect to the pillars 5 are opened to the leg portions of the pillars 5, that is, the unboxing recesses 12 provided on the side surfaces on the lower end side, and the upper end portions are the upper ends of the uppermost pillars 5. A fixing portion 7 is provided for extending and linearly extending the tension material 9 at the uppermost end thereof. Since the box opening recess 12 becomes a storage space for the fixing tool, it can be substantially said to be the box fixing portion 7.

Also in this embodiment, similarly to the first embodiment, the tension fixing work is performed from the underground beam 4 of the lower floor and the beam 8 side of the upper building, and the tension work of the tension member 9 of the beam 8 is performed. After the end, the tension fixing work of the tension material 9 to the pillar 5 is performed. The reason is also that since the building is constructed from the lower layer side, the concrete member on the lower layer side is sufficiently cured and hardened over time, so that no trouble occurs even if prestress is introduced. In this way, prestress is applied in the axial direction of the concrete member, and as a result, prestress is introduced to the entire RC building 1.
In any case, in the first to third embodiments, an anchor plate is arranged at the tip of the box fixing part and the fixing part 7 of the steel pipe sleeve, and a fixing tool such as an anchor head is arranged in the steel pipe sleeve. These are referred to as the fixing unit 7 including these.

  Further, examples of columns and beams applicable to the first to third embodiments will be described. In other words, this is a technique that can be applied when the RC building 1 becomes a middle / high-rise building and / or a horizontally long (wide) building.

First, the pillar 5 shown in FIG. 9 will be described.
Since the height (length) of the pillar 5 becomes higher (longer) when the RC building 1 becomes a middle / high-rise building, the sheath 6 and the tension material 9 embedded in the column 5 are also long in accordance with that. It becomes necessary, and handling these materials inevitably becomes cumbersome and not only disturbs the work, but also the distance is too long to apply equal prestress to the concrete parts. .

  Therefore, when the RC building 1 is a middle- or high-rise building, at a position where a plurality of tendons are inserted into the column 5, in a direction facing the side of the column 5 of the required intermediate layer with a necessary interval. A pair of box-shaped recesses 12 serving as the fixing unit 7 are provided, and the sheath 6 is arranged from the base footing 3 to the box-shaped recess 12 above the required intermediate layer and the box-shaped recess 12 below the required intermediate layer. Extend from the top to the top floor. In this case, the ends of the sheath 6 in the required intermediate layer overlap. In short, when the column 5 is long, the tension material 9 can be formed as a lap joint in the required intermediate layer without continuously forming one piece from the foundation to the top floor. Depending on the height of the building, not only one required intermediate layer but also a plurality of locations can be provided in the same manner.

Further, the beams 4 and 8 shown in FIGS. 10 and 11 will be described.
When the RC building 1 becomes a horizontally long (wide) building, the number of beams 4 and 8 across the entire span between the columns from one end of the building to the other end increases. The length of the sheath 6 and the tension material 9 that are to be used is also long, and handling these materials will inevitably be troublesome and will not only hinder the work, The distance is too long and the pre-stress can not be evenly applied to the concrete member.

  Therefore, when the RC building 1 is a horizontally long (wide) building, the horizontally long beams 4 and 8 having a required intermediate span are inserted at the positions where a plurality of tendons are inserted into the beams 4 and 8. A pair of boxing recesses 12 to be the fixing portions 7 are provided in a facing direction with a required interval on the upper surface of the frame, and the sheath 6 is arranged from the one side end of the building to the right side boxing of the intermediate span beams 4 and 8. It extends to the recess 12 and extends from the box opening recess 12 on the left side of the intermediate span beams 4 and 8 to the other end of the building. In this case, the ends of the sheath 6 in the intermediate span beams 4 and 8 overlap. In short, since the number of beams from one side end of the building to the other side end increases when the building is long, the tension material 9 is not made continuously from one side end to the other side end. The required intermediate span beams 4 and 8 can be used as lap joints. Depending on the length of the building, not only one required intermediate span but also a plurality of locations can be provided in the same manner.

In any case, the examples of the pillar 5 and the beams 4 and 8 described above can be applied to the construction methods of the first to third embodiments when the height and the width of the building are large. Thus, prestress can be effectively applied to the concrete member. In addition, the tension material used may be either a PC steel strand or a PC steel wire, and the concrete used as the RC building 1 may be any of ordinary concrete to high-strength concrete. In particular, in the case of ordinary concrete, it is desirable that the concrete design strength F = 250 N / mm ² or more. Moreover, although demonstrated as a foundation pile in embodiment, it is not limited to this, For example, various foundations, such as a solid foundation and a cloth foundation, may be sufficient. Furthermore, a seismic isolation device may be provided between the upper structure and the foundation structure to form a seismic isolation structure. In short, all the structures to which the post-PS introduction method is applied are included in the gist of the present invention in a structure designed as an RC structure as an upper structure.
Moreover, the post-PS introduction method can be applied only to the RC superstructure concrete member without introducing the post-PS into the underground beam 4 depending on the ground and the foundation condition. In any of the embodiments, after the tension member 9 is tension-fixed in the fixing unit 7, the mortar is filled and the anti-rust treatment of the fixing tool is performed.

  The post-PS introduction method for an RC building according to the present invention is a method for introducing prestress into a building structure constructed of a plurality of floors from pillars and beams from a foundation made of RC, wherein the foundation and the pillars of each floor and The RC structure is built from the foundation to the pillar and the beam by embedding a sheath for inserting the tension material in the required part of the beam in advance and constructing it as RC structure up to the top floor, and then inserting the tension material into the sheath and fixing the tension. By introducing prestress to the entire building structure, the overall seismic performance of the building structure designed as RC structure is greatly improved. Responding with the designed RC reinforcing bars during regular loads and small and medium-sized earthquakes, RC buildings with a seismic intensity of about 5 are compensated for by the prestress that has been introduced, and the seismic intensity is around 5 Since it can withstand even large earthquakes up to 7, it can be applied reasonably and easily after PS in a building designed with RC as the superstructure, so it is inexpensive. Seismic performance can be given to RC structures that can be designed and can be used widely.

DESCRIPTION OF SYMBOLS 1 RC building 2 Pile foundation 3 Footing 4 Underground beam 5 Column 6 Sheath 7 Anchoring part 8 Beam 9 Tensile material 10 Grout 11 Exhaust hole (exhaust hole)
12 Unboxing recess (fixing part)
13 Injection hole

As a concrete means for achieving the above object, the first invention according to the present invention is a method of introducing prestress into a building structure constructed with a plurality of floors with columns and beams from an RC foundation. for the pre-Symbol column, communicated from basic to the top floor of the column, for the beam is communicated to the outer cylindrical surface over the entire span between the pillars, previously embedded sheath for inserting the respective tension member and RC built up to the top floor as RC structure, and then prestressing is introduced to the entire building structure that is RC structure from foundation to column and beam by inserting tension material into the sheath and fixing the tension. The post-PS introduction method of the building is provided.

  In the first aspect of the invention, a pair of box fixing parts are formed in each of the pillars of the required intermediate layer and the beams of the required intermediate span of the building structure, and the sheath extends from the foundation to the box fixing part in the pillar, From the unfixing unit to the top floor, and in the beam from the box unfixing unit to both outer peripheral column surfaces, overlapping by the box unfixing unit and inserting a tension material to apply prestress, Is included.

A second invention according to the present invention is a building that Prestressing the building structure constructed plurality floor between pillars and beams from the base to RC structure, the pre-Symbol pillar, the top floor from basic The beam is connected to the outer peripheral column surface over the entire span between the columns, and a sheath for inserting a tension material is embedded in advance and constructed as an RC structure up to the top floor. After the construction , the pre-stress is introduced into the entire building structure from the foundation to the pillar and the beam by inserting a tension material into the sheath and fixing the tension, and the RC construction introduced after PS The building structure is provided.

Claims (4)

It is a method of introducing prestress into a building structure that is constructed with multiple floors with pillars and beams from the RC foundation.
An RC sheath is built up to the top floor by burying a sheath into which tension material is inserted in advance in the necessary parts of the foundation and pillars and beams on each floor,
A post-PS introduction method for RC buildings, wherein pre-stress is introduced to the entire building structure of RC construction from the foundation to the pillars and beams by subsequently inserting a tension material into the sheath and fixing the tension. 2. The RC structure according to claim 1, wherein the sheath is arranged to communicate from the foundation to the top floor in the column, and in the beam to communicate with the outer peripheral column surface over the entire span between the columns. Introduction method after building PS. A pair of unboxing fixing portions are formed in each of the required intermediate layer pillar and the required intermediate span beam of the building structure,
The sheath is disposed from the foundation to the boxing fixing unit in the column, from the boxing fixing unit to the top floor, and from the boxing fixing unit to both outer peripheral column surfaces in the beam, respectively.
The post-PS introduction method for an RC building according to any one of claims 1 to 2, wherein pre-stress is applied by allowing a tensioning material to pass through overlapping at a box-fixing unit. It is a building that introduced pre-stress into a building structure that is constructed with multiple floors from pillars and beams from the foundation made of RC,
An RC sheath is built up to the top floor by burying a sheath into which tension material is inserted in advance in the necessary parts of the foundation and pillars and beams on each floor,
RC building introduced after PS, wherein prestress is introduced to the entire building structure of RC structure from foundation to column and beam by inserting a tension material into the sheath of the structure and fixing the tension. Construction.

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