JP2015206227A - Method for introducing ps into constructed building and building reinforced by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to apply prestress to a building for enabling the same to resist an earthquake having intensity up to 7, in a case of a massive earthquake with the intensity unanticipated in design, in a manner that enhances aseismic performance of the building with strength thereof reinforced by the applied prestress.SOLUTION: In a method to apply prestress to a multistory building 1, comprising foundations 2, columns 5 and beams 8, after the same is constructed, sheaths 6 where tendons are inserted therein are preliminarily embedded at predetermined locations on the foundations 2 and the columns 5 and the beams 8 on every story up to a top story. Then, tendons 9 are inserted into the sheaths and fixed to the building 1 with tension applied thereto. Thus, aseismic performance of the entire building 1 designed on the basis of a conventional seismic condition can be significantly improved with the prestress applied to the predetermined locations from the foundations 2 to the columns 5 and the beams 8 in the building 1. Permanent loading and seismic loading of a small or medium-sized earthquake can be resisted by structural resistance on the basis of conventional design of the building 1. The seismic loading of a massive earthquake having intensity up to level 7 which is unanticipated in the conventional design can be resisted with the structural resistance reinforced by the applied prestress.

Description

  The present invention relates to a method (after PS introduction method) for introducing prestress into a built building later and a structure obtained by the method.

  Needless to say, in buildings such as apartment houses and offices, reinforced concrete construction (RC construction), steel construction (S construction) and steel reinforced concrete construction (SRC construction) are inexpensive due to the comfort and economy. As a structure satisfying a suitable condition, a structure having a ramen structure composed of columns and beams is generally used, and most structures are constructed.

  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 pre-stress, and cannot be obtained by RC construction, S construction, SRC construction, or the like.

        None (There are no documents that gave PS to the built building later)

  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 many buildings such as RC structures, S structures, SRC structures, etc. collapsed or were greatly deformed and damaged during a huge earthquake exceeding seismic intensity 6 and could not be repaired with residual deformation remaining after the earthquake. there were.

  The present invention applies pre-stress to all buildings that are not pre-stressed (PS) such as RC structures, S structures, and SRC structures designed in the conventional manner. Used as a street building. In the event of an earthquake that is larger than expected in the event of an earthquake, provide a building that can withstand up to a seismic intensity of 7 by supplementing the strength with the applied pre-stress to improve the seismic performance, and It is an object to provide a method for imparting prestress easily and rationally.

  As a specific means for achieving the above object, the first invention according to the present invention is a method for introducing prestress into a frame structure of a building constructed from a foundation to a multi-storey structure with columns and beams. The sheath for inserting the tension material is embedded in the required portions of the pillars and beams of each floor having the predetermined frame structure in advance to construct the top floor, and then the tension material is inserted into the sheath to form the tension material. A PS introduction method is provided later to a constructed building characterized by introducing prestress into a predetermined frame structure by applying tension introduction force and fixing the tension.

  In the first invention, the sheath communicates from the foundation to the top floor in the column, and in the beam, the sheath communicates with the outer peripheral column surface over the entire span between the columns; The frame structure is at least an outer peripheral frame structure; the tension introducing force includes 30 to 70% of the yield load of the tension material.

  According to a second aspect of the present invention, there is provided a building in which prestress is introduced later into a frame structure of a building constructed from a foundation with columns and beams, and each floor having the predetermined frame structure is provided. A sheath for inserting a tension material is embedded in a required part of the column and the beam in advance to build up to the top floor, and a tension material is inserted into the sheath and a tension introduction force is applied to the tension material to fix the tension. The present invention provides a building in which PS is later introduced into a building characterized by introducing prestress into the frame structure.

  In the second invention, the building includes a seismic isolation structure building.

According to the PS introduction method after the construction of the building according to the present invention, after building the pillars and beams as the frame structure of the building to complete the entire building structure, the PC steel material, which is a tension material, is preliminarily attached to the predetermined frame. The building structure designed as before is inserted into the sheath embedded in the column and beam to be structured, the tension is applied to the tension material, the tension is fixed and the prestress is introduced into the building. The overall seismic performance is greatly improved compared to the seismic performance of. In the case of constant load and small and medium-sized earthquakes, the earthquake resistance of the designed building structure is used. Buildings designed for earthquakes with a seismic intensity of 5 or more are compensated with prestress that has been introduced for larger earthquakes than designed. Has the excellent effect of being able to withstand even large earthquakes with seismic intensity 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 will return to its original state after the earthquake. An effect is obtained.

  In particular, according to the RC building structure, since it is designed as a conventional RC structure, it can be constructed at a low cost, and a long period of time usually elapses until the entire RC building is completed. Since it becomes long, it is ensured that the concrete strength is sufficiently achieved, and the progress of drying shrinkage of the concrete is almost completed. Therefore, the RC building is used without using the high-strength concrete required for ordinary PC structures. It is only necessary to use inexpensive ordinary concrete used for the construction, and it can be constructed at a low cost, and the prestress (PS) to be introduced has various advantages that the loss due to drying shrinkage of the concrete can be greatly reduced. Has an effect.

FIG. 1 is a side view showing a typical RC building as a first embodiment of the present invention, omitting a part of the RC building before giving PS. FIG. 2 is a plan view showing only an essential part of the RC building according to the embodiment, omitting a part of the building along the line AA in FIG. 1. It is the RC building which concerns on the same embodiment, Comprising: While showing PS, it is a side view which abbreviate | omitted and showed one part with the expanded cross section. FIG. 4 is a plan view showing only an essential part of the RC building according to the embodiment, omitting a part of the building along the line BB in FIG. 3. It is RC building based on the 2nd Embodiment of this invention, Comprising: While showing PS, it is a side view which abbreviate | omitted and showed one part with the expanded cross section. FIG. 6 is a plan view showing only an essential part of the RC building according to the embodiment, omitting a part of the building along the line CC in FIG. 5. It is RC building based on the 3rd Embodiment of this invention, Comprising: It is the side view which abbreviate | omitted and showed a part of building in the state which provides PS. It is RC structure building which concerns on the 4th Embodiment of this invention, Comprising: It is the side view which abbreviate | omitted and showed one part of the building in the state which provides PS. FIG. 9 is a plan view showing only an essential part of the RC building according to the embodiment, omitting a part of the building along the line DD in FIG. 8. It is RC building which concerns on the said 1st Embodiment, Comprising: (a) is sectional drawing of a pillar, (b) is sectional drawing of a beam. Although the building is not shown as the fifth embodiment, it is a steel reinforced concrete structure (SRC structure), in which (a) is a sectional view of a column, and (b) is a sectional view of a beam. Although the building is not shown as the sixth embodiment, it is a steel structure (S structure), (a) is a sectional view of a column, (b) is a sectional view of a beam, and (c) is a steel column. It is sectional drawing of the column of CFT structure which filled concrete in. In the said 1st-4th embodiment, it is the top view which showed schematically the example regarding the arrangement | positioning position of a tension material regarding the structure of a building. It is a seventh embodiment that can be applied to the first to fourth embodiments to make a building having a seismic isolation structure, with a part enlarged and a part of the building omitted. It is the side view shown. (A)-(d) is explanatory drawing which showed schematically the concept of the damping effect of the restoring force by the prestress of a building when prestress is provided to the frame structure of a building.

  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, for example, the RC building 1 is constructed in the conventional order of foundations, columns, and beams. 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 penetrate the insides of the pillars 5 and the beams 8, and are used to fix and fix the tension material on the outer side surfaces of the pillars 5 on both side end faces. A fixing unit 7 is provided.

In this case, for the beams 4 and 8, one sheath 6 is disposed horizontally along the cross-sectional centroid of the beam, and for the column 5, one sheath 6 is provided for the column cross-sectional centroid. Shall be placed in
In the drawing, both the beam and the column are arranged with one sheath at the cross-sectional centroid, but the present invention is not limited to this, and a plurality of sheaths may be arranged at symmetrical positions with respect to the cross-sectional centroid. In other words, it is preferable to arrange the tension material centroid so that the PS is introduced in the axial direction of the column / beam without being eccentric as much as possible in accordance with the cross-sectional centroid of the column / beam.

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, as shown in FIGS. 3 and 4, the tension members 9 are inserted into the respective sheaths 6, and the tension is fixed using a fixing tool installed at the fixing portion 7 at the end of the tension material 9. Then, after prestress is applied in the axial direction of each concrete member, the grout 10 is injected at a high pressure to fill the sheath 6. As a result, prestress is introduced into a predetermined location of the RC building 1.
In addition, by arranging the centroids of the tension members to be aligned with the cross-sectional centroids of the columns and beam members, only the axial force is introduced into the member cross-section, so the cross-section of the member designed as an RC structure is eccentric. Since no complicated stress is generated, the design content can be easily confirmed.

In this case, the tendon 9 is inserted into the sheath 6 from the lateral direction with respect to the beam, and the tendon 9 on the side of the footing 3 at the end of the underground beam 4 and on the side of the column 6 at the outer end of the beam 8. After fixing the tension using a fixing tool installed at the fixing portion 7 at the end of the core and applying prestress in the axial direction of the underground beams 4 and 8 which are concrete members, the grout 10 is injected at a high pressure. Then, the sheath 6 is filled. 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 material 9 is tension-fixed and prestress is applied to the column 5. In short, since fixing is performed by the adhesive force of the grout without using a normal fixing tool in the footing 3, the construction can be performed very easily and at low cost.
In the present invention, it is important to apply pre-stress after constructing the superstructure columns and beams, and the underground beams will be implemented as necessary. That is, depending on the design policy and construction method, prestress may not be applied to the underground beam.

When the tension member 9 is fixed to the constructed building 1, the tension fixing work is performed in order from the underground beam 4 on the lower floor to the beam 8 side of the upper building. After the end of the tension work, 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.
Further, if a tension material that has been subjected to rust prevention treatment, for example, an all-strand epoxy resin-coated type PC steel strand (trade name: SC strand) is used, it is not necessary to inject the grout after tension fixing. . In other words, if the grout injection work that bears part of the rust prevention treatment of the tendon made of steel wire is omitted, the cost can be reduced by saving labor in the field work.

  The second embodiment shown in FIGS. 5 and 6 will be described. The building which concerns on this embodiment is a case where it is a RC structure, and is set as the structure which was further excellent in earthquake resistance. Therefore, in the frame composed of the column 5 of the building 1 and the underground beam 4 and the beam 8 of the upper building, the arrangement of sheaths and tendons for the column 5 and the beams 4 and 8 is different from that of the first embodiment. However, since the other components are substantially the same, the same reference numerals are given and detailed description is omitted.

  That is, with respect to the pillar 5, the lower end portion of the four sheaths 6 is opened in a box opening recess 12 provided on the side surface of the footing 3, and the upper end portion continues to the upper end of the uppermost pillar 5. A fixing portion 7 is provided to extend in a straight line and fix the tension material 9 in tension at its 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. In addition, two sheaths 6 are arranged in parallel with respect to the beams 4 and 8, and both ends thereof are the footings 3 positioned at both end portions as in the first embodiment. The fixing portion 7 formed of a steel tube sleeve for fixing and fixing the tension material is provided on the outer side surface of each column and the outer side surface of the column 5 on each side end surface.

  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.

  In the first and second embodiments, an anchor plate is disposed at the tip of the boxing fixing portion and the fixing portion 7 of the steel tube sleeve, and a fixing tool such as an anchor head is disposed in the steel tube sleeve for fixing. These are collectively referred to as the fixing unit 7.

  Further, examples of columns and beams that can be applied to the first and second 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 which concerns on 3rd Embodiment shown in FIG. 7 is demonstrated.
Since the height (length) of the pillars 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 elongated accordingly. In addition to the need for a single piece of these materials, handling is inevitably cumbersome and can interfere with work, and the distance is too long, making it even for frame-structured concrete members. It is not possible to give a prestress.

  Therefore, when the building 1 is a medium- or high-rise building, the fixing unit is located in the opposite direction at a position where a plurality of tendons are inserted into the column 5 with a required interval on the side surface of the column 5 of the required intermediate layer. A pair of boxing recesses 12 is provided, and the sheath 6 is arranged from the base footing 3 to the boxing recess 12 above the required intermediate layer and from the boxing recess 12 below the required intermediate layer to the top. Extend to the 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 lower end portion of the tendon 9 is filled with a high-pressure injection of the grout 10 into the sheath 6 using the injection hole 13 and the discharge hole 11 in the same manner as in the first embodiment. After curing, the tension is fixed.

The beams 4 and 8 according to the fourth embodiment shown in FIGS. 8 and 9 will be described.
When the RC building 1 is a large (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 to be embedded in the material is also necessary, and handling these materials will inevitably be troublesome and will only cause trouble in the work. In other words, the distance is too long, and it is impossible to apply equal prestress to the concrete member having the frame structure.

  Therefore, when the building 1 becomes a large (wide) building having a horizontally long shape, a required space is provided on the upper surface of the horizontally long required intermediate span at the position where the tension material is inserted into the beams 4 and 8. In the opposite direction, the required number of fixings (one in the drawing) for the fixing portions 7 are provided, and the boxed concave portions 12 are provided, and the sheath 6 is arranged from one side end of the building to the intermediate span beams 4 and 8. To the right side unboxing recess 12 and from the left unboxing recess 12 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, when the pillar 5 according to the third embodiment and the beams 4 and 8 according to the fourth embodiment are high in height and width of the building, Therefore, it is possible to apply prestress effectively to the concrete member of the frame structure. Further, 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.

In the first to fourth embodiments described above, the upper structure has been described as an RC structure. However, the present invention is not limited to this, for example, an SRC structure, an S structure, or a CFT structure that is not prestressed. It is good.
Therefore, as shown in FIG. 10, for RC columns and beams, their cross-sections are as shown in FIG. 9 is embedded and the tension is fixed, and as for the beams 4 and 8, the sheath 6 and the tension material 9 are embedded in the cross-sectional centroid of the beams 4 and 8, and the tension is fixed. At the same time, a slab 14 is integrally formed on the upper surface of the beam to construct a building.

  Although not shown as a building, as shown in FIG. 11, as a fifth embodiment, as shown in FIG. The built-in steel frame 15, the plurality of sheaths 6, and the tension members 9 are embedded and tension-fixed, and the beams 4, 8 are also embedded in the built-in steel frames 15, the plurality of sheaths 6, and the tension members as shown in FIG. 9 is buried and the tension is fixed, and a slab 14 is integrally formed on the upper surface of the beam to construct a building.

  Further, although not shown in the figure as a building, as shown in FIG. 12, as shown in FIG. 12, the pillars and beams, which are S-structured frame structures, are shown in FIG. A sheath 6 and a tension member 9 are disposed at the center of the steel column 5 serving as a rectangular steel tube, and the tension is fixed. As shown in FIG. The sheath 6 penetrating the stiffener 21 provided on both sides of the cross section of the steel beam 20 and the tension material 9 are disposed and fixed, and a synthetic slab 16 is formed on the upper surface of the beam to construct a building. The In addition, in the steel column 5, as shown in (c), in addition to the sheath 6 and the tension material 9, a concrete 17 can be injected and integrated into a CFT structure.

Furthermore, the plurality of embodiments may have a composite structure in which the structure types of the cross sections of the columns and beams are freely combined, for example, a mixed structure in which the columns are RC structures and the beams are S structures. In a building designed as an upper structure composed of these, the PS introduction method can be applied to the post-construction frame structure later in the scope of the present invention.
Further, depending on the ground and the foundation situation, the PS introduction method can be applied later to the construction only for the superstructure member without introducing the PS into the underground beam 4. In any of the embodiments, after the tension member 9 is tension-fixed in the fixing unit 7, the fixing unit 7 is filled with mortar or the like and subjected to a rust preventive process for the fixing tool.
About a construction method, when a pillar and a beam are made into a concrete member, it is good also as either a cast-in-place concrete or a precast.

  In consideration of earthquake resistance and economic efficiency, as a result of examining where to place the tension material in the frame structure in the building and introducing the tension, as shown in FIG. It is preferable to introduce prestress by placing a tension member 9 including a sheath 6 on at least the pillar 5 and the beam 8 (excluding the underground beam 4) of the outer peripheral frame (frame structure). Depending on the length and the number of frames, it is desirable to introduce the prestress by placing the tendon 9 on the required frame (the center frame in the figure). In short, it is only necessary to appropriately increase the number of frames for introducing tension as needed, instead of the entire frame structure.

  Moreover, about the tension | tensile_strength introduction force given to the tension | tensile_strength 9, although it is 80% of the yield load of a tension | tensile_strength in the conventional PC structure, in this invention, it is 30-70% of the yield load of this tension | tensile_strength 9. preferable. By doing so, even a structural member of a normal building designed in the conventional manner can bear the axial compression force that is increased later, and the tension member 9 is like a spring within the elastic range without yielding even in the event of a large earthquake. It acts as a force that resists when the building is about to be deformed due to an earthquake, etc., and it is a force that tries to return the deformed building like a pendulum, and the effect of restoring force by prestress (PS) is obtained It is. Furthermore, this restoring force allows the building to return to its original state after the earthquake, thus providing an excellent seismic control effect that suppresses the occurrence of residual deformation.

Furthermore, with respect to the first to sixth embodiments described above, a seismic isolation device can be provided by providing a seismic isolation device between the superstructure of the building and the foundation structure. This will be described as a seventh embodiment with reference to FIG. In addition, about this embodiment, the building which concerns on the said 1st Embodiment is employ | adopted and explained as a representative, The same code | symbol is attached | subjected to the same part and detailed description is abbreviate | omitted.
The building 1 is supported by a pile foundation 2 formed by driving into the ground, and a footing 3 and an underground beam 4 formed on the top of the foundation pile 2. The foundation pile 2 is the lower foundation, and the footing 3 and the underground beam 4 are the upper foundation.

  Therefore, a seismic isolation device 18 is disposed between the lower foundation and the upper foundation to form a building 1 having a seismic isolation structure. In this case, as a lower foundation, a foundation slab 19 having a required thickness is placed between the foundation piles 2 as a connecting material for the head of the foundation pile 2, and the footing 3 of the head of the foundation pile 2 and the upper foundation The seismic isolation device 18 is attached between the two. In addition, as long as the foundations according to the other embodiments are formed in the same manner, the base 1 can be easily made into the base isolation structure by attaching the base isolation structure 18 to any of the foundations. Moreover, although shown as a pile head isolation in the Example, it is not restricted to this, It is possible to change to various basic forms, and in short, what is necessary is just to arrange an isolation device and make it an isolation structure. is there.

As described above, the building itself exhibits an excellent seismic control effect by providing the prestress with the tension material 9 as described above with respect to the frame structure of the building 1 according to the present invention.
The concept of the damping effect of the restoring force due to the prestress of the building 1 to which the prestress is applied will be described with reference to FIG.
(A) The frame structure is prestressed (P) in the axial direction in addition to the axial force (W) due to the building weight, and shows a state in which a horizontal force Q due to an earthquake or strong wind is acting. is there.
(B) A moderate earthquake horizontal force is applied, and the prestress applied acts as a restoring force to return the building to its original position, and the building is hardly deformed.
(C) This is a case where a horizontal force due to a large earthquake acts on the building, and it deforms to an area where it cannot be restored in a state where no prestress is applied, but since this prestress is applied in the axial direction, this prestress is applied. Stress acts as a restoring force that restores the building to its original state and suppresses shaking.
(D) When the horizontal force stops working, the building returns to its original state due to the restoring force due to prestress, and the prestress prevents it from going over its original position and falling to the opposite side. The shaking will converge early. The building is restored to its original state by the restoring force having the origin-oriented characteristic of prestress.
Therefore, the resilience due to prestress applied to the frame structure is a seismic control effect that suppresses shaking and vibration of the frame structure to a small extent during a small and medium earthquake, and when the building is greatly deformed due to a large earthquake, the resilience due to prestress is In order to return the building to its original state, it exerts strong vibration control and prevents the building from collapsing.
Although the embodiments have been described above, the present invention is not limited to the illustrated configuration, and various modifications can be made without departing from the spirit of the present invention depending on various design conditions of the building.

  A method of introducing PS into a building designed according to the present invention according to the prior art is a method of introducing prestress into a building structure constructed from a foundation to a plurality of floors with pillars and beams. The construction of the building structure from the foundation to the pillars and beams is carried out by embedding a sheath to insert the tension material in advance at the required part of the pillar and beam up to the top floor and then inserting the tension material into the sheath and fixing the tension. By introducing prestress at a predetermined location, the overall seismic performance of the building structure designed as before is greatly improved. Responding with the designed structural strength at the time of constant load and small and medium-sized earthquakes, supplementing with a pre-stress that was larger than expected in the design, introduced pre-stress, and designed with a seismic intensity of about 5 strength, for example, RC building is seismic intensity Since it can withstand even large earthquakes up to 7, it is possible to apply the PS introduction method to the building reasonably and easily later in the building designed as the superstructure, so it is inexpensive. The building structure that can be designed can be widely used with improved seismic performance.

DESCRIPTION OF SYMBOLS 1 Building 2 Pile foundation 3 Footing 4 Underground beam 5 Column 6 Sheath 7 Fixing part 8 Beam 9 Tensile material 10 Grout 11 Exhaust hole (exhaust hole)
12 Unboxing recess (fixing part)
13 Injection hole 14 Slab 15 Built-in steel frame 16 Composite slab 17 Concrete 18 Seismic isolation device 19 Foundation slab 20 Steel beam 21 Stiffener

As a specific means for achieving the above object, the first invention according to the present invention is that all the buildings which are constructed in a plurality of floors with a frame structure composed of a pillar and a beam from the foundation and which are not prestressed by design. the Oite, said a method of introducing a prestress later in the frame structure, wherein the predetermined frame structure to each floor pillars and building embedded sheath for inserting the pre-tension member to a required point of the beam structure Is constructed up to the top floor, and after the entire building structure is completed, a prestress is introduced into a predetermined frame structure by inserting a tension material into the sheath and applying a tension introduction force to the tension material to fix the tension. A PS introduction method will be provided later to the constructed building characterized by

A second invention according to the present invention, multi-storey built with a frame structure consisting of a pillar and a beam from the foundation, Oite all buildings prestressing is not granted in the design, prestress later in the frame structure there a introduced buildings, to complete the entire building to build up the top floor with embedded sheath to insert the pre-tension member to a required point of the floor columns and beams to predetermined frame structure structure Later, a tension material is inserted into the sheath, and a tension introduction force is applied to the tension material to fix the tension, thereby introducing a pre-stress into a predetermined frame structure and providing a seismic performance higher than the design. The building which PS was introduced later is provided to the constructed building.

As a concrete means for achieving the above object, the first invention according to the present invention is constructed in a building which is constructed with a plurality of floors with a frame structure consisting of a foundation and pillars and beams, and which is not prestressed by design . In this method, prestress is introduced later into the frame structure, and a sheath for inserting a tension material is buried in advance in the required portions of the pillars and beams of each floor to be the predetermined frame structure, and the building structure is placed at the top. Building up to the floor , after completing the entire building structure , inserting a tension material into the sheath and applying tension introduction force to the tension material to fix the tension, thereby introducing prestress into a predetermined frame structure and the design there is provided a method of introducing a PS after the building was constructed, characterized in that confer more earthquake resistance.

A second invention according to the present invention, multi-storey built with a frame structure consisting of a pillar and a beam from the foundation, Oite buildings not prestress is applied in the design, prestress introduced later in the frame structure a building which is, after completing the entire building structure building top floor with embedded sheath to insert the pre-tension member to a required point of the floor columns and beams to the predetermined frame structure, A construction characterized by a construction in which prestress is introduced into a predetermined frame structure and seismic performance higher than the above design is provided by inserting a tension material into the sheath and applying tension introduction force to the tension material to fix the tension. The building which PS was introduced into the building which was made later is offered.

Claims (6)

It is a method of introducing pre-stress later into the frame structure of a building that is constructed with multiple columns and beams from the foundation,
Build up to the top floor by burying a sheath that inserts a tension material in advance at the required locations of the pillars and beams on each floor with the predetermined frame structure,
A method for introducing PS later into a constructed building, wherein a prestress is introduced into a predetermined frame structure by subsequently inserting a tension material into the sheath and applying a tension introduction force to the tension material to fix the tension. . The constructed sheath according to claim 1, wherein the sheath communicates from the foundation to the top floor in a column, and communicates to the outer peripheral column surface over the entire span between the columns in the beam. How to introduce PS later in the building.   The method for introducing PS into the built building according to claim 1, wherein the predetermined frame structure is at least an outer peripheral frame structure.   The PS introduction method for the constructed building according to any one of claims 1 to 3, wherein the tension introduction force is 30 to 70% of a yield load of the tension material. A building in which pre-stress is introduced later to the frame structure of the building constructed from the foundation with multiple columns and beams,
Build up to the top floor by burying a sheath that inserts a tension material in advance at the required locations of the pillars and beams on each floor with the predetermined frame structure,
A construction in which PS is introduced later into a building, wherein a prestress is introduced into a predetermined frame structure by inserting a tension material into the sheath and applying tension introduction force to the tension material to fix the tension.   The building is a building that was later introduced into the PS, which is a seismic isolation structure.

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