JP2007270600A - Prestress introducing method to filling part between precast concrete members - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prestress introducing method to a filling part between precast concrete members capable of successively introducing a prestress equal to or more than that of a precast concrete plate to cast-in-place filling concrete in a narrow range. <P>SOLUTION: This prestress introducing method to the filling part between the precast concrete members, introduces the prestress to the filling concrete by return force of the precast concrete plate 13 by opening a load, after its filling concrete reveals required strength, by placing the filling concrete 14 in an expanded filling clearance, by elastically deforming the filling clearance between the mutually adjacent precast concrete plates 13 in the expanding direction, by applying the load for deforming this plate to the precast concrete plate 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

In the present invention, for example, precast concrete plates are installed side by side on steel girders supported by columnar members such as support piles and support columns, and cast-in-placed concrete is placed in the space between the precast concrete plates. The present invention relates to a prestress introduction method for a filling portion between precast concrete members for introducing prestress into cast-in-placed concrete when, for example, a synthetic floor board is constructed by integrating them with each other.

    Conventionally, for example, a construction method for constructing a floor slab by supporting it on a columnar member such as a support pile standing on the sea floor or a column standing on a land foundation such as a pier constructed on the sea is shown in FIG. As shown in (b), a steel girder 2 assembled in a lattice shape is supported on the upper end of the support column 1 and precast concrete plates 3, 3. , 3 is integrated by placing cast-in-place concrete 4 in the gap between them.

  In many cases, the precast concrete plate used in this case is of a prestressed concrete structure (hereinafter referred to as a PC structure) in order to lighten the floor slab itself and obtain a high bending stress.

  Further, as a method of increasing the integrated strength between adjacent precast concrete plates including the interstitial concrete, a large number of connecting reinforcing bars 5, 5... There is a method of increasing the integrated strength by setting the connecting reinforcing bars 5 and 5 of the precast concrete plates 3 and 3 to overlap each other and embedding them in the interstitial concrete 4. As shown in FIG. 19, high strength can be obtained by using loop-shaped reinforcing bars in which both ends are embedded above and below the precast concrete plate as shown in FIG. 19.

  In addition, there is a method of increasing the integrated strength between the precast concrete plates by introducing uniform prestress to the whole by making the interstitial concrete 4 and the precast concrete plate 3 into the same PC structure. As shown in FIG. 20, PC tension members 6 and 6 are inserted into a continuous arrangement across a plurality of precast concrete plates 3, 3... There is a method of introducing pre-stress that is continuous over the entire area of each unit area by fixing the tension material of the PC at the periphery of each area.

  In the conventional method for integrating the precast concrete members as described above, it is particularly preferable that the precast concrete plates 3 and 3 are supported in a butt arrangement on the steel girder 2 and the interstitial gap is arranged on the steel girder 2. 2 and the synthetic floor board on it are preferably integrated by embedding the stud 7 protruding from the steel girder 2 in the interstitial concrete in view of work efficiency. In that case, as shown in FIG. Thus, the negative bending moment caused by the downward load is maximized on the steel girder, that is, in the space between the concrete pieces.

  In order to counteract this negative bending moment, it is necessary to increase the strength of the interstitial concrete part, but in the construction method that does not employ PC construction for the interstitial concrete described above, the greater the vertical load resistance, It is necessary to increase the amount of connecting reinforcing bars, and it is necessary to manufacture a precast concrete plate with a large amount of connecting reinforcing bars protruding, which makes it difficult to manufacture and transport.

  On the other hand, in the construction method using PC that is connected to the precast concrete plate and joint concrete, it is not necessary to increase the amount of reinforcing bars or increase the connecting bars because the joint concrete is made of PC. Tension work is required for each area, and the work process may be biased, resulting in problems in work efficiency. In order to demonstrate the advantages of PC construction, the unit area needs to be increased. There is a problem that the greater the area, the greater the tension in one tensioning work, and the higher skill and skill will be required for the work.

  In view of the conventional problems as described above, the present invention provides a space between precast concrete members capable of sequentially introducing a prestress equivalent to or higher than that of a precast concrete plate in a narrow range with respect to a space-cast space concrete. It was made for the purpose of providing a prestress introduction method to the club.

  The feature of the invention described in claim 1 for solving the conventional problems as described above and achieving the intended purpose is that the interstitial portion made of cast-in-place concrete interposed between adjacent precast concrete members is used. In the prestress introduction method for the filling portion between the precast concrete members to which prestress is introduced, by applying a load for deforming the precast concrete member, the filling gap between the precast concrete members adjacent to each other is applied. Is elastically deformed in the direction in which the space is spread, and the space-filled concrete is placed in the space between the spaces, and after the space-filled concrete exhibits the required strength, the load is released by the return force of the precast concrete member. Introducing pre-stress into the concrete In the door.

  The invention according to claim 2 is characterized in that, in addition to the structure of claim 1, the jacks are used to restrain both ends of the precast concrete members adjacent to each other in a state in which movement of the end opposite to the adjacent side is restricted. The object is to elastically deform the precast concrete member in the compression direction by applying a load in a direction of expanding the gap between the precast concrete members.

  The invention according to claim 3 is characterized in that, in addition to the configuration of claim 1, the elastic deformation of the precast concrete member is different from the PC tendon for introducing prestress necessary for service during the production of the precast concrete member. By applying a surplus prestress load using a PC tendon material, the surplus prestress load is released after the interstitial concrete is placed by elastically deforming in the direction in which the interstices are widened.

  The feature of the invention of claim 4 is that, in addition to the configuration of claim 3, the surplus prestress given at the time of manufacturing the precast concrete member is such that it is elastically deformed by deformation larger than the shrinkage due to the creep of concrete. There is to be.

  According to a fifth aspect of the present invention, in addition to the configuration of the first aspect, a direction in which the intersticing gap is widened by applying a downward load to the central portion of the precast concrete plate to bend the precast concrete member downward. It is to give elastic deformation.

  The feature of the invention described in claim 6 is that, in addition to the configuration of claim 5, the downward load for bending downward is equal to or greater than the design load.

  According to a seventh aspect of the present invention, in addition to the configuration of the first aspect, a PC tension member is stretched between brackets attached to both ends of the precast concrete member, and the PC tension member is tensioned. The cast concrete member is elastically deformed in the direction in which the gap is widened, and the prestress is introduced into the gap concrete by the return force of the precast concrete member by releasing the tension after placing the gap concrete. .

  According to an eighth aspect of the present invention, in addition to the configuration of the seventh aspect, the bracket includes a compression portion that abuts against an end surface of the fredcast concrete member, and a PC tendon material that is integrally provided on the compression portion. A PC tensioning material is fixed to the fixing portion and is tensioned.

  The invention according to claim 9 is characterized in that, in addition to the configuration of claim 7 or 8, a nut with a threaded steel rod having a male thread formed on the outer periphery as a PC tension member and screwed onto the male thread after tension. Is fixed to the PC tension material fixing portion.

  In the prestress introduction method for the filling portion between the precast concrete members of the present invention, by applying a load for deforming the precast concrete member to the precast concrete member, the filling gap between adjacent precast concrete members is widened. The concrete is then elastically deformed in the direction, and concrete is placed in the widened gap, and after the concrete exhibits the required strength, the load is released by the return force of the precast concrete member. By introducing prestress into the concrete, the strength of the interstitial concrete can be increased without using many reinforcing bars for connecting the precast concrete in the interstices. Furthermore, manufacture, transportation, and installation work on a girder of a precast concrete member become easy. In addition, when many precast concrete members are arranged, prestress introduction work can be performed only on a small part of the site, so prestress introduction work is easy, and prestress is introduced to the whole. Compared to, work can be streamlined.

  Further, in the present invention, when the elastic deformation is performed, the gap between the two precast concrete plates is fixed by a jack in a state in which the movement of the end opposite to the adjacent end of the adjacent precast concrete member is restrained. By applying a load in a direction in which the pre-cast concrete member is expanded and elastically deforming the precast concrete member in the compression direction, it is easy to introduce prestress into the gaps.

  Furthermore, in the present invention, when the pre-cast concrete member is produced, an extra pre-stress load is applied by using a PC tendon different from the PC tendon used when introducing the pre-stress necessary after the erection. As a result, the precast concrete member is elastically deformed in the direction in which the gap is widened, so that prestress can be easily introduced into the gap and the precast concrete plate is not deformed on site. .

  Further, the surplus prestress given at the time of manufacturing the precast concrete member is larger than the amount of shrinkage caused by the creep of the concrete, and is elastically deformed. The prestressed state of concrete can be maintained.

  Furthermore, in the present invention, when the elastic deformation is performed, a downward load is applied to the central portion of the precast concrete member to curve the precast concrete plate downward, thereby elastically deforming in the direction of widening the interstitial gap. The filling gap can be easily expanded.

  In addition, by setting the downward load for bending downward to be equal to or greater than the design load, even when the precast concrete plate is subjected to the maximum loading load assumed at the time of service, The installed state can be maintained.

  In the present invention, a PC tension member is stretched between the brackets attached to both ends of the precast concrete member, and the PC tension member is tensioned to elastically deform the fredcast concrete member in the direction in which the interstitial gap is widened. As a device for elastically deforming a frecast concrete member by introducing prestress into the gap concrete by the return force of the precast concrete member by releasing the tension after placing the gap concrete The conventional apparatus for tensioning PC tension material can be used, and after releasing the tension, it can be removed and reused, and the workability is good and the economy is high.

  The bracket includes a compression portion that abuts against an end face of the fredcast concrete member, and a PC tension material fixing portion integrally provided on the compression portion, and fixes the PC tension material to the fixing portion. By tensioning, the tension work for compressive elastic deformation of the frecast concrete member can be performed on the precast concrete member, the workability is good, and further, a male screw is formed on the outer periphery as the PC tension member By using a threaded steel rod and fixing the nut screwed to the male screw after tension to the PC tension material fixing part, the return of compression deformation can be minimized as much as possible. Can be provided with the necessary elastic deformation.

  Next, embodiments of the present invention will be described with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of an example of a floor slab structure constructed by using a prestress introduction method for a filling portion between precast concrete members according to the present invention. In the figure, reference numeral 10 denotes a steel girder frame. This steel girder frame 10 connects between parallel floor plate supporting steel girders 11, 11... That support two parallel sides of a precast concrete plate, which will be described later, and the adjacent floor slab supporting steel girders 11, 11. It is assembled in a grid pattern by connecting beams 12.

  A precast concrete plate (hereinafter the same) 13, 13..., Which is an example of the precast concrete member of the present invention, is installed between the steel plates 11 and 11 for supporting each floor plate, and the precast concrete plates 13 are joined together. The end faces are opposite to each other on the floor support steel girder 11, and the interstitial concrete is placed therebetween.

  As shown in FIG. 2, connecting reinforcing bars 16, 16 embedded in the precast concrete plate 13 protrude from the space 15, 15 between the adjacent precast concrete plates 13, 13. By embedding in the stuffed concrete 14, a floor slab is formed in which the two precast concrete plates are integrated with each other through the stuffed concrete 14.

  Further, the end of each precast concrete plate 13, 13 opposite to the interspaced gap side surface 15 is in a state in which movement is restricted by the stopper 17, and the elastic return of the precast concrete plates 13, 13 in the extension direction is achieved. The prestress is applied to the stuffed concrete 14 by force.

  Next, a method for introducing prestress into the concrete padding 14 in the floor slab will be described.

  The precast concrete plates 13 and 13 are manufactured in a production yard such as a factory, and prestress corresponding to the design load is applied to the side surface 15 of the interstitial gap by applying tension of a PC tension material (not shown). Is provided with a connecting reinforcing bar 16.

  As shown in FIG. 3, the precast concrete plates 13, 13 are installed with the floor slab support steel girders 11, 11 supported on the lower surfaces of both ends, and a space gap 20 is formed on the floor slab support steel girders 11. The connecting reinforcing bars 16 and 16 projecting from the respective precast concrete plates 13 and 13 are overlapped in the interior. Further, the movement of the end portions of the precast concrete plates 13 and 13 on the side opposite to the interstitial gap 20 is restrained by a stopper 17 fixed to the steel plate 11 for supporting the slab. In addition, although not shown in the figure, the reinforcing bars necessary for reinforcing the interstitial concrete are provided in the interstitial gap 20.

  Next, as shown in FIG. 4, a plurality of hydraulic jacks 21, 21 are inserted into the filling gap 20 and installed between the filling gap side faces 15, 15 of both the precast concrete plates 13, 13. In this state, the jacks 21 and 21 are actuated in the extending direction, and a load is applied in the direction in which the interstitial gap 20 is expanded, that is, the direction in which both the precast concrete plates 13 and 13 are compressed. After giving a predetermined amount of elastic compressive deformation, the jack insertion part is surrounded by the partition 22 and the interstitial concrete 14 is placed in the interstitial gap other than the jack insertion part.

  In this state, the precast concrete board compression load applied by the jack is maintained. Then, the load by the jacks 21 and 21 is released after the concrete filling 14 reaches a strength at which a predetermined prestress can be introduced. Thus, prestress is applied to the interstitial concrete 14 by the force of returning to the extending direction of the precast concrete plate 13 that has been elastically compressed and deformed. In addition, you may install a jack out of a crevice gap using a support etc.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  Precast concrete plates 13 and 13 and a precast concrete plate 18 for compressing a filling portion similar to those in the above-described embodiment are installed on a steel slab 11 for supporting a slab similar to that in the above-described embodiment. The precast concrete plate 18 for compressing the filling portion is installed between the precast concrete plates 13 and 13. The joint end surfaces of the precast concrete plate 13 and the precast concrete plate 18 for compressing the filling portion are opposed to each other, and the precast concrete plates 13, 13 and the prefilled concrete plate 18 for filling the compressing portion are spaced from the gap side surfaces 15, 15. Are provided with connecting reinforcing bars 16, 16. By embedding these connecting reinforcing bars 16, 16... In the interstitial concrete 14, 14, a floor slab is formed in which the precast concrete plates are integrated with interstitial concrete.

In addition, the end of each precast concrete plate 13, 13 opposite to the interstitial gap side surface 15 is in a state in which movement is restricted by the stoppers 17, 17. Prestress is applied to the interstitial concrete 14 and 14 by the elastic return force in the extending direction.
Next, a method of introducing prestress to the concrete padded in the floor slab will be described. First, an example will be described with reference to FIGS. The precast concrete board 18 for compressing a filling part is manufactured in a production yard such as a factory, and is given an excessive prestress. This excessive prestress is imparted by the tension of the release PC tension members 19, 19. Further, in order to maintain normal prestress after releasing the tension of the release PC tension members 19, 19..., Prestress is introduced by the non-release PC tension members 41, 41.
The precast concrete plate 18 for compressing the filling portion is provided with PC tension material release holes 23, 23,... For releasing tension of the release PC tension materials 19, 19,. The PC tension member releasing hole 23 is opened on the upper surface of the pre-cast concrete plate 18 for compressing the padding portion near the center in the length direction of the PC tension member 19 embedded in the plug-casting precast concrete plate 18 for release. It is formed in a shape recessed to the bottom of the PC tension material 19 for use. Further, inside the PC tendon release hole 23, the release PC tendon 19 is passed through in an exposed state. The size of the PC tendon release hole 23 is large enough to cut the release PC tendon 19 in the PC tendon release hole 23 using a PC tendon cutting machine. The release PC tendon 19 is disposed in the precast concrete through the PC tendon insertion hole 24.

  The precast concrete plates 13 and 13 are installed on the steel girders, and the precast concrete plates 18 for compressing the filling portion are installed between the precast concrete plates 13 and 13 on the girders with the gaps 20 and 20 between them. In the same manner as the first embodiment shown in FIGS. 1 to 4 described above, the connecting reinforcing bars are overlapped in the gaps 20 and 20, and the precast concrete plates 13 and 13 are fixed by stoppers. Further, although not shown in the drawing, reinforcing bars necessary for reinforcing the interstitial concrete are provided in the interstitial gaps 20 and 20.

  Next, the interstitial concrete 14, 14 is placed in the interstitial gaps 20, 20 between the interstitial portion compression precast concrete plate 18 and the precast concrete plates 13, 13. Then, after the interstitial concrete 14, 14 has reached a strength at which a predetermined prestress can be introduced, the tension of the release PC tension members 19, 19... Disposed on the interstitial portion compression precast concrete plate 18 is released. To do. As a result, the interstitial concrete 14 and 14 is compressed by the force of returning to the extending direction of the precast concrete plate 18 that has been elastically compressed and deformed, and prestress is applied to the interstitial concrete 14 and 14. Further, after releasing the tension of the release-like PC tension members 19, 19..., Concrete is placed in the PC tension material release holes 23, 23.

  In the above-described embodiment, as a method of releasing excess prestress, the precast concrete plate 18 for compressing the padding portion provided with the PC tension material release holes 23, 23... At the center of the precast concrete plate is used. In addition, as shown in FIG. 8 and FIG. 9, jack working spaces 25, 25... Are provided at the end of the precast concrete plate 42 for compressing the padding portion, and excess prestress is released using a PC tension material tension jack. May be. In this case, the upper portion of the PC tension material fixing portion on the side where the release PC tension members 19, 19,... As shown in FIG. 8, normal prestress is also introduced into the precast concrete plate 42 for compressing the filling portion by the non-release PC tension members 41, 41.

  As shown in FIG. 8, the jack working spaces 25, 25... Are constructed by placing a precast concrete plate and a precast concrete plate for compressing a filling portion on a steel girder. Provided when placing. Then, after the interstices 14 and 14 are cured, a jack 26 is installed in the jack work space 25 as shown in FIG. 9 to release the tension of the PC tension member 19. As a result, the interstitial concrete 14 and 14 is compressed by the force of returning to the extending direction of the precast concrete plate 18 that has been elastically compressed and deformed, and 14, 14 prestress is applied to the interstitial concrete. Thereafter, concrete is placed in the jack work space 25 to fill the jack work space 25.

  Moreover, although the above-mentioned Example has fixed the precast concrete board with the stopper, as shown in FIG. 10, it is good also as a state which cannot move relatively between the precast concrete boards 13 and 13 with steel materials 27,27 .... . In FIG. 10, between the precast concrete plates 13 and 13, the PC tension members 19, 19... For release are cut at the PC tension material release holes 23, 23. Although the precast concrete plate 18 for compressing the filling portion is used, the jack working spaces 25, 25... Described with reference to FIGS. You may use the precast concrete board 42 for compression of a filling part to release.

The steel materials 27, 27... Are inserted into the steel material insertion holes provided in advance in the precast concrete 13, 13 and the precast concrete plate 18 for compressing the filling portion or the precast concrete plate 42 for compressing the filling portion. Moreover, the steel material insertion hole is provided in the position arrange | positioned on the straight line across the precast concrete boards 13 and 13 and the precast concrete board 18 for compression of a filling part.
Further, as a method of elastically compressing and deforming the precast concrete plate, in addition to the above-described example, when excessive prestress is introduced by the release PC tension member 19 as in the third embodiment shown in FIG. In addition, the preload concrete plate 18 for compressing the filling portion may be bent downward by installing the release PC tendon 19 above the precast concrete plate 18 for compressing the filling portion. In this way, the space between the gaps 20 and 20 is widened by curving the space between the gaps for compressing the space between the gaps 20 and 20, and the space between the gaps 20 and 20 is spread. After the interstitial concrete reaches a predetermined strength capable of introducing prestress, the tension of the release PC tension member 19 is released. Thereby, the precast concrete board 18 for compressing the padding portion curved downward is going to return to its original shape. As shown in FIG. 11 (b), the interstitial concrete 14, 14 is compressed by the return force of the interstitial portion compression precast concrete, and prestress is introduced into the interstitial concrete 14, 14. In addition, it is preferable that the above-mentioned surplus prestress load is the magnitude | size which carries out elastic compression deformation larger than the shrinkage amount by the creep of concrete.

Further, as a method of bending the precast concrete board downward, in addition to the above example, it may be curved by applying a downward force to the precast concrete board as in the fourth embodiment shown in FIG. In this case, the precast concrete board 13 is curved by applying a downward force generated by loading or the like near the center of the precast concrete board 13 as shown in FIG. Thereafter, in the same manner as in the above-described example, the interstitial concrete is placed in the interstitial gaps 20, 20, and the downward force is removed after the concrete reaches a predetermined hardness. As a result, a return force is generated in which the precast concrete plate 13 that has been bent downward is returned to its original shape. Due to the return force of the precast concrete plate 13, the interstitial concrete 14, 14 is compressed as shown in FIG. 11B, and prestress is introduced into the interstitial concrete 14, 14.
In the example shown in FIG. 12, two precast concrete plates were fixed and only the precast concrete plate placed between them was elastically compressed and deformed, but it was fixed as in the fifth embodiment shown in FIG. A plurality of precast concrete plates 13, 13... May be installed between the precast concrete plates 13, 13 and the precast concrete plates 13, 13.

  Further, as a method of bending the precast concrete board downward in the fourth and fifth embodiments, as shown in FIG. 14, a method of installing a reaction force beam 31 and using hydraulic jacks 32, 32. is there. This is because the reaction beam 31 is installed on the precast concrete plates 13, 13... At a distance from the precast concrete plates 13, 13. The hydraulic jacks 32, 32 ... are installed between the force beam 31 and the precast concrete plates 13, 13 ..., and the hydraulic jacks 32, 32 ... are extended to the center of the precast concrete plates 13, 13 ... There is a method of introducing a vertically downward load to the part.

  Moreover, it is preferable that these downward loads in the vertical direction are equal to or greater than the design load. The design load refers to the maximum load load planned at the time of design.

  Further, as a method of elastically deforming the precast concrete plate 13 in the compression direction in order to introduce prestress to the concrete in the floor slab, the precast concrete plate is used as in the sixth embodiment shown in FIGS. PC tension members 51 are stretched between brackets 50 and 50 attached to both ends of 13 and tensioned to elastically deform the frecast concrete member in the direction in which the gaps 52 are widened. The tension may be released after placing the interstitial concrete (not shown) in 52, and the prestress may be introduced into the interstitial concrete by the return force in the extending direction of the precast concrete plate 13 at that time.

  Each of the brackets 50 is provided with a compression portion 53 that abuts the end surface of the fredcast concrete plate 13 and a PC tension member that is integrally provided on the compression portion 53 and extends toward the other end portion along the upper surface of the precast concrete plate 13. A fixing member 54, and a PC tension member 51 is passed through a PC tension member insertion hole formed in the fixing portion 54, which is formed in the fixing plate 55 integrally provided in an arrangement perpendicular to the longitudinal direction. It is fixed by 56.

  As the fixing device 54, a conventionally used PC tension member end fixing device such as a wedge fixing method can be used. However, as the PC tension member 51, a threaded steel rod having a male screw formed on the outer periphery is used. It is preferable to use a nut as the fixing tool 56 and screw the nut, which is the fixing tool 56, into the male screw on the outer periphery of the PC tension member 51, and fix the fixing member 54 after the tension of the PC tension member 51. .

It is a partial cross section top view between the precast concrete members integrated by the method of this invention. It is sectional drawing which shows the state which poured concrete into the gap | interval in the Example of this invention method. It is sectional drawing which shows the state which constructed the precast concrete board in the Example of this invention method on the steel girder. It is a fragmentary top view which shows the state which installed the jack in the crevice gap in the 1st Example of this invention method, and laid concrete. It is sectional drawing which shows the state which released the PC tendon in the PC tendon release hole in the 2nd Example of this invention method. It is a partial top view which shows the state before releasing PC tension material in the PC tension material release hole in 3rd Example of this invention method. It is a partial expanded sectional view which shows the PC tendon release hole in an Example same as the above. It is a fragmentary top view which shows the state which left the jacking work space in the space between gaps in the Example same as the above, and laid concrete into concrete. It is a partial expanded sectional view which shows the state which installed the jack in the jack work space same as the above. It is a fragmentary top view which shows the state which fixed the precast concrete board relatively using the steel materials in 4th Example of this invention method. (A) It is sectional drawing which shows the state which introduce | transduced the excessive prestress into the precast concrete board in 5th Example of this invention method, and curvedly deformed the precast concrete board.

(B) The above-described deformation is a cross-sectional view showing a state in which surplus prestress is released and prestress is introduced into the interstitial concrete.
(A) It is sectional drawing which shows the state which performs the curve deformation in an Example same as the above by applying downward force to the center vicinity of a precast concrete board.

(B) It is sectional drawing which shows the state which removed the downward force from the above-mentioned deformation | transformation and introduced the prestress to the concrete.
It is sectional drawing which shows the other example of the state which is applying downward force to the center vicinity of the precast concrete board in 5th Example of this invention. It is sectional drawing which shows the state which is applying downward force with the hydraulic jack to the precast concrete board in 5th Example of this invention. It is a top view which shows the method of elastically deforming to the compression direction by tension | tensile_strength of PC tension material on the upper surface with respect to the frecast concrete board of 6th Example of this invention. It is a side view same as the above. (A) It is a bending moment curve in a floor slab structure using a conventional precast plate.

(B) It is a partial longitudinal cross-sectional view of the floor slab structure using the conventional precast board.
It is the elements on larger scale which show the overlapping state of the connecting reinforcement of the floor board in the floor slab structure using the conventional precast board. It is a partial expanded longitudinal cross-sectional view which shows the other example same as the above. It is a top view which shows an example of the PC floor slab using the conventional precast concrete board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Steel girder frame 11 Steel girder for floor board support 12 Connection girder 13 Precast concrete board 13a Joint end face 13b Joint end face 14 Filled concrete 15 Filled gap side face 16 Reinforcing bar 17 Stopper 18 Precast concrete board 19 PC tension material 20 Stitch gap 21 Hydraulic jack 22 Partition 23 PC tension material release hole 24 PC tension material insertion hole 25 Jack work space 26 Jack 27 Steel material 31 Reaction beam 32 Hydraulic jack 41 Non-release PC tension material 42 Precast concrete board for partial compression 50 Bracket 51 PC tension material 52 Gap 53 Compression part 54 PC tension material fixing part 55 Fixing plate 56 Fixing tool

Claims (9)

In the prestress introduction method for the interstitial portion between the precast concrete members that introduces prestress to the interstitial portion made of cast-in-place concrete interposed between the precast concrete members adjacent to each other,
By applying a load that deforms the precast concrete member, the precast concrete member is elastically deformed in the direction in which the gap between adjacent precast concrete members is widened, and the concrete is placed in the widened gap. In addition, the intersticing between precast concrete members is characterized in that prestressing is introduced into the interstitial concrete by a return force of the precast concrete member by releasing the load after the interstitial concrete exhibits a required strength. Prestress introduction method for the club.   The precast is applied by applying a load in a direction in which a gap between the two precast concrete members is pushed and widened by a jack in a state in which the movement of the end opposite to the adjacent end of the precast concrete members adjacent to each other is restrained. 2. The method of introducing prestress into a filling portion between precast concrete members according to claim 1, wherein the concrete members are elastically deformed in the compression direction.   By applying an excessive prestress load to the elastic deformation of the precast concrete member using a PC tension material different from the PC stress material for prestress introduction necessary at the time of production when the precast concrete member is manufactured, The method of introducing prestress into a space between precast concrete members according to claim 1, wherein the surplus prestress load is released after elastically deforming in a direction in which the gap is widened and placing the space between the concrete.   The surplus prestress given at the time of manufacture of the precast concrete member is larger than the amount of shrinkage due to creep of concrete, and is a size that causes elastic compression deformation. Method.   2. The space between the precast concrete members according to claim 1, wherein an elastic deformation is applied in a direction to widen the space between the spaces between the precast concrete members by applying a downward load to the central portion of the precast concrete members and bending the precast concrete members downward. Pre-stress introduction method.   The method of introducing prestress into the interstitial portion between precast concrete members according to claim 5, wherein the downward load for bending downward is equal to or greater than the design load.   A PC tension member is stretched between brackets attached to both ends of the precast concrete member, and the PC tension member is tensioned to elastically deform the frecast concrete member in the direction in which the gap is widened. The prestress introduction method with respect to the interstitial part between precast concrete members according to claim 1, wherein prestress is introduced into the interstitial concrete by a return force of the precast concrete member by releasing the tension after placing the concrete.   The bracket includes a compression portion that abuts on an end surface of the fredcast concrete member, and a PC tension material fixing portion integrally provided on the compression portion, and the PC tension material is fixed to the fixing portion and is tensioned. The prestress introduction | transduction method with respect to the filling part between the precast concrete members of Claim 7. The precast concrete member according to claim 7 or 8, wherein a threaded steel rod having a male screw formed on the outer periphery is used as a PC tension member, and a nut screwed into the male screw is fixed to the PC tension member fixing portion after tension. Prestress introduction method for interstitial spaces.

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