JP2006176986A - CONSTRUCTION METHOD OF PCaPC STRUCTURE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method of a PCaPC structure for solving the problem of generating large redundant stress in an outside column by shaft deformation of a beam member, when tensioning a large number of beam members, in the PCaPC structure having the beam members of continuous many spans. <P>SOLUTION: A girder beam 20 of the continuous many spans is respectively divided in the span center, and is formed into an RC girder beam member 20 having a pilaster 21 and an RC beam 22. A column member 30 is erected with respective stories, and a prestress is introduced by joining this member to the pilaster 21. The girder beam member 20 is formed into a joining part 40 in a span central part by a mechanical joint and post-placing concrete. A PC beam is joined to the pilaster 21 in the direction orthogonal to the ridge direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for constructing a precast prestressed concrete (PCaPC) structure.

  Conventionally, generally, a method for constructing a PCaPC structure composed of columns and beams is that a column member is erected using a PC steel rod, and a girder beam member (girder beam member) is arranged between a plurality of erected column members. It is inserted and a PC cable is inserted through the beam member, axial tension is applied to the beam member, and the beam member and the column member are joined together by pressure bonding to form a column beam frame, and then precast (PCa ) A composite floor slab is placed on a girder member, top concrete is placed on the upper surface to ensure floor rigidity, and the girder member is integrated to construct a frame of the structure and assemble it. is there. In this construction method, the main members are precast products, and all are made of high quality by factory production, so that it is possible to build a structure that is superior to the on-site construction method in terms of the performance and durability of the structure. This is also a method that takes into account.

  However, in such a PC structure, the number of spans increases, and the tension distance becomes long when a large number of beam members are continuously tensioned in the longitudinal direction. When such a multi-span girder member is tensioned, a large statically indefinite stress is generated in the column members located at both ends of the tension direction due to axial deformation of the girder member. FIG. 13 is a diagram for explaining this. When a large number of column members 100 are erected and tension is applied to the girder beam 101 connecting them, the stress 102 generated in the column member 100 is a large stress at both ends. It becomes. The statically indefinite stress becomes maximum at both ends of the tension direction, and the value sometimes becomes larger than the stress at the time of an earthquake.

  In such a multi-span PC structure, a pillar member having a large cross section or a large proof stress is required, and by introducing prestress to the girder beam member, an uneconomical design part may occur. In this case, there is also a technology to release the tension of the column member and slide it to release the statically indefinite stress, but it takes a large device to take such a measure, and construction management becomes complicated There are problems and realization is very difficult.

  There is a technique in which a column beam joint is a precast concrete member integrated with a beam member, and prestress is introduced into the beam (see, for example, Patent Document 1).

  In this technique, when the PC beam spans multiple spans, there is a problem that a large static destabilizing force is generated in the column members positioned on both ends of the tension direction. The pillar member has an RC structure.

  In addition, there is a construction method using a precast RC member in which a column beam joint is integrated with a beam in an ultra-high-rise RC apartment building aimed at improving construction reliability and quality (for example, see Non-Patent Document 1).

In this technique, all members are RC structures.
JP 2004-316322 A “Concrete Engineering” vol. 42, no. 9, 2004, 9 p. 32-39

  In the conventional construction method of a PC structure, when the number of spans increases and a multi-span girder member is tensioned, the outer column members (column members on both ends in the tension direction) are deformed by the axial deformation of the girder member. ) Has a problem that a large statically constant stress is generated.

  An object of the present invention is to provide a rational method for constructing a PCaPC structure in which such problems are solved by simple means.

  The PCaPC construction method of the present invention was made in order to solve the above-mentioned problems. In constructing a PCaPC structure having a continuous multi-span girder member, the machine is used as a continuous multi-span girder member. The RC member having a column shape and a joint portion for joining adjacent girder members to each other by a joint and post-cast concrete is used, and a column member is erected on the column shape for each floor. An upper beam beam member is placed on the column member, tension is applied to the column member, and the beam beam orthogonal direction beam member tightly connects both ends of the PC beam to the column-shaped joint portion for each span. Next, the PCaPC structure construction method is characterized in that the floor slab concrete of the floor is placed and the joint portions of the adjacent RC members are joined.

  The girder member used in the present invention is a RC member (reinforced concrete member) having a columnar shape obtained by dividing a continuous multi-span girder member at the center of each span. In some cases, an SRC member (steel reinforced concrete member) or an S member may be used. Since the beam members in the direction orthogonal to the columns (direction between the beams) are pressure-bonded to the joints by prestress, economical design is possible in the cross section of the beam member and the column member.

  Since the continuous multi-span girder member of the present invention is joined at the center of the span, the girder member has a structure having a joint at a location where stress is small.

  In the construction method of the PCaPC structure, the beam-orthogonal beam member is preferable because both ends of the beam member can be fastened to the column joint for each span.

  In the present invention, since the PC steel material is in one direction orthogonal to the beam direction, it is easy to fit the PC cable fixing tool in the column shape. Therefore, the complexity at the time of factory manufacture of the corner column type or column member is eliminated, and higher quality member manufacturing becomes possible. In addition, PC tension and grouting work on site can be reduced only in the vertical direction of the column members and in the direction orthogonal to the columns, leading to a reduction in PC construction costs.

  According to the present invention, a continuous multi-span girder member is an RC member with a columnar shape divided at the center of the span, and the center of the span is constructed by joining a mechanical joint of reinforcing steel and post-cast concrete. Therefore, the problem that the statically indefinite stress is generated in the column members in the vicinity of both ends in the tension direction due to the axial deformation is solved by applying the tension force to the continuous multi-span girder member.

  Since the continuous multi-span beam members are joined at the center portion of the span, the joint is a portion where the stress is small, and the number of reinforcing bars to be joined may be small.

  Since the tension caused by the PC steel is in one direction orthogonal to the direction of the beam, it is easy to fit the corner column type or the PC cable fixing tool in the column member, and it is possible to manufacture a high quality member.

  In the present invention, the column member is subjected to adjustment mortar on the column shape of the beam member on the floor, the column member is installed coaxially thereon, and the upper and lower column members are pressure-bonded with a PC steel rod. Therefore, it is not necessary to join the reinforcing bars of the beam members in the panel zone, to provide anchors, or to apply post-cast concrete. Also, no support work is required to support the beam.

  The rebar of the joint part with the column member of the continuous multi-span girder member is larger than the center part of the span, but since the PC cable is only in the direction perpendicular to the direction of the girder, it fits well in the column shape of the PC cable, This eliminates the complexity of manufacturing girders in the factory.

  Since the structure according to the present invention does not generate unnecessary statically indefinite stress, the cross section of the column member and the beam member can be reduced.

  Further, since the tension of the PC cable and the grout work in the PC cable sheath can be reduced, the PC construction process is simplified, and the PC construction cost can be reduced.

  Since the composite floor slab is installed on the span girder beam member orthogonal to the continuous multi-span, the span beam member bears most of the long-term load. The beam member orthogonal to the beam direction is pressure bonded to the columnar portion of the beam member by prestress. The static instability generated at that time works effectively for long-term loads, so it is possible to design economically the same as conventional PC structures that introduce prestress to beam members and beam members in the direction perpendicular to them. It is.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a construction method of a PCaPC structure 10 according to an embodiment of the present invention.

  In the construction method of the PCaPC structure 10 of the present invention, a continuous multi-span girder beam is divided at the center of each span, and a girder member 20 having a column shape 21 is used. The girder member 20 is joined to the adjacent girder member by a mechanical joint and post-cast concrete at a joint 40 at the center of the span. The central part of the girder beam originally has a small long-term stress, so that fewer reinforcing bars are to be joined.

  In the direction orthogonal to the column, the PC span beam is joined to the column-shaped joint.

  The girder member 20 used in the present invention is an RC member comprising a column mold 21 and a beam portion 22, as shown in a side view in FIG. This beam member 20 has a column 21 placed on a PCa column member 30 on each floor, an adjustment mortar 31b is provided on the upper surface of the column 21 of the beam member 20, and a column member 30b on the floor is erected thereon. Crimp with PC steel rod 32. There is no need to join the reinforcing bars of the beam members 20 in the panel zone, anchors or post-cast concrete, and there is no need to provide support for the beam members 20. The column member on the left side in FIG. 2 indicates a corner column member.

  The rebar of the column 21 of the beam beam member 20 is larger than the center of the span. However, since the PC cable is only in the direction orthogonal to the beam, the rebar and sheath in the column 21 are well accommodated, and complicated at the time of factory production. This is also resolved.

  In addition, since there is no tension in the multi-span direction, unnecessary statically indefinite stress is not generated in the column member at the end of the structure, and the cross section of the column and beam can be reduced. Moreover, since the PC tension and grout work in the multi-span direction can be reduced, the PC construction process and the PC construction cost can be reduced.

  Joining of the beam portion 22 of the beam portion 20 to the adjacent beam portion is performed by joining the reinforcing bars 23 to each other at the center portion of the span by the connecting tool 41 or the like, and placing the post-cast concrete 42.

  In the present invention, since the unidirectional composite floor slab is installed on the PC beam 50 in the row orthogonal direction, the PC beam 50 bears most of the long-term load. The cross beam PC direction beam is pressure bonded to the column 21 of the beam member 20 by prestress. The static instability generated at that time works effectively for a long-term load, so an economical design similar to that of a conventional PC structure is possible.

  FIG. 3 is a plan view of FIG. 2, showing the joint 40 at the center of the span of the adjacent beam member 20 and also showing the joint of the PC beam 50 in the direction orthogonal to the column direction in the column 21. The PC beam 50 is attached to the side surface of the column 21 via the joint 51, and a PC steel material is inserted into the sheath 52 to apply tension. The PC steel material in the sheath 52 is fixed in the column mold 21.

  FIG. 4 is a side view in the direction orthogonal to the columns and shows a construction method of the PC beam 50 in the direction orthogonal to the columns. The column member 30 of the floor is mounted on the column mold 21 of the lower beam beam member 20, the column mold 21 of the beam beam member 20 of the floor is mounted thereon, the PC steel material is inserted into the sheath, and the column member Tighten 30. Next, the cross beam orthogonal direction PC beam 50 is attached to the side surface of the beam member 20a on the floor through the joint, and the PC steel material is inserted and tightened.

  5 to 12 show the details of the construction process of the above embodiment.

  FIG. 5 shows a process of erecting the column member 30 on the girder member on the lower floor.

  Next, as shown in FIG. 6, the girder member 20 on the floor is placed on the column member 30. At this time, the column shape 21 of the beam member 20 is matched with the column member 30.

  FIG. 7 shows a process in which the connecting portions 40 are formed facing each other so that adjacent beam members 20 are connected to each other by a mechanical joint at the center of the span of the beam members 20.

  Next, as shown in FIG. 8, the column member 30 and the column mold 21 are bonded by pressure bonding 35.

  FIG. 9 shows a process of attaching the column beam orthogonal direction PC beam 50 to the side surface of the column 21.

  Next, as shown in FIG. 10, stress introduction 53 is performed on the beam 50.

  As shown in FIG. 11, a PC floor slab 70 is installed on the PC beam 50, and then cast-in-place slab concrete 71 is constructed as shown in FIG. At this time, the concrete construction is performed at the same time as the closing of the joint 40 of the RC girder member 20.

  14-17 is explanatory drawing of the stress which arises in the beam beam orthogonal direction PC beam 50. FIG.

  FIG. 14 shows the stress 55 due to the weight of the PC beam 50 and the weight of the floor slab when the PC beam 50 is installed.

  FIG. 15 shows the distribution of the stress 56 generated in the beam member when prestress is introduced into the PC beam 50 and the statically indefinite stress 57 generated in the column members at both ends.

  FIG. 16 is a diagram showing stresses 58 and 59 generated in the PC beam 50 and the column member when the top concrete is placed and a load (design load) is applied.

  And the stress by an earthquake load (design) becomes like 61 and 62 shown in FIG.

  According to the present invention, since the one-way composite floor slab is installed on the cross beam orthogonal direction PC beam 50, the long-term load is almost borne by the cross beam orthogonal direction PC beam 50. The beam beam orthogonal direction PC beam 50 is pressure-bonded to the column 21 of the beam member 20 by prestress. Since the indefinite stress generated at this time works effectively against a long-term load, it is possible to design economically as in the case of a conventional PC structure.

It is a side view of the structure of an Example. It is the elements on larger scale of the structure of an Example. FIG. 3 is a plan view of FIG. 2. It is a column orthogonal direction (wife side) side view of the structure of an Example. It is explanatory drawing of the construction process of an Example. It is explanatory drawing of the construction process of an Example. It is explanatory drawing of the construction process of an Example. It is explanatory drawing of the construction process of an Example. It is explanatory drawing of the construction process of an Example. It is explanatory drawing of the construction process of an Example. It is explanatory drawing of the construction process of an Example. It is explanatory drawing of the construction process of an Example. It is explanatory drawing of a multi-span statically constant stress. It is explanatory drawing of the stress distribution of a digit orthogonal direction. It is explanatory drawing of the stress distribution of a digit orthogonal direction. It is explanatory drawing of the stress distribution of a digit orthogonal direction. It is explanatory drawing of the stress distribution of a digit orthogonal direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 PCaPC structure 20, 20a Girder member 21 Column type 22 Beam part 23 Reinforcing bar 30, 30a, 30b Column member 31b Adjustment mortar 32 PC steel bar 35 Crimp joint 40 Joint part 41 Connector 42 Post-cast concrete 50 PC beam 51 Joint 52 Sheath 53 Stress introduction 55-62 Stress 70 PC slab 71 Floor slab concrete

Claims (1)

  When constructing a PCaPC structure with continuous multi-span girder members, as a continuous multi-span girder member, a joint that joins adjacent girder members with mechanical joints and post-cast concrete is the center of the span. In addition to using RC members with column types, column members are erected on the column types for each floor, and upper beam beams are placed on the column members, and tension is applied to the column members. In the cross beam direction beam member, both ends of the PC beam are fastened to the column-shaped joint for each span, and then the floor slab concrete of the floor is placed, and the adjacent RC members are joined. A method for constructing a PCaPC structure, characterized by joining parts.

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