JP2000144907A - Joint structure between inverted construction post and beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide joint structure between an inverted construction post and a beam capable of connecting the beam with high degree of accuracy of a position and simply to the inverted construction post with allowableness and, at the same time, rationalizing inverted construction skeleton work. SOLUTION: A beam 2 consisting of steel frame or precast concrete is set between inverted construction posts 1 consisting of precast concrete or concrete filled steel pipe or steel pipe. A void between the end of the beam 2 and inverted construction post is filled with shrinkage-compensating mortar 11 and, at the same time, PS steel materials 8 passing through the inverted construction post 1 are fastened with nuts 9 to fix.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection between a back strut and a beam in which, after a back strut is cast in an underground portion, a beam member is sequentially connected to the back strut while excavating the ground. Regarding the structure.

[0002]

2. Description of the Related Art In recent years, when constructing an underground structure, a reverse strut is installed in an underground portion, and then the ground is excavated to expose the reverse strut, and a beam is sequentially connected to the exposed reverse strut. There is a reverse striking method that builds an underground frame.
The underground framing work in this reverse construction method is, specifically,
Excavation work is carried out downward while supporting the upper load during construction on the steel column as the core of the RC (steel reinforced concrete) column, and the steel beam as the core of the SRC beam is built, and the column, wall, beam, floor It is a method to repeat the reinforced concrete work.

[0003]

However, in such a conventional reverse striking method, when installing the reverse strut, it is necessary to hold the upper end of the reverse strut and hang it in a suspended state. Therefore, a slight inclination is generated in the reverse strut, and it is difficult to secure the installation accuracy of the reverse strut.

[0004] When a beam is joined to the column core of a reverse strut whose mounting accuracy is not sufficiently ensured, the position of the beam is also shifted. However, steel beams can be easily rebuilt in the reverse-casting method, as in the case of general steel-frame construction, since the upper-floor skeleton construction has been completed and the reverse struts are restrained by the surrounding ground. Can not do.

[0005] For this reason, it is necessary to absorb errors mainly due to the accuracy of the installation of the back strut by the manufacture of a steel beam reflecting the measured dimensions after excavation, and strict process control is required in the construction. . That is, since the construction accuracy of the back strut is relatively poor, when building a steel beam by welding, it is necessary to adjust the length of the steel beam by cutting the length of the steel beam based on the measured dimensions after excavation. Becomes

On the other hand, column and beam construction accompanied with reinforced concrete construction involves complicated rebar and formwork construction, complicated construction of assembling a formwork support on soil concrete placed on an excavation floor, and concrete strength. There is a problem such as the occurrence of curing which inhibits the shortening of the process due to the presence of this until expression.

Accordingly, an object of the present invention is to solve the above-mentioned problems, to allow easy connection of beams with good positional accuracy, with tolerance to a back-strut support, and to rationalize the construction of a back-stroke frame. It is an object of the present invention to provide a connection structure between a reverse strut and a beam that can be achieved.

[0008]

In order to achieve the above object, a connection structure between a back strut and a beam according to the present invention is provided between a back strut made of either precast concrete or concrete-filled steel pipe or steel pipe. A beam made of steel frame or precast concrete is set, and the gap between the end of the beam and the striking strut is filled with grout material, and the striking strut is inserted into the end of the beam through a steel material penetrated therethrough. The part is fastened by a fastening member.

A structure in which a beam is press-bonded to a counter strut using a steel material to which a tightening force is introduced through a grout material, and a construction error can be easily absorbed by a gap filled with the grout material. There is no need to require high accuracy for the installation of the struts and the back struts. In addition, since the beam is fastened using a steel material penetrating the reverse strut, the work of welding the steel frame is eliminated.

Therefore, it is possible to use either a PC (precast concrete) column, a CFT (concrete-filled steel pipe) column or a steel pipe column as the back strut and further use a steel beam or a PC (precast concrete) beam as the beam. As a result, most labor-intensive rebar and formwork work with low labor productivity can be reduced. For this reason, a significant improvement in productivity can be expected.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment. 1 and 2 show an embodiment of a connection structure between a back strut and a beam according to the present invention. FIG. 1 is a longitudinal sectional view of a connection portion between a back strut 1 and a beam 2, and FIG. Prop 1
FIG. 3 is a plan view of a connection portion between the beam and a beam 2.

As shown in FIG. 3, a beam 2 is set by a crane 4 on a digging floor 3 between a striking column 1 installed at a predetermined interval in an underground portion. In the figure, 5 is a cast-in-place concrete pile provided at the lower part of the reverse strut 1, and 6 is a retaining wall.

In the case of this embodiment, as shown in FIGS. 1 and 2, the back strut 1 is made of a CFT (concrete-filled steel pipe) column in which concrete 1b is filled in a rectangular steel pipe 1a having a rectangular cross section. Reference numeral 2 is a steel beam made of H-section steel. This is because rebar and formwork work is not required. Therefore, from the same viewpoint, PC (precast concrete) is used as the back strut 1 instead of the CFT column.
A column or a steel tube column can be used, and a PC beam can be used as the beam 2 instead of a steel beam.

When the steel beam 2 is set between the reverse struts 1, the rectangular end plate 7 at the end of the steel beam 2 faces the side surface of the reverse strut 1 from four directions.

Thereafter, the gap between the end plate 7 at the end of the steel beam 2 and the side surface of the back strut 1 is filled with a non-shrink mortar 11 as a grout material.

Further, the end plate 7 of the steel beam 2
The end of a rod-shaped PS steel material 8 penetrated through the reverse strut 1 is inserted through the back strut 1, and the PS steel material 8 is tightened by a nut 9 as a fastening member screwed to the protruding end thereof, and a tightening force is applied. be introduced.

That is, a sheath 10 usually used together with a PS steel material 8 for inputting PS (prestress) is provided in advance in the reverse strut 1 in a penetrating state corresponding to a position where the PS steel material 8 is to be passed. The PS steel material 8 is passed through the sheath 10. Then, both ends of the PS steel material 8 are projected to the other side through small holes of the end plate 7 of the steel beam 2, and a nut 9 as a fastening member is screwed into a threaded portion of the projected end and tightened. Thereby, the steel beam 2 is firmly joined to the reverse strut 1. In particular, since the structure is such that the steel beam 2 is fastened using the PS steel material 8 penetrating the reverse strut 1, the work of welding the steel frame is unnecessary.

As described above, the present embodiment is improved as described below in order to rationalize the reverse hitting work. (1) In order to rationalize the construction of the back strut 1, a CFT column that does not require rebar and formwork will be adopted as the back strut 1. (2) In order to rationalize the construction of the beam 2, the structure of the beam 2 will be a pure steel frame that does not require rebar and formwork. (3) In order to make it easy to cope with the construction error of the installation of the reverse strut 1, a steel beam using the PS steel material 8 into which the tightening force is introduced, that is, by the crimping method which can easily absorb the construction error. Non-shrink mortar 11
The column / beam joint is constituted by a structure that is joined through the joint.

With this improvement, the following effects can be expected.

(A) Labor-intensive steel bars with low labor productivity
Since most of the formwork work can be reduced, significant productivity improvement can be expected. In other words, in the underground construction of the reverse driving method, the existing SRC columns and SRC beams are used to build
Compared with the case where the reinforced concrete work of the wall, the beam and the floor is repeatedly performed, complicated work typified by the work of the reinforced concrete, the formwork and the concrete of the column and the beam is not required, and the productivity can be improved.

(B) The CFT column used for the back strut 1 has the same stress transmission characteristics at the column-beam joint as that of the reinforced concrete. Therefore, it is necessary to provide a diaphragm for supporting the beam which requires much time and labor for steel frame processing. Therefore, the cost of manufacturing a steel frame can be reduced.

(C) A structure in which the steel beam 2 is pressure-bonded to the side surface of the back strut 1 by the PS steel material 8 via the non-shrink mortar 11, and the construction error of the back strut 1 is Since it can be absorbed by the mortar filling allowance, it is not necessary to adjust the steel frame dimensions based on the actually measured values, and it is possible to reduce the steel frame manufacturing cost and smoothly complete the process.

(D) By the synergistic effect of the above advantages, it is possible to greatly shorten the construction period and reduce the on-site labor cost.

In the above embodiment, the steel beam 2 is connected to the back strut 1
After grouting the gap between the end of the steel beam 2 and the back strut 1 with the non-shrink mortar 11, wait for the strength to develop and tighten with the PS steel material 8 penetrated through the back strut 1. To join the steel beam 2 to the reverse strut 1, but the end of the steel beam 2 is
After tightening and joining with the steel material 8, the gap between the end of the steel beam 2 and the back strut 1 can be grouted with non-shrink mortar.

This embodiment also has a structure in which the steel beam 2 is pressure-bonded to the side surface of the reverse strut 1 via the non-shrinkable mortar 11 while utilizing the tightening force introduced into the PS steel material 8. Since the construction error can be easily absorbed by the gap to be filled, it is not necessary to request the back strut 1 to have high accuracy.

[0026]

As described above, according to the present invention, there is provided a structure in which a beam is press-bonded to a counter strut using a steel material to which a tightening force is introduced via a grout material, and the grout material is filled. Since gaps can easily absorb construction errors, there is no need to require high accuracy in beam dimensions and in building back struts. Further, since the beam is fastened by using a bar-shaped steel material penetrating the reverse strut, the work of welding the steel frame is eliminated.

Therefore, the PC column or CFT is used as the reverse strut.
Either a column or a steel pipe column can be used, and further, a steel beam or a PC beam can be used for the beam, so that most labor-intensive rebar and formwork work with low labor productivity can be reduced. For this reason,
It can be expected to greatly improve productivity.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a connection structure between a reverse strut and a beam according to an embodiment of the present invention.

FIG. 2 is a plan view of a connection structure between a reverse strut and a beam according to an embodiment of the present invention.

FIG. 3 is a view showing a state of underground skeleton construction by a reverse striking method according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reverse strut 1a Square steel pipe 1b Concrete 2 Beam 3 Excavation floor 4 Beam crane 5 Cast-in-place concrete pile 6 Retaining wall 7 End plate 8 Bar-shaped steel material 9 Nut (fastening member) 10 Sheath 11 Non-shrink mortar (grout material)

Claims (1)

[Claims] 1. A beam made of steel frame or precast concrete is set between a striking strut made of either precast concrete or concrete-filled steel pipe or steel pipe, and a gap between an end of the beam and the striking strut is set. Characterized in that the grouting material is filled into the backing strut and the end of the beam is fastened to the striking strut by a fastening member via a steel material penetrating the grouting strut.