JP2619685B2 - Construction method of reinforced concrete columns - Google Patents

Description

The present invention relates to a method for constructing a reinforced concrete column.

<Prior Art> A concrete column is composed of a vertical main reinforcing bar and a shear reinforcing bar that restrains the surrounding area.

In such conventional structures, the amount of shear reinforcement must be increased in order to increase the strength of the column.

<Problems of the conventional technology> However, if the reinforcement amount is increased, the interval between the reinforcing bars becomes narrow, and the flowability of the concrete is hindered, and it becomes difficult to place the concrete. Therefore, there is a limit in maintaining the quality of the concrete. is there.

In addition, in the conventional structure, when the column is subjected to repeated bending and shearing forces, it is difficult to maintain its hysteresis characteristics in the shape of a spindle with large energy consumption, and the strength after the maximum strength rapidly deteriorates. Brittle fracture was likely to occur.

As a structure that improves this point, a structure in which reinforcing bars are arranged in an X-shape has also been developed.

This is a structure to improve the seismic resistance of the RC structure, prevent brittle fracture, and ensure sufficient altitude and toughness.

However, even with this X-shaped reinforcing bar structure, when the acting axial force increases, concrete breakage increases sharply along the X-shaped main reinforcing bar, resulting in deterioration of stickiness and fragile breakage. It has been known.

<Object of the present invention> The present invention has been made in order to improve the above-mentioned drawbacks, and an object of the present invention is to provide the following construction method.

<A> Method that can secure sufficient toughness even when high axial force is applied by using X-type reinforcing bars <B> Method of easy concrete placement <C> Omit use of formwork Possible Methods <Configuration of the Present Invention> First, members used in the working examples of the present invention will be described.

<B> X-type reinforcing bar A structure in which a plurality of reinforcing bars having a certain angle from the floor 2 are assembled into an X-type is referred to as an X-type reinforcing bar 1.

<B> Structure of Formwork The formwork used in the construction method of the present invention is a steel formwork 3 assembled around a group of assembled X streaks.

The steel form 3 can be used in a steel pipe or a steel box.

It is also possible to fix the outer surface of the steel formwork 3 by spraying or attaching a refractory coating.

The length of the steel form 3 is slightly shorter than the distance between the floor 2 and the upper slab 4 (for example, about 5 mm up and down).

 Then, no axial force acts on the steel mold 3.

<C> Member for attachment to beam The upper part of the column will intersect with the beam.

For this purpose, a steel plate cut into an H shape is combined in a cross shape, and this is configured as a support leg 5 for a reinforcing bar.

That is, the support leg 5 has four engaging legs 51 projecting upward and downward, and a reinforcing bar holding surface 52 is provided between the engaging legs 51.
Is configured.

<Construction method> Next, a construction method will be described.

<A> Assembling of X-reinforcement The X-reinforcement 1 is constructed by assembling the main reinforcement of the column in an X shape on the upper surface of the floor 2.

<B> Assembling the Formwork The steel formwork 3 is assembled so as to surround the periphery of the X streak 1.

The steel formwork 3 is different from a conventional wooden formwork, and is already integrally formed. Therefore, the steel formwork 3 can be suspended from above the assembled X streaks 1 and set.

A low-level (for example, about 5 mm) pier made of easily removable wood or the like is prepared above and below the steel formwork 3 and removed after the concrete has hardened.

It is also possible to apply or spray a known refractory coating material on the outer surface of the steel formwork 3.

<C> Assembling the lower beam reinforcement 6 The lower beam reinforcement 6 of the horizontal beam reinforcement 6 is mounted on the upper part of the steel formwork 3.

The beam reinforcement 6 group is set crossing the cross at the upper part of the steel formwork 3, but as it is, the constraint with the steel formwork 3 is not sufficient.

Therefore, the reinforcing bar holding surface 52 of the support leg 5 is mounted on the beam bar 6 group, and the engaging leg 51 is set in a state of being inserted into the steel formwork 3.

As a result, even if the lower beam reinforcement 6 moves, its range is limited to only between the engagement legs 51.

<D> Assembly of upper beam reinforcement Next, a group of beam reinforcements 6 is mounted on the upper surface of the reinforcing bar holding surface 52 on the upper side of the support leg 5.

Since the engaging legs 51 protrude around the reinforcing bar holding surface 52, the free movement of the group of beam bars 6 is also restricted.

Note that the above is an explanation in which the assembling order is disassembled for easy understanding, and in practice, the support legs 5 and the upper and lower beam reinforcements 6 are assembled on the ground, and are lifted as they are and placed on the steel form 3. It is also possible to set.

<E> Casting concrete Concrete is cast inside the steel formwork 3.

The construction method in this case is the same as that of the related art, but since there is no stirrup inside, the concrete column 7 of good quality can be constructed without obstructing the fluidity of the concrete.

<Comparative Example> The hysteresis curves of the case where parallel reinforcing bars are provided inside the steel formwork and the case where X-type bars are provided are compared in FIG.

As shown in this figure, it is clear that the toughness is improved in the case of the structure of the present invention (steel pipe form + X-type reinforcing bar).

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be expected.

<B> There is no stirrup inside the pillar.

Therefore, the fluidity of the concrete is hardly hindered, the casting is easy, and a high-quality structure can be constructed.

<B> Concrete is restrained from the outer periphery by the steel formwork.

 Therefore, large toughness can be exhibited.

<C> There is no need to prepare and assemble a mold separately from the structure.

 Therefore, construction is quick and easy.

<D> In the present invention, the use of the supporting legs can restrict the arrangement position of the beam bars. Therefore, there is no need for the work of positioning the beam bars, and the workability can be improved.

Furthermore, since the beam reinforcement can be arranged at an accurate position, the beam construction accuracy is improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 A perspective view of an assembled state FIG. 2 to FIG.

Claims (1)

(57) [Claims] 1. A method of constructing a reinforced concrete column, comprising assembling a reinforcing steel bar in an X shape on a floor, surrounding the periphery with a steel formwork, and pouring concrete into the formwork. A method of constructing a reinforced concrete column, wherein an intersection with an upper beam is constructed at an upper end of the formwork by using a support leg to restrict the arrangement position of a beam bar.