KR100651606B1 - Pc column-beam joint system for underground structure and construction method thereof - Google Patents

Abstract

A PC column-beam joint structure of an underground structure and a construction method thereof are provided to improve constructability and to secure unification by increasing shear frictional resistance on the outside of a column by increasing the area of contact pressure, forming a joint of a column and a beam without any downward projecting bar and emitting the arranging progress of connectors. A PC column-beam joint structure of an underground structure is formed by installing a pair of wide PC beams(10,10') on a PC column(20), which is manufactured in a unit for one floor and provided with fixing bars(24) having screw threads projected, by inserting the ends of the wide PC beams to the fixing bars to be put over more than 50 millimeters in the perpendicular direction of the beam, coupling nuts on the fixing bars penetrated the wide PC beams and placing concrete on a joint of the PC column and the beams. A construction method of a PC column-beam joint structure comprises the steps of installing pre-manufactured PC column on the appointed site, installing a pair of wide PC beams on the column to penetrate fixing bars, coupling the column and the beams by coupling nuts to the fixing bars passed through the beams, installing half PC slabs on the beams, arranging reinforcing bars on a slab and placing top concrete on the column-beam joint and the slab.

Description

PC Column-Beam Joint System for Underground Structure and Construction Method

1 is an exploded perspective view showing the structure of the PC column-beam connection according to the present invention.

Figure 2 is a perspective view showing a wide PC beam applied to the present invention.

Figure 3 is a perspective view showing the main portion of the PC pillar-beam connection structure according to the present invention.

4 is a cross-sectional view showing the structure of the PC column-beam connection according to the present invention.

5 is a plan view showing the ground pressure area in the PC column-beam connection structure according to the present invention.

Figure 6 is a perspective view of the inlet applied to the present invention.

7A is a graph showing the load-displacement relationship according to the ground pressure area.

Figure 7b is a graph showing the maximum strength-deformation ductility relationship according to the ground pressure area.

Figure 8 is an exploded perspective view showing a conventional PC column-beam connection structure.

<Code Description of Main Parts of Drawing>

10, 10 ': wide PC beam 11: bottom of PC beam

12, 12 ': Side wall of PC beam 13: Block out part of beam bottom

14 block out portion of beam side wall portion 15 through hole

16: Reinforcing bar 20, 20 ': PC column

22, 22 ': main column of PC column 24: fixed rod

26: splice junction 26a: injection hole

26b: outlet 30: inlet

32: embedding part 34, 34 ': upper, lower plate

36: hole 40: PC slab

42: kaiser truss muscle 50: overlay concrete

The present invention relates to the joint structure of the PC column and PC beam in the underground structure to be constructed by the PC composite method and its construction method.

The PC compounding method refers to a method of integrating a structure by installing a part or whole of major structural members such as reinforced concrete columns, beams, and slabs at the factory and assembling and installing them on site, and casting field concrete on the joints between the members and the upper part of the slab.

Among the concrete produced in the factory, pre-stressed concrete is referred to as PS concrete or PSC, and usually concrete is referred to as PC concrete or PCC. In the present specification, these are collectively referred to as PC (Precast Concrete).

This construction method is a complex construction method that combines a factory production method and a site construction method, is a joining structure by a wet joint system, and is characterized by industrial construction by factory production and field assembly construction.

Therefore, the quality of the structure is good and the construction is easy because it is manufactured at the factory, and the construction is easy, and the construction period can be shortened by the early completion of the underground construction. In particular, there is little concern about the occurrence of disaster due to the low input of manpower and temporary materials.

FIG. 8 shows a structure of a junction between a PC pillar and a PC beam, and a pair of PC beams 1 and 1 'is installed on the lower pillar 3 over a predetermined length (about 15 mm) and the PC beam 1 1 '), after installing the half PC slab again, the concrete (8) is placed on the beam-column joint and the upper part of the slab at the site, and after the concrete (8) is sufficiently cured, The elliptical splice joint formed at the lower part of the main root 4 of the lower pillar 3 is inserted into the upper part of the lower pillar 3 through the through hole formed in the lower part of the upper pillar 2. 6) High strength mortar was injected into the inlet 6a so that the main root 5 of the lower pillar 3 and the main root 4 of the upper pillar 2 were connected in the splice joint 6.

In this case, however, the construction of the beam-column connection has to be carried out in order, even if the interference between the column root (5) and the joint reinforcement hoop and the lower beam-reinforcing bar (7) occurs. Not only is it difficult, but it is also difficult to fill concrete in the joints where the rebars are placed in complex, and there are many improvements to the construction.

The present invention has been made in view of the above-mentioned problems of the prior art, and by increasing the ground pressure area to increase the shear frictional resistance of the outer surface of the column, the details of the joint without the bottom protruding reinforcement in the PC beam, and accordingly the It provides the structure of the column-beam joint structure and the construction method of PC structure underground structure, which can simplify the complexity, omit the connecting material reinforcement process, and is not restricted by the construction order. Its purpose is to.

That is, the present invention relates to a PC column-beam connection structure, the application of which is limited to underground structures.

Prestressing force, crane load, vibration, impact, dry shrinkage, creep and temperature change, elastic shrinkage, support point in addition to live load, fixed load, wind load, earthquake load, earth pressure and fluid pressure Consider the effects of various loads and external actions such as floating settling.In the Concrete Structural Design Standard (established by the Ministry of Construction and Transportation), the maximum required strength is calculated instead of 1.4D in the case of the structure where the fixed load is dominant like the underground structure. It is supposed to assign 1.1D to.

This means that the dominant load of the underground structure is considered to be the gravity load, that is, the fixed load as the dominant load. In addition, the vibration characteristics of the underground structures due to the earthquake load are different from the ground structures such as bridges and buildings, which are subject to relatively large earthquake damage because the structures vibrate in response to the ground motion in the ground.

As such, it is difficult to cause relative vibration in the underground structure and the vibration once generated disappears soon. Therefore, underground structures will be dragged around if any displacement or deformation occurs in the ground during an earthquake.

Therefore, the present invention considers this behavior of the underground structure and its object is to provide a PC column-beam connection structure suitable for the behavior of the underground structure.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view showing a PC column-beam connection structure according to the present invention, Figure 2 is a perspective view showing a PC beam applied to the present invention, Figure 3 is a coupling showing the main portion of the PC column-beam connection structure according to the present invention 4 is a cross-sectional view showing the structure of the PC column-beam connection according to the present invention, FIG. 5 is a plan view showing the ground pressure area in the structure of the PC column-beam connection according to the present invention, and FIG. 6 is applied to the present invention. It is a perspective view which shows the inlet.

As shown in FIG. 1, the column-beam joint structure according to the present invention is a pair of wide PCs on a PC pillar 20, which is manufactured in a single layer and embedded with a threaded fixing rod 24 protruding at an end thereof. The ends of the beams 10 and 10 'are inserted into the fixing rod 24 so that the ends of the beams 10 and 10' extend at least 100 mm or more in the beam right angle direction and penetrate the wide PC beams 10 and 10 '. After the nut is fastened to the end of the rod 24, concrete is poured into the joint of the PC column and the beam (the area "B" in FIGS. 4 and 5) to be integrated.

In the present invention, the PC beam 10, 10 'is a ratio of the beam width to the width of the column, that is, a wide PC beam having a beam-column width ratio of 1.67 to 2.00. The strength increased by 12-16% and the displacement ductility increased by 16 ~ 26%. This phenomenon is believed to increase the cross section of concrete with increasing beam-to-column width ratio, which increases the strength after yielding of reinforcing bars, thereby increasing the strength and displacement ductility of PC beams.

Looking at the wide PC beams 10 and 10 'applied to the present invention in detail with reference to FIG. 2, the wide PC beams 10 and 10' are upwards from the bottom 11 and both ends of the bottom 11; It is formed integrally with each other and is composed of both side wall portions (12, 12 ') spaced apart from each other at a predetermined interval to form a substantially "U" shape, both ends of the bottom portion 11 and both side wall portions (12, 12') Blocked out and recessed to a predetermined depth (in Fig. 2, reference numeral 13 denotes a block out portion of the bottom portion 11, and reference numeral 14 denotes both side walls 12, 12 '). The bottom protrusion reinforcement is removed, and a plurality of slab joining reinforcing bars 16 having hooks at their ends protrude to a predetermined length in the upper portions of both side walls 12 and 12 '.

At this time, by joining the bottom 11 of the wide PC beams 10 and 10 'and the end portions of both side walls 12 and 12' out, the joints of the PC columns 20 and the beams 10 and 10 '(Fig. In the 4, 5 "B" area to form a concrete part filled with concrete, and the concrete filled in this space is constrained in all four directions to bring the effect of increasing the integrity of the joint.

Looking at the column-beam junction in more detail with reference to Figures 3 and 4, as shown in Figure 3, the beams (10, 10 ') is to the column 20 through a fixing rod 24 embedded in the column (20) The bolted joint thus resists the shear slip strength of the column-beam connection with the pretensioning force of the bolted joint, thereby resisting the interlaminar tension due to the cyclic loading.

In addition, as shown in FIG. 5, the shear length of the outer surface of the column is increased by increasing the span length of the beams 10 and 10 that span the upper surface of the column 20, that is, increasing the ground pressure area (“A” area in FIG. 5). By increasing the resistance capacity, it is possible to eliminate the bottom protruding reinforcing bar of the beam, and the inside of the column straddling surface is constrained in all four directions by the bottom 11 of the blocked-out beam and both side walls 12 and 12 '.

6 illustrates a buried opening 30 embedded in the beam 10 at a position through which the fixed rod 24 embedded in the pillar 20 penetrates, and the buried opening 30 is embedded in the beam 10. It is composed of upper and lower plate portions 34 and 34 'coupled to the upper and lower portions of the embedding portion 32 and the embedding portion 32 and exposed to the outside of the bottom portion 11 of the beam 10. At this time, the buried portion 32 is preferably made of a cylindrical wire mesh in consideration of the coupling force between the mortar and the PC beam to be filled in the buried portion 32 may be configured as a conventional pipe or corrugated pipe.

Hereinafter, a construction method of the column-beam joint according to the present invention will be described with reference to FIGS. 1 and 4.

First, the PC pillar 20 factory-fabricated and brought into the site is installed at a predetermined position, and a predetermined length (at least 100 mm in the beam direction) is provided on the pillar 20 so as to pass through the fixing rod 24 embedded in the pillar 20. , Install a pair of wide PC beams 10, 10 'over at least 50 mm in a right angled direction, and then attach the nut to a fixing rod 24 through the beams 10, 10'. 20) bolt the beams (10, 10 ') together.

Next, the half PC slab 40 is installed on the beams 10 and 10 ', the reinforcing bars 44 and 46 are placed on the slab 40, and the beam-column junction and the top of the slab are concreted at the site. Just add 50.

On the other hand, in the case of installing the pillar 20 'on the pillar 20 again, the concrete 50 is sufficiently cured and then formed in the lower part of the main root 22' of the pillar 20 'to be installed on the slab 50. Insert the main root 22 of the lower pillar 20 exposed through the ball into the upper part of the lower pillar 20 and into the elliptical splice junction 26 formed below the main root 22 'of the upper pillar 20'. The high strength mortar may be injected through the injection hole 26a to connect the main root 22 of the lower pillar 20 and the main root 22 'of the upper pillar 20' in the splice junction 26.

Figure 7a is a test body (reference specimen, SI167-156HG) and the length of the strenght with a length of 15mm and the length of the lower protruding reinforcing bar of the beam as the applied to the existing PC column-beam connection structure and the length of 50mm The load-displacement curve of the test body (S167-500HG) according to the present invention with the lower protruding rebar removed is shown, and FIG. 7B is a graph showing a comparison between maximum strength and ductility. Here, both the reference test body and the test body according to the present invention are test bodies reduced to 1/2.

As shown in Figure 7a, 7b the test specimen according to the invention the maximum load was reduced by 3.5% compared to the reference specimen, but the displacement ductility increased by 72%. In other words, a slight decrease in strength was shown, but the initial stiffness was maintained with the same slope up to the yield strength of the test specimen, and the ability to deform plastically until the end of the final experiment, ie, the ductility ability, showed low deterioration performance after the yield strength. Indicates. Therefore, it is considered to be a structural form of PC column-beam connection of underground structures that can exhibit sufficient strain energy dissipation while preventing the collapse of the structure even if excessive deformation is caused by the earthquake.

In FIG. 7B, the displacement ductility is generally defined as the ratio between the extreme displacement and the yield displacement, and the test specimen of the present invention has a ductility of 4 or more, which is about 72% improved from the conventional joint details.

As described above, according to the present invention, by increasing the ground pressure area to increase the shear friction resistance of the outer surface of the column and bolting the column and the beam, the details of the joint without the bottom protruding reinforcement in the PC beam, and accordingly the complexity of the reinforcement in the joint It can be simplified, and the connector reinforcement step is omitted, and since the construction order is not restricted, the workability is very excellent and the integrity can be secured.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, various modifications and variations are possible without departing from the spirit and scope of the invention. Thus, the claims will cover any modifications or variations that fall within the spirit of the invention.

Claims (6)

In the PC column to beam joint structure of PC structure underground structure, An end of a pair of wide PC beams 10, 10 ′ is mounted on the fixing rod 24 on the PC pillar 20, which is formed in a single layer unit and embedded with the fixing rod 24 protruding thereon. The PC post 20 after being inserted so that at least 100 mm in the beam direction and at least 50 mm in the right angle direction and fastening a nut to an end of the fixing rod 24 penetrating the wide PC beams 10 and 10 '. And PC-column-beam joint structure of a PC-structure underground structure, in which concrete is poured and integrated into the joint portion of the wide PC beam (10, 10 '). The method of claim 1, The PC beam-beam joint structure of the PC structure underground structure, characterized in that the wide PC beam (10, 10 ') has a beam-column width ratio of 1.67 to 2.00. The method of claim 2, The wide PC beam 10 is formed of a bottom portion 11 and both side wall portions 12 and 12 'integrally protruded upwards from both end portions of the bottom portion 11 and spaced apart from each other at predetermined intervals. Both ends of the bottom portion 11 and both side wall portions 12 and 12 'are blocked out and recessed, the bottom protruding reinforcement is removed, and a plurality of hooks are formed at the ends of the upper end portions of both side wall portions 12 and 12'. PC column-beam joint structure of the PC structure underground structure, characterized in that the slab coupling reinforcing bar 16 protrudes to a predetermined length. The method of claim 3, wherein The wide PC beam 10, 10 ′ through which the fixed rod 24 protruding and embedded in the PC pillar 20 penetrates a buried portion 32 and an upper and lower plate portions 34, 34 ′. (30) is embedded, the PC pillar-beam joint structure of the PC structure underground structure, characterized in that the mortar is injected after the fixing rod 24 is inserted into the buried portion (32). The method of claim 4, wherein PC part-beam joint structure of the PC structure underground structure, characterized in that the buried portion 32 of the buried hole 30 is composed of a cylindrical wire mesh. In the construction method of the PC column-beam connection of the PC structure underground structure, Installing a plurality of PC columns 20 manufactured at a factory and brought into a site at a predetermined position; A pair of wide PC beams 10 and 10 'is installed on the pillars 20 at least 100 mm in the beam direction and at least 50 mm in the beam right angle direction so as to penetrate the fixing rod 24 embedded in the PC pillar 20. And bolting the PC pillar 20 and the wide PC beams 10 and 10 'by coupling a nut to the fixing rod 24 penetrating the wide PC beams 10 and 10'; A half PC slab 40 is installed on the wide PC beams 10 and 10 ', reinforcing bars 44 and 46 are disposed on the slab 40, and then concrete (50) is formed on the beam-column joint and the slab. Method of constructing the PC column-beam connection of the PC structure underground structure comprising the step of pouring).

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