KR100441966B1 - Applying Method of Casing as the Concrete Filled Tube - Google Patents

Abstract

Top-Down is essential for boring the ground and laying foundations and pillars in it. As the boring equipment, the Reverse Circulation Drill Method (hereinafter referred to as RCD) is widely used.In the case of soft ground, a boring hole is inserted into a boring hole by inserting a casing (35), that is, a steel pipe having a circular cross section assembled in two layers. Protect the surroundings from falling down.

Sometimes during the construction, the drawing work for recovering the expensive casing 35 has failed, and later, in the process of digging, cutting and destroying it. In addition, the steel pillars (31) attached to the auxiliary steel pillars (37) and the cylindrical reinforcing steel net (26) assembled in the boring ball, pour the pier concrete (27) to be constructed in the future steel bar reinforced concrete pillars (30) In the upper part of the casing (35) to temporarily fill the sand gravel (36), etc. in the empty space, and the casing extends to the peer part, if the concrete construction is used, the casing (Oscillator) before the concrete is hardened 35) must be taken out. Then, when digging the ground by the downward method to reach the corresponding position, the column bar (33) and column strip reinforcement (34) is placed around the steel pillars (31) and the formwork is poured, and then the pillar concrete (32) is poured, peer concrete (27) Since the slime (38, Slime) floats on the top, the concrete is poured about 1m with a margin, and then the steel beam reinforced concrete pillars (30) before the construction works to break the trouble with the breaker before construction.

The present invention not only uses the casing as an auxiliary material for boring work, but also reduces the minimum thickness to a short pipe of about 12 mm instead of the complicated and difficult work as described above. Like this, it is a new method to make concrete filled tube (CFT) column 10.

General steel reinforced concrete column 30 is to wrap the reinforced concrete around the steel pillars (31) such as H-beams, but the CFT column (10) is different from filling the circular column concrete (12) in the tube (11) made of steel to be. Therefore, the permanent formwork casing is replaced in the CFT pillar (10) the essential formwork in the steel reinforced concrete column (30). In this case, the casing (CFT 11) and the circular column concrete 12 poured into the inside together serve as a strong CFT column 10.

In a general structure constructed as an RCD peer, since the diameter of the peer serving as a foundation is at least 1.5 m or more, after drawing the casing 35, the pillar concrete (32, 33, 34) is placed on the steel column (31) that has been planted in advance. Overlaid to form steel reinforced concrete pillars 30, but the CFT pillar 10 proposed in the present invention is the same diameter as the pillar and the outer diameter of the pillar can not be used too large diameter. That is, the diameter of the casing (CFT 11) is to be resolved in the range of about 0.8m, 1.0m, 1.2m or 1.5m to allow the basement pillar size on the building plane. However, the size of the above diameter is too small for the cross section of the pier foundation, which is difficult when the column shaft load is large, thus increasing the boring depth to increase the frictional resistance with the rock, and in some cases coarse steel or steel frame inside the pier foundation. It is also possible to reinforce by adding a cylindrical reinforcing bar 26 made of a member. On the other hand, even when extending the boring depth as described above, if the foundation strength is insufficient, it is reasonable to form the T-type foundation 20 by adding the foundation concrete 21 at the bottom of the CFT 11.

If the present invention is applied to the top-down method that has been applied only to large structures so far can be used casually in small and medium-sized structures, it can be more generalized when used in combination with the advanced plan of basement plywood applied separately.

Description

Applying method of casing as the concrete filled tube

2A to 2D, there are a number of clogging methods to prevent the surrounding soil 13 from collapsing when digging the basement soil, but it is the safest and shortest construction period, and does not cause ground sinking or noise pollution. Down method is widely used. For this purpose, boring should be done in the ground to install foundations and pillars in it. Large boring RCD is most widely used as boring equipment, and in the case of soft ground, casing 35, ie, steel pipe of assembly circular cross section, is used. Insert to protect the boring hole from falling down. However, depending on the boring diameter, sometimes the drawing work of the expensive casing 35, which is 60 to 70 mm or more in thickness, fails to give up and dig it in the process of digging. In addition, after planting the steel pillars 31 in the boring hole, the cylindrical reinforcing bar 26 is inserted into the lower part of the foundation and poured concrete, and then filled with sand gravel 36 and the like temporarily into the empty space inside the casing 35. And when the concrete construction on the pier part, the casing 35 should be pulled out in a timely manner using an oscillator (Oscillator) before curing.

The diameter of the CFT 11 should be resolved in the range of 0.8m, 1.0m, 1.2m or 1.5m to be used as the basement column size on the construction plane. However, since the diameter size is too small for the cross section of the peer foundation, it is difficult when the column shaft load is large, so that the boring depth is extended to increase the frictional resistance between the periphery of the peer and the foundation ground 28, and inside the peer concrete 27. It is also possible to reinforce by adding a cylindrical reinforcing bar 26 made of coarse steel or steel member. On the other hand, even when extending the boring depth as described above, if the foundation strength is insufficient, it may be reasonable to form a T-type foundation 20 by adding a bearing strength base on the upper part of the peer foundation corresponding to the bottom of the CFT (11).

In the joint surface of the CFT 11 and the foundation concrete 21, the shear sheath is enhanced by using a general shea connector 24, and the connection with the screwed reinforcement 29 uses the threaded shea connector 25 as a medium. .

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1A is a cross-sectional plan view of a concrete filled steel pipe (CFT) column 10.

1B is a longitudinal cross-sectional view of a concrete filled steel pipe (CFT) column 10 and a T-shaped foundation 20.

Figure 1c is a reinforced cross-sectional plan view of the lower portion of the concrete filled steel pipe (CFT) column 10.

1D is a plan cross-sectional view of the T-shaped foundation 20.

Figure 1e is a cross-sectional plan view of the bottom of the concrete filled steel pipe (CFT) column 10 blooms.

2A is a plan cross-sectional view of the steel reinforced concrete column 30.

2B is a longitudinal cross-sectional view of the steel reinforced concrete column 30 and the peer foundation.

Fig. 2C is a plan sectional view of the upper end of the peer foundation.

Fig. 2D is a cross sectional plan view of the lower part of the peer foundation.

<Brief description of the symbols in the drawings>

10: Concrete Filled Steel Pipe (CFT) Column 11: Concrete Filled Steel Pipe (CFT)

12: round pillar concrete 13: soil

20: T-shaped foundation 21: foundation concrete

22: foundation root 23: near the foundation

24: shea connector 25: screwed shea connector

26: cylindrical rebar mesh 27: peer concrete

28: foundation ground 29: screwed out rebar

30: steel reinforced concrete pillar 31: steel pillar

32: pillar concrete 33: pillar freckle

34: column strip reinforcement 35: casing

36: sand gravel 37: auxiliary steel pillar

38: Slime

Hereinafter, the configuration of the present invention will be described as follows. In FIGS. 1A to 1E, the CFT column 10 has sufficient composite strength for the CFT 11 and the circular column concrete 12 filling therein necessary strength for the construction structure design. It is selected by structural calculation. In the construction plan, the pre-calculated thickness of the CFT (11) is inserted into the hole drilled by the RCD boring equipment of the size that can be accepted as the basement column, and the minimum length to the lower end is to the bottom of the foundation concrete 21. If the ground is soft, it can be extended as needed.

The minimum depth of boring is such that the frictional resistance between the pier foundation and the foundation ground 28 can support the upper load during the top-down construction, and the T-shaped foundation (combined with the bearing strength foundation for all the loads after the completion of the ground construction) 20) Set the depth to support. The cylindrical reinforcing bar 26 is determined by estimating the difference between the magnitude of the load of the upper CFT column 10 and the bearing strength of the bearing base so as to support the peer foundation.

The sheer connector 24 and the screwed sheer connector 25 are used as a measure to improve the frictional resistance and the bending resistance between the bearing capacity and the CFT 11. The threaded shea connector 25 is improved on one side to facilitate welding to the CFT column 10, and the other side is made of a thread to fix the threaded reinforcing bar 29 so as to easily carry load resistance. will be.

In the construction sequence, in the process of boring with RCD, CFT 11 is inserted into the boring hole as a casing, the cylindrical reinforcing bar 26 is inserted into the CFT 11, and then the circular pillar concrete 12 is injected through the trem tube. do. Subsequently, while digging the basement, beams and slabs are attached to the CFT 11, and when the bottom layer is reached, the sheath connector 24 and the threaded shea connector 25 are welded and screwed to the reinforcing bar 29 and the foundation bar 22. The construction is completed by pouring the foundation concrete 21 after the foundation 23 is removed.

Until now, it is recognized that the top down construction should be constructed by the continuous wall construction method, but when used together with the advanced plan of basement plywood, which can be applied separately, it can be applied to small and medium-sized structures without any burden and will help to generalize it.

Conventional RCD piercing method is boring to the hard ground with a large diameter RCD of 1.5 to 3m diameter, insert the steel column 31 and the cylindrical reinforcing bar 26 into the hole and pour the concrete concrete 27. However, in the upper soft ground, bentonite liquid is sometimes used to prevent the overmolding as the size of the boring hole increases, but this may cause deterioration of the quality of the concrete, thereby preventing the collapse of the boring hole by inserting a casing 35. Doing.

The present invention limits the diameter of the RCD to less than 1.5m and design the casing as a single thin steel pipe and leave it in a boring hole and inject concrete into it to utilize it as a pillar of the building. In other words, the casing used as a construction auxiliary material is applied as a permanent structural material, which significantly reduces the construction cost compared to the conventional construction method, and the construction procedure is simple, thereby reducing the air. The lack of strength of the peer foundation due to the decrease in RCD diameter adds the bearing strength foundation to the T-shaped foundation 20. This is based on the experience that since the RCD peer foundation is based on hard ground as the foundation ground (28), most of the top of the base of the bloom is also hard ground, so that subsidence does not occur. In general, the reduction of basement construction air can be expected to be of great help to the construction industry, given that the completion of underground construction work for large buildings is freed from the greatest risks that can occur during construction.

When the present invention is applied, the top-down method that has been applied to large structures so far can be used casually even for small and medium-sized structures, and it may be more generalized when used together with the advanced plan of basement plywood applied separately.

Claims (2)

Concrete filling steel pipe installed by permanently leaving the casing (35), which is a temporary material for preventing overmolding, in the boring process in the reverse circulation (RCD) boring process; The concrete filled steel pipe 11 is used as a concrete filled steel pipe column 10 by pouring concrete therein; The concrete-filled steel pipe column 10 is configured to be a T-shaped base 20 with a sheer connector 24 and a screwed sheer connector 25 on a peer foundation; The screwed shea connector 25 is improved on the one side to be welded to the concrete-filled steel pipe (11) and the other side is threaded in the interior of the casing, characterized in that to assemble the screwed reinforcement (29) Construction method used as filling steel pipe delete