KR20250164066A - Construction method and apparatus of the core wall structure on the ground floor using steel column and girder inside the core wall in 1st basement in top down construction - Google Patents

Abstract

The present invention relates to a method for starting a ground floor core section (core wall of reinforced concrete structure of the first floor above ground) in a top-down construction method, and more specifically, to a construction method in which, after constructing an underground reverse excavation column (PRD), a excavation is made 4 to 5 m downward from the ground (the floor of the first floor above ground), a steel column is erected by connecting it to the reverse excavation column, and after pouring a floor steel beam of the first floor above ground, a frame beam of the lower part of the first floor above ground (-2.0 to 3.0 m), and floor concrete of the first floor above ground, a framework is formed above ground, and after excavating the remaining part of the first basement floor, excavating the first part of the second basement floor (-2.0 m below the floor of the first basement floor), and after completing the floor framework of the first basement floor, the first basement floor core wall is constructed.

Description

Construction method and apparatus of the core wall structure on the ground floor using steel columns and girders inside the core wall in the first basement in top-down construction

The present invention relates to a construction method for starting the ground floor core section (core wall of the first floor reinforced concrete structure) by installing steel columns in the core wall of the first floor above ground in an underground steel-reinforced concrete structure (SRC) in a top-down construction method.

This relates to a construction method in which, after constructing a PRD (Prestressed Reinforced Demolition) column, a excavation is made 4 to 5 m (varies depending on the site) downward from the first floor above ground, a steel column is erected by connecting it to the PRD column, the first floor steel beam, the lower part of the first floor (-3.0 m to 4.0 m) of the first floor above ground, and the first floor concrete is poured, and then the frame is constructed upward to the first floor above ground, while the remaining excavation of the first basement floor, the first excavation of the second basement floor (-2.0 m below the first basement floor), and then the core wall of the first basement floor is constructed after the first basement floor frame is completed.

Top-down construction usually involves earth retaining walls, underground reverse excavation columns (PRD, RCD), excavation of the first basement floor, the first floor floor (steel beam, deck, rebar, concrete), excavation of the second basement floor, and then the first basement floor. In this way, the floor and mat are constructed up to the fifth or seventh basement floor, and then a U-turn is made to construct vertical core walls and columns upwards from the seventh basement floor to complete the basement.

Meanwhile, construction on the ground floor usually begins with the construction of the basement floor, followed by the construction of the basement core wall, and then construction of the basement core wall and the second floor above ground.

However, the lengthy preparatory work required prior to the commencement of ground floor core construction delays ground floor construction, prolonging the overall construction period (up to 48 months, etc.). Therefore, a new construction method is needed that allows ground floor core construction from the initial excavation stage.

In order to solve the above technical problem, the present invention provides a construction method and device that allows construction of the core of the above-ground floor even when the entire wall of the above-ground floor is not completed by installing a steel structure and a frame beam on the upper part of the core wall of the above-ground floor after excavating the portion of the above-ground floor, thereby constructing a foundation as a basis for construction of the above-ground floor.

In order to solve the above-mentioned technical problem, the present invention is a top-down construction site

Steps for installing the retaining wall;

Eastern part underground pile (10) insertion stage (1st floor above ground to lowest floor);

Basement 1st floor 1st excavation stage (1st floor above ground -3.0~5.0m)

Installation stage of steel columns (20) inside the core wall of the first floor above ground;

Installation stage of the steel beam on the first floor above ground;

Step 101: pouring of floor core and floor concrete on the first floor from the section -3.0 to -4.0 m above ground;

First floor core 1st concrete pouring stage (102);

Stage 2 of excavation of the remaining excavation area on the first basement floor and installation of connecting members for underground piles (10) (30);

Stage 1: Core 2 above ground floor and floor concrete pouring on the 2nd floor above ground (103);

Continuous construction stage of core walls above the second floor above ground;

Stage of installing steel beams on the first basement floor after the first excavation of the second basement floor;

Basement 1st floor concrete pouring stage;

Basement 1st floor core lower wall pouring stage;

Excavation of the 3rd basement floor and construction of the 2nd basement floor frame;

Downward excavation to the lowest level and each floor/foundation (repeat) step;

Construction stage of the uppermost core wall ~ the second basement floor core wall;

Completion stage of underground core wall skeleton construction; and

It consists of a stage where the skeleton construction is repeated on each floor up to the top floor (rooftop) and the skeleton construction is completed.

According to the present invention, the following effects can be expected.

In top-down construction, a steel structure and a frame beam are formed in the section of -3.0m to -4.0m downward from the first floor above ground in the core section of the first basement floor, and thus the frame work can be continuously constructed upward from the first floor above ground.

Even if the entire basement core wall is not completed (only the upper part is completed), the ground floor core construction can begin.

After excavating a section of -3.0m to -4.0m downward from the first floor above ground, the first floor edge beam can be constructed at that height and the formwork can be dismantled. Therefore, work (installation of scaffolding, rebar, installation of formwork, dismantling of scaffolding) in a high location (ceiling height of the first basement floor) / space due to the 6.0m to 8.0m floor height of the first basement floor is eliminated, thereby increasing work productivity and work safety.

By completing the basement core wall early, the overall construction period can be shortened by starting the ground floor construction early in the excavation process.

Figures 1 to 3 are flow charts of a method for constructing a first-floor core and an external wall using a first-floor steel member in a top-down reverse-thrust method of a wall structure according to the present invention.
Figures 4 to 13 are examples of a method for constructing a first-floor core and an external wall using a first-floor steel member in a top-down reverse-thrust method of a wall structure according to the present invention.

Below is a flow chart of a method for constructing a first-floor core wall using a first-floor basement frame beam in a top-down reverse excavation according to the present invention.

Figures 1 to 3 are flow charts of a method for constructing a core wall on the first floor above ground using a basement floor edge beam in a top-down reverse-thrust method according to the present invention.

Step 1 (S10) installs a retaining wall.

In the usual way, the soil retaining wall is constructed along the boundary of the construction site using CIP and slurry wall (ground continuous wall).

Step 2 (S20) involves driving underground piles (10) into the eastern part (from the first floor above ground to the lowest floor).

In the conventional manner, the underground piles (10) of the eastern part are first constructed using PRD and RCD methods. Next, the underground piles (10) of the remaining parts between the apartment buildings are constructed.

Step 3 (S30) is the first excavation of the basement level (ground level -3.0~4.0m).

According to the features of the present invention, in the eastern part (outer perimeter (building exterior) column, core wall) including the area going up to the upper floor, a excavation is made from the first floor above ground (top of underground pile (10), ground) downward to a height of -3.0 m to 4.0 m at which a rim beam (101) (the first floor above ground and a beam 3.0 m high below it) can be constructed. The excavation depth may vary depending on the site.

The area immediately beneath the ground is composed of sedimentary soil, not bedrock. This allows for a quick excavation period, as the soil can be removed using a forklift within a few days. Once the bottom surface has been reached, pouring a slab of concrete beneath the perimeter beam facilitates the installation of a slab support for the perimeter beam concrete pour.

Step 4 (S40) installs the steel beam (1b) on the first floor above ground.

According to the features of the present invention, the first floor steel beam (1b) is installed by connecting it to the underground pile (10). Accordingly, the first floor steel beam of the eastern section is installed.

The structure of the border guard device is as follows.

The underground pile (10) is connected to the steel column (20) of the edge beam (101), and then the steel beam (1b) inside the core wall forms a square edge beam along the core wall. In case a small-sized steel beam (1b) inside the core wall is installed depending on the thickness of the core wall, in order to increase the structural strength, the steel beams can be installed in two stages above and below the edge beam, or configured in a further reinforced truss shape. In case of a two-stage installation, one is installed on the upper part of the edge beam (the floor of the first floor above ground), and one (1c) is installed on the first floor above ground - 2.5 to 4.0 m level.

Vertical columns or inclined members (1d) may be installed inside the border beam.

Steel beams can also be installed in the partition walls inside the core.

If the steel column (20) is omitted, the steel beam (1b) and the lower steel beam (1c) can be directly connected and installed to the underground reverse pile (10).

Step 5 (S50) involves installing the reinforcing bars and formwork of the perimeter beam so that concrete can be poured onto the perimeter beam on the first basement floor.

Step 6 (S60) is to construct the first floor deck plate, deck reinforcement, and electrical/equipment piping for the first floor concrete pouring.

Step 7 (S70) is to receive inspection from the supervision team before pouring concrete (whether construction was done according to the drawings).

Step 8 (S80) is the first excavation height of the first basement floor (-3.0 to -4.0 m section from the first floor above ground) ~ the first floor floor core (first floor floor edge beam) and the first floor floor concrete pouring (101).

According to the features of the present invention, in the edge beam, at a height (location) of -3.0 to -4.0 m downward from the first floor above ground, reinforcing bars are installed around the steel beam and steel column, and the lower part of the beam is finished with a beam bottom formwork or wire mesh to prevent concrete from flowing down. After that, the wall formwork is installed, and then the edge beam concrete is poured. Subsequently, the first floor concrete is poured.

Then, the steel-reinforced concrete (SRC) is completed in a T shape from below the ground floor. The perimeter beam and the ground floor concrete can be poured separately or simultaneously. That is, the vertical perimeter beam can be poured first, and the horizontal 1st floor slab can be poured later. Alternatively, the 1st floor slab can be poured first, and then the basement 1st floor perimeter beam can be poured later. The perimeter beam (morning) and the 1st floor slab (afternoon) can be poured simultaneously on the same day.

From this state, the foundation for starting the first floor core wall is prepared.

The basement 1st floor frame is structured to secure horizontal support by connecting the floor of the above-ground 1st floor, while transmitting the load of the vertical wall above the above-ground 1st floor to the ground through the underground pile (10).

In the case where there are columns in the outer perimeter of the eastern part, the horizontal force is increased by pouring concrete in a T shape around the ceiling of the columns on the first basement floor and the floor of the first floor above ground.

(In the past, instead of pouring the slab for the column section, an opening (hole) measuring 1m x 1m was made and the pouring was done at the last stage when the column covering was raised from the underground. This is because if the floor above the column is poured with concrete, it is difficult to pour the concrete for the column on the first basement floor.)

According to these structural features according to the characteristics of the present invention, the thickness of the edge beam and the size and quantity of the steel beam inside the beam are determined according to the structural calculation (before pouring the underground foundation, before completion of the underground frame, and when the core wall of the first basement floor is completed, the height of the ground floor construction and the vertical and horizontal loads).

From the completion of the basement 1st floor core wall, as before, the basement 1st floor core wall and underground pile (10) bear the upper load, so the structural calculation of the edge beam must be performed by reflecting the ground floor height (number of floors) at the time of completion of the basement 1st floor core wall.

Step 9 (S90) is the first concrete pouring (102) of the core on the first floor above ground.

According to the features of the present invention, after the perimeter beams of the first floor are completed, construction of the ground floor begins upward. Since the first floor, which is typically the lobby, has a high ceiling, concrete is poured in two stages, with the core wall of the first floor being constructed in the first stage.

To do this, the core wall reinforcement and formwork are installed on the first floor, and then the first floor core primary concrete is poured.

Step 10 (S100) involves excavating the second remaining excavation site on the first basement floor and installing the connecting member of the underground pile (10) (30).

According to the features of the present invention, after the construction of the lower edge beam on the first floor above ground, the formwork and support of the edge beam are dismantled after a concrete curing period. Thereafter, the secondary remaining excavation of the first basement floor is carried out downwards using the conventional method.

When the underground pile (10) is exposed to the ground of the first basement floor according to the excavation, the soil on the surface of the underground pile (10) is cleaned, and then a connecting member is installed by welding (30). The connecting member (30) is commonly called a T-Bar, and a number of stud bolts (31) are attached to one side to increase the bonding strength with the concrete.

Step 11 (S110) involves pouring concrete for the second core wall of the first floor and the second floor (103).

According to the features of the present invention, after the first concrete pouring of the core wall of the first floor above ground, the remaining wall of the first basement floor and the floor concrete of the second floor above ground are poured in a T shape.

Step 12 (S120) is to continuously construct core walls above the second floor.

Afterwards, the frame of the second floor or higher is constructed using the conventional method.

Step 13 (S130) involves excavating the first basement level and installing the steel beam on the basement level.

Meanwhile, in the basement, the first excavation of the second basement floor is performed, and the excavation is performed downwardly about -2.0m from the floor of the first basement floor in order to install the floor steel beams (301, 302) of the first basement floor. The reason why only -2.0m is first excavated for the first excavation of the second basement floor is because it takes a lot of time to excavate the entire second basement floor, and it is to enable the steel frame workers for installing the floor steel beams of the first basement floor to easily and safely install brackets on underground piles, install the steel beams, bolt, and weld from their own height from the ground. Once the excavation of the second basement floor is completed, the steel beams are installed from the inside by a crane. Conventionally, the steel frame was installed upwardly from the floor height of the second basement floor, but according to the present invention, the floor steel beams of the first basement floor are installed downwardly by a crane from a height of -2.0m of the first basement floor.

Once the steel beam installation and welding are completed, the second excavation of the second basement level will continue.

Step 14 (S140) is to pour concrete for the basement floor.

Once the basement 1st floor steel beam is installed, the deck plate is installed in the conventional manner, and then the basement 1st floor concrete (104) is poured after the steel bars, electrical and equipment piping are installed.

Step 15 (S150) involves pouring the first concrete for the core wall of the first basement floor.

When the basement floor is completed, the basement floor is divided into two stages because it has a high ceiling, and concrete (105) is poured into the basement floor core wall to the first height using the conventional method.

Step 16 (S160) is to pour the second (remaining) core wall of the first basement floor.

After the first concrete pouring of the basement 1st floor core wall, scaffolding, reinforcing bars, and formwork are installed, and then the remaining basement 1st floor wall concrete (106) is poured. The basement 1st floor core wall concrete below the edge beam is poured in one or two stages, and this varies depending on the site.

With this, the skeleton of the basement core wall has been completed, and construction is currently underway on the 3rd to 5th floors above ground. The 1st and 2nd floors above ground have high ceilings, and the 3rd floor above ground is typically a pit or transition floor in apartments or mixed-use buildings. For the 4th floor above ground, a considerable amount of time is required for the external formwork (gang form), internal walls, and slab formwork setting. Therefore, the completion of the basement core wall and the 3rd to 4th floors will occur at the same time.

Step 17 (S170) involves excavating the 3rd basement floor and constructing the 2nd basement floor frame.

In the usual way, the third basement floor is excavated and then the second basement floor is constructed.

Step 18 (S180) involves excavating down to the lowest level and constructing the floor/foundation (repeatedly) on each floor. Using the conventional method, excavation is performed on each floor down to the lowest level (5th and 7th basement levels), and then the floors are constructed downward using reverse excavation.

Step 19 (S190) involves constructing the skeleton from the lowest core wall to the second basement level using a sequential method. Following the construction of the lowest floor's slab (mat), a U-turn is made to construct the vertical underground members upward. Since the walls up to the first basement level have already been constructed, construction proceeds from the lowest level to the second basement level.

Step 20 (S200) completes the underground core wall skeleton construction. Once the underground skeleton is complete, the ground floor can be extended to the rooftop without any floor restrictions.

Step 21 (S210) involves repeating the skeletal construction on each floor up to the rooftop and completing the skeletal construction. The skeletal construction is completed by completing the skeletal construction up to the rooftop. Typically, finishing work (interior decoration) takes approximately 10 to 11 months after the skeletal construction is completed, and construction is completed and occupancy begins.

Figures 4 to 47 are examples of a method for constructing a core wall on the first floor above ground using a basement floor edge beam in a top-down reverse excavation work according to the present invention.

Figure 4 is an example of construction in which an underground pile (10) is driven into the ground according to a conventional method.

Figure 5 shows the underground ground additionally colored.

Figure 6 shows the first excavation (100) -3.0m on the first basement floor in color.

Fig. 7 shows a steel column (20) of a basement first floor frame beam installed at an internal location of a core wall according to a feature of the present invention.

Figure 8 is an enlarged view of Figure 7.

Fig. 9 shows concrete poured on the first basement floor edge beam according to a feature of the present invention.

Figure 10 illustrates the device configuration of a first-floor basement frame beam according to a feature of the present invention. Frame beam columns are installed on underground piles, and upper steel beams, lower steel beams, vertical columns, or inclined members of the frame beam are installed to form a steel structure.

Fig. 11 is a plan view of a perimeter beam according to a feature of the present invention. The perimeter beam (101) is connected to a steel column (20) of an underground reverse pile (10), and then a steel beam (1b) is installed. A lower steel beam (1c) and a sloped member (vertical column) (1d) are installed below. If the steel column (20) is omitted, the steel beam (1b) and the lower steel beam (1c) can be directly connected and installed to the underground reverse pile (10).

Figures 12 and 13 are detailed views of Figure 11.

The underground pile (10) is a thick steel column constructed according to a conventional method, measuring 43 cm in width, 49 cm in height, and 7 cm in thickness. It is installed to a depth of approximately 35 m from the floor of the first floor above ground to the foundation of the lowest floors of the sixth to eighth floors underground, and serves to transfer the load of the ground floor to the underground. More than 10 of them are constructed at intervals of 5 to 6 m at a distance of 10 cm from the square core wall.

The steel frame column (20) of the border is connected to the underground pile (10) through a connecting material (steel plate) and is 20 cm wide and 20 cm long.

The thickness of the core wall is 40 cm, and the covering thickness excluding the steel column (20) and steel beam (1b) is 10 cm on each side, and wall reinforcement is installed in that area.

The steel beam (1b) on the first floor above ground has a thickness of 20 cm and its height is determined based on structural calculations. Stud bolts (31) are attached on both sides to increase the bonding strength between the beam and concrete (not shown).

The first floor steel beam (1b) can be configured in a truss shape in two stages, one at the height of the first floor and one at the lower level of the edge beam (1c).

Additional inclined members and vertical steel columns (1d) may be installed.

The edging beam (101) is constructed by installing steel frames, reinforcing bars, and formwork (installing a support beam from the excavation level of the first basement floor), and then pouring concrete into the edging beam (core height 2.5 m, core wall thickness 40 cm) and the first floor above ground (30 cm) in a T-shape by pouring concrete separately or simultaneously, and is constructed together with the core interior, exterior wall, and exterior perimeter columns, thereby forming a strong structural strength.

The method for starting a core wall on the first floor above ground using a steel structure and a frame beam on the first basement floor in a top-down reverse excavation work according to the present invention proceeds to the ground floor by reinforcing the frame beam on the first floor floor level with a steel structure, and since the reverse excavation structure can be implemented even on the first basement floor, it can be used directly in a top-down construction site.

10: Underground station piles
20: Steel frame column with edging
30: Connecting member T-Bar
31: Stud bolt
1b: Steel beam on the first floor above ground
1c: Lower steel beam of the border beam
1d: Border beam vertical or inclined member
301: Basement 1st floor steel beam
101: Concrete for the edge beam
102: 1st floor core wall 1st concrete
104: Concrete floor on the first basement level
105: Basement 1st floor core wall 1st concrete
106: Remaining concrete wall of basement 1st floor
107: Concrete wall on the second basement floor

Claims (1)

In the method of commencing ground floor core construction in top-down reverse excavation work,
Steps for installing the retaining wall;
Eastern part underground pile (10) insertion stage (1st floor above ground to lowest floor);
Basement 1st floor 1st excavation stage (1st floor above ground -3.0~5.0m)
Installation stage of steel columns (20) inside the core wall of the first floor above ground;
Installation stage of the steel beam on the first floor above ground (1c, 1b);
A step of installing reinforcing bars and formwork in the upper core portion of the first excavation;
Step 101: pouring of floor core and floor concrete on the first floor from the section -3.0 to -4.0 m above ground;
First floor core 1st concrete pouring stage (102);
Step 103 of pouring concrete for the second core of the first floor and the second floor above ground; and
Continuous construction stage of core walls above the second floor above ground
A method for commencing ground floor core construction, characterized by including: