JPH0347321A - Shore strut and underground construction work by composite steel beam - Google Patents

Abstract

PURPOSE:To make the lift-down work of each steel beam easier as well as simplify the construction work by using steel beams for the first stair and underground stair floors in which the ends of the adjacent beams are connected with each other by winding around structural straight columns with them. CONSTITUTION:Structural straight columns 3 are wound with beam ends 4a and 4'a to form a corner bracing, where steel beams 4 and 4' for the first stair and underground stair floors are built connectedly to each other. After the primary excavation, the beam 4 is lowered to a given position under the guidance of the columns 3 and temporarily supported on the columns 3, and the beams 4' are temporarily set under the beam 4. The secondary excavation is made by using the beam 4 as a shore strut, and the beam 4' is lowered to a given position and set on the columns 3 to use it as a shore strut. The same operations are repeated for construction until the lowest stair, and concrete is orderly placed from the lower stairs to construct an underground structure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a construction method for an underground framework in which synthetic steel beams also serve as struts.

(Prior Art) Conventionally, in underground framework construction, underground excavations are usually carried out by arranging struts and stand-up beams using H1iml in the shape of a foundation. At this time, since the struts are only temporary, they are dismantled and removed during or after the construction of the framework and are carried outside the site.

In addition, a reverse pouring method is used, in which concrete is poured sequentially from the upper floor of the basement.

(Problems to be Solved by the Invention) In the former method, a great deal of effort and time is required to dismantle and remove the struts and carry them out of the site, prolonging the construction period.

In addition, in the latter method, since concrete is poured sequentially from the upper floor of the basement floor, all columns and walls are poured backwards, making it extremely difficult to pour concrete.

The present invention has been proposed in view of the problems of the prior art, and its purpose is to significantly save labor in construction, and to use synthetic steel beams with high structural reliability for the construction top plate. The point is that it provides an underground construction method that can also be used as a beam.

(Means for Solving the Problems) In order to achieve the above-mentioned object, according to the underground construction method using synthetic steel beams according to the present invention, retaining walls, shafts, and structural pillars are erected, and the first excavation is carried out. After that, the first floor steel beams, whose beam ends are detoured around the structural pillars and which are tied to each other, are lowered to a predetermined position using the structural pillars as a guide. Temporarily supported by columns, a basement floor steel beam configured in the same manner as the first floor steel beam was temporarily placed below the first floor steel beam, and then secondary excavation was performed using the first floor steel beam as a strut. The first basement floor steel beam, which had been temporarily placed under the steel beam, was lowered to a predetermined position, set on the structural pillar, and acted as a strut, and the same process was repeated until the bottom floor was reached. After construction is completed, concrete will be poured in order from the lower floors and the underground framework will be built horizontally.

(Function) According to the present invention, as described above, after the retaining walls, shafts, and structural pillars are erected and the primary excavation is carried out, the beam ends do not pass through the structural pillars, but surround the studs. The first-floor steel beams are constructed by connecting the detoured adjoining pieces of steel to each other.
The floor steel beams are lowered along the line to a required position using the structural pillars as guides, and are temporarily supported by the horizontal pillars at the same position, and are placed under the first floor steel beams in the same manner as in the same structure. Temporarily place the steel beams on the lower floor.

Next, after secondary excavation was carried out using the steel beams for the first floor floor which also served as cut beams, the steel beams for the first basement floor, which had been temporarily placed under the steel beams for the first floor floor, were placed in place using the horizontal straight columns as guides. It is lowered to the position and set on the structural pillar to act as a strut, and the same steps as described above are repeated until the bottom floor is constructed.

At this time, since the space between the steel beam and the structural column at the joint between the columns and beams is large, the steel beam on the basement floor can be easily lifted down.

As described above, the steel beams are detoured around the structural pillars at their ends, the beams are tightly connected to each other, and temporarily supported by the structural pillars at predetermined positions. Since it is configured to act as a strut, axial force acts on the steel beam from all sides of the structural column, and the force from one beam is 45°.
The force is divided into two and transmitted to the left and right steel beams, and this transmitted force is further increased to 4
The force is branched at 5° and transmitted to the beam on the opposite side, and the force from the opposite side is balanced, so that the steel beam reliably functions as a strut.

After the construction to the lowest floor is completed, concrete is poured in order from the lower floor to construct an underground structure, but at this time, the steel beam used as the strut is integrated with the slab concrete. It forms part of the frame as a composite beam, so there is no need to remove or transport it after the frame is completed.

(Example) The present invention will be described below with reference to the illustrated embodiments.

Similar to the conventional reverse construction method, retaining walls (1) and counters (2)
Or erect a deep foundation and structural pillars (3) (see Figure 1)
Next, as primary excavation, excavation is carried out to a predetermined depth, and the first floor steel beam (4) and the lower floor steel beam (4') are lowered along the horizontal straight column (3) using the stud (3) as a guide. The floor steel beam (4) is supported at a predetermined position on the structure pillar (3) by the temporary support bracket (5) installed by the company (3),
The underground floor steel beams are sequentially suspended from the first floor steel beams (4) via hanging members (6) and temporarily placed. (See FIG. 2) In the illustrated embodiment, only the first basement floor steel beam (4') is shown to simplify the explanation.

Each of the above-mentioned steel beams (4) (4'l is a flint-shaped structure with a detour surrounding the main pillar (3) at the beam end (4a) (A8), as shown in Figures 5 and 6) Adjacent beams are tightly connected to each other by welding or bolts.

Next, secondary excavation was started using the 11th floor steel beam (4) as a strut, and after excavating to a predetermined depth from the 1st floor underground level, it was temporarily placed under the 1st floor steel beam (4). The first basement floor steel beam (4') is lowered using the structural pillar (3) as a guide, and is supported at a predetermined position by the temporary support bracket (5) attached to the stud (3). ) to act as a strut. (Refer to Figure 3) After repeating the same process as above until the bottom floor is constructed, concrete is poured from the bottom floor in order as in the case of a normal above-ground floor structure to complete the underground structure. . (See Figure 4) In the figure, (7) is the foundation beam, (8) is the basement wall, (9) is the basement floor concrete, 00) is the first floor concrete, θ1)
is beam concrete, O'lJ is column concrete, 03)
is for company owners, and I is for hoops.

In addition, at the joint between the steel beam (4) (41) and the structural pillar (3), there is a large gap between the two members, making it easy to lift down the steel beam (4') on the lower floor. Moreover, with this method, it is possible to construct structural pillars with relatively rough accuracy, which is required by the conventional reverse casting method.

In addition, when each of the steel beams (4) (41) is supported by the temporary support bracket (5) of the structural pillar (3) and acts as a strut,
Axial forces act on the steel beam from four directions, and the force from one direction is split at a 45° angle at the tip of the beam and transmitted to the left and right beams, further divided and transmitted to the beam on the opposite side, and the force from the other side is balance with power.

(Effects of the Invention) According to the present invention, as described above, when the first floor steel beam and the basement floor steel beam are lifted down along the same direction using the structural pillar as a guide, the beam ends are aligned with the structural pillar. By configuring adjacent beams that are detoured to surround each other and tightly connected to each other, the space between the structural pillar and each of the steel beams at the joint part is large, making it easy to lift down the steel beams. become,
Furthermore, the precision of the structural pillars does not require the same exact precision as in the conventional reverse hammer construction method, which simplifies construction.

Then, the first floor steel beam is lowered to a predetermined position using the structural pillar as a guide, and is temporarily supported by the structural pillar at that position, and the basement floor steel beam is temporarily placed below the steel beam. ,
Perform secondary excavation using the first floor steel beam as a strut,
The steel beams for the first basement floor are lowered to a predetermined position, set on the structural pillars, and act as struts, and the same process described above is repeated until the lowest floor is constructed. When acting as a strut, stress transmission between the steel beams is carried out smoothly, the steel beams fully exhibit their function as a strut, and construction work can be carried out smoothly and safely.

After construction was completed to the lowest floor, concrete was poured sequentially from the lower floor to complete the underground structure.
The column concrete is poured in order, and the ends of the steel beams do not penetrate the columns, but instead go around the company, so the steel beams do not interfere with column reinforcement and concrete pouring. This makes it possible to cast high-quality column concrete.

Furthermore, as mentioned above, the steel beams used as struts are integrated with the slab concrete and form part of the underground framework as composite beams, so there is no need to remove or transport them after the framework is completed, reducing labor. This reduces construction time and costs.

[Brief explanation of drawings]

Figures 1 to 4 are longitudinal sectional views showing the steps of an embodiment of the underground construction method using synthetic steel beams according to the present invention, which also serves as a strut, and Figure 5 shows the steel beams and structural beams that act as struts during excavation. A plan view showing the relationship with the columns, taken from the arrow V-V in Figure 6, a side view showing the V-V view taken from the arrow in Figure 5, and Figure 7 showing the columns and beams when the underground framework is completed. A plan view showing the joint section, viewed from the arrow in Figure 8 ■
Figures -■ and 8 are longitudinal sectional views taken along arrows -■ in FIG. 7. (1)...Mountain retaining wall, (2)...Pile, (3)
−...Structural pillars, (4)...1st floor steel beams, (
4a)... End of the steel beam on the first floor, (4'l... Steel beam on the first basement floor, (a)... End of the steel beam on the first basement floor, (5)... Temporary Support bracket, (6)... Hanging material, (7)... Foundation beam, (8)... Basement wall, (9)... Basement floor concrete, 00)... First floor concrete , 00...Beam concrete, 0ri...Column concrete.

Claims (1)

[Claims] After erecting retaining walls, piles, and structural pillars, and conducting the first excavation,
The first-floor steel beams, in which adjacent beams are tied together so that the beam ends surround the structural pillars, are lowered to a predetermined position using the structural pillars as a guide, and temporarily attached to the structural pillars. A basement floor steel beam constructed in the same manner as the first floor steel beam is temporarily placed below the first floor steel beam, and then secondary excavation is performed using the first floor steel beam as a strut. The steel beams for the first basement floor, which had been temporarily placed under the beams, were lowered to a predetermined position, set on the structural pillars, and acted as struts, and the same process described above was repeated until the bottom floor was constructed. , an underground construction method using synthetic steel beams that can be used for both sills and beams, which is characterized by constructing an underground framework by pouring concrete from the lower floors.