JPH02190521A - Fixing of legs of steel column - Google Patents

Abstract

PURPOSE:To simplify operations by a method in which metal laths are set on the surrounding wall of pits for constructing base columns, concrete (SFR concrete) with steel fibers is placed on the surrounding of the pits and hardened, and steel columns are set in the pits and concrete is placed into the pits. CONSTITUTION:Concrete for foundation or underground beam 3 is placed, and before the concrete hardens a support metal 7 is partly buried in the peripheral side of a position where columns are to be set. The outside of the support metal 7 is surrounded by a metal netting 6 such as metal lath to form a pit 5. SFR concrete for underground beam 3 is then placed into the hole. A steel column 8 is set in the hole 5 and installed by using a temporary receiver 10 on the upper part of the beam 3, followed by level regulation. SPR concrete 9 is further placed into the hole 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to an improved method for fixing the legs of a steel column in a building.

(Conventional technology) The steel columns that make up buildings are designed with column base pins and column base fixings, but due to earthquake resistance issues, in buildings without basement floors, first floor column bases are used. The method of fixing steel frames inside underground beams has become mainstream.

This is because the stiffness of the foundation beam is usually so high that yield hinges form at the base of the column.

This anchoring method has become commonplace by embedding column bases in underground beams. For example, it is called the embedded construction method. As shown in Fig. 4, after the reinforcing of the foundation 2 and the lower end reinforcement of the underground beam 3 have been arranged on the top of the waste concrete 1, the concrete of the foundation 2 is poured. Next, on basic 2,
Adjust the level using mortar 4 at the position of the pillar.

The remaining reinforcement of the underground beam 3 is arranged, and the steel column 8 is temporarily fixed on the mortar 4 using anchor bolts (not shown).
Assemble formwork for underground beam 3, pour concrete and build steel column 8
This is to fix the

(Problem to be Solved by the Invention) Due to the work procedure explained above, the concrete for the underground beam 3 cannot be poured until the erection of the steel column 8 is completed, so the time for backfilling and the time for assembling the external scaffolding is delayed. I'll be late. In addition, a certain period of time is required from ordering the steel frame to erecting the steel frame, and at sites where there is no construction period, this period (no work is done on site) becomes a bottleneck. Furthermore, since underground beams are generally large, there were other problems such as the need for a truck pier for steel frame erection unless the backfilling work was completed.

In addition, in a steel structure or steel reinforced concrete structure, holes for installing columns are drilled in the foundation concrete in advance, and the steel columns are erected after the foundation is completed (hole-in method), in which the holes for installing the columns are drilled in advance. The wall surface requires surface roughening and other treatments to transfer shear with the post-cast concrete. For this reason, metal lath is used as the formwork for the holes for the pillars, and measures are taken to create an uneven surface after the concrete is poured.

In any case, while the column base is required to have deformation energy absorption performance, there is a drawback that the surrounding concrete cover thickness of the underground beam or foundation part in which the steel column is embedded becomes thinner, and the column base and foundation Alternatively, there remained difficulties in integrating underground beams.

The present invention has been made in view of the above circumstances, and its purpose is to relate to a method for fixing the legs of a steel column that realizes a high degree of integration of the foundation or underground beam and the steel column.

(Means for Solving the Problems) In order to achieve the above object, the method for fixing the legs of a steel frame column according to the present invention is to fix the legs of a steel column in a steel reinforced concrete structure or a steel frame structure by fixing the legs of the steel column to the foundation of the reinforced concrete structure or underground. For those that are fixed to beams, a hole slightly larger than the outside diameter of the steel column is provided in the foundation or underground beam, and the surrounding wall is made of metal lath, perforated steel plate, etc., and then at least the area around the hole is The foundation or underground beam is cast using concrete mixed with steel fiber (SFR concrete), and after the SFR concrete hardens, the steel column is erected in the hole, and then the hole is filled with post-cast concrete. It is.

(Function) Metal lath or perforated steel plates are used for the pillar erection holes in the foundation or underground beams, and SFR concrete containing steel fibers is used in the concrete, so there is no risk of contamination in the foundations or underground beams. Steel fibers as concrete reinforcement protrude from holes such as metal lath that define the peripheral wall of the column base hole, increasing the bonding force with the post-cast concrete that will be filled later.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3.

After reinforcing the foundation 2 and the lower ends of the underground beams 3, pour concrete for the foundation 2, and before the concrete hardens, embed part of the supporting hardware 7, such as reinforcing rods, around the positions where the columns will be installed, After the concrete has hardened, the remaining underground beams 3 are reinforced, the outer periphery of the supporting hardware 7 is surrounded by metal lath, hexagonal wire mesh, etc. 6, the holes 5 are secured, and SFR concrete for the underground beams 3 is poured.

After confirming the required strength of concrete for underground beam 3, the formwork will be dismantled, backfilling, and work on external scaffolding will begin.

In parallel with or before that, Figures 2 (a) to (C)
The rear steel column 8 is erected into the hole 5 as shown in FIG. Pillar 8 and temporary bracket 1
0 by welding or the like, or attach the temporary bracket 10 to the pillar in advance and temporarily fix the bracket 10 on the underground beam 3, or insert SFR concrete or steel fiber into the hole 5. The mixed mortar 9 is filled and the work is completed. Of course, ordinary concrete is also fine. In addition, if the steel column 8 is insufficient to withstand the pulling force etc. with the filling concrete 9 alone, this can be dealt with by providing a stud dowel or the like in advance in the portion of the column to be filled.

Further, in the embodiment, the concrete for the foundation 2 and the underground beam 3 is poured in two steps, but of course it may be poured in one step. In this case, the supporting hardware 7 for securing the hole 5 is firmly attached to the reinforcing bars of the underground beam 3, and the wire mesh 6 is also attached to the outer periphery of the supporting hardware 7 in advance.

(Effects) Since the present invention uses the construction method described above, if the concrete is placed for the underground beams 3, backfilling is performed, and the concrete for the first floor is poured, the truck for steel frame construction can be easily used. This eliminates the need for a pier, greatly simplifying on-site work and contributing to shortening the construction period.

Furthermore, since steel columns can be erected at any time after concrete is placed for the foundation or underground beams, on-site work (backfilling, external scaffolding, etc.) can proceed regardless of the timing of steel frame fabrication, shortening the construction period and ultimately This has advantages such as reduced construction costs.

In addition, since SFR concrete has a higher shear strength than ordinary concrete, it is possible to omit or reduce the hoop reinforcement around the pillar erection hole, and it is also possible to integrate underground beams or foundations with post-cast filling mortar, etc. You can increase your sexuality. Since steel fibers are also mixed in the filling mortar, etc., the strength around the construction holes of the steel column base is improved, the energy absorption of the column base is large, and there is an excellent earthquake resistance effect.

[Brief explanation of the drawing]

1 to 3 are explanations of the construction method according to the present invention. Figure 1 is a plan view showing the installation of reinforcing bars for underground beams, the wire mesh for securing holes, and the arrangement of supporting hardware; Figure 2 shows the construction procedure for fixing the legs of steel columns; B shows the state in which the hole has been secured in the beam, B shows the state in which the steel column is erected in the hole and is temporarily fixed using temporary brackets, and C shows the state in which concrete is filled between the hole and the steel column to fix the column. The sectional view shown in FIG. 3 is a plan view of the previous C. FIG. 4 is a sectional view of the conventional construction method. 1.....waste concrete 2.....base
Foundation 3... Underground beam 4... Mortar 5... Hole 6... Wire mesh such as metal lath 7... Support for reinforcing bars, etc. Hardware 8... Steel column 9... Filled concrete or mortar 10.
・・Temporary bracket for pillar erection

Claims (1)

[Claims] (1) In steel reinforced concrete construction or steel frame construction,
When the legs of a steel column are fixed to a reinforced concrete foundation or underground beam, a hole slightly larger than the outer diameter of the steel column is provided in the foundation or underground beam, and the surrounding wall is made of metal lath, perforated steel plate, etc. After configuring it with
At least around the hole, a foundation or underground beam is cast using concrete mixed with steel fiber (SFR concrete), and after the SFR concrete hardens, the steel column is erected in the hole, and then the steel column is placed in the hole. A method for fixing the legs of a steel column, characterized by filling the legs with poured concrete.