JPH02164932A - Foundation construction method for building - Google Patents

Abstract

PURPOSE:To shorten the construction period and reduce the construction cost by installing anchor bolts inside a footing connecting head sections of multiple piles and fastening the anchor bolts to steel frame pillar legs after placing the concrete of the footing. CONSTITUTION:A reinforced cage 6 is arranged in a footing 3. The lower end of an anchor bolt 5 is temporarily fixed with a bracing reinforcing bar 7 welded to a steel pipe pile 1, and its upper end is fixed to a template 9 welded with a reinforcing bar 8 inserted into the steel pipe pile 1 on the rear face. A recess forming block 14 is installed on the template 9 to be mounted by the leg of a steel frame pillar 2, then the concrete at the portion of the footing 3 and the concrete at the portion of a floor slab 4 are concurrently placed. The block 14 is removed, the base plate 2a of the steel frame pillar 2 is mounted on the template 9 and fixed to the anchor bolt 5 with a nut 13, then a grout material is filled around the pillar leg.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a foundation construction method in which steel columns of a steel building frame are directly connected to footings and vertical pile heads.

[Conventional technology]

In the conventional piled foundation, as shown in Fig. 3, a footing 54 is provided on top of the shaft 51, and a foundation beam (underground beam) 5 is installed.
3 is installed and the steel column 52 is hardened with reinforced concrete to restrain the rotation of the column base.

In this case, the foundation beam 53 has two roles: one is to bear the bending that occurs in the column base and stop rotation, and the other is to act as a connecting beam to prevent the steel columns 52 from moving apart.

As a method of connecting such a pile foundation and a steel column in a steel frame building frame, for example, a connection structure described in Japanese Patent Application Laid-Open No. 59-31320 is known, in which the legs of the steel column are fixed to the foundation or underground beam. In this case, by embedding a cylindrical body in the pile head and connecting the lower end of the steel column to anchor bars installed inside the cylindrical body, it is possible to integrally drive the footing provided on the pile head. There is.

[Problem to be solved by the invention]

By the way, in multi-pile (vertical pile) foundations in which multiple comparatively small-diameter piles such as copper pipe piles are installed for one steel column of a steel frame building frame, structurally speaking, multiple piles and steel frames are installed. It is difficult to connect columns directly, and piles simply receive vertical loads through footings. For this reason, in conventional multi-pile foundations, the horizontal resistance of buildings is handled by foundation beams, and it is necessary to use underground beams with large structures. Therefore, in addition to the trench construction, construction of underground beams requires a large amount of earthwork and foundation work, which leads to problems such as prolonging the construction period and increasing construction costs.

The present invention aims to solve the above-mentioned problems.

[Failure to solve the problem]

In the construction method of the present invention, in a multi-pile (vertical pile) foundation, anchor bolts are installed inside the footing that connects the heads of the plurality of piles, and after pouring concrete for the footing,
The pile, the footing, and the steel column base are integrated by tightly connecting the anchor bolt and the steel column base.

[For production]

According to the above construction method, the piles, footings, and steel column bases are integrated, so when horizontal external forces such as during an earthquake act on the building, the various forces generated on the column bases are directly transmitted to the vertical piles. Ru. Therefore, it is also possible to create a structure in which the bending that occurs at the bottom of the column is transmitted directly to the piles, and the lateral movement of the bottom of the column is stopped by the floor slab of the first floor or the concrete floor, without intentionally providing a foundation beam or the like. In this case, the floor slab or earthen floor concrete I. is not only used to connect each column base to each other, but also to integrate with the ground through friction, and from a structural standpoint,
It will be advantageous (safe side). In addition, in the case of group piles, when the bending is applied to the superstructure, a tensile force is applied to the − side pile,
Since compressive force acts on the pile on the opposite side via the footing, it is designed to deal with axial force.

〔Example〕

Next, the illustrated embodiment will be described.

FIGS. 1 and 2 show a state before the bases of a steel column 2 of a steel frame are fixed in an embodiment of the present invention.

In this example, the counter head was cut off, resulting in a total of four steel pipe piles]
's head is restrained by footing 3, and footing 3
It has a structure in which a heath plate 2a of a steel column 2 is tightly connected to a set of anchor bolts consisting of a plurality of anchor bolts 5 fixed inside.

Inside the footing 3, a pre-processed reinforcing bar cage 6 is placed. The lower end of the anchor bolt 5 is temporarily fixed by a steady rest reinforcing bar 7 welded to the steel pipe pile 1, and the upper end is fixed to a ten-brake 1-9 having a reinforcing bar 8 inserted into the steel pipe pile 1 welded to the back surface. In the figure, 10 is a positioning notch stamped on the template 1-9, and 11 is a hole for going around the concrete.

In addition, after positioning the contact point 12 between the reinforcing bar 8 and the upper end of the steel pipe pile 1,
Fix by spot welding. In the figure, 13 is a naso I for level adjustment.

A recess formation block 14 made of polystyrene foam or the like is installed in advance on the top surface of the template 9 where the column base of the steel column 2 comes, and in this state, the concrete of the footing 3 and the concrete of the floor slab 4 are installed. 1~ will be poured at the same time. A depression is created in the concrete by the depression forming block 14, and after the concrete has cured, the tenbrai 1
The heath plate 2a of the steel column 2 is placed on -9 and fixed to the anchor bolt 5 with the nut 13. The area around the column base is then backfilled with grouting material such as non-shrinkage mortar. In addition, in the figure, 15 is a concrete stopper provided in the steel pipe pile 1, and when concrete is placed in the footing 3 and floor slab 4 portions, concrete is filled up to this position and the reinforcing bars 8 are fixed.

〔Effect of the invention〕

■ Various forces generated on the column base due to horizontal external forces such as during an earthquake are directly transmitted to the pile group, making it possible to effectively utilize the strength of the piles.

■ There is no need to install a foundation beam, and by installing the floor slab or earthen floor concrete I-1 integrally with the piles and columns, each column base does not behave differently from each other and provides stable strength. be able to.

■ By eliminating the need for foundation beams, foundation work can be simplified, shortening the construction period and reducing construction costs.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, FIG. 2 is a plan view of the counter head, and FIG. 3 is a vertical sectional view showing a conventional example.

Claims (1)

[Claims] (1) In multi-pile foundations in which multiple piles are installed for one steel column of a steel building frame, an anchor bolt is installed inside the footing that connects the heads of the multiple piles, and the concrete of the footing is A building foundation construction method characterized in that, after driving, the anchor bolt and the steel column base are tightly connected to integrate the pile, the footing, and the steel column base.