JPH0368972B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing foundations for structures such as bridge abutments and piers.

As is well known, in elevated bridges built along rivers, etc., the ground is generally soft, so a foundation is constructed underground, and footings and pillars are formed above it.

When constructing a foundation, a construction method, the so-called caisson construction method, was conventionally employed in which this part was formed on the ground surface in advance and then submerged.

However, as is well known, this caisson construction method involves dangerous work under high pressure, and
There was a problem with extremely poor work efficiency.

For this reason, the present applicant has developed a method for constructing a foundation safely and efficiently without using the caisson construction method, and has disclosed it in Japanese Patent Application Laid-Open No. 163323/1983.

In this method, the foundation of the structure is constructed using a continuous underground wall construction method, so in addition to the above effects, it also has construction features such as low noise, low vibration, and can be applied to any geology, and is similar to cast-in-place piles. Because it is constructed as a structure, it has various excellent features such as high frictional force with the ground and high horizontal and vertical strength.

However, the construction of the foundation using this construction method is
This feature is effectively demonstrated in relatively large-scale bridges, but in small-scale construction, the following problems arise. In other words, for small-scale bridges, the planar dimensions of the foundation are, for example, 4 to 5 meters on each side.
becomes smaller.

For this reason, there is no need to ensure that the frictional force with the ground that is required for the foundation is so large.
Constructing this using the construction method described above would increase the construction period and cost, making it impractical.

Therefore, it is possible to completely excavate a considerable part of the foundation from the ground surface and construct a solid foundation using the same method as cast-in-place piles, but since the foundation is solid with this method, it is necessary to Concrete must be poured to the areas that are not covered, which is extremely uneconomical.

This invention was made in view of the above-mentioned background, and its purpose is to provide foundations for structures such as relatively small-scale bridges that can be constructed economically while ensuring the necessary strength. It provides construction methods.

In order to achieve the above object, the present invention provides bridge abutments,
When constructing the foundation of a structure such as a bridge pier underground, a vertical hole that matches the shape of the foundation is excavated from the ground surface, and then a reinforcing cage is built into the vertical hole and concrete is poured to build the structure. In the method for constructing a foundation, a formwork forming a sealed hollow portion is attached to the reinforcing bar cage in advance at a predetermined distance from the outer peripheral surface of the foundation to be constructed.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1 a to 2 e and 2 a to e sequentially show each construction step of the method for constructing the foundation of a structure according to the present invention.

In the method shown in the figure, first, as shown in Figures 1a and 2a, a work floor is placed at the site where the foundation is to be constructed.
The earth retaining wall 2 is formed to a predetermined depth.

The earth retaining wall 2 surrounds the outer periphery of the foundation to be constructed and is formed from a reinforcing material 3 such as H-beam steel and a muddy water solidification wall 4.

When the formation and solidification of the earth retaining wall 2 is completed, as shown in FIG. 1b and FIG. Excavate 7.

When the vertical hole 7 matching the shape of the foundation to be constructed is excavated to a predetermined depth, the reinforcing bar cage 8 is erected using a crane 9 or the like (see FIGS. 1c and 2c).

What should be noted here is that a formwork 10 is attached to the reinforcing bar cage 8 at a predetermined distance from the outer circumferential surface of the foundation constructed in advance to form a sealed hollow section.

The formwork 10 is made of wood, steel, foamed polystyrene, or the like, and the distance from the outer peripheral surface of the foundation is appropriately set based on the shape and size of the foundation, the footing, the weight of the pillars, and the like.

Then, when the reinforcing bar cage 8 is erected, Fig. 1d,
As shown in FIG. 2d, concrete 12 is poured using a tremie tube 11 while replacing the stabilizing liquid 6.

When the poured concrete 12 hardens and the construction of the foundation is completed, footings 13 and pedestals 14 are constructed on this foundation as shown in FIGS. 1e and 2e.

Now, in the construction method of the foundation with the above-mentioned structure, there is a hollow part formed by the formwork 10 in the foundation, but this part originally does not have much influence on the strength of the foundation. be.

Therefore, even if the formwork 10 is attached and a foundation is constructed, the strength of the foundation will not be impaired.

Further, since the poured concrete 12 does not enter the formwork 10 forming the hollow portion, the amount of poured concrete 12 can be significantly reduced.

Furthermore, the concrete 12 poured and formed between the outer peripheral surface of the foundation to be constructed and the formwork 10 is relatively thin, and therefore generates less heat when the concrete hardens, and less heat is generated during cooling after the concrete has generated heat. Cracks in concrete can also be reduced.

As described above in detail in the examples, in the method for constructing the foundation of a structure according to the present invention, even with a relatively simple structure in which a formwork for forming a sealed hollow part is attached to a reinforcing bar cage, Excellent effects such as being able to construct this economically without reducing the strength of the foundation can be obtained.

[Brief explanation of drawings]

Figures 1a to e and Figures 2a to e show an embodiment of the present invention in the order of steps. Figures 1a to e are longitudinal sectional views, and Figures 2a to
FIG. 3 is a top view corresponding to figures a to e; 1...Working floor, 2...Earth retaining wall, 3...Reinforcing agent,
4... Mud water solidification wall, 5... Excavator, 6... Stabilizing liquid, 7... Vertical hole, 8... Rebar cage, 9... Crane, 10... Formwork, 11... Tremie pipe, 12...
...Concrete, 13...Footing, 14...
pedestal.

Claims (1)

[Claims] 1. When constructing the foundations of structures such as bridge abutments and piers underground, a vertical hole matching the shape of the foundation is excavated from the ground surface, and then a reinforcing bar cage is built into the vertical hole and concrete is poured. A method for constructing a foundation for a structure using a method for constructing a foundation for a structure, characterized in that a formwork forming a sealed hollow portion is attached to the reinforcing cage in advance at a predetermined distance from the outer peripheral surface of the foundation to be constructed. construction method for the foundation of a structure.