JPH11200395A - Earthquake-resistant reinforcing structure of structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide earthquake-resistant reinforcing structure, in which the site of a structure is utilized sufficiently and which is used for improving the earthquake-resistant performance of the structure including even a ground. SOLUTION: Steel sheet piles 5 are driven at a fixed distance so as to surround the building frame 1 of the structure. The top sections of the steel sheet piles 5 and the foundations 2 of the structure are connected and unified by concrete beams 6 horizontally projected from the structure building frame 1. The horizontal resistance force of a ground received by the whole surfaces of the steel sheet piles 5 brought into contact with the ground in the load working direction resists against the horizontal force. The maximum value of a ground reaction degree generated is inhibited by the foundation widening effect of the concrete beams 6, etc., projected from the building frame 1 to vertical force while the side movement of the ground is prevented by constraining the ground by the steel sheet piles 5, effective confining pressure is increased and ground strength is elevated. Vertical resistance force is burdened even by peripheral-surface frictional force among the concrete beams 6 protruded from the building frame 1 and the steel sheet piles 5 driven around the structure and the ground.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic reinforcement structure for a structure, particularly to a reinforcement of a support mechanism against horizontal force and vertical force. It is suitable for seismic reinforcement of existing structures that are judged to be affected, new structures that need to be strengthened, or structures that have been damaged by a large earthquake.

[0002]

2. Description of the Related Art Generally, in a building structure, seismic design of foundation piles and the like is performed within a plane of projection of the structure onto the ground. For example, a structure designed in accordance with the pre-revised seismic design standard in 1981. There may be things.

[0003] In addition, even if the structure is designed in accordance with the revised standard, the strength of the foundation structure may be insufficient for a direct earthquake such as the Great Hanshin Earthquake.

[0004] Conventionally, as a method of seismic reinforcement at the foundation of an existing structure, a steel sheet pile is driven into the vicinity of a tank body of an oil tank to increase the supporting force against a vertical load concentrated immediately below a side plate of the tank. What we have planned (Japanese
In addition, as a countermeasure against liquefaction in the event of an earthquake on the ground immediately below the base of the tank, a steel sheet pile placed around the outside of the base surrounds the liquefiable ground. There is one in which the head is integrated with concrete (see JP-A-6-212616).

[0005]

The above-mentioned conventional reinforcing structure for the existing tank is intended to increase the supporting force directly below the side plate or to prevent liquefaction, and the mechanism for supporting the horizontal and vertical forces of the foundation is mechanical. It does not mean that it will be improved in terms of safety and that it will be strengthened against earthquakes.

[0006] Further, in many cases, there is a restriction that the building must be reinforced within a narrow site.

[0007] The present invention was invented in view of the above background, and a seismic reinforcement structure for fully utilizing the site of the structure and improving the seismic performance of the structure including the ground. The purpose is to provide.

[0008]

According to a first aspect of the present invention, there is provided a seismic retrofitting structure for a structure, in which a steel sheet pile is driven around a structure at a predetermined appropriate distance, and a top of the steel sheet pile is formed. The foundation of the structure is connected to and integrated with concrete beams that project horizontally from the structure body, thereby enhancing the structural strength including the ground surrounded by steel sheet piles.

[0009] The steel sheet pile referred to here includes all steel materials that are cast into the ground and have a certain length that exerts a soil retaining function and other sheet pile functions, and are relatively commonly used U-shaped steel sheet piles. Needless to say, the cross-sectional shape and the like are not particularly limited as long as they exhibit a sheet pile function as a function, such as a steel pipe.

In addition, the distance from the structural body to the steel sheet pile varies depending on the site conditions when the site is narrow.
Basically, it is designed so that the structural strength including the ground becomes more than a predetermined strength according to the seismic design standards and the target seismic performance.

In the present invention having the above structure, the horizontal force resists the horizontal force of the ground received on the entire surface of the steel sheet pile in contact with the ground in the load acting direction.

That is, by driving a steel sheet pile around the structure, the ground immediately below the structure is restrained and integrated to increase the shear resistance of the ground, and at the same time, to the ground near the structure. In other words, a steel sheet pile existing in the ground is intended to resist horizontal force by passive earth pressure generated when the steel sheet pile wraps around the entire ground in contact with the steel sheet pile and moves.

On the other hand, against the vertical force, the maximum value of the ground reaction force generated is suppressed by the effect of widening the foundation of a concrete beam or the like protruding from the skeleton, and the ground is restrained by a steel sheet pile driven around the structure. By doing so, the lateral movement of the ground can be prevented, and the ground strength can be increased by increasing the effective constraint pressure.

The vertical resistance can also be borne by the frictional force between the concrete beam protruding from the skeleton and the steel sheet pile cast around the structure and the ground.

Therefore, considering the structure-ground system as a whole, both the horizontal resistance and the vertical resistance are increased, so that the seismic performance is increased. As a result, the seismic safety of the upper structure is improved.

In order to effectively transmit the horizontal force generated at the time of the earthquake by the underground beam overhanging from the existing structure, the portion surrounded by the adjacent underground beam, the structural foundation beam and the overhanging underground beam is used. You may connect with floor slab concrete etc.

In a second aspect of the present invention, in the structure for seismic reinforcement of a structure according to the first aspect, a case where an asymmetric U-shaped steel sheet pile is used as the steel sheet pile is limited.

An asymmetric U-shaped sheet pile is disclosed in, for example, Japanese Patent No. 268.
As described in Japanese Patent No. 9794 and Japanese Patent Application Laid-Open No. Hei 9-100541, the shape of the central portion of the cross section is U-shaped,
The joint shape at both ends is asymmetrical, and the cross-sectional shape can be aligned in the same direction so that it can be joined on a straight line. Are suitable.

In the seismic retrofit structure of the present invention as well, since it is necessary to drive steel sheet piles around the structure at a predetermined distance, the asymmetric U-type steel sheet pile is used as a steel sheet pile when the site is narrow. The effect of the present invention can be exerted by using.

[0020]

Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a plan view showing an embodiment of the present invention, and a sectional view taken along the line AA of FIG.

In the drawing, 1 is a frame of an existing structure, 2 is its foundation, 3 is a foundation beam, and 4 is a foundation pile. 5 is a steel sheet pile for reinforcement that is cast around the structure at a predetermined distance,
6 is a concrete beam for reinforcement, which extends horizontally from the column base of the structure, and connects and integrates the foundation 2 and the steel sheet pile 5.
Is a concrete beam which joins and integrates the head of the steel sheet pile 3 and receives the concrete beam 6, and 8 denotes a construction ground.

However, the setting position of the steel sheet pile 5 and the specifications of the concrete beams 6 and 7 are appropriately examined according to the required degree of seismic reinforcement of the structure, site conditions, ground conditions, and the like.

In the present invention, a steel sheet pile surrounding the ground immediately below the structure is surrounded by a steel sheet pile at a predetermined distance from the frame 1 of the structure, and the foundation 2 of the structure and the head of the steel sheet pile 5 are concrete beams 6. By connecting and integrating, the horizontal force acting at the time of the earthquake is shared between the foundation pile 4 and the steel sheet pile 5.

The steel sheet pile 5 resists the horizontal force due to the passive earth pressure of the ground 8 generated when the steel sheet pile 5 is deformed in response to the horizontal force borne by the concrete beam 6.

On the other hand, the concrete beam 6 overhanging from the skeleton 1 has the same effect as increasing the width of the skeleton of the structure.
The maximum value of the ground reaction force generated by the acting horizontal force is suppressed, and the vertical force is also resisted by the peripheral friction force generated between the steel sheet pile 5 and the ground 8.

Further, since the steel sheet pile 5 cast around the structure increases the shear resistance of the ground by restraining and integrating the foundation directly under the structure, the horizontal resistance is considered as the whole structure-ground system. In order to increase both force and vertical resistance,
The seismic capacity is increased, and as a result, the occurrence of liquefaction during an earthquake can be prevented.

FIG. 3 shows an embodiment of an asymmetric U-shaped steel sheet pile and a connection state thereof as an example of a steel sheet pile 5 suitable for applying the present invention to a structure constructed on a narrow site. .

FIG. 3 (a) is a plan view of the asymmetric U-shaped sheet pile 5 alone. The left and right joints 5a and 5b are formed asymmetrically with respect to the basic structure of the conventional U-shaped sheet pile, and the adjacent asymmetrical sheet pile 5 is formed. Between the U-shaped steel sheet piles 5, the joint portion 5 facing upward in the figure
a and the joint portion 5b facing downward in the drawing is attached in the axial direction of the member (longitudinal direction).
As shown in FIG. 3 (b), the cross sections can be aligned in the same direction so that they can be connected linearly.

Further, in this example, the asymmetric U-shaped sheet pile 5 has a flat portion 5c in the same direction as the casting normal in the vicinity of the joint portions 5a and 5b, so that the joint portions 5a and 5b are engaged with each other. In this state, the engaging portion is not exposed to the sheet pile wall surface.

By providing the flat portion 5a, the occurrence of rotation and torsion of the asymmetric U-shaped sheet pile 5 in the ground at the time of driving is suppressed, the driving performance is improved, and the construction of the sheet pile wall with high construction accuracy is achieved. Becomes possible. Also, the joints 5a, 5b
Is located at the outermost edge of the sheet pile wall, and the joint portion is not exposed to the sheet pile wall surface to form a flat wall surface, so that space can be effectively used. However, as described above, the steel sheet pile 5 used in the present invention is not limited to the one shown in FIG.

[0032]

[Effects of the Invention] Horizontal and vertical support of existing structures that are judged to have insufficient ground and foundation seismic performance, new structures that require increased ground strength, and structures that have been damaged by a major earthquake, etc. The reinforcement of the mechanism is facilitated by making full use of the site of the building structure and including the ground, and as a result, it is an effective prevention measure against the occurrence of liquefaction.

According to a second aspect, the steel sheet pile is asymmetric U
When a steel sheet pile is used, the seismic retrofit effect can be exerted even when the site is narrow.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3A is a plan view showing an embodiment of an asymmetric U-shaped steel sheet pile, and FIG. 3B is a plan view showing a connection state thereof.

[Explanation of symbols]

1 ... frame of existing structure 2 ... structure foundation 3 ... foundation beam
4: foundation pile, 5: steel sheet pile, 6: concrete beam, 7: steel sheet pile head concrete, 8: ground

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshiaki Masuda 4-5-33 Kitahama, Chuo-ku, Osaka City Sumitomo Metal Industries Co., Ltd.

Claims (2)

[Claims] 1. A steel sheet pile is cast around a structure at a predetermined distance from the structure, and a top of the steel sheet pile and a foundation of the structure are connected by a concrete beam horizontally extending from the structure body. A seismic reinforcement structure for a structure, wherein the structural strength of the structure including the ground surrounded by the steel sheet pile is enhanced by being integrated. 2. The steel sheet pile has a U-shaped cross section at the center.
The seismic retrofitting structure for a structure according to claim 1, wherein the shape is asymmetric U-shaped steel sheet piles having joints at both ends which are bilaterally asymmetric, and whose cross-sectional shapes are aligned in the same direction and can be connected linearly.