JP2006342636A - Building structure and its construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure constructed by a rational design method. <P>SOLUTION: This structure is a structure having a building 1, a pile 2 for supporting the building and an earth retaining wall 3 constructed on the ground around the building 2, and is formed by joining the earth retaining wall 3 and the building 1 by an anchor member 12, and is characterized in that a part lower than at least a foundation beam or a mat slab 11 of a steel frame member for constituting the earth retaining wall 3, is formed as a permanent structure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a building structure having excellent seismic performance and a rational cross-sectional design of the structure, and in particular, at least a portion below a foundation beam or a mat slab among steel members of a retaining wall is a permanent structure. The present invention relates to a structure and a building structure in which a cross section of a building and a foundation is designed in consideration of a horizontal load burden on at least a portion of a steel member of a retaining wall below a base beam or a mat slab in stress analysis, and the design method.

  FIG. 3 is a cross-sectional view showing a state in which a building such as a general high-rise building is constructed. The structure has a building 1, a pile 2, and a mountain retaining wall 3. The mountain retaining wall 3 is placed in the ground in order to demarcate a section where the lower part of the building 1 is buried in the ground, and is connected to the outer wall of the underground part of the building 1. The pile group 4 is composed of a plurality of piles 2 driven into the ground to support the building 1 and supports the building's own weight and also supports the earthquake load in the vertical direction of the building during an earthquake. The code | symbol 9 acts from the ground with respect to the retaining wall 3 and the pile 2 (a group of piles 2 may be named generically as the pile group 4) when a load is added to the right direction in the figure from the building 1. The direction of the horizontal reaction force is shown. The shape and size of the cross section of each pile 2 are determined by the weight of the building and the load during an earthquake.

In the case of a building having a retaining wall, it can be expected that the retaining wall 3 bears a horizontal load during an earthquake by connecting the retaining wall 3 and the building 1, that is, the retaining wall supports the building during an earthquake. It is done. Japanese Patent Application Laid-Open No. 10-298976 discloses a structure in which a mountain retaining wall upper part and a building lower part are connected.
JP-A-10-298976

  According to the prior art, it can be understood that by connecting the upper part of the retaining wall and the bottom of the building, the retaining wall is integrated with the building and exhibits the effect of resisting earthquakes. However, the inventors have found that the effect of the retaining wall is not the only one. That is, since the retaining wall supports the vertical and horizontal loads of the building in the same manner as the pile, the load burden due to the portion below the building foundation beam or mat slab of the retaining wall, which is not considered in the above-described conventional technology. Proper design should be able to streamline pile design. In addition, appropriate consideration of the existence of retaining walls also leads to rationalization of the seismic design of buildings. Here, the retaining wall is generally composed of a row of steel members such as H-shaped steel and I-type steel driven into the ground in the vertical direction and a soil cement placed around the row of the steel members.

  However, since the retaining wall is conventionally designed as a temporary structure and the design specifications are also different from that of the main structure, it is not possible to consider the load burden on the retaining wall, especially in the case of an earthquake. There wasn't. Conventionally, the reason for not including the retaining wall in the seismic design of the building is that the retaining wall, which is a temporary structure, has a different design philosophy from the actual structure, and it is costly to design the retaining wall as a permanent structure. It seems that there was a concern that it would be high.

  Contrary to the conventional recognition as described above, the inventors of the present invention set the structure of the retaining wall, in particular, at least the portion of the steel member below the foundation beam or mat slab, and at the same time, the building, the foundation, and the retaining structure. In a structure composed of walls, it was discovered that the design of the entire structure can be rationalized by appropriately considering the load burden on the retaining wall, and the cost of the entire structure can be reduced, leading to the present invention. It is.

  (1) In order to achieve the above object, the building has a pile supporting the building, and a retaining wall constructed on the ground around the building, and the retaining wall and the building are joined by an anchor member. A structure is proposed in which at least a portion below the foundation beam or mat slab of the steel member constituting the retaining wall is a permanent structure.

  (2) Further, according to a preferred embodiment of the present invention, the structure proposed by the present invention takes into account the horizontal load burden on the portion below the foundation beam or mat slab of the steel member constituting the retaining wall. A structure that reduces the burden on buildings and piles.

  (3) Furthermore, the present invention includes a building, a pile that supports the building, and a retaining wall constructed on the ground around the building, and a structure in which the retaining wall and the building are joined by an anchor member. A method of design, wherein at least a portion below the foundation beam or mat slab of the steel member constituting the retaining wall is a permanent structure, and the cross section of the stress member of the pile and retaining wall in consideration of the horizontal load burden due to the portion. We propose a design method to determine

(1) According to the invention according to claim 1, since the steel member of the retaining wall has a permanent structure particularly at least the part below the foundation beam or mat slab, the horizontal load burden due to the retaining wall is taken into consideration. The horizontal load such as seismic load or earth pressure of the building can be distributed to the stress members of the retaining wall, and the load that the building and the pile should bear can be reduced more than before.
(2) According to the invention which concerns on Claim 2, considering the horizontal load burden by a mountain retaining wall, the cross-sectional reduction of a building and a pile is achieved as a result.
(3) According to the invention according to claim 3, at least a portion below the foundation beam or mat slab is a permanent structure among the steel members of the retaining wall, and the pile and Since the cross section of the stress member of the retaining wall is determined, a rational and economical structure can be designed as compared with the conventional structure.

  Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In addition, the same code | symbol is used for the same element in an accompanying drawing, and the description is abbreviate | omitted suitably.

  FIG. 1 illustrates a two-dimensional analysis model obtained by modeling a structure in which each pile 2 of the pile group 4 in FIG. 3 and the stress member 3 of the retaining wall are connected by a foundation beam or a mat slab 11 with a wire rod. . In the two-dimensional analysis model, the ground reaction force is considered as the spring 9 reaction force. The two-dimensional analysis model can be a three-dimensional analysis model in consideration of the depth direction.

An example of a design method using the two-dimensional analysis model will be described.
First, the dynamic behavior of the building at the time of the earthquake is calculated, and the dynamic load applied from the bottom of the building to the top of the pile head and the retaining wall (portion connected to the building) is calculated. The seismic response analysis in this case may be based on a so-called ground building coupled system model, or may be an analysis model of only a building assuming that the earthquake acceleration is directly input to the bottom of the building foundation. Which model or further modeling method should be used can be determined as appropriate according to the conditions of the ground and the building. The important thing is that the retaining wall, which is a permanent structure, especially at least the part below the foundation beam or mat slab of steel members must comply with the design conditions for the permanent structure, but in the event of an earthquake, the horizontal load The burden can be taken into account.

Next, the load applied to the top of the pile head and the retaining wall is input from the bottom of the building foundation obtained by the above dynamic analysis, and the stress of the stress member of each pile 2 and the retaining wall 3 of the pile group 4 is calculated. . In this case, the load can be subjected to a stress analysis of the pile and the retaining wall as a dynamic load, but can also be subjected to a static stress analysis in which the maximum value of the dynamic load is added as a static load. Which analysis method is more reasonable should be determined by conditions such as selection of ground, piles, retaining walls, buildings and input loads.
In addition, the ground response including buildings, piles, retaining walls, and the entire building may be modeled as a coupled system to perform earthquake response analysis.

As described above, by modeling the foundation, pile, mountain retaining wall, and ground and performing stress analysis for horizontal loads due to earthquakes, the shape and dimensions of pile steel materials and mountain retaining wall stress members can be appropriately determined. .
Note that the present invention does not exclude the possibility of designing a portion above the building foundation or mat slab of the steel member of the retaining wall as a permanent structure. Further, not only the steel member of the retaining wall but also other parts can be designed as a permanent structure, and the present invention does not exclude this possibility, but generally only the steel member is a permanent structure. Is considered preferable from the viewpoint of return on investment.

  FIG. 2 is an enlarged view of A of FIG. 3, and is a schematic diagram showing a connecting portion between the stress member 3 of the retaining wall and the foundation beam or mat slab 11 of the building. The connection is made by an anchor member 12 such as a stud bolt arranged near the end in the thickness direction or the width direction of the foundation beam or mat slab 11, and the stress member 3 of the retaining wall is the underground of the building 1. It contacts along the outer wall surface 13 embedded in. The anchor member 12 should just be arrange | positioned at least 2 or more, and the rotational rigidity with respect to the stress member 3 of a mountain retaining wall is designed firmly. The anchor member may also be provided at the bottom of the building 1. Thereby, since the stress member 3 of a retaining wall can bear much horizontal load by an earthquake, the earthquake resistance by an earthquake can be improved.

  FIG. 4 shows a numerical analysis model performed to confirm the effect of the present invention. A structure according to an embodiment of the present invention includes a building having 12 floors above ground and two floors below ground having a plane shape of 4 spans × 5 spans, 30 φ1500 piles, and the building foundation around the foundation of the building. It was assumed that it had a series of mountain retaining walls with SMW as a core material, which were continuously provided and joined to the foundation of the building. The comparison target structure has the same structure as the embodiment of the present invention except that the pile diameter is φ1800 and there is no retaining wall in the analysis.

  FIG. 5 shows the moment, shearing force and displacement acting on the pile when a horizontal force of 26550 kN is applied. As the result shows prominently, for example, the bending moment is reduced to 1/3 or less by considering the load burden of the retaining wall, and the reduction in the displacement and shear force of the pile head is also remarkable. . Furthermore, as a result of the rough estimation, it was confirmed that the pile construction and the concrete volume of the pile can be reduced to about 70% by considering the load burden with the retaining wall as the main structure.

The two-dimensional analysis model which made the structure by this invention a wire. The state figure which showed the connection of the stress member of a mountain retaining wall, and the foundation beam or mat slab of a building. Sectional drawing which showed the structure where buildings, such as a general high-rise building, were constructed. Stress analysis model for examples (and comparative examples) of the present invention Stress analysis results of examples (and comparative examples) of the present invention

Claims (3)

  A structure having a building, a pile supporting the building, and a retaining wall constructed on the ground around the building, wherein the retaining wall and the building are joined by an anchor member, and constitutes the retaining wall A structure in which at least the part below the foundation beam or mat slab of steel members is a permanent structure.   A structure in which the burden load on the building and the pile is reduced in consideration of the horizontal load burden on the portion below the foundation beam or mat slab of the steel member constituting the retaining wall.   A design method for a structure having a building, a pile supporting the building, and a retaining wall constructed on the ground around the building, wherein the retaining wall and the building are joined by an anchor member. A method of determining the cross section of the stress member of the pile and the retaining wall in consideration of the horizontal load burden by at least the part below the foundation beam or mat slab of the steel member constituting the steel structure.

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