JP2003301455A - Method for designing composite wall - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable highly reliable checking. <P>SOLUTION: In a design method, after an earth retaining wall 10 is designed in step S10-S13, a composite wall 14 is designed in steps S14-S19. When the composite wall 14 is designed, a load in permanent erection is set in the step S14, and a structural calculation for the composite wall 14 is performed according to the setting of the load in the following step S15. Next, a gradual decrease rate of secondary sectional moment of inertia is set in the step S16; after that, the distribution of section force between the wall 10 and a permanently erected wall 12 is determined in the step S17; and the performance of the composite wall 14 is checked in the step S18. When the performance is checked in the step S18, a generated shear force Qs, which is assigned to the wall 10, and a generated shear force Qc, which is assigned to the wall 12, are computed according to the gradual decrease rate and the distribution of the section force; the composite wall 14 is separated into the walls 10 and 12; it is confirmed that the shear force Qs does not reach shearing strength Qsd of the wall 10; and it is confirmed that the shear force Qc does not reach shearing strength Qcd of the wall 12. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for designing a synthetic wall, and more particularly to a method for designing a synthetic wall in which a temporary wall for earth retaining and a main wall are integrated.

[0002]

2. Description of the Related Art When constructing an underground structure, a temporary earth retaining wall is usually formed in the ground, the inside of the earth retaining wall is excavated, and then the structure is constructed inside the earth retaining wall. . FIG. 9 shows a construction state of an underground wall conventionally used in the field of civil engineering.

In the example shown in the figure, a reinforced concrete main wall 4 is constructed inside a soil retaining wall 3 consisting of a soil cement wall 2 constructed with an H-shaped steel as a core material 1.

Conventionally, in constructing such a composite wall 5, in the field of civil engineering, an earth retaining wall 3 having an H-shaped steel as a core material 1 is used.
Since it is a temporary structure to the last, it was designed by ignoring its existence when designing the main wall 4.

On the other hand, in the field of construction, there is a track record of using this as a part of the main body when constructing a temporary wall with H-shaped steel as a core material in the basement of a building. It is being considered for use as a permanent wall, and this is in the stage of practical application.

When designing a composite wall based on such a technical idea, it is generally considered that the design is performed according to the procedure shown in FIG. In the procedure shown in the figure, first, the earth retaining wall 3 is designed in steps S1 to S4, and then the synthetic wall 5 is designed in steps S5 to S4.
It will be held up to 8.

In designing the earth retaining wall 3, in step S1,
The load at the time of temporary installation is set, and based on this, in the subsequent step S2, the structural calculation of the earth retaining wall 3 at the time of temporary installation is performed,
Step S to check the obtained calculation result and the performance of the retaining wall 3.
Do in 3.

If the performance of the earth retaining wall 3 does not satisfy the conditions in this performance check, the specifications of the earth retaining wall 3 are changed and assumed in step S4, and the process returns to step S2 to calculate the structure. In addition, the obtained calculation result and the performance of the retaining wall 3 are checked in step S3, and when the performance of the retaining wall 3 satisfies the conditions by sequentially repeating such steps, the retaining wall 3 is constructed. The specifications are decided.

On the other hand, in the design of the synthetic wall 5, step S5
Then, the load at the time of permanent installation is set, and based on this, in the subsequent step S6, the structural calculation (bending moment, axial force, shearing force) of the composite wall 5 is performed, and the obtained calculation result and the composite wall The performance check of No. 5 is performed in step S7.

If the performance of the composite wall 5 does not satisfy the condition in this performance check, the specification of the composite wall 5 is changed and assumed in step S8, and the process returns to step S6 to perform the structural calculation. When the performance of the composite wall 5 satisfies the conditions by performing the obtained calculation result and the performance check of the composite wall 5 in step S7 and sequentially repeating such steps, the construction specification of the composite wall 5 is determined. become. However, such a conventional synthetic wall designing method has the following problems.

[0011]

That is, in the designing method of the procedure shown in FIG. 10, for example, the shear check is performed on the entire synthetic wall 5, and more specifically, on the design load. It is performed by confirming that the calculated shearing force Q of the composite wall 5 has not reached the proof stress Qd.

However, in the shear strength Qd of the synthetic wall 5 in this case, the core material 1 made of H-shaped steel and the main wall 4 made of reinforced concrete are completely rigidly connected and are completely integrated. I was assuming that.

However, according to the knowledge of the present inventors, the shear strength of the core material 1 made of H-shaped steel and the main wall 4 made of reinforced concrete is, of course, not the same value. Is smaller than the H-section steel,
Such a design method does not deal with partial shear failure of the reinforced concrete wall, and has a problem in reliability of verification.

The present invention has been made in view of such conventional problems, and an object thereof is a highly reliable inspection capable of coping with partial shear failure of a reinforced concrete wall. It is to provide a method of designing a synthetic wall that enables

[0015]

In order to achieve the above object, the present invention provides a synthetic wall designing method in which a temporary earth retaining wall and a main building wall are integrated with each other, with respect to a design load at the time of designing. Then, the generated shear force of the synthetic wall is calculated, and then, when the shear strength of the synthetic wall is checked, the synthetic wall is divided into the earth retaining wall and the permanent wall, and among the generated shear force. , The shear force shared by the earth retaining wall does not reach the shear strength of the soil retaining wall, and, of the generated shear forces, the shear force shared by the main wall is the shear strength of the main wall. I'm trying to make sure both are not reached.

According to the method of designing a synthetic wall constructed as described above, as is clear from the test results described later, it is possible to carry out highly reliable verification capable of coping with partial shear failure of a reinforced concrete wall. Become.

In the designing method of the present invention, before the performance of the composite wall is checked, the reduction rate of the second moment of area of the composite wall is set, and then the distribution of the sectional force between the earth retaining wall and the main wall is distributed. Can be determined.

Further, in the designing method of the present invention, the synthetic wall includes the earth retaining wall formed of a soil cement wall having H-shaped steel as a core material, and the main wall formed of reinforced concrete, The generated shear force Qc shared by the main wall and the generated shear force Qs shared by the earth retaining wall can be calculated based on the following equations. Qc = {(1−Js / ψJ ′) × Dl + (EcJc / EsψJ ′) × Hu} × Q / (Dl + Hu) (1) Qs = {(Js / ψJ ′) × Dl ten (1−EcJc / E s ψJ ') × Hu} × Q / (Dl + Hu) (2) ψ = J / J' ・ ・ ・ (3) J = Js + Ec / Es × Jc + (Dl + Hu) ² / [{(π ^{2 / (1x 2 × bu × k} ) + 1 / (E c × Ac) + 1 / (Es As)) × Es} ··· (4) J '= Js + Ec / Es × Jc + (Dl + Hu) 2 × Ec Ac / [{1+ (Ec Ac) / (Es As)} × Es] (5) Where: Q: Shear force of synthetic wall ψ: Cross sectional second moment of synthetic wall Decrease J: Synthetic wall Moment of inertia of section (converted to steel) J ': Moment of inertia of section of a composite wall of complete synthesis (k → ∞) (converted to steel) k: Shear rigidity of joint surface of composite wall Jc: Moment of inertia of section of main wall Js : Moment of inertia of section of H-section steel Ec: Young's modulus of concrete Es: Young's modulus of H-section steel Ac: Section area of main wall (1y × h) As: Cross-sectional area of H-section steel 1x: Span length of composite wall 1y: Effective width of composite wall (usually the spacing between H-section steels) bu: Flange width of H-section steel h: Main installation Thickness of wall Dl: Length from center of gravity of main wall to joint surface of composite wall Hu: Length from center of gravity of H-shaped steel to joint surface of composite wall π: Circular ratio.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Figure 1
8 to 8 show one embodiment of the method for designing a synthetic wall according to the present invention.

In the method for designing a synthetic wall of this embodiment, as shown in FIG. 1, when a synthetic wall 14 for integrally integrating a temporary earth retaining wall 10 and a main construction wall 12 is installed horizontally, When the shearing force of the synthetic wall 14 is calculated with respect to the design load at the time, and then the shearing strength of the synthetic wall 14 is checked, the synthetic wall 1
4 is divided into a retaining wall 10 and a permanent wall 12, and retaining wall 1
The generated shear force Qs of 0 does not reach the shear strength Qsd of the earth retaining wall 10, and the generated shear force Qc of the main wall 12 is the shear strength Qc of the main wall.
It has a basic configuration that confirms that both of them do not reach d.

The check at this time is expressed by the following equation. Checking shear strength of main wall 12: Qc / Qcd ≦ 1.0 (6) Checking shear strength of retaining wall: Qs / Qsd ≦ 1.0 (7) In the example shown in FIG. The temporary earth retaining wall 10 is made of the core material 1
0a and the soil cement body 10b, the H-shaped steel is used as the core material 10a, and the soil cement body 10b in which the core material 10a is embedded is constructed so as to overlap each other in the lateral direction.

In the earth retaining wall 10 having such a structure, the generated shearing force Qs shared by the earth retaining wall 10 is substantially H
This corresponds to the value of the core material 10a made of shaped steel, and the shear strength Qsd also corresponds to the value of H-shaped steel.

In the case of this embodiment, the main wall 12 is made up of the reinforcing bar 12a and the concrete body 12 in which the reinforcing bar 12a is embedded.
It is constructed from reinforced concrete with b, and the generated shear force Qc and shear strength Qc shared by the main wall 12 are shared.
d likewise corresponds to the value of a reinforced concrete wall.

The member indicated by reference numeral 16 in FIG.
Earth retaining wall 10 and main wall 1 embedded in main wall 12 with one end fixed to the surface of core 10a made of shaped steel.
It is a shear connector that integrally connects the two.

2 and 3 show the basic concept of the designing method according to the present invention, and the symbols shown in these figures are:
It has the following contents. 1x: span length of the composite wall 12, 1y: effective width of the composite wall (usually the H-section steel arrangement interval), bu: H-section flange width, h:
Thickness of main wall 12, Cc: center of gravity of main wall 12, Cs: center of gravity of H-shaped steel, Dl: length from center of gravity Cc of main wall 12 to composite wall joint surface, Hu: H type Length between center of gravity Cs of steel and joint surface of composite wall In the composite wall 14 having such a dimensional structure, the generated shear force Q (Qs + Qc) acts from the main wall 12 side as shown in FIG. At this time, the core material 10a made of H-shaped steel and the main wall 12 made of reinforced concrete are connected by the shear connector 16, but they are not completely integrated and there is a gap between them. It is considered that the strain distributions are different from each other and have different behaviors, and the strain distribution becomes as shown in FIG.

However, in the conventional design method described above,
As shown in FIG. 11, the core material 1 of the synthetic wall 5 and the main wall 4 made of reinforced concrete are completely integrated without any displacement, and the external shear force Q acts from the main wall 12 side. When this is done, it is based on the concept that these transform as a unit.

Therefore, the inventors of the present invention tried a verification experiment to confirm such a basic concept. In this demonstration experiment,
A total of 5 test pieces having the dimensions and shapes shown in FIG. 4 were produced. The detailed contents of each sample are shown in Table 1 below.

[0028]

[Table 1] In the verification experiment, the specimen was supported with a span length of 4750 mm from the lower side, a load P was applied from above the center of the supporting point, and the shearing force until the specimen fractured due to shearing was measured.

In the five test pieces, stud bolts were used as members corresponding to the shear connector 16, and these were welded only to the surface (flange) of the H-shaped steel on the main wall side. When 84 bolts were used in 3 rows, the degree of synthesis was 1.0 (specimen No. 5), and the degree of synthesis was set to 4 stages.

5 to 7 are graphs showing the test results. FIG. 5 shows the relationship between the shear strength Qd of the composite wall and the generated shear force Qmax of the composite wall at the time of failure. FIG. 6 shows the relationship between the shear strength Qcd of the reinforced concrete wall and the generated shear force Qcmax shared by the reinforced concrete wall at the time of failure. Figure 7 shows the shear strength Qsd of H-section steel.
And the generated shearing force Qsmax shared by the H-section steel at the time of fracture. The graphs shown by the polygonal lines in each figure are the results of shear check (Q / Qd), (Qcmax / Qcd), (Qsmax
/ Qs d), where the crosses indicate partial shear failure of the reinforced concrete wall, and the black circles indicate bending failure.

As is clear from the test results, first,
In FIG. 5, although the result of shearing inspection (Q / Qd) is 1.0 or less, No. Shear failure was observed in 2, 3 and 5 specimens, and this failure mode was partial shear failure of the reinforced concrete wall.

From this, it can be said that the conventional design method assumes that the H-section steel and the reinforced concrete wall are in a perfect composite, but the design that embodies a form very close to this state is realized. Even in Specimen 5, although the generated shear force Qmax of the composite wall does not exceed the shear strength Qd, shear failure of the reinforced concrete wall was recognized. In the conventional design method, the failure mode of the composite wall (reinforced concrete wall It has been found that the partial shear failure of () is unpredictable.

On the other hand, when the shear check (Qcmax / Qcd) of the reinforced concrete wall shown in FIG. 6 and the shear check of the H-section steel (Qsmax / Qsd) shown in FIG.
It can be seen that shear failure of the concrete wall does not occur until these values do not exceed 1.0.

That is, as shown in FIG.
Shear failure has occurred in reinforced concrete walls in 2, 3 and 5, but in the case of these specimens, shear test (Qc
max / Qcd) exceeds 1.0.

Further, in FIG. 7, the specimen No. Two
Shear failure occurred in the reinforced concrete walls in Nos. 3 and 5, but all the specimens had shear test (Qsmax / Qsd).
It does not exceed 1.0.

Accordingly, when the shear strength of the composite wall is checked, the shear check is performed separately for the reinforced concrete wall and the H-shaped steel, and if both check values do not exceed the limit values, the concrete It was confirmed that the partial shear fracture did not occur and the inspection could be performed with high reliability.

In the above-mentioned verification test, Qsd is H
The design shear strength of the shaped steel was used, and the design shear strength of the reinforced concrete wall was used for Qcd. Also, Qcd and Qs
The calculation of d was based on the concrete standard specification, design edition (JSCE), various synthetic structure design guidelines, and the same commentary (Architectural Institute of Japan).

FIG. 8 is a flow chart showing the procedure of the design method according to the present invention more specifically. In the procedure shown in the figure, first, when starting, the earth retaining wall 10 is designed in steps S10 to S13, and then the composite wall 14 is designed in step S1 as in the conventional design method.
It is performed from 4 to S19.

In designing the earth retaining wall 10, step S10 is performed.
Then, the load at the time of temporary installation is set, and based on this, in the subsequent step S11, the structural calculation at the time of temporary installation of the earth retaining wall 10 is performed, and the obtained calculation result and the performance of the earth retaining wall 10 are checked. Performed in S12.

If the performance of the earth retaining wall 10 does not satisfy the conditions in this performance check, in step S13, the earth retaining wall 1
Assuming that the specification of 0 has been changed, the process returns to step S11 again, structural calculation is performed, and the obtained climbing result and performance check of the retaining wall 10 are performed in step S12, and such steps are sequentially performed. By repeating the above, when the performance of the retaining wall 10 satisfies the condition, the construction specification of the retaining wall 3 is determined.

On the other hand, when designing the composite wall 14, the load at the time of permanent installation is set in step S14, and based on this, in the subsequent step S15, the structural calculation of the composite wall 14 (bending moment, Axial force, shear force).

Next, in step S16, the sectional moment of inertia of the composite wall is set to ψ, and after that, in step S17, the distribution of the sectional force between the earth retaining wall 10 and the main wall 12 is determined. Then, the performance check of the composite wall 14 is performed in step S18.

In this case, the setting of the deceleration ψ and the distribution of the sectional force performed in steps S16 and S17 can be performed by the following equations 3 to 3.
It is calculated based on 5. ψ = J / J ′ (3) J = Js + Ec / Es × Jc + (Dl + Hu) ² / [{(π ² / (1x ² × bu × k) + 1 / (Ec × Ac) + 1 / (Es As)} × Es) (4) J ′ = Js + Ec / Es × Jc + (Dl + Hu) ² × Ec Ac / [{1+ (Ec Ac) / (Es As)} × Es] (5) ) Here, Q: Shear force generated by synthetic wall ψ: Second moment of area of inertia of synthetic wall J: Reduction of second moment of area of synthetic wall (steel equivalent) J ': Synthetic wall of completely synthetic (k → ∞) Second moment of area (converted to steel) k: Shear rigidity of joint surface of composite wall Jc: Second moment of area of main wall Js: Second moment of area of H-section steel Ec: Young's modulus of concrete Es: of H-section steel Young's modulus Ac: Cross-sectional area of main wall (1y × h) As: Cross-sectional area of H-section steel 1x: Span length of composite wall 1y: Effective width of composite wall (usually the interval between H-section steels) bu: Flange width of H-section steel h: Thickness of main wall Dl: From center of gravity of main wall Length between synthetic wall joint surface Hu: Length between center of gravity of H-section steel and synthetic wall joint surface π: Circularity.

When performing the performance check in step S18,
The shear force response value Qs of the earth retaining wall 10 and the shear response value Qc of the main wall 12 are calculated by the following equations 1 and 2 based on the distribution of the deceleration ψ and the sectional force obtained in steps 16 and 17. Is calculated. Qc = {(1−Js / ψJ ′) × Dl + (Ec Jc / Es ψJ ′) × Hu} × Q / (Dl + Hu) (1) Qs = {(Js / ψJ ′) × Dl + ( 1−EcJc / E s ψJ ′) × Hu} × Q / (Dl + Hu) (2) Then, in the performance check, the shear strength Qsd of the earth retaining wall 10
And the shear strength Qcd of the main wall are calculated and determined by the following formula. Checking shear strength of main wall 12: Qc / Qc d ≤ 1.0 ・ ・ ・ (6) Checking shear strength of earth retaining wall 10: Qs / Qs d ≤ 1.0 ・ ・ ・ (7) With this performance check If the performance of the composite wall 14 does not satisfy the conditions, the specification of the composite wall 12 is changed (the thickness and the reinforcing bar amount of the main wall 12, and the specification of the shear connector 16 are changed) in step S19. And again, step S1
5, the structural calculation is performed, the obtained calculation result and the performance of the composite wall 14 are checked in step S18, and such steps are sequentially repeated, whereby the composite wall 14
If the performance of 1 satisfies the condition, the construction specification of the composite wall 14 is determined.

By the way, according to the method of designing the synthetic wall constructed as described above, as is clear from the results of the above-mentioned verification test, the reliability of the shear failure of the reinforced concrete wall can be coped with partially. High verification is possible.

[0046]

As described above in detail, according to the method for designing a synthetic wall according to the present invention, it is possible to carry out highly reliable inspection capable of coping with partial shear failure of a reinforced concrete wall. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a synthetic wall to which a designing method according to the present invention is applied.

FIG. 2 is a conceptual explanatory diagram of a design method according to the present invention.

FIG. 3 is a conceptual explanatory diagram of a design method according to the present invention.

FIG. 4 is an explanatory diagram of a test piece used in a verification experiment of a design method according to the present invention.

FIG. 5 is a graph showing test results of a verification experiment of the design method according to the present invention.

FIG. 6 is a graph showing test results of a verification experiment of the design method according to the present invention.

FIG. 7 is a graph showing test results of a verification experiment of the design method according to the present invention.

FIG. 8 is a flowchart showing an embodiment of a method for designing a synthetic wall according to the present invention.

FIG. 9 is a cross-sectional view of a composite wall to which a conventional design method is applied.

FIG. 10 is a flowchart showing an example of a conventional synthetic wall designing method.

FIG. 11 is a conceptual explanatory diagram of a conventional design method.

[Explanation of symbols]

10 earth retaining wall 10a Core material (H-shaped steel) 10b soil cement body 12 main wall (iron section concrete wall) 12a rebar 12b concrete body 14 synthetic walls 16 sheer connector

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Junji Sayama             1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo East             Inside Kyoden Electric Co., Ltd. (72) Inventor Masahiro Yoshimoto             1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo East             Inside Kyoden Electric Co., Ltd. (72) Inventor Mitsuo Kurihara             3-3-3 Higashi Ueno, Taito-ku, Tokyo Toden             Design Co., Ltd. (72) Inventor Yukihiro Naito             3-3-3 Higashi Ueno, Taito-ku, Tokyo Toden             Design Co., Ltd. F-term (reference) 2D049 EA02 EA09 FB03 FB13 GB05                       GC11 GE03

Claims (3)

[Claims] 1. In a method of designing a composite wall in which a temporary earth retaining wall and a main wall are integrated, a shearing force generated by the composite wall is calculated with respect to a design load at the time of main installation, and thereafter, When checking the shear strength of the composite wall, the composite wall is divided into the earth retaining wall and the main wall, and the shearing force shared by the earth retaining wall among the generated shearing force is the earth retaining wall. It is confirmed that both the shear strength of the wall is not reached and that among the generated shear forces, the shear force shared by the main wall does not reach the shear strength of the main wall. How to design a wall. 2. The distribution of the sectional force between the earth retaining wall and the main wall is determined after the reduction rate of the second moment of area of the synthetic wall is set before the performance check of the synthetic wall. The method for designing a synthetic wall according to claim 1, wherein: 3. The composite wall comprises the earth retaining wall formed of a soil cement wall having H-shaped steel as a core material, and the main wall formed of reinforced concrete, and shears shared by the main wall are provided. Force Qc and shearing force Qs shared by the retaining wall
The method for designing a synthetic wall according to claim 1 or 2, wherein and are calculated based on the following equation. Qc = {(1−Js / ψJ ′) × Dl + (EcJc / EsψJ ′) × Hu} × Q / (Dl + Hu) (1) Qs = {(Js / ψJ ′) × Dl ten (1−EcJc / E s ψJ ') × Hu} × Q / (Dl + Hu) (2) ψ = J / J' ・ ・ ・ (3) J = Js + Ec / Es × Jc + (Dl + Hu) ² / [{(π ^{2 / (1x 2 × bu × k} ) + 1 / (E c × Ac) + 1 / (Es As)) × Es} ··· (4) J '= Js + Ec / Es × Jc + (Dl + Hu) 2 × Ec Ac / [{1+ (Ec Ac) / (Es As)} × Es] (5) Where: Q: Shear force of synthetic wall ψ: Cross sectional second moment of synthetic wall Decrease J: Synthetic wall Moment of inertia of section (converted to steel) J ': Moment of inertia of section of a composite wall of complete synthesis (k → ∞) (converted to steel) k: Shear rigidity of joint surface of composite wall Jc: Moment of inertia of section of main wall Js : Moment of inertia of section of H-section steel Ec: Young's modulus of concrete Es: Young's modulus of H-section steel Ac: Section area of main wall (1y × h) As: Cross-sectional area of H-section steel 1x: Span length of composite wall 1y: Effective width of composite wall (usually the spacing between H-section steels) bu: Flange width of H-section steel h: Main installation Thickness of wall Dl: Length from center of gravity of main wall to joint surface of composite wall Hu: Length from center of gravity of H-shaped steel to joint surface of composite wall π: Circular ratio.