Method for calculating the tensile strength of an insert, method for designing an insert, and system for calculating the tensile strength of an insert.

Abstract

To provide an evaluation method for an insert and an evaluation system for the insert to properly evaluate slip-out yield strength of the insert.SOLUTION: An evaluation device evaluates insert tensile yield strength of an insert 10 buried in a concrete member C1. The insert 10 includes a high nut 15, and an attachment bolt 11 screwed in the high nut 15. The evaluation device evaluates slip-out yield strength Pa5 of the insert 10 as the tensile yield strength using a separation distance hb1 from a boundary of a head part 11a and a shaft part 11b of the attachment bolt 11 to an end part of the attachment bolt 11 side of the high nut 15 and a virtual cylindrical surface area calculated in accordance with a cylindrical shape of the head part 11a of the attachment bolt 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention provides an insert for evaluating the tensile strength of an insert embedded in a concrete member, comprising a high nut and a threaded member with a projection that screws onto the high nut. Method for calculating tensile strength, design of inserts Method and insert Calculation of tensile strength Regarding the system. [Background technology]

[0002] In concrete structures, inserts embedded in concrete members are sometimes used (for example, Patent Document 1). The embedded insert in Patent Document 1 comprises an insert body consisting of an anchor bolt that passes through a through hole in the formwork and a tall nut (long nut) that screws onto it, and a dummy bolt that screws onto the tall nut opposite the anchor bolt.

[0003] Furthermore, as shown in Figure 11, the insert 60 embedded in the concrete member C6 comprises a bolt 61 with a projection (shaft with projection) and a tall nut 65. In addition, a bolt 67 is screwed into the threaded portion on the opening side of the tall nut 65.

[0004] In designing such an insert 60, the short-term allowable tensile strength is calculated (see Non-Patent Literature 1). As described in Non-Patent Literature 1, conventionally, the short-term allowable tensile strength has been calculated using the minimum value of the following four types of strengths (min(Pa1, Pa2, Pa3, Pa4)).

[0005] • The tensile strength Pa1 of the steel material when determined by the yield of the bolt shaft. • Cone failure strength Pa2 when determined by cone-shaped failure of the concrete structure • Head concrete bearing capacity Pa3, determined by the bearing pressure at the head of the cap nut or the head of the bolt with projections. • Head concrete bearing capacity Pa4, determined by the concrete bearing pressure of the cap nut head or the bolt head with projections.

[0006] The above short-term allowable tensile strength assumes that the head diameter Dn6 of the projection-equipped cap nut and projection-equipped bolt is sufficiently larger than the shaft diameter d6 (Dn6 ≥ 2.5 × d6). Furthermore, Non-Patent Literature 1 states that when the head diameter Dn6 is smaller than the long nut diameter dn6, the height nut 65 and the length h6 under the head should be at least 8 times the projection dimension a6 of the head diameter to prevent pull-out failure. Moreover, it states that even when the head diameter Dn6 is larger than the long nut diameter dn6, it is desirable to ensure that h6 ≥ 3.5 × d6. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Utility Model Publication No. 04-20567 [Non-patent literature]

[0008] [Non-Patent Document 1] "Design Guidelines for Joints and Mounting Frames of Seismic Isolation Components," published by the Japan Seismic Isolation Association, January 1, 2020, pp. 6-19. [Overview of the project] [Problems that the invention aims to solve]

[0009] Inserts are sometimes used at joints where bending moments are small, such as when connecting secondary steel members to reinforced concrete members. In this case, the minimum dimension value that satisfies the above-mentioned insert specifications was adopted. This was because there was no method to evaluate the tensile strength of inserts that did not satisfy the above-mentioned specifications. Consequently, it was not possible to implement inserts with appropriate tensile strength according to their application. To achieve this implementation, it is necessary to properly evaluate the tensile strength of the inserts. However, conventionally, there has been no known method for properly evaluating the tensile strength of inserts used in areas with small bending moments. [Means for solving the problem]

[0010] The insert for solving the above problems Method for calculating tensile strength includes a high nut and The aforementioned a threaded member with a protrusion that is screwed into the high nut, and increases the tensile strength of the insert embedded in the concrete member calculation by calculation a method, from the boundary between the protrusion and the shaft of the threaded member with a protrusion to the end of the high nut on the side of the threaded member with a protrusion, the separation distance, The projection in the plane perpendicular to the extending direction of the shaft portion. the outer shape of the starting part The circumference of the circular or hexagonal projection and By multiplying by the calculated virtual cylindrical surface area The concrete compressive strength of the concrete member is multiplied by a predetermined coefficient to calculate the following: to make the withdrawal strength of the insert Identify as equal to the tensile strength. Furthermore, a method for calculating the tensile strength of an insert that solves the above problem comprises a tall nut and a hexagonal bolt that screws into the tall nut, and is a method for calculating the tensile strength of an insert embedded in a concrete member, wherein the tensile strength is determined by multiplying the surface area of ​​a cylindrical shape calculated by multiplying the distance between the boundary between the head and shaft of the hexagonal bolt and the end of the tall nut on the hexagonal bolt side by the circumference of a circle whose diameter is the width across flats of the head of the hexagonal bolt and the distance between flats, by the concrete compressive strength of the concrete member and a predetermined coefficient. Furthermore, a method for designing an insert that solves the above problems is a method for designing an insert that is embedded in a concrete member, comprising a tall nut and a threaded member with a projection that screws onto the tall nut, wherein the pull-out resistance of the insert is determined as the tensile strength by multiplying the virtual cylindrical surface area, which is calculated by multiplying the distance between the boundary between the projection and the shaft of the threaded member with the projection and the end of the tall nut on the threaded member side by the circumference of the projection, which is the outer shape of the projection, which is a circle or hexagon on a plane perpendicular to the extending direction of the shaft, by the concrete compressive strength of the concrete member and a predetermined coefficient, and if the pull-out resistance does not meet the required strength for the insert, the distance between the parts and the size of the outer shape of the projection are changed to obtain a pull-out resistance of the required strength or greater. Furthermore, a method for designing an insert that solves the above problems comprises a tall nut and a hexagonal bolt that screws into the tall nut, and is embedded in a concrete member. The method specifies the pull-out resistance of the insert as the tensile strength, which is calculated by multiplying the distance between the boundary between the head and shaft of the hexagonal bolt and the end of the tall nut on the hexagonal bolt side by the distance, and the surface area of ​​a cylindrical shape calculated by multiplying the circumference of a circle whose diameter is the width across flats of the head of the hexagonal bolt by the distance, and the concrete compressive strength of the concrete member by a predetermined coefficient. If the pull-out resistance does not meet the required strength for the insert, the distance between the nut and the surface area of ​​the hexagonal bolt on a plane perpendicular to the extending direction of the shaft are changed to achieve a pull-out resistance of the required strength or greater.

Effect of the Invention

[0011] According to the present invention, the withdrawal strength of the insert can be appropriately evaluated.

Brief Description of the Drawings

[0012] [Figure 1] It is an explanatory diagram for explaining the structure of the insert in the embodiment, (a) is a left side view, and (b) is a front view. [Figure 2] It is an explanatory diagram of the evaluation device in the embodiment. [Figure 3] It is an explanatory diagram of an example of the hardware configuration of the evaluation device in the embodiment. [Figure 4] It is an explanatory diagram of the concept for explaining the calculation formula for calculating the virtual cylindrical shear strength of the insert in the embodiment. [Figure 5] It is a table showing the detailed dimensions of the test piece used in the experiment in the embodiment. [Figure 6] It is a graph showing the relationship between the separation distance and the virtual cylindrical shear strength in the test piece that caused withdrawal failure in the embodiment. [Figure 7]This graph shows a comparison between the calculated experimental results for each type of failure in the embodiment and the experimental values ​​for maximum load-bearing capacity. [Figure 8] This is a flowchart illustrating the processing procedure for load-bearing capacity evaluation in the embodiment. [Figure 9] This is a flowchart illustrating the processing steps for the redesign process in the embodiment. [Figure 10] This is an explanatory diagram for calculating the virtual cylindrical surface area of ​​the insert in the modified example. [Figure 11] This is an explanatory diagram illustrating the structure of an insert in conventional technology. [Modes for carrying out the invention]

[0013] The following uses Figures 1 to 9 to explain the insert. Method for calculating tensile strength, design of inserts Method and insert Calculation of tensile strength An embodiment of the system will be described. In this embodiment, the yield strength of a simple assembly insert equipped with a high nut and a bolt with a projection is evaluated. This easy-to-assemble insert is installed in reinforced concrete or steel-reinforced concrete buildings at the structural connection point of the gusset plate base plate at the end of a steel member that primarily transmits shear force to the concrete structure. Here, "primarily transmitting shear force" means transmitting a shear force of a magnitude where the effect of bending moment can be ignored. Specifically, it is applicable to the following parts: • Steel beams and studs that are pin-connected to the structural frame • Steel suspension columns, etc., that are pin-connected to the side of the building structure.

[0014] (Insert configuration) First, the configuration of the insert used to evaluate load-bearing capacity in this embodiment will be described. Figures 1(a) and 1(b) are the left side view and front view, respectively, of the insert 10 of this embodiment.

[0015] As shown in Figure 1(b), the insert 10 of this embodiment is embedded in the concrete member C1. The insert 10 includes a mounting bolt 11 and a high nut 15 as threaded members with protrusions.

[0016] As shown in Figure 1, the mounting bolt 11 is a hexagonal bolt and comprises a head 11a with a width across flats Dn1 and a shaft portion 11b with a shaft diameter d1. Here, the head 11a functions as a projection. A threaded portion 11c with an external thread is formed on the outer circumference of the tip side of the shaft portion 11b. In this embodiment, the (tip) overhang length a1 is from half the width across flats Dn1 of the head 11a to half the shaft diameter d1. Furthermore, the threaded portion 11c of this mounting bolt 11 is screwed into the tall nut 15.

[0017] The tall nut 15 is a long hexagonal nut. In this embodiment, the tall nut 15 has the same size as the head 11a of the mounting bolt 11. The end of the tall nut 15 is positioned to coincide with the side surface of the concrete member C1. Furthermore, the threaded hole 15a of the tall nut 15 that is not threaded into the tip of the mounting bolt 11 is left open. When attaching the insert 10, a bolt (not shown) may be screwed into the opening of the threaded hole 15a.

[0018] Furthermore, in Figure 1, with the mounting bolt 11 screwed into the tall nut 15, the effective embedment length le1 is defined as the distance from the end of the concrete member C1 to the head 11a of the mounting bolt 11. Also, the distance hb1 is defined as the distance from the boundary between the head 11a and the shaft portion 11b of the mounting bolt 11 to the end of the tall nut 15 on the mounting bolt 11 side.

[0019] (Description of the evaluation device) Next, using Figure 2, we will describe the evaluation device 20 for evaluating the tensile strength of the insert 10 described above.

[0020] (Description of hardware configuration) Here, using Figure 3, the hardware configuration of the information processing device H10 that constitutes the evaluation device 20 will be explained. The information processing device H10 includes a communication device H11, an input device H12, a display device H13, a storage device H14, and a processor H15. Note that this hardware configuration is just one example, and it can also be implemented with other hardware.

[0021] Communication device H11 is an interface that establishes a communication path with other devices and performs data transmission and reception. The input device H12 is a device that receives input of various types of information and input from evaluators, etc., such as a mouse or keyboard. The display device H13 is a display or touch panel, etc., that displays the input information and output information such as evaluation results.

[0022] The storage device H14 is a storage device that stores data and various programs for executing the various functions of the evaluation device 20. Examples of storage devices H14 include ROM, RAM, and hard disks. The processor H15 uses the programs and data stored in the memory device H14 to control each process in the evaluation device 20 (for example, the process in the control unit 21, which will be described later).

[0023] (Functions of the evaluation device 20) Next, we will explain the functions of the evaluation device 20 using Figure 2. The evaluation device 20 is a computer system that evaluates the yield strength of the insert 10. The evaluation device 20 includes a control unit 21, an evaluation formula storage unit 25, an evaluation target information storage unit 26, and a component specification information storage unit 27.

[0024] The control unit 21 performs the processes described later (including the evaluation stage and the redesign stage). By executing the processing program for this purpose, the control unit 21 functions as the evaluation unit 211, the redesign unit 212, etc.

[0025] The evaluation unit 211 acquires detailed information about the insert 10 to be evaluated, such as the required yield strength, and executes a process to evaluate the yield strength of the insert 10 using the evaluation formula stored in the evaluation formula storage unit 25.

[0026] If the load-bearing capacity of the insert 10 calculated by the evaluation unit 211 is less than the required load-bearing capacity, the redesign unit 212 identifies and outputs redesign information for the insert 10 that will have a load-bearing capacity equal to or greater than the required load-bearing capacity. Here, the separation distance hb1 and the nominal diameter of the mounting bolt 11 are used as the redesign information for the insert 10.

[0027] The evaluation formula storage unit 25 stores evaluation formulas for calculating the load-bearing capacity of the insert 10. In this embodiment, the calculation formulas for the three load-bearing capacity types (Pa1, Pa2, Pa4) that have the greatest influence among the four load-bearing capacity types described above, and the pull-out resistance capacity Pa5 of the insert 10 using the virtual cylindrical surface area Act as the virtual cylindrical surface area, are stored. Details of the calculation formula for this pull-out resistance capacity Pa5 will be described later.

[0028] The evaluation target information storage unit 26 stores data relating to detailed information of the evaluation target member. This evaluation target data is recorded when information of the evaluation target member is acquired from the input device H12. The evaluation target data consists of data relating to the insert identifier, concrete compressive strength, bolt identifier, high nut identifier, high nut length, separation distance, redesign value, etc.

[0029] The insert identifier data area contains data about an identifier used to identify each insert 10 being evaluated. The concrete compressive strength data area contains data relating to the compressive strength of the concrete member C1 in which this insert 10 is embedded.

[0030] The bolt identifier data area contains data relating to an identifier for identifying the mounting bolt 11 used in this insert 10. In this embodiment, the nominal diameter of the bolt is used as the bolt identifier.

[0031] The high nut identifier data area contains data relating to an identifier for identifying the high nut 15 used in this insert 10. In this embodiment, the nominal diameter of the thread of the high nut 15 is used as the high nut identifier.

[0032] The data area for the length of the tall nut contains data related to the length of this tall nut 15. The separation distance data area records data related to the separation distance hb1. In this embodiment, the ratio of the overhang length a1 is used as the separation distance hb1.

[0033] The redesign value data area records data regarding the redesigned spacing distance and the nominal diameter of the mounting bolt 11. This data is recorded when the calculated minimum load-bearing capacity is the pull-out load-bearing capacity Pa5, and this pull-out load-bearing capacity Pa5 is smaller than the required load-bearing capacity, and the spacing distance and nominal diameter of the mounting bolt 11 that result in a load-bearing capacity equal to or greater than the required load-bearing capacity are specified.

[0034] The component specification information storage unit 27 stores data regarding detailed specifications of bolts and high nuts. This component specification information data is acquired and recorded before acquiring information on the member to be evaluated. The component specification information includes bolt specification information and high nut specification information. The bolt specification information includes data regarding the nominal diameter, wrench size, shaft diameter, and overhang length of the bolt. The high nut specification information includes data regarding the nominal diameter and wrench size of the high nut.

[0035] The bolt nominal diameter data area records data related to the nominal diameter of each bolt. Through this nominal diameter, the wrench size, shaft diameter, and overhang length of the mounting bolt for the data being evaluated can be identified. The data areas for the bolt's wrench size, shaft diameter, and overhang length record data related to the wrench size, shaft diameter, and overhang length of the bolt of this nominal diameter. The nominal diameter data area of ​​the tall nut records data related to the nominal diameter and the width across flats.

[0036] (Calculation of resistance to uplift) Next, we will explain the formula for calculating the pull-out resistance Pa5 mentioned above. As shown in Figure 4, the pull-out resistance Pa5 is the pull-out resistance per insert 10, determined by the virtual cylinder V1, which is a virtual cylindrical body. The virtual cylinder V1 is a cylinder formed in the space between the virtual cylinder 31 of the head 11a of the mounting bolt 11 and the virtual cylinder 35 of the tall nut 15, and is a cylindrical object with a distance hb1 between them. Since the head 11a and the tall nut 15 have the same width across flats Dn1, the virtual cylinders 31, 35, and V1 are cylinders with this width across flats Dn1 as their diameter.

[0037] The pull-out resistance Pa5 is given by the following equation (1). Pa5 = Φ2·Act·β·σ B …(1) Here, Φ2 is the reduction factor, Act is the virtual cylindrical surface area, β is the coefficient, σ B This represents the compressive strength of the concrete. The virtual cylindrical surface area Act is calculated by multiplying the circumference of a circle whose diameter is the width across flats Dn1 of the head 11a of the mounting bolt 11 by the separation distance hb1. The reduction coefficient Φ2 is set to 2 / 3, and the coefficient β is set to 0.75, as explained below.

[0038] The pull-out resistance Pa5 is the resistance force resulting from the adhesion force of the insert 10 to the concrete member C1. In this case, it is considered that the longer the separation distance hb1 and the larger the head 11a of the mounting bolt 11, the less likely pull-out failure will occur in the insert 10.

[0039] Therefore, assuming that the pull-out resistance of insert 10 could be ensured by using the virtual cylindrical surface area Act of the virtual cylinder V1 with a pull-out resistance Pa5, the following two experiments were conducted on various test specimens. • Fracture behavior and yield strength of insert 10 under combined stress • Confirmation of the properties of the separation distance hb1 of insert 10. Here, in the experiment, the mounting bolt 11 is of strength grade 4.8, and the high nut 15 is made of a steel grade equivalent to SS400. Further, as the mounting bolt 11, a nominal diameter of M16 to M24 is used, and as the separation distance hb1, 6×a1 (protrusion length) to 10×a1 is used.

[0040] Figure 5 shows the dimensions of the test specimens used in the experiment and the number of test specimens. Further, in the remarks of Figure 5, the failure mode of the inserts destroyed by the experiment is described. Also, as shown in Figure 5, in this embodiment, the name of the test specimen is used by combining identifiers meaning the concrete compressive strength, bolt shaft diameter, and separation distance in this order. The "L" at the beginning of the name of the test specimen indicates that the concrete compressive strength is 24 N / mm 2 , and the "H" indicates that the concrete compressive strength is 36 N / mm 2 . As the bolt shaft diameter, 16 mm or 24 mm is used. As the separation distance hb1, the ratio of the protrusion length a1 (6a, 8a, 10a, 16a) is used. Therefore, the test specimen "L-16-8a" means a test specimen with a concrete compressive strength of 24 N / mm 2 , a bolt shaft diameter of 16 mm, and a separation distance hb1 that is 8 times the protrusion length a1.

[0041] Figure 6 is a graph showing the relationship between the virtual cylindrical shear strength σ cs specified from the experimental results of the pull-out failure of multiple inserts and the concrete compressive strength σ B . In this graph, the coefficient β is set to 0.75 based on the value of the test specimen with the lowest virtual cylindrical shear strength σ B with respect to the concrete compressive strength σ cs .

[0042] Figure 7 shows the calculated strength Pa, the maximum strength Pmax, and the failure mode at that time. In Figure 7, the triangles indicate failure modes caused by the tensile strength Pa1 of the steel. The white circles indicate failure modes caused by the cone failure strength Pa2. The diamonds indicate failure modes caused by the pull-out strength Pa5. The black circles indicate failure modes caused by the head concrete bearing strength Pa4. Pull-out failure occurs when the calculated strength Pa is 150kN or less, and it can be seen that the experimental maximum strength is about 1.5 times greater than the calculated strength.

[0043] (Insert strength evaluation) As shown in Figure 8, when evaluating the insert 10, a load-bearing capacity evaluation process is performed. Here, the evaluator inputs information about the insert 10 to be evaluated and the required load-bearing capacity for this insert 10 into the input device H12 of the evaluation device 20 and instructs the device to execute the load-bearing capacity evaluation process. The information about the insert 10 includes the nominal diameter of the mounting bolts 11, the nominal diameter and length of the high nuts 15, the spacing distance, and the compressive strength of the concrete in which the insert 10 is embedded.

[0044] As a result, the control unit 21 of the evaluation device 20 performs the process of acquiring information about the insert to be evaluated (step S11). Specifically, the evaluation unit 211 of the control unit 21 acquires information about the insert 10 to be evaluated and the required yield strength, etc.

[0045] Next, the control unit 21 of the evaluation device 20 performs the tensile strength calculation process (step S12). Specifically, the evaluation unit 211 of the control unit 21 inputs the acquired information of the insert 10 into the calculation formulas for each strength (Pa1, Pa2, Pa4, Pa5) stored in the evaluation formula storage unit 25, and calculates each strength. The evaluation unit 211 then identifies the smallest calculated value among the calculated strengths as the tensile strength of this insert 10. The evaluation unit 211 then displays the identified tensile strength and the failure mode corresponding to that strength on the display device H13.

[0046] Next, the control unit 21 of the evaluation device 20 performs an evaluation determination process (step S13). Specifically, the evaluation unit 211 of the control unit 21 determines whether the pull-out strength is the minimum and is less than the required strength. If the minimum strength value is not the pull-out strength Pa5 (i.e., "NO" in step S13), the evaluation unit 211 displays the failure mode of the minimum strength value on the display device H13 and terminates the process.

[0047] Furthermore, if the minimum bearing capacity is equal to the pull-out bearing capacity Pa5, the calculated minimum bearing capacity (pull-out bearing capacity Pa5) is compared with the required bearing capacity. If the pull-out bearing capacity Pa5 is greater than or equal to the required bearing capacity (i.e., "NO" in step S13), the evaluation unit 211 displays on the display device H13 that there is a pull-out bearing capacity greater than or equal to the required bearing capacity, and terminates the process.

[0048] On the other hand, if the pull-out resistance Pa5 is smaller than the required resistance (if the answer is "YES" in step S13), the control unit 21 of the evaluation device 20 performs a redesign process (step S14).

[0049] The redesign process (step S14) will be explained using Figure 9. Here, first, the redesign unit 212 of the control unit 21 performs a separation distance adjustment process (step S21). Specifically, the redesign unit 212 calculates the pull-out resistance Pa5 when the separation distance hb1 of the insert 10 to be evaluated is increased to within the allowable range. Then, the redesign unit 212 determines whether the pull-out resistance Pa5 calculated by increasing the separation distance hb1 is equal to or greater than the required resistance.

[0050] If the pull-out resistance Pa5 is equal to or greater than the required resistance (if the answer is "YES" in step S22), the redesign unit 212 of the control unit 21 performs output processing of the redesigned insert (step S25). Specifically, the redesign unit 212 calculates the distance hb1 at which the pull-out resistance Pa5 and the required resistance are equal, and records the determined distance hb1 and the determined nominal diameter of the mounting bolt 11 in the redesign value data area of ​​the evaluation target information storage unit 26. Furthermore, the redesign unit 212 displays the determined distance hb1 and the nominal diameter of the mounting bolt 11 on the display device H13.

[0051] On the other hand, if it is determined that the pull-out resistance Pa5 when the separation distance hb1 is increased to the maximum allowable range is less than the required resistance (if the answer is "NO" in step S22), the redesign unit 212 of the control unit 21 performs a process to change the mounting bolts (step S23). Specifically, the redesign unit 212 obtains bolt specification information for a bolt with a nominal diameter one size larger than the nominal diameter of the mounting bolt 11 used in the previous separation distance adjustment process (step S21) from the component specification information storage unit 27. Then, the redesign unit 212 calculates the pull-out resistance Pa5 using the bolt from the obtained bolt specification information and the evaluated separation distance hb1, and determines whether this pull-out resistance Pa5 is equal to or greater than the required resistance.

[0052] If the pull-out resistance Pa5 becomes greater than the required resistance (if the answer is "YES" in step S24), the redesign unit 212 of the control unit 21 performs output processing of the redesigned insert 10 (step S25). Here, the redesign unit 212 records the changed nominal diameter of the bolt, bolt standard information, and separation distance hb1 in the evaluation target information storage unit 26 and displays them on the display device H13.

[0053] On the other hand, if the pull-out resistance Pa5 is smaller than the required resistance (if the answer is "NO" in step S24), the redesign unit 212 of the control unit 21 repeats the process from step S21 onwards, which involves adjusting the spacing distance using the mounting bolts 11. This allows the system to increase the spacing distance hb1 and change to larger mounting bolts 11, thereby identifying an appropriate spacing distance for the insert 10 and a suitable size for the mounting bolts 11 that can ensure the required resistance.

[0054] (action) The pull-out resistance Pa5 is calculated using the virtual cylindrical surface area Act of a virtual cylinder V1 formed by the size (width across flats Dn1) of the head 11a of the mounting bolt 11 of the insert 10. Since the pull-out resistance Pa5 is due to the adhesion force and increases with the size of the head 11a of the mounting bolt 11, the pull-out resistance can be evaluated using the virtual cylindrical surface area Act.

[0055] According to this embodiment, the following effects can be obtained. (1) In this embodiment, the pull-out resistance Pa5 of the insert 10 is calculated using the separation distance hb1 and the virtual cylindrical surface area Act. This allows for the appropriate calculation and evaluation of the pull-out resistance Pa5 of the insert 10.

[0056] (2) In this embodiment, the coefficient β used to calculate the pull-out resistance Pa5 of the insert 10 is calculated using the relationship between experimental and calculated values. This makes it possible to calculate the pull-out resistance Pa5 of the insert 10 in a manner that is consistent with the actual situation.

[0057] (3) In this embodiment, the insert 10 comprises a bolt 11 for mounting a hexagonal bolt and a tall nut 15. This simplifies the configuration of the insert 10. Furthermore, the surface area of ​​a virtual cylinder V1 whose diameter is the width across flats Dn1 of the head 11a of the mounting bolt 11 is used as the virtual cylindrical surface area Act used to calculate the pull-out resistance Pa5. This allows for efficient calculation of the pull-out resistance Pa5.

[0058] (4) In this embodiment, the control unit 21 of the evaluation device 20 executes a redesign process (step S14) when the pull-out resistance Pa5 is at its minimum and is less than the required resistance (when the answer is "YES" in step S13). This makes it possible to efficiently identify an insert 10 that can secure the required resistance.

[0059] (5) The insert 10 in this embodiment is provided at the structural connection portion of the base plate for the gusset plate at the end of the steel frame member that mainly transmits shear force to the concrete structure. This makes it possible to adjust the load-bearing capacity of the insert 10 that was placed in a portion that had excessive load-bearing capacity in conventional designs, thereby making the insert 10 smaller or simpler.

[0060] This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically. In the above embodiment, inserts 10 were evaluated in which the width across flats Dn1 of the head 11a of the mounting bolt 11 and the width across flats Dn1 of the high nut 15 were the same. The threaded member with a projection that screws onto the high nut used in the insert 10 is not limited to a hexagonal bolt. For example, the threaded member with a projection may be a headed bolt having a disc-shaped head, or it may be a configuration comprising a fully threaded rod, a perforated plate that screws onto it, and two hexagonal nuts sandwiching this plate. In the latter case, the pull-out resistance of the insert is calculated using the virtual cylindrical surface area calculated according to the external shape of the projection of the perforated plate.

[0061] Furthermore, in the insert, the head 11a of the mounting bolt 11, which serves as a projection, and the external shape (shape and size) of the tall nut 15 may be different. For example, the insert 40 shown in Figure 10 consists of a mounting bolt 41 and a tall nut 15. The mounting bolt 41 has a head 41a and a shaft portion 41b. Even when the head 41a of the mounting bolt 41 is larger than the tall nut 15, the pull-out resistance Pa6 of the insert is calculated using the virtual cylindrical surface area. In this case, the virtual cylindrical surface area is the surface area of ​​a virtual cylinder V2 with a diameter Dn2 of the head 41a and a separation distance hb2.

[0062] In the above embodiment, the pull-out resistance Pa5 was calculated using the virtual cylindrical surface area Act of a virtual cylinder V1 whose diameter is the width across flats Dn1 of the head 11a of the mounting bolt 11. The calculation of the pull-out resistance Pa5 is not limited to the virtual cylindrical surface area Act, and the pull-out resistance of the insert may also be calculated using the surface area of ​​a virtual hexagonal prism formed by the outer shape (hexagon) and the distance between the heads 11a of the mounting bolt 11.

[0063] In the above embodiment, the control unit 21 of the evaluation device 20 calculated the tensile strength of the insert 10 using four types of strengths (Pa1, Pa2, Pa4, Pa5). The control unit 21 only needs to evaluate the tensile strength used to calculate the tensile strength, including the pull-out strength Pa5. For example, it may evaluate using five types of strengths (Pa1 to Pa5), including the head concrete bearing strength Pa3 determined by the bearing pressure at the cap nut head or the bolt head with projection. Furthermore, it may use several important strengths from these five types of strengths, or it may evaluate using only the pull-out strength Pa5.

[0064] In the above embodiment, the control unit 21 of the evaluation device 20 determines if the pull-out resistance Pa5 of the insert 10 to be evaluated is less than the required resistance at the minimum resistance level (in step S13, "YES"). in the case of), and the redesign process was executed (step S14). However, the processes from step S13 onwards may be omitted, or the mounting bolts 11 and high nuts 15 that meet the required load-bearing capacity Pa5 may be designed from the beginning. In the latter case, instead of the nominal diameter of the mounting bolts 11 and the nominal diameter and length of the high nuts 15 from the information of the insert to be evaluated, design information such as the size of the placement area may be obtained.

[0065] The insert 10 in the above embodiment is provided at the structural connection portion of the base plate for the gusset plate at the end of the steel frame member that mainly transmits shear force to the concrete structure. The location where the insert is applied is not limited to this, and inserts can be evaluated in locations where the tensile strength is low and pull-out failure is expected to occur.

[0066] In the above embodiment, the control unit 21 of the evaluation device 20 calculated the pull-out resistance Pa5 using the virtual cylindrical surface area Act. The entity that calculates the pull-out resistance Pa5 using the virtual cylindrical surface area Act is not limited to a computer terminal, but may also perform calculations by hand or other means.

[0067] Next, the technical concepts that can be understood from the above embodiments and alternative examples are described below. (a) The evaluation method according to any one of claims 1 to 3, characterized in that the tensile strength of the insert is evaluated using the minimum value of the steel tensile strength, cone fracture strength, head concrete bearing strength, and the calculated pull-out strength.

[0068] (b) The evaluation method according to (a), characterized in that the insert is placed at the structural connection portion of the base plate for the gusset plate at the end of the steel member that transmits a shear force to the concrete structure that is of a magnitude in which the effect of bending moment can be ignored.

[0069] (c) A design method for an insert embedded in a concrete member, comprising a tall nut and a threaded member with a projection that screws onto the tall nut, characterized in that the required tensile strength for the insert is obtained, the pull-out resistance of the insert is calculated using the distance between the boundary between the projection and the shaft of the threaded member with projection and the end of the tall nut on the threaded member with projection side, and the surface area of ​​a virtual cylindrical body calculated according to the external shape of the projection of the threaded member with projection, and the distance between the projection and the size of the projection of the threaded member with projection is determined so that the calculated pull-out resistance is equal to or greater than the required tensile strength.

[0070] (d) A design system comprising a control unit for designing an insert to be embedded in a concrete member, the insert comprising a tall nut and a threaded member with a projection that screws onto the tall nut, wherein the control unit obtains the required tensile strength for the insert, calculates the pull-out strength of the insert using the distance between the boundary between the projection and the shaft of the threaded member with projection and the end of the tall nut on the threaded member with projection side, and the virtual cylindrical surface area calculated according to the external shape of the projection of the threaded member with projection, and determines the distance between the projection and the size of the projection of the threaded member with projection so that the calculated pull-out strength is equal to or greater than the required tensile strength. [Explanation of Symbols]

[0071] β... coefficient, Φ2... reduction coefficient, σ B ...concrete compressive strength, σ cs...Virtual cylindrical shear strength, Act...Virtual cylindrical surface area, a1...Overhang length, C1...Concrete member, Dn1...Width across flats, Dn2...Diameter, d1...Axis diameter, hb1, hb2...Separation distance, le1...Effective embedment length, Pa...Calculated value, Pa1...Tensile strength of steel, Pa2...Cone failure strength, Pa3, Pa4...Head concrete bearing strength, Pa5, Pa6...Pull-out strength, Pmax...Maximum strength, V1, V2...Temporary Imaginary cylinder, 10, 40... insert, 11, 41... mounting bolt as threaded member with projection, 11a, 41a... head as projection, 11b, 41b... shaft part, 11c... threaded part, 15... high nut, 15a... threaded hole, 20... evaluation device, 21... control unit, 25... evaluation formula storage unit, 26... evaluation target information storage unit, 27... component standard information storage unit, 31, 35... virtual cylinder, 211... evaluation unit, 212... redesign unit.

Claims

1. A method for calculating the tensile strength of an insert embedded in a concrete member, comprising a tall nut and a threaded member with a projection that screws onto the tall nut, A method for calculating the tensile strength of an insert, characterized in that the tensile strength of the insert is determined by multiplying the distance from the boundary between the projection and the shaft of the projection-equipped screw member to the end of the high nut on the projection-equipped screw member side by the circumference of the projection, which is the outer shape of the projection (circular or hexagonal) on a plane perpendicular to the extending direction of the shaft, and the resulting virtual cylindrical surface area, which is then multiplied by the concrete compressive strength of the concrete member and a predetermined coefficient.

2. A method for calculating the tensile strength of an insert embedded in a concrete member, comprising a tall nut and a hexagonal bolt screwed into the tall nut, A method for calculating the tensile strength of an insert, characterized in that the distance between the boundary between the head and shaft of the hexagonal bolt and the end of the tall nut on the hexagonal bolt side, and the surface area of ​​a cylindrical shape calculated by multiplying the distance by the circumference of a circle whose diameter is the width across flats of the head of the hexagonal bolt, are multiplied by the concrete compressive strength of the concrete member and a predetermined coefficient, thereby determining the pull-out resistance of the insert as the tensile strength.

3. A method for designing an insert to be embedded in a concrete member, comprising a tall nut and a threaded member with a projection that screws onto the tall nut, The tensile strength of the insert is determined by multiplying the virtual cylindrical surface area, calculated by multiplying the distance from the boundary between the projection and the shaft of the projection-equipped screw member to the end of the high nut on the projection-equipped screw member side by the circumference of the projection, which is the outer shape of the projection (circular or hexagonal) on a plane perpendicular to the extending direction of the shaft, by the concrete compressive strength of the concrete member and a predetermined coefficient. A method for designing an insert, characterized in that, if the pull-out resistance does not meet the required resistance for the insert, the separation distance and the size of the outer shape of the protrusion are changed to achieve a pull-out resistance equal to or greater than the required resistance.

4. A method for designing an insert to be embedded in a concrete member, comprising a tall nut and a hexagonal bolt that screws into the tall nut, The tensile strength of the insert is determined by multiplying the distance between the boundary between the head and shaft of the hexagonal bolt and the end of the tall nut on the hexagonal bolt side, and the surface area of ​​the cylindrical shape calculated by multiplying the circumference of a circle whose diameter is the width across flats of the head of the hexagonal bolt by the distance, and the concrete compressive strength of the concrete member by a predetermined coefficient. A method for designing an insert, characterized in that, if the pull-out resistance does not meet the required resistance for the insert, the separation distance and the size of the outer shape of the hexagonal bolt head on a plane perpendicular to the extending direction of the shaft portion are changed to achieve a pull-out resistance equal to or greater than the required resistance.

5. A calculation system comprising a memory unit and a control unit, wherein the control unit calculates the tensile strength of an insert embedded in a concrete member, the insert comprising a high nut and a screw member with a projection that screws onto the high nut, The memory unit stores a predetermined coefficient used for calculating the pull-out resistance, The control unit, via the input device, Specific information that identifies the size of the circular or hexagonal outer shape of the projection of the screw member with projection on a plane perpendicular to the extending direction of the shaft portion of the screw member with projection, The distance from the boundary between the projection and the shaft to the end of the tall nut on the side of the screw member with the projection, The concrete compressive strength of the concrete member is obtained, A system for calculating the tensile strength of an insert, characterized in that it calculates the pull-out resistance by multiplying the virtual cylindrical surface area, which is calculated by multiplying the circumference of the outer shape of the protrusion identified from the acquired specific information by the acquired separation distance, by the acquired concrete compressive strength and the coefficient stored in the memory unit, and displays the said pull-out resistance as the tensile strength.

6. A calculation system comprising a memory unit and a control unit, wherein the control unit calculates the tensile strength of an insert embedded in a concrete member, the insert comprising a high nut and a hexagonal bolt screwed onto the high nut, The memory unit stores a predetermined coefficient used for calculating the pull-out resistance, The control unit, via the input device, The specific information that identifies the width across flats of the hexagonal bolt, The distance from the boundary between the head and shaft of the hexagonal bolt to the end of the tall nut on the hexagonal bolt side, The concrete compressive strength of the concrete member is obtained, A system for calculating the tensile strength of an insert, characterized in that it calculates the pull-out resistance by multiplying the surface area of ​​a cylindrical shape, which is calculated by multiplying the circumference of a circle whose diameter is the width of the two sides identified from the acquired specific information by the acquired separation distance, by the acquired concrete compressive strength and the coefficient stored in the memory unit, and displays the pull-out resistance as the tensile strength.

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