JP5751862B2 - Steel plate concrete structure design system and steel plate concrete structure design method - Google Patents

Description

  The present invention relates to a steel plate concrete structure design system and a steel plate concrete structure design method.

  As a concrete structure, a reinforced concrete structure (RC structure) using a reinforcing bar as a tension member is common, but in recent years, a steel plate concrete structure (SC structure) using a steel plate as a tension member has attracted attention. This SC structure is, for example, placed in a steel plate frame, a steel plate frame formed of a plurality of surface steel plates, a tie bar connecting the plurality of surface steel plates, a stud fixed to the inner surface of each surface steel plate, and a steel plate frame. (See, for example, Patent Document 1).

  In addition, when attaching an accessory such as a pipe support to the RC structure, for example, the attachment position of the accessory is determined in advance, and concrete is placed after bolts are placed there. The accessory is connected to the bolt portion protruding from the wall surface of the structure. In contrast, in the SC structure, the accessory can be joined directly to the surface steel plate by welding or the like, so there is no need to predetermine the attachment position of the accessory and the accessory can be attached regardless of the concrete hardening time. it can. For this reason, compared with RC structure, SC structure has the big advantage that the attachment time of an attachment or the freedom degree of an attachment position is high, and can improve the attachment construction property of an attachment.

  On the other hand, when designing such an SC structure, the failure mode of the stud 2 embedded in the concrete 1 is a cone that breaks at a 45 degree angle at the stud center shown in FIGS. 7 (a) and 7 (b). Two types of failure modes are examined: failure and steel failure (stud failure). Of these, in the current proof strength (strength) evaluation method against cone fracture, it is generally performed to evaluate the proof strength of one stud 2 based on the following formula (1). Here, in FIG. 7B and Equation (1), Le is the stud embedding depth, D is the stud diameter, φ is the reduction factor (safety factor), Ac is the projected area, and Fc is the concrete strength.

  As shown in this equation (1), the yield strength of the stud 2 at the cone fracture depends on the projected area Ac. As shown in FIG. 8A, when the number of the studs 2 is one, a circular area whose radius is the embedding depth Le is the effective projection area Ac. Further, as shown in FIG. 8B, when a plurality of studs 2 are arranged in a group, the intervals between the studs 2 are narrow, and the circular areas having the embedment depth Le of each stud 2 as a radius overlap. A rectangular area having an interval between adjacent studs 2 as one side is defined as an effective projection area Ac. Further, as shown in FIG. 8C, when a plurality of studs 2 are arranged in a group and the interval between the studs 2 is sufficiently wide, a circular area with the embedded depth Le as the radius is an effective projected area Ac. Become. When the studs 2 are arranged in groups so that the effective projection areas Ac overlap, and the pull-out load is applied uniformly (in the uniform loading state), a large effective projection area Ac as shown in FIG. Is set to evaluate the resistance to cone destruction.

JP 2007-169968 A

  However, in the conventional SC structure design method, as shown in FIG. 8 (b), a large pulling load is applied to one central stud 2 in a state where the load is uniformly applied to the studs 2 arranged in groups. In the case of the action, the effective projection area Ac becomes smaller than in the case of FIG. 8A in which one stud 2 is pulled out, and the proof strength in cone destruction is evaluated to be small. That is, in the conventional SC structure design method, the pull-out strength of the stud 2 when a frame load (a load that can be considered in the design other than the load due to an accessory such as the weight of the SC structure or an earthquake load) acts on the SC structure. Has not been evaluated.

  A design system for a steel plate concrete structure according to the present invention includes a steel plate frame formed of a plurality of surface steel plates, a stud fixed to an inner surface of the surface steel plate, and a concrete cast in the steel plate frame. A steel plate concrete structure design system comprising: a structural condition input means for inputting structural conditions including stud spacing and stud length; and a structural load for calculating a structural load based on the structural conditions input by the structural condition input means A calculation means; a reference load calculation means for calculating a reference load that can be supported per stud when supported by a plurality of studs; a load ratio calculation means for calculating a load ratio of the housing load to the reference load; Refer to the relationship between the load ratio and the effective projection area, the storage means for storing the relationship between the load ratio and the effective projection area, and the relationship between the load ratio and the effective projection area stored in the storage means. An effective projected area calculating means for calculating an effective projected area, and a load calculating means for calculating a supportable load including incidental loads with one stud based on the effective projected area calculated by the effective projected area calculating means. It is characterized by.

The method for designing a steel plate concrete structure of the present invention comprises a steel plate frame formed of a plurality of surface steel plates, a stud fixed on the inner surface of the surface steel plate, and a concrete cast in the steel plate frame. The steel plate concrete structure design system is a design method according to the present invention, wherein the frame load calculation means of the design system is based on the structure conditions including the stud interval and the stud length input by the structure condition input means of the design system. When the reference load calculation means of the design system supports the entire stud, the reference load that can be supported per stud is obtained, and the load ratio calculation means of the design system determines the housing for the reference load. calculated load ratio of the load, the effective projected area calculation means of the design system, previously obtained et the storage means of the design system stores Was with reference to the relationship between the load ratio and the effective projected area, determine the effective projected area from the load ratio, based on the effective projected area determined, a load calculating means of the design system, comprising a supplementary material load in one stud It is characterized in that a load that can be supported is obtained.

  In the design system of steel plate concrete structure and the design method of steel plate concrete structure of the present invention, by reexamining how to determine the effective projected area in cone fracture, the conventional stud steel structure structure design method can provide a reasonable stud strength. An evaluation can be performed.

It is sectional drawing which shows the steel plate concrete structure which concerns on one Embodiment of this invention. It is a mimetic diagram showing stud arrangement of a steel plate concrete structure concerning one embodiment of the present invention. 2A is a front view, and FIG. 2B is a plan view. It is a block diagram which shows the design system of the steel plate concrete structure which concerns on one Embodiment of this invention. It is a figure which shows how to obtain | require the effective projection area in the design method of the steel plate concrete structure which concerns on one Embodiment of this invention. It is a figure which shows an example of the relationship between the load ratio and the effective projection area in the design method of the steel plate concrete structure which concerns on one Embodiment of this invention. It is a figure which shows an example of the relationship between the load ratio and stud strength in the design method of the steel plate concrete structure which concerns on one Embodiment of this invention. It is a figure which shows the cone destruction of the stud in a steel plate concrete structure. It is a figure which shows how to obtain | require the effective projection area in the design method of the conventional steel plate concrete structure.

  Hereinafter, a design system for a steel plate concrete structure and a design method for a steel plate concrete structure according to an embodiment of the present invention will be described with reference to FIGS.

  First, an SC structure (steel plate concrete structure) 10 of the present embodiment includes, for example, a steel plate frame 5 formed of a plurality of surface steel plates 3 and 4 and a plurality of surfaces forming the steel plate frame 5, as shown in FIG. Among the steel plates 3 and 4, a plurality of tie bars 6 that connect the pair of surface steel plates 3 and 4 facing each other, a plurality of studs 2 fixed to the inner surfaces of the respective surface steel plates 3 and 4, and the steel plate frame 5 It is comprised including the cast concrete 1.

  The tie bar 6 has one end joined to one surface steel plate 3 of the pair of surface steel plates 3 and 4 and the other end joined to the other surface steel plate 4 and disposed in the steel plate frame 5 (concrete 1 Embedded). The stud 2 is for improving the connectivity between the surface steel plates 3 and 4 and the concrete 1. And the stud 2 of this embodiment is a stud with a head provided with a head portion 2b on one end side of the shaft portion 2a, and the other end of the shaft portion 2a is joined to the inner surfaces of the surface steel plates 3 and 4 by fillet welding or the like. And disposed in the steel plate frame 5 (embedded in the concrete 1). In the SC structure 10 of the present embodiment, a plurality of studs 2 are arranged in a group as schematically shown in FIGS. 2 (a) and 2 (b).

  Further, as shown in FIG. 1, an accessory 7 is attached to the SC structure 10. In the present embodiment, the accessory 7 is a pipe support 7a for supporting the pipe 8, and is formed using, for example, H-shaped steel. The pipe support 7a of the accessory 7 is attached with a base plate (attachment plate) 7b, which is a steel plate, and is attached to the SC structure 10 by joining the base plate 7b to the surface steel plate 3 by welding or the like.

  Next, in this embodiment, as shown in FIG. 3, the structural condition input means 11, the frame load calculation means 12, the reference load calculation means 13, the load ratio calculation means 14, the storage means 15, the effective projection area calculation means 16, The SC structure 10 having the above-described configuration is designed using a design system (design system for steel plate concrete structure) 20 including the load calculating means 17.

  When the SC structure 10 is designed in the present embodiment (in the SC structure design method of the present embodiment), the load is uniformly applied to the studs 2 arranged in groups (FIG. 8B). In the case where a large pulling load is applied to one central stud 2 in the state shown in FIG.

  First, the following formula (2) is used as a calculation formula for the stud strength in cone fracture.

ここで、φは低減係数（安全係数）、Ａｃは投影面積、Ｆｃはコンクリート強度を示す。

Here, φ is a reduction factor (safety factor), Ac is a projected area, and Fc is concrete strength.

  Next, in this embodiment, the stud interval a, the stud length Le, and the stud diameter D are input by the structural condition input means 11. Based on the structural condition input by the structural condition input unit 11 as described above, the frame load calculation unit 12 calculates the frame load. Here, the frame load indicates a load that can be considered in design other than the load due to the accessory 7 such as the weight of the SC structure 10 or an earthquake load.

  Further, the reference load calculating means 13 calculates a reference load that can be supported per stud when the entire stud is supported. Here, the reference load means an allowable load of the stud 2, and a plurality of studs 2 shown in FIG. 8B (shown in FIG. 4B described later) are arranged in a group, and the stud 2 Means the cone pulling-out strength when the effective projection area is A □ when the intervals of the circles are narrow and the circular areas having the embedment depth Le as the radius of each stud 2 overlap. In other words, the reference load means how much the cone pulling force has when the effective projected area is A □.

  Next, the load ratio calculation means 14 calculates the load ratio α of the housing load with respect to the reference load. The effective projection area Ac is calculated from the load ratio α by the effective projection area calculation unit 16 with reference to the relationship between the load ratio α and the effective projection area Ac stored in the storage unit 15.

  For example, in this embodiment, the relationship between the load ratio and the effective projection area as shown in FIG. Then, the effective projection area calculating means 16 obtains the area A ○ shown in FIG. 4A by the equation (3) and the area A □ shown in FIG. 4B by the equation (4), and these equations (3) From the respective areas obtained by the expression (4) and the load ratio α of the housing load to the reference load calculated by the load ratio calculating means 14, the effective projection is performed according to the relationship between the load ratio α and the effective projection area Ac (expression (5)). The area Ac is calculated.

  Then, based on the effective projection area Ac calculated by the effective projection area calculation means 16, the load calculation means 17 calculates a load that can be supported including one incidental load by one stud. Here, FIG. 6 shows the result of trial calculation of the stud strength by applying the above design method with the stud interval a being 200 mm, the stud diameter D being 35 mm, the stud length Le being 170 mm, and the concrete strength Fc being 30 MPa.

  As shown in this trial calculation result, in the design method of the present embodiment, a state in which the body load is not acting at all (state of the effective projection area A ○) and an allowable load (reference load) of the stud 2 acts as the body load. In a load state (a state where the effective projected area A □ is a state) (a state in which 1/3 of the stud allowable load is applied as the housing load or a state in which 2/3 of the stud allowable load is applied as the housing load). Stud strength is obtained.

  That is, in the design system 20 of the steel plate concrete structure 10 and the design method of the steel plate concrete structure 10 of the present embodiment, the method for obtaining the effective projected area in cone fracture is reviewed and acts on the conventional steel plate concrete structure design method. By determining the effective projected area Ac according to the load, it is possible to perform a reasonable evaluation of the stud strength.

  As mentioned above, although one embodiment of the design system of the steel plate concrete structure and the design method of the steel plate concrete structure according to the present invention has been described, the present invention is not limited to the above one embodiment, and does not depart from the spirit thereof. It can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Concrete 2 Stud 2a Shaft part 2b Head 3 Surface steel plate 4 Surface steel plate 5 Steel plate frame 6 Tie bar 7 Attachment 7a Piping support 7b Base plate 8 Piping 10 Steel plate concrete structure (SC structure)
DESCRIPTION OF SYMBOLS 11 Structural condition input means 12 Housing load calculation means 13 Reference load calculation means 14 Load ratio calculation means 15 Storage means 16 Effective projection area calculation means 17 Load calculation means 20 Steel plate concrete structure design system

Claims (2)

A steel plate frame formed of a plurality of surface steel plates, a stud fixed to the inner surface of the surface steel plate,
A design system of a steel plate concrete structure comprising concrete placed in the steel plate frame,
A structural condition input means for inputting a structural condition including a stud interval and a stud length;
A body load calculating means for calculating a body load based on the structural condition input by the structural condition input means;
Reference load calculating means for calculating a reference load that can be supported per stud when supported by a plurality of studs,
Load ratio calculating means for calculating the load ratio of the housing load to the reference load;
Storage means for storing the relationship between the load ratio and the effective projected area;
With reference to the relationship between the load ratio stored in the storage means and the effective projection area, effective projection area calculation means for calculating the effective projection area from the load ratio;
A design system for a steel plate concrete structure comprising load calculating means for calculating a supportable load including incidental load with one stud based on the effective projected area calculated by the effective projected area calculating means . A steel plate frame formed of a plurality of surface steel plates, a stud fixed to the inner surface of the surface steel plate,
A design method using a steel plate concrete structure design system comprising concrete placed in the steel plate frame,
Based on the structural conditions including the stud interval and the stud length input by the structural condition input means of the design system, the structural load calculation means of the design system obtains the structural load,
When the reference load calculation means of the design system supports a plurality of studs, a reference load that can be supported per stud is obtained,
The load ratio calculation means of the design system obtains the load ratio of the housing load to the reference load,
The effective projection area calculation means of the design system refers to the relationship between the load ratio obtained in advance and the effective projection area stored in the storage means of the design system, and determines the effective projection area from the load ratio,
A design method of a steel plate concrete structure, wherein the load calculation means of the design system obtains a load that can be supported including an incidental load with one stud based on the obtained effective projected area.

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