JP4515437B2 - Method for producing filled steel pipe concrete column - Google Patents

Description

  The present invention relates to a filled steel pipe concrete column that is reinforced by filling concrete inside a steel pipe columnar body.

  FIG. 1 is a transverse sectional view (a) and a longitudinal sectional view (b) of a conventional filled steel pipe concrete column. This filled steel pipe concrete column 1 is filled with filled concrete 2 over the entire axial direction inside the steel pipe 4, and one or more of the filled steel pipe concrete pillars 1 have a length extending almost the entire length in the center and axial direction of the filled concrete 2. The bundled large-diameter deformed reinforcing bars 5 are embedded in the central portion of the steel pipe columnar body with spacers 6 horizontal in four directions at right angles, and the deformed reinforcing bars 5 bear a part of the axial force. ing. Moreover, the closing board 3 is provided in the upper part of the filling type steel pipe concrete pillar 1 (refer patent document 1).

  FIG. 2 is a cross-sectional view (a) of a general concrete utility pole and a cross-sectional view (b) of a steel pipe utility pole. In FIG. 2A, the concrete utility pole 11 is composed of reinforcing bars 12 provided at predetermined intervals on the circumference and concrete 13 formed in a columnar shape so as to cover the reinforcing bars 12. The increase in strength of the concrete electric pole 11 is realized by increasing the outer diameter, increasing the amount of the reinforcing bars 12, or increasing the thickness of the concrete 13.

  Moreover, in FIG.2 (b), the steel pipe utility pole 21 is comprised by the cylindrical steel pipe 22 which has the thickness of a predetermined | prescribed outer diameter and internal diameter. The high strength of the steel pipe utility pole 21 is realized by increasing the outer shape of the steel pipe 22 or increasing its thickness.

  In addition, as an example of a filled steel pipe concrete column, a partition in the steel pipe provides a hollow area between the filled concrete, realizing sufficient strength for the purpose of use, and reducing the amount of concrete used and lightweight There is known a technique for reducing the cost and cost (see Patent Document 2). Furthermore, a method for reinforcing a steel pipe column that makes it possible to easily and economically increase the strength of an existing steel pipe column is also known (see Patent Document 3).

JP-A-5-321402 JP-A-5-051999 JP 2005-60992 A

  However, in the filled steel pipe concrete column 1 shown in FIG. 1, it is necessary to fill the filled concrete 2 up to the upper layer portion (top end portion) where the closing plate 3 is provided. For this reason, there existed a problem that weight became heavy as the whole filling type steel pipe concrete pillar 1, and conveyance became difficult and workability | operativity worsened.

  Further, in the concrete utility pole 11 shown in FIG. 2 (a), it is necessary to increase the amount of the reinforcing bars 12 or increase the thickness of the concrete 13 in order to satisfy the required load when realizing high strength. There is. For this reason, there was a problem similar to that of the filled steel pipe concrete column 1 of FIG.

  Further, the steel pipe utility pole 21 shown in FIG. 2 (b) can be formed lighter and thinner than the concrete utility pole 11 so as to have the same strength as the concrete utility pole 11 of FIG. 2 (a). . For this reason, since it does not become difficult to carry compared with the concrete electric pole 11, the difficulty of work can be reduced. However, since the outer diameter of the steel pipe 22 must be increased in order to satisfy the required load when realizing high strength, the installation space is required when installing the steel pipe utility pole 21 on a narrow road or a residential area. It was necessary to consider aesthetics.

  Therefore, the present invention has been made to solve the above-mentioned problems, and its object is to provide a method for producing a filled steel pipe concrete column that satisfies the required strength and can achieve weight reduction and cost reduction. It is to provide.

  In general, the cable crossing position of the utility pole is approximately 6 m from the ground due to restrictions of laws and regulations, and a load is applied to the height (load application point). Therefore, in the present invention, attention is paid to the fact that it is not necessary to fill concrete over the entire length of the utility pole as in the past in consideration of the actual required bending moment. In other words, the present invention is characterized in that a height that satisfies the required strength is obtained, and that the reinforcement is performed with the minimum necessary concrete with reference to the height. Thereby, while reinforcing the vicinity of the ground part where a required load is large, the upper part filled with concrete can be handled by the strength of the steel pipe. That is, the required strength can be satisfied, the amount of concrete used can be reduced, and weight reduction and cost reduction can be realized.

  That is, the method for producing a filled steel pipe concrete column according to the present invention is a method for producing a filled steel pipe concrete column in which concrete is filled in a steel pipe columnar body. By the applied load, the required bending moment at the height from the ground part is obtained, the yield strength of the steel material used for the steel pipe columnar body, and the section modulus at the ground part of the steel pipe, the yield bending moment is obtained, A region of the necessary bending moment with respect to the height from the ground where the necessary bending moment is larger than the yield bending moment is used as a reinforcing region, and concrete is filled with the reinforcing region as a region requiring reinforcement.

  The method for producing a filled steel pipe concrete column according to the present invention is characterized in that the reinforcing region is used as a region requiring reinforcement, and the steel tube columnar body is filled with concrete and a steel rod is embedded.

Further, in the method of manufacturing a filled steel pipe concrete column according to the present invention, the load applied to the load acting point at the height of h from the ground portion is T, and the required bending moment at the height of y from the ground portion is m (y ) = T (hy), where the yield strength of the steel used for the steel pipe columnar body is σ, the section modulus at the ground part of the steel pipe is Z, and the yield bending moment is m _y = σZ, the reinforcement The region is y <h _c = h−m _y / T, the concrete according to claim 1 is filled at least at the height of h _c , and the steel rod according to claim 2 is embedded.

  As described above, according to the present invention, it is possible to realize a method for manufacturing a filled steel pipe concrete column that satisfies the required strength and can achieve weight reduction and cost reduction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 3 is a diagram for explaining the load T applied to the load application point of the utility pole and the maximum required bending moment m at the ground. In FIG. 3, the electric pole which is the filled steel pipe concrete pillar 100 has a vertical height h position from the ground part which is a boundary part between the electric pole and the ground shown by the hatched portion as a load application point due to cable crossing. A load T is applied to the load application point.

Here, the required bending moment m (0) at the subterranean part is calculated by the following equation.
m (0) = m = T × h (1)
At this time, a required bending moment m (y) at a height y from the ground is calculated by the following equation.
m (y) = m (0) * (1-y / h) = T * (hy) (2)
Here, the required bending moment m (y) refers to a moment of height y that accompanies the application of a load T to a load application point of height h.

  FIG. 4 is a diagram showing the relationship between the height of the utility pole from the ground and the required bending moment. In FIG. 4, the x-axis indicates the required bending moment m, and the y-axis indicates the height y from the ground. Point H represents a load application point having a height h, and point M represents an intersection between a perpendicular line from the point H and the ground part. The straight line on the x and y axes is expressed by equation (2), and is an equation when x = m (y).

FIG. 5 is a diagram for explaining a section modulus of a steel pipe utility pole. When the inner diameter of the steel pipe 101 is d1 and the outer diameter is d2, the section modulus Z is expressed by the equation shown in FIG. Further, as the yield strength defined by steel used for this steel pipe electric pole sigma, the yield bend moment m _y, is calculated by the following equation.
m _y = σ × Z (3)
Here, the yield bend moment m _y, refers to a moment destruction steel pipe utility pole when unreinforced occurs.

Further, (2) requires bending moment m (y) of the equation (3) comparing the yield bend moment m _y of equation to calculate the shortage bending moment according to the following equation.
_{m (y) -m y ··· (} 4)
Then, a region of y where this value is positive is obtained. And this area | region is set as a minimum reinforcement area | region for calculating | requiring the filling height of concrete and the embedding length of the steel bar (equivalent to the deformed reinforcing bar 5 in FIG. 1). That is, a positive under-bending moment region is set as the reinforcing region. Here, the filling height of the concrete and the embedding length of the steel bar refer to the size corresponding to the height from the ground part in FIG. When concrete is filled to its height, in fact, concrete is also filled into the ground in addition to its height. The same applies to the case of embedding steel bars.

  Then, the concrete is filled and the steel bar is buried so that the concrete filling height obtained from the reinforcing region and the steel bar burying height are obtained so as to satisfy the required strength. Thus, with reference to the height obtained from the set reinforcement area | region, reinforcement with fillers and reinforcement materials, such as concrete, is performed.

  Next, the reinforcing region will be specifically described. FIG. 6 is a diagram for explaining a reinforcing region in consideration of a load application point and a necessary bending moment. As in FIG. 4, the x-axis shows the required bending moment m, the y-axis shows the height y from the ground, and the straight line l to the right shows the relationship between the required bending moment m and the height y. Yes. A diagram showing the straight line 1 is referred to as a “height from the ground (h) −necessary bending moment (m)” diagram (HM diagram).

In the HM diagram shown in FIG. 6, the straight line 1 is expressed by the following equation.
y = h−hx / m (0) = h−x / T (5)
Here, the intersection of the straight line 1 and the y axis is the point H, and the intersection of the x axis is the point M.

Then, pull the HM view of line a is the yield bending moment m _y of steel pipe electric pole _(x = m _y), the intersection of the straight line a and the straight line l and the point A. Then, in the HM diagram in which the straight line l and the straight line a are drawn, a region surrounded by the straight line a, the straight line l, and the x axis is set as a minimum necessary reinforcing region for satisfying the required strength.

H _c indicating the filling height of the concrete and the buried length of the steel rod for covering the reinforcing region set in this way, that is, for satisfying the required strength, is expressed by the following equation.
_{h c = h-m y /} T ··· (6)
It becomes.

Thus, the concrete is filled at a height h _c that covers the minimum necessary reinforcement area for satisfying the required strength, filled steel concrete column 100 steel bar is embedded, the minimum filling concrete It becomes a utility pole model set to the filling height of steel and the buried length of steel bars.

  Next, the manufacturing method of the filling type steel pipe concrete pillar 100 by embodiment of this invention is demonstrated. FIG. 7 is a flowchart showing the manufacturing method. First, the height h of the load application point is determined (step S71), and the load T applied to the load application point is determined (step S72). Then, the required bending moment m (y) is calculated by the equation (2) (step S73). These steps 71 to 73 are condition setting sections in the manufacturing process of the filled steel pipe concrete column 100.

Then, the yield bend moment m _y of steel pipe electric pole constituting a filled steel concrete column 100 (3) is calculated by equation (step S74), the bending yield in need bending moment m (y) and the step 74 in the step 73 the moment and a m _y, the lack of the bending moment is calculated by equation (4) (step S75). Then, set the reinforcing region, the height h _c for covering the reinforcing region (6) is calculated by equation, the steel tube electric pole reinforced insufficient bending moment calculated in step 75 as a reinforcing region, filled The steel pipe concrete pillar 100 is formed (step S76). That is, the concrete was filled at a height h _c that covers the reinforcing region, burying the steel bar. These steps 74 to 76 are analysis processing units in the manufacturing process of the filled steel pipe concrete column 100.

  As described above, according to the embodiment of the present invention, the insufficient bending moment is calculated from the required bending moment and the yield bending moment, and the height obtained from the reinforced region by the insufficient bending moment is set to the steel pipe of the steel pipe utility pole. The inside was filled with concrete. Thereby, the required intensity | strength as the filling type steel pipe concrete pillar 100 can be satisfied.

  Further, according to the embodiment of the present invention, in addition to filling the concrete with the height obtained from the reinforcing region due to the insufficient bending moment, one or more steel bars are embedded in the steel pipe. did. Thereby, the intensity | strength which can fully endure a tensile load can be satisfied. Moreover, since the steel rod to embed is strong to tension, the effect of preventing buckling to the outside of the steel pipe pole can be enhanced.

Further, according to the embodiment of the present invention, the yield strength of the steel pipe electric pole sigma, be determined outer and inner diameters or the thickness of the steel pipe, it is possible to calculate the yield bend moment m _y, and shortage bending By calculating the moment, the required amount of reinforcement of the concrete and steel bar can be obtained. Thereby, compared with what fills concrete over the full length like the filling type steel pipe concrete pillar 1 shown in FIG. 1, since it only has to fill concrete partially, the usage-amount of concrete is reduced significantly. Can be made lighter and less expensive. Furthermore, it is possible to satisfy the required strength of the ground portion where the required bending moment is maximum. As a result, it is possible to avoid an excessive quality and realize an economical utility pole structure suitable for the purpose of use.

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the technical idea thereof. For example, although the example of the steel bar was shown as a reinforcing material, this steel material may be one rebar or a plurality of rebars. Moreover, the steel bar does not necessarily need to be the deformed reinforcing bar 5 as shown in FIG.

(A) is a cross-sectional view of a conventional filled steel pipe concrete column, and (b) is a vertical cross-sectional view. (A) is sectional drawing of a general concrete utility pole, (b) is sectional drawing of a steel pipe utility pole. It is a figure explaining the maximum required bending moment m in the load T added to the load action point of a utility pole, and a subterranean part. It is a figure which shows the relationship between the height from the ground part of a utility pole, and required bending moment. It is a figure explaining the section modulus of a steel pipe electric pole. It is a figure explaining the reinforcement area | region which considered the load application point and the required bending moment. It is a flowchart which shows the manufacturing method of the filling type steel pipe concrete pillar which concerns on embodiment of this invention.

Explanation of symbols

1,100 Filled steel pipe concrete pillar 2 Filled concrete 3 Closing plate 4 Steel pipe 5 Deformed bar 6 Spacer 11 Concrete electric pole 12 Reinforcing bar 13 Concrete 21 Steel pipe electric pole 22, 101 Steel pipe

Claims (3)

In the method of manufacturing a filled steel pipe concrete column in which concrete is filled into the steel pipe columnar body,
The required bending moment at the height from the ground part is obtained by the load applied to the load application point of the predetermined height from the ground part,
According to the yield strength of the steel material used for the steel pipe columnar body, and the section modulus at the ground part of the steel pipe, the yield bending moment is obtained,
The required bending moment is greater than the yield bending moment, and the region of the required bending moment relative to the height from the ground is used as the reinforcing region.
A method for producing a filled steel pipe concrete column, characterized by filling concrete with the reinforcing region as a region requiring reinforcement. In the manufacturing method of the filled-type steel pipe concrete pillar of Claim 1,
A method for producing a filled-type steel pipe concrete column, characterized in that concrete is filled in a steel pipe columnar body and a steel rod is buried while the reinforcing area is a necessary area. In the manufacturing method of the filling type steel pipe concrete pillar of Claim 1 or 2,
The load applied to the load acting point at the height of h from the ground part is T, the required bending moment at the height of y from the ground part is m (y) = T (hy), and used for the steel pipe columnar body. the yield strength of the steel to be sigma, the section modulus at Chisai portion of the steel pipe Z, the yield bend moment when the m _{y =} σZ,
The reinforcing region is y <h _c = h−m _y / T,
At a height of at least the h _c, filled with concrete in claim 1, method for producing a filled steel tube concrete columns, characterized by embedding the steel rods in claim 2.

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