JPS62197572A - Construction of side wall in tank made of prestressed concrete - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of constructing a side wall in a prestressed concrete tank having a segment structure.

[Conventional example]

As a method of constructing the side wall of a concrete liquid tank,
P in the circumferential and axial directions on conventionally cast concrete.
There is a method of arranging C steel materials, introducing prestress to the axial PC steel materials, and then introducing prestress to the circumferential direction PC steel materials. However, with this construction method, it is difficult to control the quality of concrete poured on site, and therefore a prefabricated construction method has been desired. Therefore, as a method of constructing the side walls of a concrete liquid tank in response to the above request, prefabricated segments, which are manufactured to a certain shape and size in advance at a factory, are assembled into an annular shape on the bottom panel of a concrete liquid tank. Introducing prestress in the circumferential direction to the first stage segment connected in an annular manner by means of a PC steel material wrapped around the outside of the first stage segment.
A method is provided in which a cylindrical side wall is constructed by stacking second-stage segments in the same manner as the first-stage segments on top of the first-stage segments provided in this manner, and repeating this process one after another. ing.

[Problem that the invention seeks to solve]

However, in the above method for constructing side walls of prestressed concrete tanks, the process of introducing prestress into each stage of the sidewall is performed, so the diameter of the sidewall changes before and after introducing prestress, causing the prestress to deteriorate. Segment movement ff1 (shrinkage m) between the lower segment layer to which stress has been introduced and the upper segment layer assembled on top of this segment layer before introducing prestress.
Due to this, a difference in level occurs.

For this reason, it is necessary to assemble the segments while taking this level difference into consideration, but conventionally, the segments were simply stacked one after the other from the bottom, so the upper segment was prestressed on top of the lower segment that was connected in a ring. It is difficult to connect the segments while shifting them outward by the amount of radial shrinkage due to There were drawbacks.

An object of the present invention is to provide a method for accurately and easily constructing a cylindrical side wall of a segment structure by stacking segments while accurately setting the radial shrinkage of the segments due to the introduction of prestress. It is said that

[Means for solving problems]

In this invention, a cylindrical side wall is constructed by the following method as a means for solving the above problems.

Among the bolt holes of the joint fittings that connect the segments in the axial direction, when the bolt holes of the fitting fitting located in the upper stage are inserted into the bolt holes of the upper stage segment, when the segments are assembled in the axial direction and a bolt is inserted into the bolt hole. is a given m in the radial direction
formed into a size that allows relative movement. When assembling the upper segment onto the lower segment connected in an annular manner, both joint fittings are connected to the bolt holes of the fitting fittings that connect the upper and lower segments, and each of the fittings is connected to the bolt holes of the fittings connecting the upper and lower segments. A tight-fitting locating guide pin is fitted, which allows the upper segment to be assembled over the lower segment radially outwardly by exactly the amount of prestress contraction, and the bale guide pin is removed to guide the bale. Insert a bolt into the bolt hole where the pin was fitted, temporarily tighten the fittings with the bolt, and introduce prestress in the circumferential direction to the upper segment that can move in the radial direction.
Thereafter, by repeating the process of fully tightening the temporarily tightened bolts, the segments are sequentially stacked in an annular shape to construct a cylindrical side wall.

〔Example〕

FIGS. 1 to 4 (A), (B), and (C) are diagrams showing one embodiment of the present invention.

First, prior to explaining the method for constructing the side wall of the segmented prestressed concrete tank of the present invention, the structure of the side wall of the segmented prestressed concrete tank will be described with reference to FIGS. 1 to 3.

FIG. 1 is a vertical plan view schematically showing the side wall of a tank made of breast-stressed concrete with a segment structure. As shown in the figure, this side wall connects a plurality of concrete segments 3 in the circumferential direction along the peripheral wall 2 inside the reinforced concrete vertical underground tank 1, and connects them by stacking them in a staggered manner in the axial direction. It is built by A PC steel material 4 is wound around the outer periphery of the annularly connected segments 3.

As shown in FIGS. 2 and 3, the segment 3 is a curved plate-shaped concrete member, and a plurality of segments (in the illustrated example, a plurality of segments are provided at both ends in the axial direction (4 pieces each on each side, 3 pieces each on both end faces in the circumferential direction)
A joint fitting 20°6.7.8 is embedded. The joint fittings 20, 6°7.8 are composed of substrates 9, 9... and approximately U-shaped side portions 10, 10, erected thereon.

This side portion 10.10 is provided with openings 11.11 for bolt fastening operations. Further, each of the joint fittings 20, 6, 7.8 has bolt holes 20a, 6a, 7a for inserting the bolt 12 therethrough.

8a is formed.

Here, the bolt hole 20a of the joint fitting 20 embedded in the axially lower end face of each segment 3 is formed to have a larger diameter than the upper bolt hole 6a.

That is, this bolt hole 20a is a hole of a size that allows the upper segment 3 to move relative to the same predetermined amount in the radial direction when the segment 3 is assembled in the axial direction and the bolt 12 is inserted into the bolt hole 20a. It is formed.

Next, a method for constructing a side wall of a prestressed concrete tank having a segment structure according to the present invention will be described in FIGS. 1 to 4.
This will be explained with reference to the figures.

First, the bottom surface is placed on the bottom 10 of the existing underground tank 1 shown in FIG. 111 is constructed on site, and the segments 3 are connected in a ring shape on this bottom panel 11. The connection method in this case is as shown in FIG. This is done by matching.

Next, prestress is introduced in the circumferential direction by wrapping the PC steel material 4 around the outer periphery of the annularly connected segments. After this prestress introduction work is completed, concrete 13 is placed in the gap between the peripheral wall 2 of the underground tank 1 shown in Fig. 1 and the annularly connected first stage segment 3, and Firmly fix segment 3.

In order to assemble the second stage segment 3 onto the first stage segment 3, the first stage segment 3
The segments 3 of the second stage are stacked on top of each other in a staggered manner, and prestress is introduced to form the joint fittings 6 embedded in the axial end faces of the segments 3 of the first and second stages. A construction method in which 20 pieces are bolted together is applied, but in the present invention, the bolt holes 6a are connected before bolting them together.

20a, as shown in FIG. 4(a), the fitting 6.2
0, by fitting the positioning guide pin 21 that connects the
A wedge 30 is driven in from above and fixed, and the second stage segment 3 is placed on top of the first stage segment 3 at a predetermined f.
While assembling it radially outward by f1 (the amount of shrinkage due to the introduction of prestress), the bolt holes 6a and 20a in which the guide pin 21 is not fitted are aligned. The guide pin 21 is fitted in the position indicated by the chain line X in FIG. and then screw together with a nut 16 and temporarily tighten the bolt 12.

As shown in FIG. 3, the guide pin 21 for positioning is formed on an upper disk portion 21a with a diameter larger than the diameter of the bolt hole 20a of the joint fitting 20, and on the lower surface of this upper disk portion 21a. , a lower disk portion 2 that tightly fits into the bolt hole 20a.
1b, and a round bar portion 21c that protrudes downward from the lower surface of the lower disk portion 21b and tightly fits into the bolt hole 6a, and extends radially outward from the side surface of the upper disk portion 21a. , a rotating gripping part 2 whose tip is bent downward
1d allows attachment and detachment work to the bolt holes 6a and 20a.

Further, in the case of the embodiment, when the guide pin 21 is attached, the gripping portion 21d for preventing rotation thereof engages with the end of the joint fitting 20, so that the guide pin 21 cannot move in the circumferential direction. Therefore, the amount of prestress shrinkage is accurately maintained, and the segments 3 can be assembled as planned.

Note that if the bolt hole 20 is an elongated hole and the lower disk portion 21b of the guide pin 21 is shaped to tightly fit into this elongated hole, the gripping portion 21d can be omitted.

Then, by attaching the guide pin 21, the upper segment 3 is accurately positioned while being shifted outward by the amount of shrinkage m caused by the prestress.

When the work of assembling the second stage segment 3 to the first stage segment 3 is completed, the guide pin 21 is removed and the bolt hole 5a into which the guide pin 21 was fitted is opened.
As shown in FIG. 4(b), the bolt 12 is inserted into the bolt 20a and temporarily tightened. Here, in the second stage segment 3, the guide pin 21 that had been fitted into the bolt holes 5a, 20a of the joint fittings 6, 20 was removed and the bolt 12 was inserted.
It is in a state where it can move in the radial direction and the circumferential direction. and,
Prestress is introduced into the second stage segment in the circumferential direction by the PC steel material 4 arranged on its outer periphery, and the second stage segment 3 is moved radially inward by the predetermined amount, that is, the shrinkage. to make the side wall surface uniform, and then fully tighten the bolts 12 (see Fig. 4 (c)). And the second
A cylindrical side wall is constructed by sequentially stacking the segments 3 in six annular shapes on top of the tiered segments through the same process as above.

In addition, in the case of the example, the bolt hole 2 of the upper joint fitting 20
0a is formed into a circular shape with a larger diameter than the lower bolt hole 6a, so the segment itself can move not only in the radial direction but also in the circumferential direction, but the segment is positioned at a predetermined position. When prestress is introduced in this state, the annularly connected segments move only in the radial direction, so there is no fear that the amount of prestress introduced will change.

In the above embodiment, a cylindrical side wall is constructed inside the underground tank 1, but the present invention can be applied to a case where a segmented prestressed concrete tank is constructed in another location such as underground. can also be applied.

〔Effect of the invention〕

According to this invention, when assembling the upper segment onto the annularly connected lower segment, one of the bolt holes located in the upper stage of the joint fittings that connect the segments in the axial direction. By forming holes with a larger diameter than the lower bolt holes and fitting guide pins for positioning into the bolt holes of these fittings, the bolt holes of the upper fittings can be prestressed as planned. The amount of shrinkage (can be oriented outwardly) allows for accurate positioning of the upper segment relative to the lower segment by the amount of prestress transfer WJ, making it easier to fit into the cylindrical side wall of the segment structure. The advantage is that prestressing can be introduced and that this side wall can be constructed accurately and easily.

However, since the holes (68, 20a) in the upper and lower segments are circular, there is a possibility that they will move in the circumferential direction when prestress is introduced, but in reality, the upper segments will rotate in the circumferential direction all at once. The desired effect can be obtained.

[Brief explanation of drawings]

Figures 1 to 4 (a), (b), and (c) are diagrams showing one embodiment of the present invention, and Figure 1 schematically shows the side wall of a tank made of prestressed concrete with a segment structure. A vertical sectional view, FIG. 2 is a perspective view showing a method of constructing a side wall of a prestressed concrete tank with a segment structure, and FIG. 3 is a perspective view showing a connecting part of the segments.
Figure 4 (a) is a vertical sectional view of the main part showing the upper segment assembled to the lower segment, and Figure 4 (b) is the upper segment and lower segment temporarily tightened with bolts. FIG. 4(c) is a longitudinal sectional view showing a state in which the upper segment and the lower segment are fully tightened with bolts after introducing prestress. 3...Segment, 6.7.8.20...
...Joint fittings, 5a, 7a, 6a, 20a...--
Bolt hole, 12... Bolt, 21...
guide pin. Applicant: Ishikawajima Kenzai Kogyo Co., Ltd. Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] Curved plate-shaped concrete segments are arranged in an annular manner and stacked in multiple stages, and joint fittings are embedded in the circumferential and axial end faces of each of the segments,
By passing bolts into the bolt holes formed in these and tightening them, the segments are connected in the circumferential and axial directions, and by introducing prestress in the circumferential direction of each stage of segments arranged in an annular shape, a cylindrical shape is formed. In the method of constructing the side wall, the bolt holes of the joint fittings located at the upper level among the respective bolt holes of the joint fittings that connect the segments in the axial direction are set in advance by assembling the segments in the axial direction and bolts are inserted into the bolt holes. When the upper segment is passed through, the upper segment is formed to a size that allows relative movement by a predetermined amount in the radial direction, and when assembling the upper segment on the annularly connected lower segment, (A) A positioning guide pin that connects both joint fittings and tightly fits into each bolt hole is fitted into the bolt holes of the joint fittings that connect the upper and lower segments. The process of assembling the upper segment radially outward by the prestress shrinkage amount, (B) After the process of (A), remove the guide pin and insert the bolt into the bolt hole where the guide pin was fitted. A process of temporarily tightening the through joint fittings together with bolts, (C) a process of introducing prestress in the circumferential direction to the radially movable segments, (D) a process of finally tightening the temporarily tightened bolts, A method for constructing a side wall in a prestressed concrete tank, etc., characterized in that the steps are repeated in sequence.