JPH03147932A - Manufacture of precast pc well - Google Patents

Abstract

PURPOSE:To carry out such execution as joint faces have no space to fit-in each other by forming upper well blocks subsequently in a state to join adjacent well blocks up and down each other. CONSTITUTION:A form C1 is placed on the basic foundation, a lower bearing pressure plate 11 to the lower end, an upper bearing pressure plate 12 to the upper end, after the first step well block B1 burying a PC steel plate inserting sheath 13 between them is formed, a release layer 18 is formed on the surface including a guide key, a form C2 is assembled thereon and the second step well block B2 is formed to drop it on another basic foundation, the form C1 is assembled thereon to form the third step well block B3, and the required number of well blocks are subsequently formed. According to the constitution, in the event of installation, such execution as joint faces have no space can be carried out by using each divided block formed in a state to arrange up and down of the well blocks continuously and, at the same time, strong pre- stress can be provided.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a well mainly used for the foundation of a bridge pier, which is made by piling up a plurality of blocks manufactured in advance at a factory or a nearby block manufacturing yard to create a well that is prestressed. The present invention relates to a method for manufacturing a precast PC (prestressed concrete) well that imparts.

(Prior art) Wells used in conventional bridge pier foundations, etc. are shown in Figure 9 (
As shown in Figure 9 (B), formwork l is assembled on the ground surface, and the first stage divided well block A+ is formed using cast-in-place concrete. As shown in Fig. 9, the first stage divided well block A1 is lowered, and the second stage 9th well block A2 is continuously formed on top of it using cast-in-place concrete. While gradually excavating and descending, the uppermost nB-th divided well block A is formed with cast-in-place concrete, and the well frame A is thus completed.
A method has been adopted in which prestress is applied to the entire length of the PC steel material 2 by tensioning it.

On the other hand, for precast concrete wells, the entire well body is divided into multiple lengths, and divided well blocks are pre-formed in a factory and delivered to the site, and are stacked and lowered one after another while excavating underground. The method used to manufacture the divided well blocks was to use a cylindrical mold and utilize centrifugal force.

(Problems to be Solved by the Invention) The conventional PC well using cast-in-place concrete described above requires molding, concrete pouring, and curing work each time each divided well block is excavated, and a lot of on-site work is required.
There is a problem that the construction period will be long.

On the other hand, conventional precast concrete wells use split well blocks that are preformed in the factory.
Although the construction period is short, conventional split well blocks are molded using centrifugal force, which poses problems during production and transportation, especially when they are large. There were gaps in the blocks, making it impossible to match the joints perfectly, and this caused the problem that cracks would occur in the blocks when attempting to apply prestress in the vertical direction.

In view of the above-mentioned conventional problems, the present invention uses precast blocks and can apply strong prestress by vertically extending between each block, allowing for short-term work in the field where there are few thin and strong wells. The purpose of this invention is to provide a method for manufacturing a precast PC well that can be installed between the two.

(Means for Achieving the Object) The feature of the present invention for solving the above-mentioned conventional problems and achieving the intended purpose is to divide the entire length of the well body into a plurality of divided well blocks, each of which is divided into a stationary type. In the method for manufacturing a precast PC well, in which each divided well block is manufactured separately by pouring concrete within a frame, each divided well block is stacked at the installation location, and the divided well blocks are integrated by applying prestress to the whole. After pouring concrete into the formwork of the first stage divided well block at the bottom and forming it, extend it upwards and assemble the formwork for forming the second stage dissection well block. , a plurality of guide keys are provided protruding from the upper end surface of the first-stage divided well block molded previously, and a second-stage divided well block is molded with a release layer interposed, and in the same way, the top-stage divided well block is molded. Furthermore, when molding each of the divided well blocks, a bearing pressure plate for fixing the end of the PC steel material is embedded and fixed to be exposed on the upper end surface, and on a plurality of the bearing pressure plates,
A guide key is removably protruded to engage with the divided well blocks stacked above the divided well blocks.

(Function) According to this method, when forming the upper part of the vertically adjacent divided well blocks, concrete is cast on the lower divided well block through a peeling layer. By stacking them at the same relative angles at the time of molding on site, the divided well blocks are tightly joined without any variation in joint spacing, and no cracks occur when prestress is applied to the entire well.

In addition, when molding the split well block, by removably protruding the guide key from the bearing pressure plate for fixing the PC steel material f4 buried in the upper surface of the well block, a special embedding material for the guide key is no longer required. Since the guide key can be removed, damage during transportation can be prevented.

(Example) Next, the implementation of the present invention will be explained with reference to FIGS. 1 to 8.

FIGS. 1(a) to 1(d) show the molding process of divided well blocks B+ to B in the present invention.

In this molding, at least two molds C+ and ex each having one length are prepared by dividing the well frame to be manufactured into a plurality of circular slices. And one formwork C1 among them
is installed on a base as shown in FIG. 1(a), concrete is placed inside it, and the first stage divided well block B1 at the bottom is formed. At this time, as shown in Fig. 2, a lower bearing plate 11 for fixing the end of the PC steel material is buried in the lower end, and an upper bearing plate 12 is buried in the upper end surface with the upper surface exposed, and both bearing plates are buried. A sheath 13 for inserting a PC steel material is buried so as to straddle the sheath guide strips 11a and 12a protruding from the opposing surfaces. A large number of these bearing plates and sheaths are installed at regular intervals in the circumferential direction of the first stage divided well block B1.

Furthermore, among the upper pressure plates, guide key mounting and pressure plates 14 shown in FIGS. 4 and 5 are used at three positions equidistantly spaced from each other (shown in FIG. 3).

This bearing plate 14 has two sides 14a and f4b facing in the radial direction of the first stage divided well block B1 that are slightly longer than the other sides, and a guide key is attached to the extended plate part 14c using screws. A hole 14d is formed. This screw hole 14d has a constriction 15a in the center as shown in FIG.
The guide key 16 can be attached by screwing in one end side of the bolt 15, which has b-threads 15b carved on both end sides, and screwing the guide key 16, which has a substantially truncated cone shape, onto the protruding end of the bolt 15. ing.

In addition, in the figure, 17 is a hole for grout injection.

After molding the first stage divided well block B1 as described above, as shown in FIG.
After installing the guide key 16, the first
A release agent is applied to the entire upper surface of the stage-divided well block B to form a release layer 18, and a formwork C2 is assembled on top of the release agent.
Concrete is poured inside to form the second stage divided well block B2. At this time, the upper pressure plate 12 is buried in the upper end surface of the second stage divided well block B2 in the same manner as the first Pi-th plate described above, and the sheath 19 is buried under the upper pressure plate 12. This sheath 19 is provided with an expanded portion 19a at the lower end.

Further, as the upper bearing pressure plate, bearing pressure plates 14 which also serve as guide key attachments are used at equally spaced locations as described above.

After molding the 2F1-th divided well block B2 in this way, the 21"ffi-th divided well block B2 is lowered onto another base as shown in FIG.
As shown in d), a mold cl is assembled, and a third stage divided well block B1 is molded in the same manner as the second stage divided well block B2 described above.

In this way, a required number of upper divided well blocks are successively molded in succession on the lower divided well block, overlapping at least 2 Pi above and below.

In addition, although the above-mentioned example shows the case where two molds are used and molded in two layers, it is also possible to use three molds and mold in three layers. good.

When using the divided well blocks Bl, B2...B, which have been molded in advance so that the upper and lower sides are arranged in a continuous manner, each of them must be individually transported to the installation location, and the
As shown in Figure (A), first install the first stage divided well block B1 at the bottom, excavate underneath it and lower it as shown in Figure (B), and then lower it as shown in Figure (C). The second-stage divided well block B2 is stacked on top of it, and the whole is lowered as shown in FIG.

On the other hand, during stacking, as shown in FIG. It is fixed on the upper bearing pressure plate 14 (and 12), and the upper PC steel material is connected thereon, and prestress is sequentially applied thereto, and at the same time, the divided well blocks that are vertically adjacent to each other are connected. Note that a resin adhesive is applied between each divided well block. In this way, a precast PC well is installed which is given strong prestress in the vertical direction throughout.

(Effects of the Invention) As described above, in the method for manufacturing a precast PC well of the present invention, when molding the precast divided well blocks, the upper ones are molded one after another with the vertically adjacent ones joined to each other. Therefore, the upper surface of the lower divided well block forms the formwork for the lower end surface of the upper one, and the joint surfaces are molded into exactly the same curved surface that fits into each other. By stacking them at the same relative angles, they are joined with no gaps at all, and no cracks will occur even if a great deal of pressure is applied to the joints. Therefore, strong prestress can be applied to the precast This made it possible to obtain a PC well with a strong structure.

Furthermore, some of the pressure plates can also be used as guide key mounting plates to keep the relative angle between each divided block the same as when molding, making it easy to install a large number of pressure plates at small intervals. It was also great that the guide key could be easily placed in the required position.

[Brief explanation of the drawing]

Figures 1 (a) to (d) are cross-sectional views showing the molding process of the split well block, Figure 2 is a partially enlarged cross-sectional view of the same molding process, Figure 3 is a plan view of the same, and Figure 4 is the guide key installation. A plan view of the dual-purpose bearing plate, Fig. 5 is a vertical sectional view of the same, Fig. 6 is a sectional view of the guide key installed state, Figs. 7 (a) to (d) are sectional views of the well installation process, and Fig. 8 9 is a partially enlarged sectional view of the same well, and FIGS. 9(a) to 9(d) are sectional views of the conventional well installation process. B,, B2...B,...Divided well block, C,,C2...Formwork, D,,D2...D,... ...PCA material, 1
1... Lower pressure plate, 12.14... Upper pressure plate, 15... Bolt, 16...
Guide key 17... Grout, 18...
・Peeling M layer, 13.19...sheath, 20...
...Force 1r (a) (1)) No. (c) (d) Fig. 3 Fig. 2 (a) Fig. Fig. 7 (b) (c) (d) (a) (b) No. 9 (c) (d)

Claims (2)

[Claims] (1) The entire length of the well body is divided into multiple well blocks, each of which is manufactured separately by pouring concrete into a stationary formwork, stacking the divided well blocks at the installation location, and applying prestress to the whole. In the method for manufacturing a precast PC well in which concrete is applied and integrated, the lowermost first-stage divided well block of the divided well blocks is cast and molded in its formwork, and then the upper part of the divided well block is A mold for molding the second-stage divided well block was built by extending the mold, and a plurality of guide keys were provided protruding from the upper end surface of the first-stage divided well block molded previously, and a peeling layer was interposed between the molds and the second-stage divided well block. A method for manufacturing a precast PC well, characterized by molding a second stage divided well block and sequentially molding it in the same way up to the top stage. (2) When molding each divided well block, a bearing pressure plate for fixing the end of the PC steel material is embedded and fixed by exposing it on the upper end surface,
2. The method according to claim 1, wherein a plurality of the bearing plates are provided with removably protruding guide keys for engaging with the divided well blocks stacked above the divided well blocks. Method for manufacturing precast PC wells.