JPS5922027B2 - Automatic centralized tensioning method and device for prestressed concrete structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for automatically centrally managing tensioning of prestressing in prestressed concrete structures and to an apparatus for carrying out the method.

In general, a prestressed concrete structure is made up of a large number of prestressing steel materials, but when tensioning is performed to introduce prestress, when a single thread of prestressing steel material is tensioned by the structure (e.g. beam materials, etc.) and some PCs
This is limited to cases in which a group of steel materials are tensed simultaneously under the same conditions (for example, in a tank).

In the former case, there is no problem, but in the latter case, multiple workers were mobilized to handle multiple PC steel materials using individual pumps and jacks, so strict tension control was impossible. It is.

For this reason, there were many variations in the tension force, and the precision of prestress introduction was poor.

Moreover, it not only required a lot of manpower, but also resulted in a loss of work time and an extension of the construction period.

The present invention has been devised to solve these problems, and it is an object of the present invention to provide a method and apparatus capable of tensioning a large number of PC steel members at the same time and under the same conditions, particularly in a PC tank.

Furthermore, by detecting the tensile load applied to the prestressing steel material and the actual amount of elongation (normally, the tensile load does not completely act on the prestressing steel material due to sheath friction, etc.), we develop extremely accurate tensioning methods and devices. This is what we are trying to provide.

Following a general description of known techniques, a detailed description of the present invention will be developed.

FIG. 1 shows a conventional method of introducing prestress in a PC tank, and tensioning is carried out in the following order.

l) A hydraulic jack 4 is attached to a pilaster (fixing column) 3 provided in a cylindrical concrete tank 1 made of a large number of PC steel materials 2.

Each hydraulic jack 4 is connected to a hydraulic pump 6 through a hose 5.

2) At the command of the tension manager, a worker assigned to each pump 6 starts the pump 6 and opens a hydraulic valve (not shown).

3) A worker placed on the hydraulic jack 4 closes the hydraulic valve of the hydraulic pump 6 at the planned load point while sequentially measuring the reading of a load cell (not shown) and the stroke of the jack piston.

4) Based on the sequentially measured stroke values of the jack pistons and the readings of the load meters, the tension management supervisor manually calculates whether or not there is a shortage of tension force due to friction of the PC steel materials for all the PC steel materials.

5) If the predetermined tension is insufficient for the prestressed steel material, the elongation of the prestressed steel material is further measured, and the tension is fully maintained.Finally, when the load of the hydraulic jack is lowered, the wedge (not shown) of the fixing metal works. Then, the PC steel material is fixedly fixed to the Pirasuf 3.

The conventional method, which uses the above methods, requires a) a large number of personnel.

(Example) Many workers are nervous due to multiple unrelated jacks, and due to timing discrepancies, each jack is working alone, making it difficult to maintain relationships among jacks.

c) There are many variations in the tension force and the amount of steel material elongation, and the precision of prestress introduction is inaccurate.

2) It takes a lot of work time.

e) The amount of elongation of the steel material must be checked by hand calculation each time.

f) The accuracy is poor because the jacking stroke value is measured visually.

g) Since all machines are operated manually, it is not only difficult to operate, but there is also a risk of malfunction.

H) It is difficult to thoroughly report jacking strokes and communicate work to managers because they are remote.

) Requires highly skilled workers.

I was at the peak of things like that. According to the present invention, all of the above-mentioned problems are solved, and will be explained below with reference to FIG. 2.

a) A special hydraulic jack 8 equipped with an electric scale sensor 7 is attached to several pirus pipes 3 installed in a cylindrical concrete tank 1 made of a large number of PC steel materials 2, and a hose distributed from a hydraulic pump 9. 10 (the length of the hose 10 is the same for each jack 8).

b) Connect the signal cord of the scale sensor 7 equipped on each jack 8 to the PC steel elongation automatic measuring device 11.

C) Preset a predetermined tension force in the load setting device 13 on the control panel 12 of the hydraulic pump 9.

d) PC steel (e) Preset the necessary elongation amount of the PC steel material for a predetermined tension force in the elongation degree setting device 14 of the elongation degree automatic measuring device 11.

e) When the worker on the jack side sends a signal indicating that the jack installation is complete, red lamps displaying each jack signal are lit on the pump control panel 12.

f) When the tension switch button 12' on the pump control panel 12 is pressed, the digital load meter 15 displays the state of both tension types from time to time.
will be displayed.

Further, the stroke of the jack piston is displayed on the digital display 16 from time to time on the elongation measuring device 11.

g) Piston of jack 8] The loaf value and load reading are stored by a microcomputer built into the elongation measuring device 11.

h) When the tension reaches the preset value, the solenoid valve of the pump 9 closes and the jack 8 automatically stops.

l) The elongation of the steel material is immediately calculated by a microcomputer and the result is displayed digitally.

In this case, if the preset value is satisfied, the printer 17 is automatically activated and the calculation contents are recorded.

J) If the amount of elongation of the steel material is insufficient compared to the preset value, an alarm buzzer sounds, the insufficiently elongated steel material is displayed with a red lamp, and the printer 17 does not operate.

In this case, by pressing the full tension switch button (not shown), only the insufficient steel and steel are automatically tensioned again to the preset value and automatically stopped, and the microcomputer recalculates and displays the result digitally.

At the same time, the alarm buzzer stops, the shortage indicator red lamp goes out, and the printer 17 operates to record the calculation contents.

k) In this way, the printer 17 is designed to end its operation only after confirming that the predetermined tension is accurately obtained for all the prestressing steel materials. It means that it gave a satisfying tension.

1) When the operation of the printer 17 is completed, an automatic signal is sent to the pump 9 side, and by switching the solenoid valve, return pressure is sent to the jack 8, and the wedge of the fixing metal is brought to the set pressure by the starter piston provided inside the jack. It is possible to eliminate the so-called setting amount by pushing the sheet in place, thereby preventing a decrease in the prestress introduction force during fixing.

m) After the operation of the screwdriver piston is completed, continue to automatically return the screwdriver piston.

n) The reduction state of the jack piston stroke is digitally displayed on the elongation measuring device 11.

0) When the digital display becomes "0", it means that the jack piston has returned to its pre-tension state, so it automatically sends a signal to the pump 9 side and automatically closes the solenoid valve of the pump 9. , stop jack 8 and release the bond.

According to the present invention constructed and operated as described above, the problems of the known tensioning methods described above can be solved at once, and extremely excellent effects as shown below are exhibited. .

1) Work can be done with a small number of people.

2) No experienced personnel required.

3) It is possible to shorten the working time.

4) Since the machine automatically measures the jack stroke value, accurate tension is possible, and since all jack operations are automated, there is no malfunction.

5) Since an automatic centralized control method is adopted, there is no variation in tension force and it is accurate.

6) Since the operation of the machine is fully automated, there is no need for mutual communication between workers, even though it is operated remotely.

7) Since the tension is detected by a pressure transducer, the load reading is accurate.

8) Since the elongation is calculated by a microcomputer,
Fast and accurate.

9) Since it is recorded by a printer, there is no need to create data.

[Brief explanation of drawings]

FIG. 1 shows a conventional method of introducing prestress into a PC tank. FIG. 2 shows a device implementing the method for introducing prestress in PC tanks according to the invention. In the figure, 1...Tank, 2...P
C Steel O, 3...Pirasufu, 4...Hydraulic jack, 5...Hose, 6...Hydraulic pump, 7...Scale Sensor, 8...
・Jacket, 9...Hydraulic pump, 10...
... Hose, 11 ... PC steel elongation automatic measuring device, 12 ... ° Hydraulic pump automatic control panel, 13 ...
...Load setting device, 14...Elongation setting device, 15
...Digital load cell, 16...Digital display, 17...Printer, 18...
...Load converter.

Claims (1)

[Claims] Pressure oil from 11 hydraulic pumps is supplied to a plurality of hydraulic jacks, and the tension applied by the hydraulic pumps and the PC
It is characterized by automatically measuring the amount of elongation of the steel material, calculating the relationship between tension and elongation using a microcomputer, and when a predetermined amount is obtained, a printer is activated to digitally display the results. Prestress automatic centralized control tensioning method in prestressed concrete structures. 2 A hydraulic jack for tensioning PC steel material equipped with a scale sensor and connected to one hydraulic pump with a hose of the same length, a load setting device that can preset the tension force, and the status of the tension load can be known. A hydraulic pump control panel equipped with a digital load meter, an elongation setting device that can preset the required elongation amount, a digital display for the stroke of the jack piston, and an elongation force (i) for the steel material relative to the preset value.
In a prestressed concrete structure, the prestressed concrete structure is characterized by comprising an automatic measuring device for the degree of elongation of the prestressed steel material and equipped with a printer to record the calculation contents, and capable of centrally managing the prestressing of the prestressed steel material. Prestress automatic central control tensioning device.