JPS6342810A - Method of automatically controlling pc steel material stretching force - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an automatic tension control method for prestressing steel material, and more specifically, an automatic tension control method that allows tension work to be performed in a short time without requiring special skills. Regarding control method.

[Prior Art] In conventional tensioning work for prestressed steel materials, tensioning work is one of the important steps in introducing a predetermined tension force into a concrete structure and fully demonstrating the performance of the prestressed concrete structure.

However, in this stressful work, specialized workers rely on their intuition and experience to open and close hydraulic valves, measure the load with a pressure meter, measure the elongation with a scale, and check it step by step while writing on a control graph. The current situation is that the load is increased to a predetermined value. In this kind of method, ■
Since the final management is a check after the tension work, the values of group management cannot be reflected in the individual tension work. - Since the management graph is created manually, there is a possibility that mistakes may occur. There were other problems, such as the need to work on tension while writing, which took time and required a large number of workers (including those who created tension management graphs).

Therefore, in order to solve the above problems, and also to deal with the high labor cost of specialized workers, which has become a particular problem in recent years, and to manage strict tension mainly in PC containment vessels at nuclear power plants, we have developed an automatic tension system using computers. Management is about to be introduced. Prestress tensioning technology based on automatic tensioning and automatic management is still in its early stages, and complete systemization has not yet been achieved.Only automatic management systems that are easy to develop are used, and tensioning (hydraulic jack operation) Currently, we rely on manual operations. It is conceivable to introduce a large computer to enable online automatic tension management, but this would increase the size of the equipment and increase costs, making it easier for on-site workers without specialized knowledge to manage tension easily and quickly. It has the disadvantage of not being able to work.

[Object of the invention] The purpose of the present invention is to provide an automatic control method for tensioning a PCm material, which can perform prestress tensioning at low cost without requiring a large-scale device or a specialized engineer. do.

[Means for Solving the Problems] The present invention was developed as a result of extensive research to achieve the above object.

That is, the method for automatically controlling the tension force of a PC steel material according to the present invention involves setting a hydraulic jack on a PC steel material disposed at a predetermined position, and supplying hydraulic pressure to the hydraulic jack from a hydraulic system to control the PC steel material.
When applying a predetermined tension to steel materials, a microcomputer device is installed at the tension site, tension management information including at least control limit values is input into the microcomputer device, and then automatically measured tension data is introduced. death,
After comparing and determining the control limit value, the microcomputer device transmits a tension control signal to the hydraulic system to control the tension.

In the present invention, "setting a hydraulic jack to a prestressed steel material placed at a predetermined position" means fixing the prestressed steel material to a grip etc. provided at the bottom of the hydraulic jack.
"Supplying hydraulic pressure from a hydraulic system" means supplying hydraulic pressure from a hydraulic pump via a hydraulic pressure supply pipe.

"Installing microcomputer equipment at a stressful site" means that microcomputer equipment is installed at the site where the hydraulic jack is set or in the vicinity (for example, a site office, etc.). There is a method of installing a microcomputer device at a location, inputting measurement data, making necessary judgments, and transmitting a tension control signal to the hydraulic system. There are two methods: a method of transmitting a signal to control the amount of oil from the hydraulic pump, and a method of controlling the amount of oil by operating a solenoid valve or the like provided in the hydraulic pressure supply piping.

■There is also a method of directly incorporating microcomputer equipment into the hydraulic system. There are two methods of directly incorporating it into the hydraulic system: a method of incorporating it into a hydraulic pump and a method of incorporating it into the supply piping.

``Inputting tension management information including at least a control limit value into the microcomputer device'' means inputting tension management information including a control limit value for P-δ management or final management. P-δ control here refers to control based on the jack load indication (prestress amount) during tension and elongation of the PCM material, and pot control refers to control by setting control limits based on the friction coefficient between the PC steel material and the sheath. It means to do something.

"Inputting automatically measured tension data" differs depending on the management method, but for example, in the case of P-δ management, automatically measuring the load reading (prestress amount) of the jack during tension and the elongation of the PC steel material. It is necessary to input the

Note that as the "PC steel material", an unbonded PC steel wire may be used.

[Embodiment] An example of an apparatus for carrying out the control method of the present invention will be explained based on FIG.

In the figure, l is a hydraulic jack that moves a PC steel grip (not shown) in accordance with the reciprocating motion (left and right movement in the drawing) of the piston IA, thereby applying tension to the PC steel material whose one end is fixed.

An oil supply pipe 2 and an oil discharge pipe 3 are connected to the hydraulic jack 1. In addition, the hydraulic jack 1 has 0N10 for starting.
Switches for FF switch, switch and tension stop are installed. 4 is a hydraulic pump. 5 is a personal computer (hereinafter referred to as a personal computer) with an input keyboard and display; 6 is a control system (not shown, but may include a printer); and 7 is for a pressure transducer and a T4.1a valve, which will be described later. Measuring equipment, 8 is a data insertion part such as the amount of prestress and the amount of elongation of the PC steel material,
These 5 to 8 are microcomputer devices, which may be integrally installed and shielded into the circuit board of the hydraulic pump 4, or may be installed externally.

Reference numeral 9 denotes a pressure transducer, and lO denotes a solenoid valve (with a switch circuit and drive valve).The pressure transducer 9 and the solenoid valve lO are integrated into the hydraulic pump 4. The opening/closing and opening/closing time of the solenoid valve IO is controlled by a computer control system 6.
It is done through. 11 is a displacement meter. The displacement meter 11
Any device that can measure the amount of movement in and out of the piston may be used; for example, an electric or potentiometer displacement meter may be used. Note that 12 is a 100V power line, which is used here to transmit signals for opening and closing the electromagnetic valve from the combinator 5.

Next, based on FIG. 2, the automatic control method of the present invention and the microcomputer software employed in the control method will be outlined.

i) Is the tension management information input management method P-δ management or μ management? In this embodiment, P-δ management is used.

First, input the control limit lines. The outline of this limit line will be explained based on No. 312I. In the same figure, G+ is the upper control limit line and G2 is the lower control limit line e P
I is the retaining load.

The value of the tension control limit is determined for each group that constitutes a plurality of tension tatami materials. The tension management limit value for the first group to be nervous is determined by theoretical calculations taking into account empirical values, but for the second and subsequent groups, a new tension management limit value is determined by calculating the standard deviation from the previous tension results. Manually calculating the new tension management limit value takes time and prevents the user from proceeding to the next tension task.In the present invention, the microcomputer automatically performs this task, so it can be done in a short time.

ii) Introducing tension force (detection of prestressed hair and elongation) Measure the values of the pressure transducer 9 and displacement meter 11 with the meter@equipment 7 and transmit them to the computer 1.

1ii) CRT screen display or XYRec embossing display An upper control limit line C+ and a lower control limit line G2 are displayed in advance on the control graph screen.

For each increase in tension (usually a certain unit increase in tension), the load ff
Plot l (P) and elongation (δ).

Next, after removing the initial slip amount from the transmitted data, the origin of the measured load and elongation is corrected using the least squares method, and the P-6 curve is plotted on the control graph (see Figure 3).
Display.

iV) If the measured value is within the control values (upper and lower limits) on the control graph screen, issue a command to increase the load.

If the control values (upper and lower limits) are exceeded, a warning is displayed and the load is increased.

Whether or not the control values (upper and lower limits) are exceeded may be determined based on only one plot, or may be determined by referring to the previous and subsequent plots.

M) When the predetermined load is reached, compare it with the control value again, and if it is within the control value (issue a lock-off command), it is fixed and completed. If the control value is exceeded, an error is displayed and the load is stopped automatically (without issuing a lock-off command), and the current load is held and the next manual command is waited for.

M) Record and save the construction management graph on a floppy disk. This data can be output even after stressful work.

The software described above completes one task and leads to the first process of introducing tension. In addition to the above software, there is also a tension interrupt function during automatic computer control, a reloading function for repeated tension, an output function for data for updating control limits, a tension control chart creation output and recording machine, and a manual tension control function. Automatic measurement, display 1 of measured values, display of comparison with management values, recording of measured values, etc. may be added.

In addition, it is preferable to create the above software program using Basic, etc., and then use it as a ROM pack to target the computer.

Although one embodiment of the present invention has been described above, the present invention is not limited thereto, and the following ideas may be adopted.

That is, as shown in FIG. 4, the microcomputer equipment is connected to the oil supply and discharge pipe. , 3 may be installed.

In the same figure, 13 is a microcomputer device for automatic tension/automatic management system, and this device 13 includes a board computer (with numeric keypad) and a small display 'A'.
A small printer device 1, a small floppy disk device (or a small diskette device), a solenoid valve drive device, and a measuring instrument are built in, and a pressure transducer 9 and a solenoid valve 10 are also included.

14 is the hydraulic pump circuit board, 15 is 200V'7i (source,
16 is a 100Vt source. In this figure, parts with the same reference numerals as those shown in FIG.

The board computer used in this embodiment has a machine f@ as a terminal of the host computer. Therefore, the host computer can control multiple board computers (while keeping the timing right), which is effective when simultaneous tension is required, such as when tensioning both sides.

That is, when performing interlocking tension such as double-pulling tension, the timing can be automatically determined by the host computer that centrally controls each microcomputer, so it is easy to introduce the tension force of the -leg.

The control method of the present invention is based on the "Reinforcement method for slabs around pillars and openings in prestressed flat plate structure" (Japanese Patent Application No. 117526/1988) previously proposed by the applicant.
(see issue).

[Effects of male onset] According to the present invention, there are the following effects.

(1) It is possible to bring a microcomputer to the site and completely automate everything from the introduction of tension to its management, resulting in low costs, no need for specialized engineers, and savings in labor costs.
This reduces the time required for stressful work and allows for safer work.

(2) It is also possible to introduce a certain tension force, ensuring quality.

(3) Traditionally, tension control charts and control tables must be submitted to the administrator without delay, but because they are done manually, they may be submitted after all tension work has been completed. Therefore, even if inappropriate tension points are discovered at that time, it may be too late. In contrast, in the present invention, the above problem can be solved because the microcomputer automatically performs the process.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing an example of the equipment for implementing the control method of the present invention, Fig. 2 is a flow chart of the software used in the present invention, and Fig. JS3 is used as an example of the control method of the present invention. Figure P-6 and Figure 4 for tension management are schematic explanatory diagrams showing other examples of devices for carrying out the control method of the present invention. 1: Hydraulic jack 2: Oil supply pipe 3: Oil discharge pipe 4: Hydraulic pump 5: Computer 6: Control system 7: Measuring device 8: Data insertion section 9: Pressure transducer lO: Solenoid valve l: Displacement meter 12: 100V Power line 13: 9-hour tension order automatic management system equipment group 14:
Hydraulic pump circuit board 15: 200V power supply 16: 100V power supply

Claims (2)

[Claims] (1) A hydraulic jack is set on the prestressed steel material placed at a predetermined position, and when the hydraulic jack is supplied with hydraulic pressure from the hydraulic system to apply a predetermined tension force to the prestressed steel material, the microcomputer equipment is placed at the tension site. The microcomputer device is installed at A method for automatically controlling the tension force of a PC steel material, characterized in that the tension force is controlled by transmitting a tension force control signal to the hydraulic system. (2) P according to claim 1, characterized in that the microcomputer device is incorporated into a hydraulic system.
Automatic control method for C steel tension.