The railway bridge prestressed automatic tensioning system is the computer full-automatic control bridge tensioning system developed according to the enterprise standard Automatic Tensioning System for Railway Prestressing Concrete Bridge issued by China Railway Corporation and Temporary Provisions on the Data Interface of Automatic Control System of Railway Prestressing Concrete Simple-supported Beam Static Load Test issued by the Engineering Management Center of China Railway Corporation. The system has the simple operation and high degree of automation, reduces the number of construction personnel, greatly improves the prestressing bridge steel strand tensioning construction quality, and lowers the labor intensity, thus improving the future safety and reliability of bridge and increasing the bridge service life. 

Patent and software copyright 

Hardware structure 

Hydraulic pressure station - high-performance radial piston pump, with working oil pressure up to 70 MP; Applicable temperature range: -10 ℃ ~ +45℃; Power supply voltage: 380V. 

Front jack - it is the special jack used together with the automatic tool anchorage, and saves 50% of steel strand compared with the traditional tensioning jack. The jack is installed with the force sensor and displacement sensor and equipped with the high-pressure oil pipe. 

Force sensor - the force sensor of the system is the spoke type sensor. It measures force directly, and the force value is not affected by the jack friction and temperature. 

Displacement sensor - stay wire (lever) type sensor. It uses the slide guide for the oriented support, and the jack and displacement contact adopt the sliding contact, thus solving the problem of impact of jack piston rotation upon the displacement during tensioning. 

Hydraulic sensor - variable resistance type hydraulic sensor for oil pressure measurement Range: 0-60Mpa; Accuracy: ±0.3%FS; Environmental conditions: -25~85℃. 

Wireless module - the wireless module used in the system is the industrial special wireless module, with the visual transmission distance of 300km. It provides the convenience for the remote transmission of tensioning data. 

Industrial computer - the computer control part includes the control cabinet formed by the high-quality ICP. It can be suitable for the industrial environment, harsh climate and site, and has high hardware stability and strong anti-jamming capability. 

Automatic tool anchorage - it can realize the automatic clamping of steel strand and withdraw the anchorage automatically. 

System function 

• It can meet the tensioning requirements of various bridge girders - precast girder, cast-in-situ girder and lateral tension.

• It can realize the one-time tensioning, repeated tensioning and staged tensioning;

• It can realize the real-time reading of tensioning force value and elongation of steel strand in the tensioning process, realize the synchronous control of two or four jacks in the tensioning process, and really realize the "double control" tensioning of tensioning force value and elongation; 

• The automatic jack adopts the supporting calibration and completes the linear regression calculation automatically;

• It can facilitate the selected use of force sensor and pressure sensor for detecting the tensioning force;

• The convenient steel strand retraction range detector can realize the automatic measurement and automatic recording; 

• It can generate and store the tensioning data automatically, and the data can be uploaded to the railway engineering management platform.

Software introduction

Main software interface - the intelligent tensioning system software of the prestressing bridge is the core of the system. The tensioning system software can meet various tensioning process demands, with simple operation. The system has the powerful auxiliary computing function, simple entry of parameters and easy data management. It can complete the relevant process through one-key operation. 

Tensioning equipment selection interface - after the user operates the system software, the first interface of software operation is the selection of tensioning equipment. In this interface, it makes the selection of the basic situation of the tensioning equipment, thus making preparation for the subsequent software operation. 

Basic information and tensioning process preparation of prestressing bridge - the basic information and tensioning process information interface of the bridge girder are as shown in the figure. 

Real-time tensioning data of prestressed girder - after inputting all data, click the button of "start-up" in the figure. The equipment starts to carry out the tensioning process, the progress bar in the dialog box starts to move forward, and the tensioning process is completed automatically according to the parameters set in the previous steps. 

Tensioning curve dynamic display interface - tensioning curve dynamic display interface in the tensioning process. Every group has three groups: curve time - force curve, time - displacement curve and displacement - force curve. The number of groups of curve display also adopts the dynamic display according to the tensioning process. 

Supporting verification of force sensor and jack

The user clicks "pressure ring calibration" button and can use the pressure ring to carry out the automatic calibration of the pressure sensor. During the calibration, as long as the electronic dial indicator is connected, it can realize the automatic loading and automatic reading of dial indicator data and pressure sensor data, thus realizing the real automatic verification. 

After clicking the "sensor calibration", the system will pop up the force sensor verification interface. After the sensor serial port is connected, the initial value, final value and interval value of the reading will be set. After clicking the "start" button, the system will read the data of both sides automatically, thus realizing the automatic verification. 

Tensioning data uploading interface- the system has the function of uploading tensioning data. The interface is as shown in the figure. After uploading the data at various tensioning stages, the detailed record chart can be seen on the industrial management platform. 

Technical parameters 

Specifications 

GBT3766 Hydraulic Fluid Power - general Rules and Safety Requirements for Systems and Their Components 

GB7251.1 Low-voltage Switchgear and Controlgear Assemblies - Part 1: General Rules 

GBT7935 Hydraulic Fluid Power - General Rules of Technical Requirements for Hydraulic Components 

GB16796 Safety Requirements and Test Methods for Security Alarm Equipment 

GBT 18806-2002 General Specification for the Resistance Strain Pressure Transducer/Sensor 

GB50171 Code for Construction and Acceptance of Switchboard Outfit Complete Cubicle and Secondary Circuit Electric Machines Electric Equipment Installation Engineering 

JB/T5000.13 Heavy Mechanical General Techniques and Standards 

JGT319 Electric Oil Pump for Prestressing 

JGT321 Hydraulic Jack for Prestressing

JGT 5012 Construction Machinery and Equipment General Specification for Product Packages 

JJG391-2009 Working Dynamometers JJG455-2000 Working Dynamometers 

JJF 1305-2011 Calibration Specification for Linear Displacement Sensors 

CECS 49 Code for the Reception Criterion for Low-voltage Switchgear Assemblies 

System advantages 

1. High degree of automation: Whole-process computer control, automatic data acquisition and "one-key" start-stop 

2. Multi-purpose machine: It can carry out the verification of various sensors and jacks for static load test and tensioning; 

3. High test data accuracy: The force sensor is used for directly reading the force value, and the indirect reading of force is eliminated, with the force sensor error within 0.5%; 

4. The variable frequency motor is used, with stepless variable speed and micro control precision, energy saving and consumption reduction, thus avoiding the rapid rise of oil temperature; 

5. The synchronism is good, with the synchronization error of 1%; The error between theoretical elongation and actual elongation is controlled at 6%, and the success rate can reach 99.9%; (Error range: -8%~12%); 

6. The front jack can realize the automatic clamping of steel strand and withdraw the anchorage automatically, greatly saving the steel strand, improving efficiency and saving costs; 

7. It can generate and store the tensioning data automatically, and the data can be uploaded to the railway engineering management platform; 

8. The spoke type force sensor is used, so there is no need to extend the steel strand, thus guaranteeing the higher detection precision; 

9. Compared with the equipment currently used in the railway, every end can save 110mm steel strand. If every tensioning hole has 10 bundles of steel strand, every hole can save 2.2m, and there are 650 girders in every girder field, so 38610m steel strand can be saved. If the steel strand is 1.12kg every meter, 43.2 tons of steel strand can be saved. 

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