GB/T 21296.2-2020Automatic instruments for weighing road vehicles in motion—Part 2: Weighing whole loads (English PDF)

3.4 Axle-group load

The sum of all axle loads in the defined axle-group. [GB/T 21296.1-2020, definition 3.3.16]

3.5 Wheel and axle recognizer

A device used to identify the wheel and axle of a vehicle.

Note: The method installed in the weighing platform is called the embedded wheel and axle recognizer. It can also be installed on both ends of the load receptor.

3.6 Scale interval; d

The difference, expressed in mass units, between two adjacent indicating values or printed values of weighing-in-motion. [GB/T 21296.1-2020, definition 3.3.23]

3.7 Controlled weighing area

The specific location where the WIM performs the weighing operation; the location meets the installation requirements of this Part. [GB/T 21296.1-2020, definition 3.2.1]

3.7.1 Weigh zone

The road surface area consisting of the load receptor and its aprons forward and backward in the direction of travel.

Note 1: The length from the starting point to the end point of the weigh zone along the driving direction is called the length of the weigh zone.

Note 2: The end of the incoming vehicle is the starting point of weigh zone. The end of the vehicle driving away is the end point of weigh zone. [GB/T 21296.1-2020, definition 3.2.2]

3.7.2 Apron

The rigid foundation with the physical properties of load receptor, which is located at the two ends of the load receptor along the driving direction.

Note: The main function is to, during weighing, provide a relatively straight, relatively horizontal and smooth travel route for the vehicle under test when it enters the load receptor.

3.8 Operating speed; v

The average speed, the vehicle under test passing through the load receptor, at which normal weighing-in-motion can be carried out. [GB/T 21296.1-2020, definition 3.3.25]

3.9 Maximum operating speed; vmax

The maximum vehicle speed at which normal weighing-in-motion can be carried out as stipulated by the design of the weighing instrument. If this speed is exceeded, the weighing result may cause excessive relative error. [GB/T 21296.1-2020, definition 3.3.26]

4.1 Product type

The product type shall comply with the provisions of GB/T 26389 and 4.6 of GB/T 21296.1-2020.

4.2 Basic width

The width of the load receptor shall meet the economical width required by the weighed vehicle. Its typical values are 3 m and 3.4 m. The length of single section structure is generally less than 7 m.

5.1 Accuracy level

5.1.1 Principles for determining accuracy level

If the WIM is not suitable for liquid-loaded vehicles, it shall be clearly indicated in the manual and nameplate.

6.2 Suitability for use

6.2.2 The welding parts shall be welded firmly and reliably. The welds shall be uniform, flat, free of cracks, have no welding slag. There shall be no defects such as undercut or solder skipping. It shall meet the requirements of QB/T 1588.1.

6.2.3 The surface of the casting shall be smooth and clean. There shall be no defects such as shrinkage porosity, cold separation, cracks, pores and slag inclusion.

6.2.4 Forgings shall be free of defects such as cracks, interlayers, and slag inclusions. Machinery cutting parts shall meet the requirements of QB/T 1588.2.

6.2.5 The surface of the electroplated parts shall be uniform in color. There shall be no defects such as spots and rust.

6.2.6 Before the load receptor is painted, the surface shall be de-rusted. It shall meet the requirements of GB/T 8923.1.

6.2.7 The paint layer on the surface shall be smooth, consistent in color, bright and firm. The paint layer shall not have defects such as brushing, sagging, wrinkling, air bubbles, peeling, shedding. After painting, the surface shall be intact without exposed undercoat. It shall meet the requirements of QB/T 1588.4.

6.3 Structural requirements

6.3.1 Load receptor

The load receptor of the full-draught WIM shall be able to ensure that, all the tyres of the tested vehicle are located on the load receptor. The load receptor can be a single-section structure, or a multi-section structure connected (combined) together. For the needs of axle weighing, a combination of embedded weighing platform or multi-section load receptor can be used. There shall be anti-skid measures on the surface of the load receptor. When the full-draught WIM bears the load of 125% the maximum capacity, the components of the weighing instrument shall not be permanently deformed or damaged.

6.3.2 Wheel and axle recognizer

The wheel and axle recognizer can be installed on the load receptor, as an integrated structure. It can also be installed on both ends of the load receptor, as a separate structure.

6.3.3 Vehicle identification device

6.4 Control instrument

6.4.3 Partial load

The error of the indicating values of the same load at different positions of the load receptor shall not be greater than the maximum permissible errors of the verification in 5.5.

6.4.4 Discrimination

When the weighing instrument is in a balanced state, gently put on or take off the weight, which is equivalent to 1.4 times the scale interval for static verification. At this time, the original indicating value of the weighing instrument shall be changed.

6.4.5 Repeatability error

The difference between the results of multiple weighings of the same load shall not be greater than the absolute value of the maximum permissible errors under the load.

6.5 Anti-disturbance performance

The full-draught WIM, as an electronic vehicle weighing instrument, shall meet the requirements of electronic instrument. It shall meet the requirements of 6.4 in GB/T 21296.1-2020.

7.1 General

The realization of the accuracy level of the full-draught WIM is not only related to the design, production, and installation of the weighing instrument itself; but also related to the conditions such as levelness, slope, curvature, and road strength of the weigh zone. In addition, it is related to the daily maintenance of the weighing instrument. Users shall have a correct understanding of this.

In addition to meeting the requirements of Clause 7 in GB/T 21296.1-2020, it shall also meet the requirements of 7.2~7.3.

7.2 Load receptor

7.2.1 General

The height of the installation fixing point of each load cell of the load receptor shall be consistent; meet the requirements of the drawing.

8.1 General

Users shall realize that, the realization of the performance of the full-draught WIM not only depends on the weighing instrument itself; but also includes the environmental conditions of the site, where the weighing instrument is installed, and the use and maintenance level of the WIM. The performance required by the user shall match the environmental conditions of the site installation. If restricted by objective conditions, the installation environmental conditions cannot meet the requirements, then the WIM shall be degraded and used.

8.2 Installation site conditions

8.2.1 Principles for selection of installation site

The selection of the installation area of the full-draught WIM follows the following principles:

a) The road conditions before and after the installation area shall be consistent;

b) It shall not be installed under high-voltage power lines or near radio transmission stations and railway tracks;

c) The concrete pavement construction in the installation area shall be implemented in accordance with the relevant requirements of the transportation industry;

d) The asphalt pavement construction in the installation area shall be implemented in accordance with the relevant requirements of the transportation industry;

e) The distance between the installation location of the weighing instrument and the entrance and exit of the highway tunnel on the same road section shall be no less than 2 km and no less than 1 km, respectively.

8.2.2 Installation road surface conditions

The installation position of the load receptor of the full-draught WIM shall ensure that, the center line of the load receptor is located near the center of the weigh zone in the driving direction. The installation road surface conditions are as specified in Table 8. […]

8.3 Maintenance management

8.3.4 Equipment lubrication and maintenance

Regularly check whether the parts of the full-draught WIM that need to be lubricated meet the manufacturer's requirements. If not, perform lubrication according to the requirements. Check whether the welding part of the load receptor is un-welded. If yes, perform repair-welding in time. Check whether the paint of the load receptor is peeling off or aging; whether the road traffic sign lines are clear. When peeling off or aging, touch up the paint in time.

8.3.5 Pavement inspection and maintenance

Regularly check the condition of the road surface in the controlled weighing area; to see if there are loose roads, pits, subsidence, bulges, cracks, and chaps that affect the weighing. When it appears, fix it in time.

8.3.6 Power supply and grounding inspection

Regularly check whether the power supply of the equipment is stable and appropriate; whether the ground wire is firmly connected; whether there is rust.

If necessary, it shall test the grounding resistance. If it does not meet the manufacturer's requirements, take corrective measures in time.

8.3.7 Weighing accuracy check

Regularly (according to the frequency of use, laws and regulations, user or manufacturer designation, etc.) check the weighing accuracy. When inaccuracy is found, repair or re-adjust in time. When necessary, the control instrument can be used for inspection.

8.3.8 Full-time equipment maintenance and management

Users shall set up full-time maintenance and management personal positions for weighing equipment; receive corresponding professional training; formulate care and regular inspection and maintenance systems; to ensure that the weighing equipment is not accidentally adjusted.

9.1 Basic functional requirements

9.1.1 General

The weighing accuracy of the full-draught WIM shall be consistent with the accuracy level of the full-draught weight, axle load, and axle-group load (if […]

10.2 Preparation before testing

10.2.2 Adjustment

All adjustments are carried out at the actual installation location of the full-draught WIM; including static adjustment, in-motion adjustment and speed adjustment. The in-motion adjustment shall use the vehicle expected to be used by the full-draught WIM; shall be carried out in accordance with the adjustment method provided by the manufacturer. When the adjustment is over, the corresponding records shall be kept.

All adjustments shall be carried out before delivery or submission to the metrological department for verification.

10.2.3 Installation and visual inspection

Check whether the combination between the full-draught WIM and the road surface is smooth after installation. Check whether the flatness and slope of the apron at both ends meet the requirements. Check whether there is debris at the joint between the full-draught WIM and the road surface. Visually inspect whether the appearance (paint quality, welding quality, etc.) meets the requirements.

10.3 Static weighing test

For the full-draught WIM with a static working mode used as a control instrument, all static tests are performed in accordance with Appendix D of GB/T 21296.1-2020. The relevant module test requirements shall be implemented in accordance with Appendix E of GB/T 21296.1-2020.

10.4 In-motion weighing test

It shall be carried out in accordance with 10.4 of GB/T 21296.1-2020.

11.1 Type test

11.1.1 General

The full-draught WIM designed and manufactured by the manufacturer shall undergo a type test.

Under the following conditions, the full-draught WIM shall be type tested:

a) Before the new product is put into production for the first time;

b) The first lot of products after major changes in design, technology, and key […]