GB/T 21296.4-2020Automatic instruments for weighing road vehicles in motion-Part 4: Bending plate type (English PDF)

3.1 Bending plate sensor

An integral elastic element with attached strain gauges for measuring static or dynamic wheel forces of a wheel or axle.

Note 1: The bending plate sensor is based on bending stress, so it is called bending plate.

Note 2: The size range of the bending plate sensor involved in this Part along the driving direction is: 30 mm~900 mm.

Note 3: When the size of the bending plate sensor in the driving direction is more than 100 mm and less than 300 mm, it is called a small bending plate.

Note 4: When the size of the bending plate sensor in the driving direction is less than 100 mm, it is called a narrow strip. [GB/T 21296.1-2020, definition 3.7.4]

3.2 Partial weighing

Divide a whole vehicle into two or more parts on the same loader and weigh sequentially. [GB/T 21296.1-2020, definition 3.3.2]

3.3 Maximum capacity of bending plate sensor; Emax

The maximum load value which can be applied to the bending plate sensor during a single measurement and for which the measurement result error does not exceed the maximum permissible error of bending plate sensor.

3.4 Error of bending plate sensor

The difference between the measurement result of bending plate sensor and the conventional true value of the measured load (in mass).

Note: The center of the applied load may be any position on the longitudinal centerline of the entire bending plate sensor; and is completely applied to the bending plate sensor.

3.5 Maximum permissible error of bending plate sensor; MPEbp

Permissible limit value of error of bending plate sensor.

4.1 Composition

Bending-plate-type dynamic vehicle weighing instrument is composed of bending plate sensor, electronic weighing meter and apron, etc. In order to meet specific system functions, bending-plate-type dynamic vehicle weighing instrument system may also include interface-connected axle identifier; vehicle identification devices (such as vehicle detector, vehicle separator, vehicle license plate identifier, etc.); vehicle guidance device; vehicle speed detection device; and vehicle contour size detection device, etc.

4.2 Classification and designation

The classification and designation of bending-plate-type dynamic vehicle weighing instruments are in accordance with the provisions of Clause 4 in GB/T 21296.1-2020.

5.1 Basic accuracy classes

5.1.1 Basic accuracy class of whole loads

Bending-plate-type dynamic vehicle weighing instrument is an automatic instrument for weighing road vehicles in motion by partial weighing. The basic accuracy class of whole loads of bending-plate-type dynamic vehicle weighing instrument is divided into 4 classes, which are represented by symbols: 1, 2, 5, 10.

5.1.2 Basic accuracy class of vehicle axle loads (single-axle or axle-group loads)

6.1 General technical requirements

The relevant technical requirements of bending-plate-type dynamic vehicle weighing instruments shall comply with the provisions of Clause 6 in GB/T 21296.1-2020.

6.2 Design and production requirements

6.2.1 Overall requirements

The design and production of bending-plate-type dynamic vehicle weighing instruments shall meet the requirements of Clause 7 of GB/T 21296.1-2020.

6.2.2 Structural design

The structural design shall take into account the possibility and durability of manufacture, inspection, transportation, installation, disassembly, use, and maintenance, etc.

6.2.3 Overload capacity

In order to ensure that the metering performance is maintained during the service cycle, the structural design of bending plate sensor shall be strong and meet the expected use requirements. The ultimate overload capacity shall not be less than 1.5 times the maximum capacity (Emax) of bending plate sensor.

6.2.4 Anti-skid requirements

The upper surface of the loader of bending-plate-type dynamic vehicle weighing instruments shall have anti-skid design (or measures). The anti-skid design (or measures) shall be able to withstand repeated rolling of vehicle tires in the corresponding use site and application.

If grooves and ridges are designed on the upper surface of the loader of bending-plate-type dynamic vehicle weighing instruments, the height difference between the grooves and the ridges shall not be greater than 2 mm. And it shall be ensured that the bending- […]

6.3.4 Protection requirements

The degree of protection provided by the enclosure of bending plate sensor shall not be lower than IP68.

The degree of protection and test conditions comply with the provisions in Table 2 and Table 3 in GB/T 4208-2017.

6.4 Electronic weighing meter

The electronic weighing meter equipped for bending-plate-type dynamic vehicle weighing instruments shall meet the requirements of GB/T 7724.

7.1 Layout types

According to the different installation positions and applications, the bending plate sensor layout types of bending-plate-type dynamic vehicle weighing instruments are divided into single-lane layout and multi-lane layout.

The single-lane layout shall use mechanical (including building structure) lateral vehicle guidance devices, to ensure that the vehicle completely passes the bending plate sensor. This layout is usually used for tolling by weight and traffic law enforcement.

In the multi-lane layout, solid line signs that are conducive to weighing detection shall be set between adjacent lanes in the weighing area, as well as between the motor vehicle lane and the non-motor vehicle lane. Mechanical (including building structure) or electrical vehicle guidance devices can also be installed on both sides of the road. This layout is usually used in traffic law enforcement, auxiliary law enforcement, and statistical analysis.

In the same lane, along the driving direction, it shall use one row (or multiple rows) of bending plate sensors to measure the wheels on the left and right sides at the same time, to complete the weighing of the vehicle's wheel load (or axle load). Or use one row (or multiple rows) of bending plate sensors to measure the wheels on the left and right sides in turn, to complete the weighing of the vehicle's wheel load (or axle load).

Where a vehicle guidance device is installed, it shall comply with the requirements of traffic safety signs and warnings, so that the driver can easily find it; and it does not affect the traffic safety of motor vehicles.

7.2 Requirements along the width of lane

8.4 Base groove cleaning

For the bending-plate-type dynamic vehicle weighing instrument installed by cutting and grooving on the concrete road and pouring glue, the edge of the base groove shall be cut neatly to avoid gaps. The bottom surface of the base groove shall be flat. The edges of the base groove shall be chiseled.

All surfaces of the base groove shall be free of dust. The base groove can be rinsed with clean water. The surrounding and bottom surface of the base groove can be scrubbed with a wire brush or wire ball.

Before pouring, the cleaned base groove shall be air-dried (or by appropriate drying measures) and kept clean.

8.5 Positioning of bending plate sensor

The longitudinal centerline of bending plate sensor is consistent with the width direction of lane.

In a bending-plate-type dynamic vehicle weighing instrument, the longitudinal centerlines of all bending plate sensors shall be parallel (or coincident).

After positioning (including installation), measures such as grinding installation materials and road surface shall be taken, to ensure that the upper surface of the bending plate sensor is consistent with the road slope and is in the same plane. The flatness shall comply with the provisions of 8.2 in GB/T 21296.1-2020.

8.6 Anchorage safety

The bending plate sensor shall be firmly embedded in the road surface. There shall be no gap between the bending plate sensor and the road surface. Reliable measures shall be taken to prevent the bending plate sensor or its installation accessories from loosening and popping out under the condition of continuous impact of vehicle.

8.7 Grounding

A grounding device shall be set up in an appropriate position, to ensure that the bending plate sensor, electrical box, electrical equipment enclosure, etc. are firmly grounded. The grounding resistance is <=4 ohm.

8.8 Drainage

According to the manufacturer's design requirements, a bending plate sensor for drainage needs to be installed; to ensure that the accumulated water can be discharged smoothly during the rainy season. The drainage channel shall be smooth and have an inclination of no less than 1% towards the drainage direction. The structure, material and burial depth of the drainage channel shall meet the design requirements of the pavement bearing capacity.

8.9 Setting of lane separation device

When applied in the form of a single-lane layout, lane separation devices such as safety islands or isolation devices shall be set up on both sides of the bending-plate-type dynamic vehicle weighing instrument. The test shall be carried out according to the intended purpose of use.

When applied in the form of a multi-lane layout, no-lane-changing signs and solid line signs shall be set up, and shall be tested and used according to the lanes. Separation devices or solid line signs that comply with traffic safety regulations shall also be used between motor vehicle lanes and non-motor vehicle lanes.

9.1 General requirements

The system function and data requirements of bending-plate-type dynamic vehicle weighing instruments shall comply with the provisions of Clause 9 in GB/T 21296.1-2020.

9.2 Vehicle crossing prompt

In the application of the multi-lane layout, when the vehicle rides across different lanes, bending-plate-type dynamic vehicle weighing instruments shall give a violation prompt according to the requirements of 9.3.8 in GB/T 21296.1-2020.

10.1 General

The test shall be carried out on the site where the bending-plate-type dynamic vehicle weighing instrument is used. The bending-plate-type dynamic vehicle weighing instrument shall not be used as a control weighing instrument.

10.2 Preparation before testing

11.2.3 Test of bending plate sensor

Bending plate sensor shall meet the requirements of Clause 6. See Appendix B for the test method.

11.2.4 On-site inspection

11.2.4.1 Preparation before on-site installation

Before the product arrives at the installation site, an on-site installation condition investigation shall be carried out. If the requirements are not met, it shall fully communicate with the user; make rectification or change the location first. After the equipment is delivered to the site and ready to be installed, check whether the installation tools are available and whether the installation materials are sufficient. Equipment installation shall be carried out when weather conditions permit.

11.2.4.2 Inspection after on-site installation

After the product is installed for the first time, on-site inspection shall be carried out.

Only after passing the inspection, can the product be delivered and attached with the corresponding product conformity certificate. The on-site inspection shall be carried out according to the items specified in Table 8. In the case of multi-lane layout, the dynamic test is carried out respectively according to the expected lanes.