1 General
1.0.1 In order to clarify the work procedures for on-site inspection of highway bridges in use, to rationalise the selection of inspection methods and to standardise the operational requirements for on-site inspection, these regulations have been developed.
Article Description
On-site inspection of highway bridges is the preliminary basic work for bridge assessment and maintenance and repair. The development of in-service highway bridge field inspection technical regulations to further standardize the implementation and operation of field inspection, improve the accuracy and reliability of test data, to better support and ensure the bridge assessment work based on the current "Highway Bridge Technical Condition Assessment Standards" (JTG/TH21), "Highway Bridge Bearing Capacity Testing and Assessment Regulations" (JTG/TJ21), etc.
1.0.2 These regulations are applicable to the on-site inspection of bridges in use on all levels of highways.
Article Description
These regulations are mainly for the on-site inspection of bridges in use, and the inspection items include apparent and internal damage, material condition, geometry, etc. For load tests and other testing items for which special regulations have been issued, these regulations do not make relevant provisions.
1.0.3 On the premise of ensuring accuracy and reliability, on-site inspection shall encourage the use of advanced and mature methods, software, equipment and other new technologies.
2 Terminology
2.0.1 Coding rules codingrule
The rules and methods of numbering structures and members developed for carrying out on-site inspection of highway bridges.
3 Basic provisions
3.1 General procedures and requirements for inspection work
3.1.1 The general procedures for the on-site inspection of road bridges shall be in accordance with the provisions of Figure 3.1.1.
4 Field inspection records and coding rules
4.1 Inspection records
4.1.1 Field inspection records for all types of defects are to be recorded in accordance with the relevant appendices provided in these Regulations. Continuous observations of important diseases shall be recorded using the recording methods and recording forms provided in these Regulations. For field inspection items not mentioned in these Regulations, the record forms may be designed by the inspection unit itself with reference to the relevant forms in these Regulations.
5 Apparent disease detection
5.1 - General provisions
5.1.1 Apparent defects should be inspected by manual visual inspection, but can also be inspected using auxiliary tools such as binoculars or other image acquisition devices.
Article description
Auxiliary tools for manual visual inspection mainly include telescopes, graduated magnifiers, comparison cards, steel rulers, tape measures, stoppers and distance measuring devices, etc.; image acquisition devices mainly include camera photography equipment, drones, climbing robots, underwater robots and other types of specialised disease detection devices, etc.
5.1.2 initial inspection, periodic inspection and special inspection, it is appropriate to use special maintenance channel, bridge inspection vehicles and other conventional inspection platform close to the surface of the components for apparent disease detection; for conventional inspection platform is not easy to reach the region, can use image acquisition devices and other auxiliary inspection.
Article description
Conventional inspection platform is not easy to reach the area of the general including high piers, towers, pulling cables, large-span arch bridge arch and underwater structures.
5.1.3 For initial, periodic and special inspections, full component-by-component on-site inspection of apparent defects is desirable. Typical defects affecting the safety and durability of the structure and those requiring repair and treatment shall be recorded and photographed in detail.
Article description
When carrying out special inspections such as the apparent defects of the cable sheathing and the apparent defects of the submerged foundations, full inspection is required in accordance with the inspection content and commissioning requirements, and additional testing can be carried out on the basis of the periodic inspection if relevant periodic inspection data has recently been available.
5.1.4 Photographic information on apparent defects is desirable to include dimensional markings or references and to reflect the local characteristics of the defect and the location and distribution of the defect on the structure or member.
6 Internal disease detection
6.1 - General provisions
6.1.1 Internal disease detection projects should include internal disease detection of concrete structures, grouting compactness detection of prestressing pipes, corrosion detection of prestressing anchor heads, concrete filling compactness detection of steel pipes and internal disease detection of steel welds.
7 Testing of material condition and durability parameters
7.1 Strength testing
7.1.1 The compressive strength of concrete in bridge structures can be tested using the rebound method, ultrasonic rebound synthesis method and core drilling method.
Article description
The rebound method, ultrasound-echo synthesis method and drill core method can be used to test the compressive strength of concrete in bridge structures, where the rebound method and ultrasound-echo synthesis method are indirect non-destructive testing methods and the drill core method is a direct testing method.
7.1.2 Concrete members with loose or spalling surfaces caused by frost, chemical attack, fire, high temperature, etc., should not be subjected to the rebound and ultrasonic-echo methods for concrete strength determination.
7.1.3 When the rebound method is used for the presumption of compressive strength of concrete, the surface quality of the concrete being tested shall be representative and the compressive strength and age of the concrete shall not exceed the limits set by the corresponding technical regulations.
8 Inspection of structural dimensions and geometry
8.1 General
8.1.1 Bridge structure size and geometry testing should include bridge length, width, member and section size, elevation line and deflection observation, main arch deformation and arch foot displacement, suspension bridge main cable line shape, main tower tilt deformation, high pier verticality and other testing projects.
8.1.2 for large span continuous beam (rigid) bridges, arch bridges, cable-stayed bridges and suspension bridges, etc., should be set up for long-term tracking of the geometry of the structure of permanent observation points, should be set up and not set up permanent observation points of the bridge, should be set up in accordance with the provisions.
8.1.3 Elevation (arch axis) alignment and deflection testing should be carried out in the case of closed traffic, if closed, should be selected in the traffic flow is small, a thousand disturbance is small or temperature change is small time.
8.2 General, component and section dimensions of bridges
8.2.1 The geometry of the bridge should include the length, width and cross-sectional dimensions of the bridge, which can be measured using measuring tools such as steel rulers, steel tape measures and laser distance meters.
8.2.2 The length and span of the bridge should be measured in 3 lines: the centre line of the bridge span structure and the upper and lower edge lines of the carriageway. In cases where traffic cannot be closed or where there is a high volume of traffic, the measurement can be carried out at the outer edge of the carriageway.
8.2.3 The width of the bridge can be measured in longitudinal sections along the bridge, with no fewer than three sections per span.
8.2.4 The thickness of the bridge floor and web can be measured through the ventilation holes and other reserved apertures, and other non-destructive testing methods such as the impact echo method can be used if there are no direct measurement conditions.
9 Other tests
9.1 Bearing testing
9.1.1 Before testing for bearing defects, the bearing design and installation drawings, previous test reports and maintenance and replacement records should be consulted.
Article description
By consulting the bearing design and installation drawings, it is easier for the inspector to detect common bridge bearing installation defects during on-site inspection, such as bearing temporary connection plates not removed, incorrect installation of movable bearing main displacement direction and inaccurate bearing installation position. By reviewing the previous inspection reports and maintenance and replacement records, the inspectors were able to select the key bearings to be inspected and make an analysis of the development of bearing defects.
9.1.2 For initial, periodic and special inspections, it is advisable to test all bearings within the bridge, and to focus on large displacement movable bearings, and slab rubber bearings on curved sloping bridges.
Appendix A member code rules schedule
1 General
2 Terminology
3 Basic provisions
4 Field inspection records and coding rules
5 Apparent disease detection
6 Internal disease detection
7 Testing of material condition and durability parameters
8 Inspection of structural dimensions and geometry
9 Other tests
Appendix A member code rules schedule
