Standard No.:	YB 9257-1996
English Name:	Technical Specification for inspection Assessment and Strengthening of Steel Structures
Chinese Name:	钢结构检测评定及加固技术规程
Chinese Classification:	P26    Metal structure engineering
Professional Classification:	YB    Professional Standard - Metallurgy
ICS Classification:	91.080.10 91.080.10    Metal structures 91.080.10
Issued by:	Ministry of Metallurgical Industry
Issued on:	1996-11-08
Implemented on:	1997-7-1
Status:	valid
Language:	English
File Format:	PDF
Word Count:	13000 words
Price(USD):	320.00
Delivery:	via email in 1 business day

1.0.1 For the purpose of unifying the inspection, assessment and strengthening methods of the steel structure buildings or structures and improving actual operation level, this specification is formulated to implement the national technical and economic policies and relevant standard code and achieve advanced technology, economic rationality and safety and reliability.

1.0.2 This specification is applicable to the inspection, assessment and strengthening design, construction and acceptance of the steel structure of the existing industrial buildings or structures under any one situation below:

1.0.2.1 New operation requirements have been proposed for the mill construction due to the production equipments update, technical process change or production scale enlargement;

1.0.2.2 The reliability shall be assessed again and the structural function shall be recovered due to structural damage arising from all kinds of accidents and disasters;

1.0.2.3 At the time when the reliability of the original structure is doubtable after long-term usage or variation of the production environment;

1.0.2.4 Some serious defects have been remained during original structure design or manufacturing and installation process, so the actual bearing capacity shall be appraised;

1.0.2.5 If it is out of repair for long years or the service life has already exceeded the design reference period;

1.0.2.6 Other conditions where the reliability evaluation shall be made for the steel structure of the plant buildings.

Note: The inspection, assessment and strengthening of the steel structure of civil building may also refer to this specification.

1.0.3 This specification is prepared according to the technical documents like the national standards "Criteria for Reliability Appraisal of Industrial Buildings" (GBJ 144), "Code for Design of Steel Structures" (GBJ 17) and "Code for Construction and Acceptance of Steel Structure Engineering" (GB 50205) and the professional standard "Reliability Evaluation Regulation of the Steel Industry Buildings or Structures" (YBJ 219) as well as long-term practical experiences. If the steel structure engineering with special requirements adopts this specification, relevant current standards or special provisions shall be carried out.

1.0.4 Under the basic principles of reliable safety measures and minimum production impacts, the manufacturer shall arrange the inspection and strengthening in a unified way, organize and coordinate them according to the work plan proposed by the unit assuming the inspection and strengthening.

1.0.5 The inspection, assessment and strengthening of the steel structure must be carried out according to the following stages after the client (the manufacturer) and the executive parties discuss jointly the enforcement regulations and procedures:

1.0.5.1 The structure inspection;

1.0.5.2 Structural performance and the state assessment as well as strengthening scheme suggestion;

1.0.5.3 Strengthening design;

1.0.5.4 Construction organization design and strengthening engineering construction;

1.0.5.5 Completion acceptance;

1.0.5.6 Establishment of the regular maintenance system.

The written materials shall be proposed after the completion of each stage of the work and attached by necessary source materials (such as completion drawing etc.) and inspection data. They shall be filed independently according to the projects after all the works are completed.

1.0.6 The safety, labor protection and fire/explosion protection etc. of the inspection and strengthening of the steel structure must be in the charge of the specific personnel and meet the special provisions.

1 General Provisions
2 Steel Structure Inspection
2.1 General Requirements
2.2 Investigation
2.3 Inspection
3 The assessment Grade of the Structural Members
3.1 General Requirements
3 2 Crane Beam System Grade
3.3 Evaluation on the Bearing Capacity of the Impaired Steel Structures
3.4 Structural Test
4 General Requirements for Strengthening
4.1 Strengthened Principle and Methods
4.2 Material
4.3 Loads
4 5 Structure Requirements
5 Strengthening Method of Adding Section
5.1 General Requirements
5.2 Strengthening Calculation of Flexural Members
5.3 Strengthening Calculation of Axially-stressed Members
5.4 Strengthening Calculation of Stretch-bending and Compression-bending Members
5.5 Structure Requirements
6 Connection during the Strengthening
6.1 General Requirements
6.2 Weld Connection
6.3 Bolted Connection
6.4 Mixed Connection
7 Crane Beam System Strengthening
7.1 General Requirements
7.2 Crane Beam Strengthening
7.3 Braking Structure and Support
7.4 Connection Strengthening and Orbit Trimming
8 Welding Strengthening under the Action of the Load
8.1 General Requirements
8.2 Welding Strengthening and Operation
9 Acceptance and Maintenance
9.1 Acceptance of Inspection and Assessment
9.2 Acceptance of Strengthening Engineering
9.3 Maintenance
Appendix A Comparison of the Designations of the Structural Steel in the New and Old Standards
Appendix B Comparison of New and Old Welding Rods for the Steel Structure
Appendix C Painting Dressing of Steel Structure after Maintenance and Strengthening
Appendix D Explanation of Wording in This Specification
Additional Explanation