The steel structure has many advantages such as shock resistance, wind resistance, durability, heat preservation, sound insulation and comfort. These advantages are inseparable from the hard work of the steel structure builders. After the construction of the steel structure is completed, The safety inspection of steel structure engineering is crucial. The main points of the steel structure inspection, Xiaobian here to give you a detailed introduction, I hope to help everyone:

 

1, construction

1.1 The detection and calculation of the slenderness ratio of steel structural members can be measured according to the provisions of Section 6.4 of this Chapter. The slenderness ratio of the members should be calculated according to the actual size.

1.2 The connection of the steel structure support system may be tested in accordance with the provisions of Section 6.3 of this Chapter; the dimensions of the support system components may be determined in accordance with the provisions of Section 6.4 of this Chapter; they shall be verified or assessed according to the design drawings or the corresponding design specifications.

1.3 The width-to-thickness ratio of the cross-section of steel structural members may be measured and calculated according to the provisions of Section 6.4 of this Chapter, and shall be assessed according to the design drawings and relevant specifications.

 

2, painting

2.1 The quality of steel structure protective coatings shall be tested according to the relevant national product standards for coating quality.

2.2 The descaling level of the steel surface can be determined by the picture comparison observation of the current national standard “Steel surface corrosion grade and derusting grade before painting” GB8923.

2.3 The coating thickness of different types of coatings shall be tested by the following methods:

1 The thickness of the paint film can be tested by the paint film thickness gauge. The number of sampled components should not be less than the minimum capacity of the Class A test sample in Table 3.3.13 of this standard, and should not be less than 3 pieces; 5 pieces per piece, The value of each place is the average of three dry paint film thicknesses of 50 mm apart.

2 For the coating thickness of thin fireproof coating, it can be tested by coating thickness measuring instrument. The measuring method should meet the requirements of CECS24 of “Technical Regulations for Application of Steel Structure Fireproof Coatings”.

3 For thick fireproof coating thickness, it should be tested by stylus and steel ruler. The measurement method should meet the requirements of CECS24 for “Technical Regulations for Application of Steel Structure Fireproof Coatings”. The thickness value and deviation value of the coating shall be assessed in accordance with the provisions of GB50205 for the Acceptance of Construction Quality of Steel Structure Engineering. 6.7.4 The appearance quality of the coating may be tested and evaluated according to the provisions of GB50205 of the “Quality Acceptance Specification for Steel Structure Engineering” according to different materials.

 

3, steel grid

3.1 The detection of steel grid can be divided into the bearing capacity of the joint, the weld seam, the size and deviation, the unevenness of the rod and the deflection of the steel grid.

3.2 The test of the bearing capacity of the welded ball joints and bolt ball joints of the steel grid shall be carried out in accordance with the requirements of JGJ78 of the “Quality Inspection and Evaluation Standard for Grid Structure Engineering”. For the existing bolt ball node grid, the node can be taken out from the structure to test the ultimate bearing capacity of the node. When intercepting the bolt ball node, measures should be taken to ensure structural safety.

3.3 Welds in steel grids can be inspected by means of ultrasonic flaw detection. The inspection operation and assessment should be based on the method of ultrasonic flaw detection and quality classification of welded ball joint steel grid welds JG/T3034.1 or "bolt ball joint steel mesh" Ultrasonic flaw detection and quality classification method for frame welds are carried out according to the requirements of JG/T3034.2.

3.4 The appearance quality of the weld in the steel grid shall be tested in accordance with the requirements of GB50205 of the “Quality Acceptance Specification for Steel Structure Engineering”.

3.5 Detection of welding ball, bolt ball, high-strength bolt and rod deviation, detection method and deviation allowable value shall be carried out in accordance with the provisions of JGJ78 of "Grid Structure Engineering Quality Inspection and Evaluation Standard".

3.6 The wall thickness of steel mesh steel pipe members can be detected by ultrasonic thickness gauge. The finish layer should be removed before testing.

3.7 The unevenness of the axis of the rod in the steel grid can be detected by the method of pulling the wire, and the unevenness should not exceed one thousandth of the length of the rod.

3.8 The deflection of steel grid can be detected by laser range finder or level gauge. The number of points in each half span should not be less than 3, and there should be 1 measuring point in the span. The end point should not be larger than the end bearing. 1m.

 

4, structural performance real load test and dynamic test

4.1 For large complex steel structure systems, in-situ non-destructive load testing can be performed to directly verify structural performance. The actual load test of structural properties may be carried out in accordance with the provisions of Appendix H of this standard. The loading factor and the determination principle can be determined in accordance with the provisions of Appendix H.2, and can be appropriately adjusted according to the specific circumstances.

4.2 If there is any doubt about the bearing capacity of the structure or component, the prototype or full-scale model load test may be performed. The test should be commissioned by a specialized agency with sufficient equipment capabilities. A detailed test plan shall be prepared before the test, including the purpose of the test, the selection or fabrication of the test piece, the loading device, the arrangement of the test points and the test instrument, the loading procedure, and the evaluation method of the test results. The test plan may be formulated in accordance with Appendix H and shall be approved by the parties concerned prior to the test.

4.3 For large-scale important and new steel structure systems, the actual structural dynamic test should be carried out to determine the dynamic parameters such as the natural vibration period of the structure. Structural dynamic testing should be in accordance with the provisions of Appendix E of this standard.

4.4 The stress of the steel structural members can be selected according to the actual conditions using a resistance strain gauge or other effective methods.