Structural steelwork-4

Steel space frame

a. The detection of steel space truss can be divided into the bearing capacity of nodes, weld, size and deviation, uneven straightness of bars and the deflection of steel structure building.

b. The test of the bearing capacity of the welded ball receiving node and the bolt ball node of the steel frame should be carried out according to the requirements of the quality inspection and evaluation standard of the grid structure JGJ78. For the existing grid structure of bolted spherical joints, the nodes can be removed from the structure to test the ultimate bearing capacity of the joints. Measures should be taken to ensure the safety of the structure when the bolt ball joints are intercepted.

c.The detection of weld bead of steel truss,  can be used for ultrasonic flaw detection, should be carried out according to "welding ball node steel weld grid method for ultrasonic testing and classification of JG/T3034.1" or "bolt ball node steel lattice weld ultrasonic inspection and quality classification method" the requirements of the JG/T3034.2 operation and evaluation of detection. The appearance quality of the weld seam in the 3.4 steel grid should be tested according to the requirements of the code for construction quality acceptance of steel structure engineering GB50205.

d. Detection of welding ball, bolt, high strength bolt and bar deviation, detection method and deviation should be according to "standard" provisions of truss structure engineering quality inspection JGJ78 execution allowable value.

e.The wall thickness of the steel pipe member of steel grid can be detected by ultrasonic thickness gauge, and the finish layer should be removed before testing.

f.The unflatness of the axis of the steel bar in the steel grid can be detected by the method of bracing wire , and its unflatness should not exceed 1/1000 of the length of the member.

g.The deflection of steel truss, could detect by the laser range finder or level detection, the points of each half span range not suitable less than 3, and the cross should have 1 gauging point, the end of the end support of the measured point should not be greater than 1m.

Steel structure cold storage in DingHao-3

Real load test of structural performance and dynamic test

a.    For large complex steel structures, the in-situ non-destructive loading test can be carried out, and the structural performance is checked directly. The real load test of structural performance can be carried out in accordance with appendix H of this standard. The loading coefficient and the judging principle can be determined according to the provisions of appendix H.2, and can be adjusted according to the specific conditions.

b.    When the bearing capacity of the structure or component is doubtful, the prototype or full scale model load test can be carried out. The test should be commissioned by a specialized institution with sufficient equipment capacity. Before the test should formulate a detailed test plan, including test purpose, test piece selection or production, loading device, measuring point arrangement and test instruments, loading steps and test result evaluation method etc.. The test plan can be formulated according to appendix H, and should be agreed by the parties concerned before the test.

c.     For large and important steel structures, the actual structural dynamic test should be carried out to determine the parameter of dynamic vibration of structure. The structural dynamic test should comply with the appendix E of this standard.

The stress of steel structure bar can be checked by resistance strain gauge or other effective methods according to the actual conditions.

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