High strength bolt

· Strong

· torque coefficient

· anti-slip coefficient

· final torque

· club head check

High-strength bolt test items:

1.main inspection items

Including: bolts physical minimum load inspection; Pretension reinspection of high strength torsional shear bolt coupling; High strength bolt joint torque test; High strength large hexagon head bolt connection torque coefficient reinspection; Test the anti - slip coefficient of high strength bolt joint friction surface.

2. main control project

(1) steel structure production and installation should be in accordance with gb50205-2001 attached to the relevant provisions of B for high-strength bolt connection friction surface test and retargeting, on-site treatment of the friction surface of components should be carried out separately friction surface test, the results should meet the design requirements.

(2) high strength large hexagon head bolt connection pair end screw finish 1h, 48h should be the end screw torque inspection, inspection results should meet the specifications. Inspection quantity: 10% according to the number of nodes, and no less than 10 nodes; Each node selected for inspection shall be selected for 10% according to the number of bolts, and shall not be less than 2.

(3) after the end of the twisted shear type high-strength bolt connection, the number of bolts that have not been unscrewed in the end should not be more than 5% of the number of the joint bolts, except for those that cannot be unscrewed with a special wrench due to structural reasons. All torsional shear type high-strength bolt connection pairs with untwisted plum heads shall be finalized by torque method or corner method and marked, and the finalized torque shall be checked according to the provisions of the above article.

Inspection quantity: check 10% according to the number of nodes, but not less than 10 nodes. Check the final torque of the torsional shear type high-strength bolt connection pair with the unscrewed plum head in the selected points.

3.  general items

(1) high-strength bolt connection pair of the screw order and the initial twist, retwist torque should meet the design requirements and the national current industry standard "steel structure high-strength bolt connection design, construction and acceptance regulations" JGJ82.

(2) after the end of the high-strength bolt connection, the bolt screw shall be exposed to 2 ~ 3 buttons, and 10% of the bolt screw shall be exposed to 1 button or 4 buttons. Inspection quantity: select 5% according to the number of nodes, and should not be less than 10.

(3) high-strength bolt connection friction surface should be kept dry, clean, there should be no flash, burr, welding spatter, welding scar, iron oxide, dirt, etc., in addition to the design requirements of friction surface should not be painted.

(4) high strength bolts should be free through the bolt hole. High-strength bolt holes shall not be reamed by gas cutting, the number of reaming shall be approved by the design, and the aperture after reaming shall not exceed 1.2d (d is the bolt diameter).

(5) after the total assembly of bolt ball node network frame, the high-strength bolt and ball node should be tightly connected, the thread length of the high-strength bolt into the bolt ball should not be less than 1.0d (d is the bolt diameter), the connection should not appear clearance, loose and other untightened conditions.