(1) High-strength boβλlts are usually divided ←↕ into friction connection, tension ↑ connection and pressure connection€≠ < according to the connection fo£¥rm. Among them, friction connection is♣‌ the basic connection fo≥ rm widely used at pr§∏'↑esent.

(2) The treatment method§₹÷s of the friction surface of γ the high-strength bolt co§λnnection usually include'λ↓σ sandblasting (shot) method, pickli §₹ng method, grinding wheel g≠™‌rinding method and wire brushεα manual rust removal method. The treat±×ment process can be selected accor♠↕® ding to the requirements of the design ¶γanti-slip coefficient, and the anti-sli✔¥p coefficient must meet the design reqφ©uirements.

(3) The friction surface of t♦π★®he high-strength bolt connection after§¥ surface treatment should me•£↑"et the following requirements:

A. The friction surface of the connec€<tion should be kept dry ★ and clean, and there should ₽§‍≤be no flashes, burrs, welding spatter>♥↔β, welding scars, iron∏  oxide scale, dirt, etc.;

B. Take protective measures for the β✔π✔treated friction surface¶£, and no mark shall be made on the♥‍≈ε friction surface;

C. If the friction surface i≠©s treated with rust, the rust on the ∑>§₹friction surface should be removed with↔Ω≤ a fine wire brush per£≥pendicular to the force direc↕&tion of the component b®§™"efore installation.

D. The high-strength large hexagon♣  head bolt connection pair is coβ✘♣mposed of a bolt, a nut and two washerφ↔s, and the torsion-shear type ♣≈high-strength bolt connection ↑♠pair is composed of a bolt, a nut and ‍✔γ a washer.

E. The temperature of th↕×♥'e installation environment should₹≠ ¶ not be lower than -10&Prime₩→;C. When the friction surf<≈ace is wet or exposed to rain and sno→→★±w, stop the operation. ↔$✘

F. When installing hig↓  h-strength bolts, install bolts an∏σ≥∏d punching nails sho> uld be used first. The number of in£♠↕stallation bolts and punching nail±¥™"s must be able to withstand th♠✘∞e weight of the component and the ¥<external force durin ₹↑g connection correction. T↔¥$he minimum number of installatioΩ n of each node is to preveΩγnt the position of the component₽♥ from shifting after the c••onnection, and at the same♠♥✔ time limit the amount of punching na& $$ils. High-strength bolts must not be us¥‍ed as mounting bolts<≤.

G. When high-strength bolts are i→←nstalled on site, they should be ≤¶→>able to pass through th ×e bolt holes freely, and no forced peneγ₹×δtration. If the bolt cannot<<♣✘ pass through people freely,★£ the bolt hole can be trimmed with a ∑×dumpling knife or a knack knif<€e. Gas cutting reaming is¥λ₩¶ not allowed. The numbεΩer of reaming holes should $α∏be approved by the design. The holeσ‌∏ diameter after trimming or reami∞ ​ ng should not exceed 1.≥ε♣♦2 times the bolt diameter.

H. High-strength bolts shoul∞₩d be replaced if they are over-Ω★γtightened, and the rep☆₽"laced bolts should be dλ©↕αiscarded and not reused. It ÷¥®≤is strictly forbidden  ↔to use flame or electric welding to cut£α★← high-strength bolt ε£±plum heads.

I. The length of high-strength bolts s♦‌φ hould be calculated based on the 2-3 thδ↕read exposed after the fi€βnal tightening of the bolt conne‌"ction, and should be tightβ'™↔ened after the component instal§∏↓±lation accuracy is adjuste​εd. The final tightening inspection ¥π↕♠of torsion shear type☆$→© high-strength bolts is qua♥σlified by visual insp"∏♣φection of the torx end of the tγ™ail.

J. The torch method or the €¥♣angle method can be ♣φΩused to tighten the connectio£πδn pair of high-strength>÷¥♣ large hexagon head bolts. In th¥↑​↕e same joint, the initial screwing,  <'∞re-tightening and final screwing of th₹←♣↓e high-strength bolt  ™♣←connection pair should be λ ↕δcompleted within 24 hoursλ©. In principle, the initial tighte♥βα€ning, re-tightening and final tight→σening of the high-strength b÷®£∞olt connection should be carried out₹≥β in the order of the greater δ$∑✘joint stiffness to the less res÷δtrained direction and the center ofσ♠↓→ the bolt group to the sδ< ≤urroundings.

K. For connection nodes ↔Ω that use high-strengt✔✘​£h bolts and welding toget ₽™×her, when there is no r§"→'equirement in the design documenα♠ts, the construction sequence of↑≈≈ bolting first and then welding should ∑σ¥ be followed.