10.9S Steel Structure Torsional Shear Bolts
Principle: Tightened using a specialised electric torque-shear wrench; when the bolt reaches the design preload, the star-shaped head at the end is sheared off at the torque-shear groove. The detachment of the star-shaped head indicates that the preload has been achieved; this can be verified visually, minimising human error.
Product Description
Features:
Tensile strength ≥ 1040 MPa, yield strength ≥ 940 MPa, ensuring stable preload;
Simple and reliable installation and quality inspection;
Suitable only for friction-type steel structural joints.
Structural Features：
The bolt features a star-shaped torsional shear head at the tip and a pre-formed shear groove at the base;
When tightened to the design preload using a specialised electric torsional shear wrench, the star-shaped head at the tip fractures along the shear groove and breaks off;
Applications:
Main steel structural connections in high-rise steel frames, industrial plant steel structures, steel trusses, towers, etc.
Key Construction Points
- Tightening sequence, work outwards from the centre of the joint; generally divided into two stages: initial tightening and final tightening; initial tightening should apply 50%–70% of the final preload;
- Friction surfaces must be clean and dry, and the coefficient of friction must meet design requirements;
- the cylindrical side of the nut must face the chamfered side of the washer; the chamfered face of the washer must face the nut;
- do not use a standard impact wrench to forcefully break off the star-shaped head, as this will result in inaccurate preload;
- if the star-shaped head has not broken off after final tightening: replace the bolt and repeat the procedure; breaking it off by hand is strictly prohibited.
Installation Prohibitions
Do not strike, gas-cut or heat bolts with a flame.
Use this space to add a medium length description. Be brief and give enough information to earn their attention.
If the star-shaped head is stripped or cannot be sheared off, do not apply excessive force by twisting it; the bolt must be scrapped and replaced immediately.
Once the star-shaped head of a torque-shear bolt has been sheared off during final tightening, the bolt must not be dismantled or reused; it must be replaced with a new bolt upon removal.
Advantages
Pre-tension control is less susceptible to human error, and the quality is visually apparent.
Friction-type connections offer excellent performance, with good seismic and fatigue resistance.
High construction efficiency, making it suitable for large-scale standard beam-column joints.
On-site inspection is straightforward, eliminating the need for extensive torque spot checks.