What Is 10.9S Torsion Shear Bolt? Standard & Construction Guide

1. Introduction

In modern steel structure engineering, connection quality directly determines the overall safety, stability and service life of buildings and infrastructure. Among all structural fasteners, 10.9S torsion shear bolts stand out as professional high-strength connecting parts specially designed for steel structure friction connections. Unlike ordinary 10.9-grade hex bolts that rely on manual torque detection, 10.9S torsion shear bolts adopt a fixed-value shear structure, realizing automatic torque calibration and visual construction acceptance.

2. Overview of 10.9S Torsion Shear Bolt

2.1 Definition of 10.9S Grade 10.9S is a special high-strength structural bolt grade for steel structures, different from ordinary 10.9 hex bolts. The letter "S" represents torsion shear type, which is dedicated to steel structure friction connection scenarios. Its mechanical properties strictly follow GB/T3632-2018, with tensile strength ≥1040MPa and yield strength ≥900MPa, reaching the highest safety level of civil engineering structural fasteners.

2.2 Structural Features The biggest feature of the 10.9S torsion shear bolt is the precision stress concentration shear neck reserved at the bolt tail. The bolt body, thread and shear neck are integrally forged and heat-treated, with uniform overall strength. Cooperated with matched high-strength nuts and washers, the whole set forms a closed stress system, avoiding local stress concentration and structural loosening.

2.3 Core Advantages Over Ordinary Bolts First, fixed-value torque locking, no need for manual torque detection, effectively eliminating human operation errors; second, visual construction effect, tail breaking means qualified locking, convenient for engineering acceptance; third, stable fatigue resistance, suitable for long-term vibration and alternating load environments; fourth, complete set of supporting accessories, unified performance, higher overall connection safety.

3. GB/T3632-2018 Standard Core Specifications

4.1 Stress Concentration Design The shear neck at the tail of the 10.9S bolt is precisely calculated and machined according to the standard torque value. Under normal tightening state, the bolt body and thread bear the pre-tightening force normally; when the torque reaches the standard preset value required by GB/T3632-2018, the shear neck will reach the ultimate shear stress and break automatically.

4.3 Long-Term Stability Mechanism After the shear neck is broken, the bolt forms a stable friction connection with the steel structure. The integral heat treatment structure has strong shear resistance and fatigue resistance, which can resist long-term wind load, vehicle vibration and structural alternating stress, ensuring the long-term safe operation of steel structures.

5. Standard Construction & Complete Installation Guide

Step 1: On-site Inspection & Preparation Check the integrity of 10.9S bolt, 10H nut and hardened washer complete set, confirm no thread damage, no rust, no deformation. Verify that the steel structure hole position and aperture meet the matching standard to ensure smooth penetration and fitting of bolts.

Step 2: Sequential Assembly of Accessories Penetrate the 10.9S torsion shear bolt into the steel structure connecting hole in place, sleeve the high-hardness flat washer and 10H high-strength nut in sequence, and manually screw the nut to close fitting without gap and skew.

Step 3: Professional Wrench Tightening Use a special torsion shear electric wrench for construction, stably clamp the bolt tail and nut clamping position, and tighten at a uniform speed to avoid jitter and eccentric force.

Step 4: Automatic Shear & Acceptance Confirmation When the tightening torque reaches the GB/T3632-2018 standard value, the bolt shear neck breaks automatically, the tail falls off naturally, and the construction is completed. All bolts with complete tail breaking are qualified products with standard preload.

6. Common Misunderstandings & Construction Taboos

Misunderstanding 1: Mixing ordinary nuts and washers Risk: Ordinary low-strength accessories cannot match the 10.9S high pre-tightening force, which is easy to cause thread slipping, nut cracking and connection failure. Solution: Strictly use the original supporting 10H nut and hardened washer complete set.

Misunderstanding 2: Forcibly breaking the bolt tail manually Risk: Manual forced breaking cannot reach the standard torque, resulting in insufficient pre-tightening force and loose structural connection. Solution: Rely entirely on professional wrench torque for automatic shearing.

Misunderstanding 3: Reusing disassembled torsion shear bolts Risk: The internal stress of disassembled bolts is released, and the mechanical performance is attenuated, which cannot meet the standard preload requirements again. Solution: 10.9S torsion shear bolts are disposable structural fasteners and cannot be reused.

Misunderstanding 4: Ignoring on-site hole position deviation Risk: Skewed hole position causes eccentric stress on bolts, resulting in shear deformation and reduced service life. Solution: Correct the hole position in advance to ensure vertical and flat assembly.

7. Main Application Scenarios

7.1 High-Rise Steel Structure Buildings Used for beam-column connection, steel truss assembly and external wall steel structure fixing of high-rise buildings, ensuring structural rigidity and seismic resistance.

7.2 Bridge & Traffic Infrastructure Suitable for steel bridge decks, bridge support connections and viaduct steel structures, adapting to long-term vehicle vibration and impact load.

7.3 Industrial Factory Steel Frames Standard fasteners for large factory steel frames, workshop supports and space steel structure connections, with stable load-bearing performance.

7.4 New Energy & Heavy Equipment Applied in photovoltaic support steel structures, wind power base supports and heavy mechanical equipment frames, meeting long-term outdoor stable fastening needs.

8. Conclusion

10.9S torsion shear bolt is a standardized, high-safety and easy-to-inspect structural fastener formulated based on GB/T3632-2018 national standard. Its unique torsion shear fixed-value locking principle completely solves the quality instability problem of traditional high-strength bolt construction. With ultra-high mechanical strength, excellent fatigue resistance and intuitive construction effect, it has become the preferred connecting solution for modern steel structure engineering. Standard selection and standardized construction are the key to ensure the overall safety and long-term stability of steel structures.

9. FAQ

Q1: What is the difference between 10.9S torsion shear bolt and ordinary 10.9 bolt? A: 10.9S is a special torsion shear type for steel structures, with fixed-value automatic shearing function and matched 10H supporting accessories, featuring standardized construction and convenient acceptance; ordinary 10.9 bolts rely on manual torque detection with large error and unstable quality.

Q2: Does 10.9S torsion shear bolt need torque detection? A: No need for artificial sampling detection. The automatic breaking of the bolt tail is the most intuitive qualified standard, which fully complies with GB/T3632-2018 engineering acceptance specifications.

Q3: Can 10.9S torsion shear bolts be used repeatedly? A: No. After one locking and shearing, the bolt internal stress is released, and the mechanical performance cannot reach the standard again. It must be replaced with new bolts for secondary construction.