The requirements for using square column fasteners(also called square column clamps)focus mainly on component quality inspection and installation operation specifications.The core requirements are summarized below.
I.Quality Inspection Requirements Before Installation
Before using square column fasteners,each component must be strictly inspected to ensure it is in good condition:
Threaded parts:No cracks,no damage exceeding two threads,no rust,and no signs of elongation at the bottom of the last few threads.
Rod parts:No bending,elongation,significant wear,or severe impact marks.
Screw heads/nut edges:No significant damage;a standard wrench should fit properly without slipping.
II.Technical Requirements for Installation Operation
1.Horizontal Installation
Square column fasteners must be installed horizontally to provide effective reinforcement.During installation,use a tape measure to mark a uniform height line,then install the four clamp plates in pairs,interlocking them along the same horizontal line.
2.Installation Spacing and Clearance from Ground
Clearance of the first set from the ground:Recommended 20–30 cm to facilitate later removal.
Spacing between fastener sets:Typically 20–40 cm,depending on column dimensions and design requirements.
Spacing reference for different column sizes:
For 800 mm columns:20 cm spacing at the bottom,gradually increasing to 30–40 cm toward the top.
For 600 mm columns:20 cm spacing at the bottom,gradually increasing to 50–60 cm toward the top.
3.Fastening Operation
After inserting the wedge‑shaped pin,tap it evenly with a hammer to secure it firmly.
The four clamp plates should interlock in pairs,with the bent edges aligned with the outer edges of the square column formwork.
Wedges should be stored centrally in woven bags to prevent loss.
4.Special Requirements for Tall Columns
When the column height exceeds 2.44 m,the upper and lower sections of the formwork should be staggered at the joint to ensure the verticality and integrity of the square column.
III.General Requirements for Bolt‑Type Fasteners
For bolts,nuts,and related components used in square column fasteners,the following general requirements apply:
Screw‑in depth(cast iron parts):Not less than 1.1 times the thread diameter.
Screw‑in depth(steel parts):Not less than 0.8 times the thread diameter.
Exposed bolt threads after tightening:2–3 threads.
Margin for blind threaded holes:2–3 threads of margin left inside the hole.
Symmetrical tightening:When securing components,bolts should be tightened evenly and in a symmetrical sequence to prevent distortion.
IV.Protection Requirements During Use
Rust prevention:For bolted connections on outdoor equipment,bolts should be coated with oil.Where possible,insert bolts from top to bottom to prevent rainwater from entering and causing rust.
Anti‑slip measures:Drive nails into the horizontal platform below the square column fasteners to prevent them from sliding down.
Base treatment:Seal the bottom of the square column formwork with concrete to facilitate easy formwork removal.
Safe operation:Scaffolding should be used when installing square column fasteners at height to ensure safe working conditions.
V.Replacement and Repair Requirements
When replacing bolts or nuts,their specifications,model,strength grade,and other technical requirements must comply with the design drawings or match the original components.For critical bolted connections,a torque wrench should be used as specified in the design.Threads of stainless steel bolted connections should be coated with a lubricant.
VI.Summary of Key Requirements
Installation direction:Must be horizontal.
Clearance of first set from ground:20–30 cm.
Spacing between fastener sets:20–40 cm.
Exposed bolt threads after tightening:2–3 threads.
Allowable thread damage:No more than 2 threads.
Tall columns(height>2.44 m):Stagger formwork joints.