Wall-Tie Bolt

A Wall-Tie Bolt is a tensioning device used in concrete formwork systems.It consists of a threaded steel rod,nuts at both ends,and often a central waterstop(for waterproof applications).Its primary function is to resist the lateral pressure of freshly poured concrete,preventing formwork deformation and ensuring dimensional accuracy and surface quality of concrete elements.

II.Components

Steel Rod

Material:Typically Q235 or Q345 steel,often galvanized or painted for corrosion resistance.

Thread:Fully or partially threaded ends for fastening.

Diameter:Common sizes include M12,M14,M16,M18,and M20,selected based on concrete pressure.

Nuts

Matched to the rod threads,usually double-nut design to prevent loosening.

Waterstop(for waterproof concrete)

Material:Steel plate,welded to the rod.

Shape:Square or circular,positioned at the center.

Function:Blocks water penetration paths,enhancing impermeability.

PVC Sleeve(optional)

Installed over the rod for easy extraction and reuse(in non-waterproof applications).

III.Working Principle

The rod connects opposite formwork panels into an integrated system.Tightening the nuts generates clamping force to balance concrete lateral pressure during pouring,controlling formwork displacement and deformation.

IV.Main Types

Standard Through-Wall Tie Rod

For non-waterproof structures(e.g.,columns,beams),often with PVC sleeves for reuse.

Waterstop Tie Rod

For waterproof structures(e.g.,basement walls,water tanks),with a permanent central waterstop.

Three-Piece Waterstop Tie Rod

Components:One inner rod(with waterstop)and two removable outer rods.

Advantages:Outer rods are reusable;inner rod remains embedded.Reduces material waste and surface damage.