Complete reference for pin and wedge
Anatomy of Pin and Wedge Connection
A comprehensive guide to selecting, installing, and maintaining metal connections in modular concrete formwork systems; from theory to execution in construction sites.
Introduction: The Beating Heart of Formwork
In the modern construction industry, speed and accuracy are two key parameters. Modular metal formwork systems, to maintain their integrity under immense hydrostatic pressures of fresh concrete, require connections that are both quick to install and have high shear resistance. Pin & Wedge is recognized as the most economical and efficient connection method in Iran, replacing time-consuming bolt and nut methods.
Technical Analysis and Mechanism of Operation
The function of this component is based on the law of friction and inclined plane. The wedge (male part) has a gentle slope that, when placed inside the pin’s groove (female part) and struck, converts vertical force into a very large horizontal force.
- Creating tension in formwork straps
- Completely joining the two panel edges
- Preventing concrete leakage (Water-tightness)
This simple yet engineered mechanism ensures that the components do not loosen during concrete pouring vibrations (vibrating).
Why Pin and Wedge? (Comparison with Alternative Methods)
Advantages of Pin and Wedge
- Execution Speed: Installation with just one hammer blow (much faster than bolts and nuts).
- No need for special tools: Unlike bolts that require a wrench, a pin only needs a hammer.
- Resistance to concrete: Bolt threads get damaged in contact with concrete slurry, but the smooth surface of the pin is easily cleaned.
Disadvantages of Clamps
Although clamps are stronger connections, their price is about 5 to 10 times that of pin and wedge, and they have a heavier weight, which makes transportation difficult. Pin and wedge strike a golden balance between “economy” and “efficiency”.