Wall Forms

Facade Wall Forms
Double Side Wall Forms
One Side Wall Forms
Climbing Forms
Jump Form System
Self-Climbing Form System

Double Side Wall Formwork

This method is the most common in wall formwork because it is possible to use the forms for other structural elements as they are modular forms. In this method, pipes and boxes are used as wales, which are connected to the forms by Medium or Long B- Clamps and to back of the pipes by J-clamps.
Two sides of wall forms are connected to each other by bolts to sustain the hydrostatic pressure of concrete and the bolts are anchored by nuts and washers in the back of the soldiers.
In impermeable walls, the watertight should be used to fill holes in the wall.

Structural design of wall formwork system

In formwork system, usually stress and deflection of all elements of forms are controlled separately to specify maximum allowable load.

Surface Plate

For wall formwork, usually 50 centimeters width modular forms are used and stiffeners
are welded on them with a distance of in 25 Cm of each other. Therefore, according to
the ratio of the length to the width(50/25=2), the surface plate between stiffeners acts
like a one-side slab.

Bending Stress Criteria

Section Modulus for 1 Cm Strip of Surface Plate
 

Moment of Inertia for 1 Cm Strip of Surface Plate

Allowable Bending Stress (St37,fy= 2400 kg / cm²)

 

Allowable Bending Moment of Surface Plate
Maximum Applied Bending Moment of Surface Plate

From Equation (a) and (b):

  Allowable load

Deflection Criteria

According to ACI code, maximum permissible deflection of the formwork is 3.6mm and the maximum deflection of the surface plate is as follows:

   (For the beam continuous more than two equally spaced supports)
So, Bending Criteria is governed and allowable load of each modular forms is about 4300 Kg/m2.

Wales

Considering the 50 Cm distance between two pipe-wales, one-meter span between two soldiers and equal load distribution:

Bending Stress Criteria

Deflection Criteria

If we use box (80x40x3mm) instead of pipe, and S=13.3 Cm3, I=53/1 Cm4 so:

Section Modulus and moment of inertia for double solider (Produced by Boozarjomehr Industrial group) is as follows:

Soldiers

Soldiers are supported by bolts in a distance of one meter. Pipe reactions on soldier are acted in a distance of 25 centimeters of bolt. The reaction of pipe is called P so:

Bending Stress Criteria

From Equation (a) and (b):

Deflection Criteria

Accordingly, deflection of the beam is as follows:

If Ð_max is equal to 3.2 mm then we have:

If the reaction of a pipe with a spam of 100 cm and a loading width of 50 cm is considered P, then the distributed load will be calculated as follow:

Bolts

Bolts are made from 16 mm bar and their applied load area is one square meter because they are used in 1x1 meter grid.

Cross Section of Bar Allowable tension stress of Bolt Allowable tension capacity of Bolt Allowable pressure on form

Summery of Allowable loads

Item	Description	Bending Criteria(ton/m2)	Deflection Criteria(ton/m2)
1 2.1 2.2 3 4	Surface Plate Pipe 50x2.5 mm Box 80 x40x3 mm Bolt Soldier	4.3 1.55 4.21 9.3 2.45*	6.43 2.44 10.53 29 -
*Criteria of Allowable tension stress

As you consider, bending criteria of pipe is less than other formwork elements and they can be allowable to used in concreting with short height or low speed concreting. If we use box (80x40x3mm) instead of pipe, bolt will govern the capacity, and forms can Sustain 2.45 ton/m2. If concrete pressure raise, it is possible to use bolt in a distance of 75 cm from each other so, the allowable pressure of bolt resistance will be: