Construction companies and contractors routinely use formwork when undertaking a building project. Formwork is a mold that can be temporary or permanent, depending on the specifications of the job at hand. It must be strong enough to bear the weight of the material poured into it, such as concrete. This framework requires a shoring and bracing support system to keep the wet material secure during the curing phase. Construction companies usually separate formwork according to the type of building materials used. However, dividing it into foundation or slab formwork, wall formwork, beam formwork, and column formwork is another classification method.
A building relies on all of its components working together to give it strength and durability over time. It all starts with the pouring of a slab. To create a stable base, a Slab Formwork System needs to firmly contain the wet material in a level position until the product has hardened and can support itself. A solid base is necessary for carrying the weight of any structure erected upon it.
Most contractors use concrete as the foundation material. Concrete can conform to any shape necessary while it is still wet and pliable. Carpenters build a complex mold, or formwork system, to contain the concrete when it is in a liquid state. This mold must be securely braced and able to withstand the weight of the concrete, reinforcing steel, and the temporary pressure from any workers and equipment standing on top of it. Concrete formwork happens in three stages: assembling and erecting the supportive frame, pouring the concrete, and dismantling the formwork afterward.
Wall formwork requires framing made from metal, wood, or another type of heavy-duty material. Since vertical walls are load-bearing, proper formwork construction is crucial to ensure straight or curved walls that can hold up to the pressure placed upon them. When building concrete walls, a grid pattern of vertical and horizontal steel bars inside the walls helps the concrete retain its shape and strength. Concrete walls are often chosen for earthquake-prone areas since they hold up better during an earthquake than walls constructed from other materials.
Beam formwork takes the shape of a three-sided box that encases a beam’s location. This box is then supported and propped in the proper position and set to the desired level. The beam’s mold must remain in place until the beam has cured. Drying time varies depending on weather, humidity, and air temperature.
Creating columns for a project requires careful measuring and planning. Formwork for a column must accommodate any curves or arches. A vertical mold for a column should also consist of the desired shape and size and may require steel or timber clamps for batch fillings. In some scenarios, the formwork of a column may tie into the beam formwork.
Summing Up Formwork
Timber, plywood, steel, and aluminum are materials used for creating the formwork of a building. Determining which type to use depends on the size of a structure and its overall design. As a project comes to life, the formwork plays an invaluable part in creating a secure, durable building and holds everything in place during the construction phase. Slab formwork can be temporary or permanent, like in a firewall.
Falsework and re-shoring must have sound and rigid footings capable of carrying the maximum load without settlement or deformation of the soil or structure below the footings. They must be protected to prevent damage from frost heave.
Re-shoring must be constructed according to a professional engineer’s design drawings.
If single post shores are arranged more than one tier high, each junction must be braced against a fixed support in at least two directions in order to prevent any lateral movement.
Formwork and falsework may be removed if the concrete can support itself and any loads or the concrete and structure are adequately re-shored.
Each design drawing by a professional engineer for the formwork, falsework, or re-shoring must:
Formwork, falsework and re-shoring must be designed, constructed, supported, and braced so that they can withstand all their likely loads and forces. They must be inspected, before placement, by a professional engineer or a competent worker designated in writing by a professional engineer. Design drawings must be on site while the formwork, falsework or re-shoring is in use. The person carrying out the inspection must confirm in writing that the system was constructed according to the design drawings and have all available test results.
To be done safely, each of these jobs requires planning, knowledge, and skill from both supervisors and workers. Design and planning are a supervisory function that may also legally require a professional engineer's involvement. Small construction and renovation jobs, however, sometimes call for design on site by workers.
Shoring and bracing support the forms that contain the wet concrete. Formwork must also support the temporary weight of material such as bundles of reinforcing steel and live loads of workers and equipment. There are three stages in formwork operations:
Construction Projects
O. Reg. 213/91
Part II GENERAL CONSTRUCTION
Section 87
87. (1) Formwork, falsework and re-shoring shall be designed, constructed, supported and braced so that they are capable of withstanding all loads and forces likely to be applied to them,
(a) without exceeding the allowable working loads established for any component of the structure; and
(b) without causing uplift, sliding, overturning or lateral displacement of the system.
(2) No formwork, falsework or re-shoring shall be loaded in excess of the load that it is designed and constructed to bear.
(3) The allowable working load of the formwork, falsework or re- shoring shall be established,
(a) by a professional engineer in accordance with good engineering practice; or
(b) by testing the principal components to their ultimate strength in a manner that simulates the actual loading conditions to which the formwork, falsework or re-shoring is likely to be subjected and by applying a reduction factor, in accordance with good engineering practice, to the values of ultimate strength.
(4) The results of the testing in clause (3)(b) shall be verified and certified by a professional engineer and made available to an inspector upon request.
(5) If single post shores are placed more than one tier high, the junction of each tier shall be braced against a fixed support in at least two directions in order to prevent any lateral movement.
Section 88
88. Formwork and falsework shall not be removed unless,
(a) the concrete is strong enough to support itself and any loads that may be applied to the structure; or
(b) the concrete and the structure are adequately re-shored.
Section 89
89. (1) This section applies with respect to formwork, falsework and re-shoring that includes,
(a) a tubular metal frame;
(b) a column whose effective length is dependent upon lateral restraints between the ends of the column;
(c) shores placed one upon another to form a supporting system that is more than one tier in height;
(d) shores which are three metres or more in height;
(e) a truss;
(f) members so connected to one another that a load applied to one member may alter or induce stress in another member; or
(g) a unitized modular formwork or falsework structure intended to be moved as a unit.
(2) Formwork and falsework shall be designed by a professional engineer in accordance with good engineering practice and be installed or erected in accordance with the design drawings.
(3) Formwork and falsework shall, before the placement of concrete, be inspected by a professional engineer or by a competent worker designated in writing by the professional engineer.
(4) The person carrying out the inspection shall state in writing whether the formwork and falsework is installed or erected in accordance with the design drawings for it.
(5) The constructor shall keep the design drawings and the statements on the project while the formwork or the falsework is in use.
Section 90
90. Re-shoring shall be designed by a professional engineer in accordance with good engineering practice and be erected in accordance with the design drawings.
Section 91
91. Falsework and re-shoring,
(a) shall have sound and rigid footings capable of carrying the maximum load to which the footings may be subjected without settlement or deformation of the soil or structure below the footings; and
(b) shall be adequately protected to prevent deformation caused by frost heave.
Section 92
92. (1) Design drawings by a professional engineer for the formwork, falsework or re-shoring,
(a) if a manufactured system is used, shall identify the components;
(b) if non-manufactured system components are used, shall show the size, grade and specifications of the non-manufactured system components;
(c) shall show the design loads for the structure and shall detail the bracing and external ties required to adequately support the design loads;
(d) if the structure is a unitized modular formwork or falsework structure intended to be lifted or moved as a unit, shall show the attachment points for rigging and hoisting; and
(e) shall set out the erection instructions that are specified by the manufacturer or by the professional engineer.
(f) Repealed. [O. Reg. 85/04, s. 11]
(2) The constructor shall keep the design drawings on the project while the formwork, falsework or re-shoring is in use.
[O. Reg. 85/04, s. 11]
Equipment, General