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:
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.
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.
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.
O. Reg. 213/91
Part II GENERAL CONSTRUCTION
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.
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.
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.
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.
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.
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]