Constructs Wall and Grade Beam Formwork

Chapter C2 – Constructs Wall and Grade Beam Formwork

Topic 1- Erect Grade Beam Formwork

Key Competencies

The NOA for Carpenter (2013) identifies the required competencies (skills) for the task of erecting grade beam formwork. These are:

1. Place sleepers and void forms under grade beams to allow for frost heave
2. Follow chalk line to determine placement of formwork
3. Determine formwork system according to concrete volume requirements, and system availability and capabilities
4. Erect forms to achieve required measurement according to determined formwork system
5. Assemble prefabricated forms according to manufacturers’ specifications or engineering drawings
6. Install keyways and control joints in wall forms
7. Place formwork and ensure components are plumb, level, straight, square, and accessible for concrete placement and finishing
8. Install window and door bucks, penetrations, water stops and bulkheads according to measurements and job specifications
9. Install form restraints such as snap ties, coil ties and taper ties according to manufacturers’ specifications
10. Install bracing such as turnbuckles, standards, strongbacks and kickers in order to support formwork in place and according to specifications
11. Install spreader bars, blocks or cleats at top of formwork in order to maintain required wall thickness
12. Inspect formwork components and installation to prevent blowouts and distortion
13. Determine finish elevation by using methods such as chamfer strips, brick ledge and grade nails (NOA, p. 37).

Grade beams may be included as part of the foundation to transfer load from bearing walls and may also be used for crawl spaces. Grade beams often rest on piles but can be supported by pads, piers, or footings. Rebar connects the grade beam to the piles and can be poured monolithically. Formwork for grade beams often rest on sleepers. Void form is placed under the grade beam to prevent soil pressure against the bottom of the beam.

FNDT 100 (p. 40 – 61):

• IS 2.2 Erecting Grade Beam Formwork

Review Questions

1. How are grade beams usually supported?
2. State two or more methods of supported grade beam formwork at the proper elevation.
3. Give at least two methods of providing a void underneath grade beams to allow for heaving and expansion of the soil.
4. How can treated plywood strips be fastened to the sides of a grade beam which will settle later?
5. What should be checked prior to aligning the forms?
6. How are the inside and outside forms aligned at the top and bottom?
7. How should keys in bulkheads be attached?
8. Why are wooden blockouts treated with form oil?
9. When should the layout of blockouts be checked?
10. What material should rough bucks be made from?
11. Rough bucks for window or door frames are made”

1. Slightly smaller than finished frame
2. Same size as finished frame
3. Slightly larger than finished frame

12. The minimum distance from the edge of a key to the face of the concrete wall is:

1. 38 mm
2. 50 mm
3. 75 mm
4. 100 mm

13. In residential construction, anchor bolts must be embedded a minimum of _____ mm.