FORM MATERIALS
Book Overview
We finished Chapt. 1 & 2
and we are reviewing Chapt. 3 & 4!!!
Chapter One- Introduction to Forming
Chapter Two- General Objectives in
Formwork Building
Chapter Three-Overall Planning for
Formwork
Chapter Four-Materials, Accessories,
Proprietary Products
What are the objectives of any form design?
The form design must provide,
THE BEST QUALITY
SAFETY
ECONOMICS
(PLANNING & COST)
What types of forms are used in formwork?
1. Prefab Forms
2. Pans and Domes for concrete joist
3.Void and Duct Forms
4.Column Forms
5. Stay-in-place forms
What types of shoring is used in formwork?
1.Shoring Scaffolding
2.Vertical Shores
3.Scaffold-Type Shoring
4.Horizontal Shoring
What materials and accessories are used
in formwork?
1. Lumber
2. Steel
3.Aluminum
4. Glass-Fiber-Reinforced Plastics(4-16)
5.Fabric Forms(4-18)
6. Form Lining Materials(4-20)
7.Fasteners (4-25 to 4-33)
8. Ties(4-34)
9.Anchors(4-36)
10 Hangers(4-37)
11. Jacks(4-37)
12. Spreaders & Spacers(for rebars) 4-38
13. Steel Strapping & Column Clamps
(4-39&40)
14. Prefab Forms (4-41) video
15. Pans and Domes (4-45)
1. Lumber (overview)
•Choice of lumber is affected by the
availability and cost
•Lumber is required to be straight, structurally
sound, and partially seasoned (19-25%)
Note: Do not use old lumber with new. If
lumber is too dry it will swell under moist
conditons, and if too moist it will shrink in dry
conditions.
•Commonly used lumber is the DF-L, DF-S,
Spruce-Pine Fir, and Hem-Fir
•Dressed lumber is used for formwork, and
the rough sawn boards are used in bracing and
shoring.
(formwork used here means the members that
are used to shape the concrete)
1. cont. Lumber (overview)
•Dressed lumber is surfaced lumber
(i.e. S1SE,S1S2E,S4S,etc)
Refer to P. 4-4 for wood properties
also P.4-6 for wood stresses, note there
is no Ft (tension parallel to the grain)
•Note adjustment factors as noted on
P. 4-6 & 4-7.
No size adjustment is required for
construction and standard grade lumber
• Engineered Wood Products are becoming
more common due to dwindling supplies
of sawn lumber and in many cases can
give us better strength characteristics.
(i.e. glulam, LVL, etc.)
1. cont. Lumber(Plywood/Sheathing)
•Plywood is common in most systems as
sheathing
•Sheathing is used in direct contact with
concrete. It is primarily : plywood, steel,
aluminum, etc.
It does not include liner panels or other
surfacing directly contacting concrete
Why do we need to protect plywood?
•Concrete has water
•Concrete is an alkaline
•Concrete has abrasive constituents
•Concrete is heavy & a fluid
1. cont. Lumber(Plywood/Sheathing)
How do we protect plywood?
•We bond interior with water-resistant
glue and exterior with water-proof glue
•exterior plywood is required for reuse
What is overlaid plywood?
•Overlaid plywood is exterior plywood
with additional resin-impregnated fiber
faces permanently fused under heat and
pressure
It is either High Density Overlaid
(HDO) or Medium Density Overlaid
(MDO)
Overlays provide high strength, light
wt., dimensional stability, rock
resistance
What is overlaid plywood?
•High Density Overlaid (HDO) P. 4-12
Overlays provide high strength, light wt.,
dimensional stability, rock resistance, hard
and smooth
•Resin Overlay- add ability to
•Withstand severe exposure w/o
further finishing
•Resists abrasion
•Prevent water penetration
•Prevent deterioration from chemicals
&solvents
•Overlay thickness -.012 w/60#per
1000sf of panel surface
•Ply Bonding - 100% water proof glue
•Construction- Inner plies: C or C
plugged and face is B or better
•Maximum reuse (200 pours)
What is overlaid plywood? (cont)
•Medium Density Overlaid (MDO) P. 4-12
Sanded two sides, oiled at will
•Needs good quality edge sealer before
1st pour (10 to 20 reuses)
•Not recommended for forms but can be
used.
•Recommended use of a release agent
•Other overlays
•glass-fiber-reinforced plastic
•formica
•epoxy resin
•Non Overlaid Plywood
•Classification for veneer is A-D
•Classification for Panel Strength is
Group 1 to 5(i.e DF-L is Strongest and
in group#1)
2.& 3. Steel/Aluminum
Pretty much used the same way as wood
but allows for greater spans or heavier
loads
(i.e. channels,angles, I-beams, etc.)
Aluminum is lighter weight and can
produce forming units larger than other
materials can manage.(i.e can be 50%
wider than plywood, and have the same
weight)
For section 4-15 on the slide see video and
follow textbook.
*4. Glass-Fiber-Reinforced Plastics(fig.4-53)
*5.Fabric Forms(fig. 4-15)
*6. Form Lining Materials(fig 4-17)
7.Fasteners (4-25 to 4-33)
*8. Ties(4-34)
9.Anchors(4-36)
10 Hangers(4-37)
*11. Jacks(fig 4-35)
*12. Spreaders & Spacers(for rebars) 4-38
13. Steel Strapping & Column Clamps
(4-39&40)
14. Prefab Forms (4-41)
15. Pans and Domes (4-45)