The document serves as a guide to concrete formwork, detailing its definition, types, and structural support roles. It distinguishes between formwork and falsework, clarifying their functions in retaining and supporting concrete during the curing process. Key considerations include design, materials, and successful conformance to project specifications.

1. CONCRETE FORMWORK
CONCRETEDavid H. Glabe, P.E.
Presented by
FORMWORK
© 2012, DH Glabe & Associates, Westminster, CO 80031 All Rights Reserved

2. Guide to Formwork for Concrete
ACI 347R-03
• Chapter 1 – Introduction
• Chapter 2 – Design
• Chapter 3 – Construction
• Chapter 4 – Materials

3. FORMWORK
• ACI 347, Chapter 1, Section 1.2
Formwork – total system of support for freshly placed concrete, including the
mold or sheathing that contacts the concrete and all supporting members,
hardware, and necessary bracing.
• CDOT, Section 601.11
Falsework is defined as any temporary construction used to support vertical
loads for a structure until it becomes self-supporting. Formwork is the
temporary structure or mold used to retain plastic or fluid concrete in its
designated shape until it hardens.

4. Formwork or Falsework??

5. Formwork v. Falsework
• ACI - Formwork includes Falsework
• CDOT – Formwork and Falsework are
separate
• Formwork is the “Jello” Mold that holds
fresh concrete
• Falsework supports formwork and other
structures (such as precast girders)

6. Formwork – the “Jello Mold”
There are two types of Formwork:
1. Vertical Forms
2. Horizontal Forms
Vertical Forms are used to hold pressure
Horizontal Forms are used to hold weight

7. Vertical Forms
Vertical Forms are used to form:
 Walls
 Columns
 Piers
 Abutments
 Beamsides
 Other Vertical Concrete Surfaces

8. Vertical Form: Wall Form

9. Vertical Form: Shear Wall

10. Vertical Form: Retaining Wall

11. Vertical Form: Sidewall/Abutment

12. Horizontal Forms
• Horizontal Forms are used to form:
Bridge Decks
Floors
Overhangs
Other Horizontal Concrete Elements

13. Horizontal Form: Metal Bridge Deck

14. Horizontal Form: Bridge Overhang

15. Horizontal Form: Bridge Overhang
(Cantilevered Beams)

16. Formwork or Falsework?

17. Pressure or Weight?

18. Pressure
• Vertical Forms are designed to resist
pressure. Form Pressure is affected by:
The Concrete Mix
The Rate of Placement
The Temperature of the Concrete
The Weight of the Concrete

19. Weight
• Horizontal Forms are designed to hold the
weight of the concrete. The design weight
is determined by:
The Depth of the Concrete
The Unit Weight of Concrete
The Amount of Reinforcing

20. Concrete Structures
The Quality of the finished product is
determined by:
Materials
Design
Construction
Placement of the Concrete

21. Manufactured Forms
What is the Pressure Capacity?

22. Job-Built Forms
Is it designed according to specification?
Is it constructed according to the design?

23. Does it meet Project Specifications?

24. Success?
Success is measured by how well the Jello
Mold conforms to the owner’s expectations.
Is it the right shape?
Are the length, height and width correct?
Is it within tolerance?
Is it in the right location?

25. The Perfect Wall??
Bad Joint
Blemish

26. What do you think?

27. Is the concrete being placed properly?

28. Falsework
Falsework is used to support fresh concrete
and the Jello Mold it is in. Falsework is
also used to support other structures such
as precast girders, steel girders, and
existing bridges.

29. Falsework Supporting Pier Cap Formwork

30. Falsework Supporting Precast Concrete Girders

31. Formwork-the “jello”
mold
 Wall forms hold pressure.
 Deck Forms hold weight.
 Falsework holds formwork.
 Watch your tolerances.
 What are their qualifications?
 What are your qualifications?