2120 Ch 10 PowerPoint

1. Building Construction Related to
the Fire Service
Fourth Edition
Chapter 10 — Concrete Construction

2. ‣ Identify material properties of
concrete.
Learning Objective 1

3. Concrete is the hardened form of
cement.

4. Aggregates are inert mineral ingredients that
reduce the amount of cement that would
otherwise be needed.

5. Admixtures can help tailor a batch of
concrete for specific functions.

6. Concrete structural elements usually
retain their integrity.

7. Concrete is widely used in fire-
resistive (Type I) construction.

8. Concrete is strong in compression
but weaker in tension.

9. Depending on the load the concrete will
support, reinforcements may be added.

10. Ordinary reinforcing uses steel bars placed in the
formwork, and wet concrete is placed around the
bars.

11. Concrete must be properly
compacted as it is placed in forms.

12. The actual tensile and compressive forces
developed within structural components are
complex.

13. Concrete beams are frequently cast in the shape
of a tee which permits support of a greater load.

14. Reinforced steel in concrete can be used to
support some of the compressive and bending
forces.
Courtesy
of
Ed
Prendergast

15. Compressive forces in a column can cause steel
reinforcing bars embedded in concrete to buckle.

16. Ordinary reinforcing is a fundamental and useful
construction method but it has inherent
limitations.

17. The technique of prestressing is a more efficient
use of concrete than ordinary reinforcing.

18. Reinforcing steel should not be cut during fire
fighting operations unless it is necessary to
rescue trapped victims.

19. CAUTION
‣ Post-tensioned reinforcing steel can
recoil with violent force and destroy
surrounding supports.

20. The prestressing process requires large loads to
be applied to the concrete along the axis of the
beam.

21. Pretensioned reinforcement concrete uses
steel strands stretched between anchors.

22. Posttensioned reinforcement concrete uses steel
cables that are not tensioned until after the
concrete has hardened.
Courtesy
of
McKinney
(TX)
FD

23. Prestressed concrete systems may be more
vulnerable to failure than ordinary reinforced
concrete.

24. ‣ Differentiate between precast and cast-
in-place concrete.
Learning Objective 2

25. Concrete can be precast or cast-in-
place.

26. Concrete can be precast or cast-in-
place.

27. Both cast-in-place and precast concrete buildings
can achieve required fire-resistance ratings.
Courtesy
of
McKinney
(TX)
FD

28. Regardless of where the concrete is cast,
concrete in almost all structural applications is
reinforced with steel.
Courtesy
of
McKinney
(TX)
FD

29. ‣ Determine factors that affect the
finished quality of concrete.
Learning Objective 3

30. Great care must be exercised in mixing, placing,
and curing of concrete to ensure good quality.

31. The quality of concrete must be tested to ensure
the suitability of the mixture for the purpose.

32. Water reacts with the cement
powder in the hydration process.

33. Hardening of concrete involves a
chemical process known as hydration.

34. Concrete in the process of curing must be
maintained at the correct temperature.

35. The slump test uses a standard-sized cone-
shaped mold and a sample of wet concrete to
check the moisture content.

36. Compression testing uses small test cylinders of
a concrete batch to determine the compression
strength.

37. ‣ Recognize factors that influence fire
resistance in concrete construction.
Learning Objective 4

38. Concrete structural systems can have fire-
resistance ratings from one to four hours.

39. NOTE
‣ Although the steel used in reinforced
concrete is not fire-resistive, the
concrete surrounding the steel acts as
insulation to protect it from the heat of
the fire.

40. Some types of concrete are better
insulators than others.

41. NOTE
‣ Structural lightweight concrete is not
used for load-bearing applications.

42. The fire resistance of concrete assemblies
can be compromised in a variety of ways.
Courtesy
of
Dave
Coombs

43. An explosion may compromise the fire
resistance of a concrete assembly.
FEMA
News
Photo

44. The primary cause of spalling is the expansion of
moisture within concrete when heated or frozen.
Courtesy
of
Ed
Prendergast

45. Concrete tends to retain the heat of an exposing
fire and release it slowly — referred to as the
heat sink effect.

46. ‣ Describe types of concrete framing
systems.
Learning Objective 5

47. Large cast-in-place structures cannot
be cast in one operation.

48. A flat-slab concrete frame is a simple system that
consists of a concrete slab with concrete columns
for support.

49. The flat-slab concrete frame is a simple system
that consists of a concrete slab with concrete
columns for support.

50. Slab and beam framing consists of a
concrete slab supported by concrete beams.

51. Slab and beam framing consists of a
concrete slab supported by concrete beams.

52. Slab and beam systems are often highly
susceptible to fire damage because of the
thinness of the slab.

53. Two-way slab construction features
concrete beams running in two directions.

54. Structural steel beams can replace concrete
beams to support a poured concrete slab.

55. Precast concrete may be produced at a
precasting plant some distance from the work
site.
Courtesy
of
McKinney
(TX)
FD

56. There are advantages to using
precast concrete.

57. There are advantages to using
precast concrete.
Courtesy
of
Gregory
Havel,
Burlington,
WI.

58. A major disadvantage to using precast concrete
is the need to transport finished components to
the job site.

59. Precast concrete buildings can be built
using whole precast modular units.

60. NOTE
‣ Precasting concrete became a common
practice after World War II.

61. Precast concrete slabs for floor systems
can be cast in standard shapes.

62. In tilt-up construction, reinforced wall panels are
cast at the job site in horizontal casting beds.
Courtesy
of
McKinney
(TX)
FD

63. In tilt-up construction, reinforced wall panels are
cast at the job site in horizontal casting beds.
Courtesy
of
McKinney
(TX)
FD

64. In precast concrete structures, connections
between individual components is a critical
aspect.

65. In precast concrete structures, connections
between individual components is a critical
aspect.
Courtesy
of
McKinney
(TX)
FD

66. In precast concrete structures, connections
between individual components is a critical
aspect.