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Trang 1Construction methods and management
Chapter 9
Concrete reinforcing steel
Trang 2©2010 by Do Thi Xuan Lan , M.E 2
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Chapter 9 Concrete
reinforcing steel
9.1 Classification of reinforcing steel9.2 Placement of reinforcing steel
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Concrete reinforcing steel
• Concrete is a brittle material, with low
tensile strength and strain capacities;
→reinforcement has to be used to
balance this deficiency
• Main bar reinforcement is used in tensile zones to enhance the capacity of
concrete elements
4
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CLASSIFICATION OF
REINFORCING STEEL
Chapter 9 Concrete reinforcing steel
5
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Classification of reinforcing steel
By diameters By cross section
shape By grades
By manufacturing procedure
By function
Classification of reinforcing steel
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• By grades: CI, CII, CIII
• By manufacturing procedure: hot-rolled
steel and cold-rolled steel
• By function: working reinforcement,
distribution reinforcement, erection
reinforcement
7
Deformed reinforcement
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≥10
< 10 mm,
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Requirements
Steel before and after cutting and
bending be placed under cover
and be raised from the ground
9
Source: HCMCUT student
The reinforcement tensile capacity must be tested
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PLACEMENT OF REINFORCING STEEL
Chapter 9 Concrete reinforcing steel
10
Nguồn: sinh viên TTTN - ĐHBK
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• Cleaning of contact surface and
removing rust: provide sufficient bond
between reinforcing steel and surrounding concrete
• Cutting: to prescribed lengths
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Prefabrication of reinforcement
Source: HCMCUT student
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Prefabrication of reinforcement
• Bending: using bending machines or
operating manually
13
Source: HCMCUT student
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Prefabrication of
reinforcement
• Splicing: welded splices, mechanical
splices (coupling) and lap splices
– Lengths of lap splices are established
by the structural designer according
to code requirement
14
Trang 15©2010 by Do Thi Xuan Lan , M.E 15
Nguồn:http://image.made-in-china.com/2f0j00ietEfFpGoUrQ/Rebar-Coupler.jpg Source: HCMCUT student lap splices
mechanical splices (coupling)
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Erection of reinforcement
• Reinforcement should be placed only
after forms have been inspected and
accepted
16
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Erection of reinforcement
• Sufficient cover must be provided to
protect the reinforcing steel from the
environment
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spacer
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Erection of reinforcement
• Proper spacing must be provided
between the bars to ensure that
concrete flows around the bars and
develops the necessary bond ssive with the bars
• The vertical distances required between layers of bars maintained by reinforcing steel supports
18
Source: HCMCUT student
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Source: Nunnally 2007
Source: HCMCUT student
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Source: HCMCUT student
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Wall reinforcement
22
Source: HCMCUT student
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Wall reinforcement
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Source: HCMCUT student
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Wall reinforcementt
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Source: HCMCUT student
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Source: HCMCUT student
reinforcing
steel frame
for wall
being lifted
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Beam reinforcement
26
Source: HCMCUT student
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Beam reinforcement
27
Source: HCMCUT student
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Beam reinforcement
28
Source: HCMCUT student
Note the concentration
of steel in the top of
the beam above/under
the column
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Nguồn:http://www.concrete-accessory.com/products/images/rebar-cap-with-steel-plate.jpg Nguồn:http://centerpointdi.com/Photos/SCPC/Rebar%20Caps.JPG
Rebar cap
Trang 30Rebar coupler
Trang 31©2010 by Do Thi Xuan Lan , M.E
Cutting machines
31
Nguồn:http://www.supplierlist.com/photo_images/121810/ Rebar_Cutting_Machine.jpg
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Bending machines
32
Source :http://www.chinarebartool.com/smallpic/2008012807219799.jpg
Spurce: :http://www.fascut.com/images/FR800.4.jpg
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