Section 5
Reinforced Concrete
5.1 Basics of Reinforced Concrete 1
PCA Video, VC114 ’88 Mod ‘07: Fundamentals 3 of Reinforcing and Prestressed Concrete
Structural Engineering Concepts 4
Reinforcement Inspection 10
CRSI Video, Mod ‘08: Field Inspection of 11 Reinforcing Bars
WCI Video: Jobsite Handling of Epoxy Coated 21 Rebar
CRSI: MSP Chp. 8, Placing Reinforcing Bars 22
Bar Supports 24
Bar Ties 27
Clearances 29
Splices 37
Reinforced Concrete Section 5.1
Concrete Cracks
Basics of Reinforced Concrete
• Concrete is strong in compression and weak in tension.
Compression Tension • Tensile capacity is approximately 10% of the compressive strength of concrete.
January, 2020 1 Reinforced Concrete Section 5.1
Beam Exercise
Basics of Reinforced Concrete Cont’d:
• Steel reinforcement is strong in tension. • Reinforcement is added to carry tensile loads in concrete members. • Temperature reinforcement is added to carry tensile loads due to thermal expansion of concrete members.
January, 2020 2 Reinforced Concrete Section 5.1
Why Use Rebar? Simply supported beam example
Applied Load
View PCA Video
Fundamentals of Reinforcing and Prestressed Concrete
(PCA VC114 ’88 Mod ‘07)
January, 2020 3 Reinforced Concrete Section 5.1
Structural Engineering Concepts
Shear & Moment Diagram Uniformly Loaded Simple Beam
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Maximum Shear Load at Bridge Ends and Piers
Larger Stirrup Spacing @ Midspan
Tighter Stirrup Spacing Near Abutments
Tighter Stirrup Spacing at Beam Ends
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Shear & Moment Diagram Uniformly Loaded Continuous 3 Span
Uniformly Loaded Continuous Beam 3 Spans
Maximum negative moment in deck over piers.
Additional longitudinal reinforcement added in top mat.
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Beam Capacity
Strength of the Beam
Beam Cross-section Beam Side View
M = Astfy(d-1/2a) = 0.85fc′ab(d-1/2a)
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Case Study I-25: Walnut Street Denver, CO
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Thoughts?
Deck To Be Placed Later
Construction Joint
I-25: Walnut Street Pier Collapse
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Pier Collapse
I-25: Walnut Street, Denver, CO Oct. 4, 1985 Fatalities: 1 Injuries: 4
Reinforcement Inspection
January, 2020 10 Reinforced Concrete Section 5.1
View CRSI Video
CRSI Field Insp Reinf Bars Mod 08
Type of Reinforcement
• Source • Certifications • Grade • Epoxy coated or uncoated or stainless
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Documentation
Bills of material – what was delivered
Certifications
Rebar (steel) mill certificate
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January, 2020 13 Reinforced Concrete Section 5.1
English Rebar Numbers
• #3 - #8; Diameter in 1/8″ units #8/8 = 1″ dia.
• #9 - #18; Based on area of square bars formerly used with sides of 1″, 1-1/8″, 1-1/4″, 1-1/2″ & 2″ and then rounded to closest 1/8″ unit diameter.
Metric to English Bar Conversion
• (Bar # - 1) divided by 3 then round to nearest english bar #
• #25 metric = (25-1)/3 = #8 english
January, 2020 14
Reinforced Concrete Section 5.1
QPL Appendix A http://www.oregon.gov/ODOT/HWY/CONSTRUCTION/QPL/Docs/QPL.pdf
Rebar Exercise
Mill: Size: Dia: Type: Grade:
January, 2020 15 Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 1 Appendix A—Approved Reinforcing Steel Producers
The ASTM specifications for billet-steel and low-alloy reinforcing bars (A615 and A706, respectively) require identification marks to be rolled into the surface of one side of the bar to denote the producer’s mill designation, bar size, type of steel and minimum yield designation. Grade 420 bars show these marks in the following order:
1st ---Producing Mill (usually a letter)
2nd --- Bar Size Number (# 4 through # 18)
3rd --- Type of Steel: S Billet (A 615) W for Low Alloy ( A 706)
4th ---Minimum Yield Designation
The minimum yield designation for Grade 420 bars is either one (1) single, longitudinal line (grade line) or the number 4 (grade mark).
A grade line is smaller and is located between the two main ribs, which are on opposite sides of all bars made in the United States. A grade line must be continued through at least 5 deformation spaces, and it may be placed on the side of the bar opposite the bar marks. A grade mark is the fourth mark on the bar.
VARIATIONS: Bar identification marks may also be oriented to read horizontally (90° to those illustrated). Grade numbers may be placed within consecutive deformation spaces to read vertically or horizontally.
The Identification marks for the Approved Producers are shown in the following figures. Rebar grades shown on these pages are for reference only. Check the specs for the appropriate requirements.
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 2 ArcelorMittal Vinton, Inc. El Paso Texas ODOT # 1841
Nucor Steel Utah ODOT # 1112
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 3
CMC Steel Mesa Arizona ODOT #4118
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 4
Nucor Steel Seattle Washington ODOT # 2935
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 5
Optimus Beaumont Texas ODOT #4838 Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 6
CMC Steel California ODOT #1842 Was Gerdau @ Rancho Cucamonga California
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 7
CMC Steel California ODOT #1842 Was Gerdau @ Rancho Cucamonga California
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 8
Gerdau St. Paul Minnesota ODOT # 1623
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 9
Cascade Steel Mc- Minnville Oregon ODOT # 1111
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 10
A706/A615 GRADE 60 REBARS MARKINGS Rebar sizes: #3 thru #6 NUCOR STEEL – KINGMAN, AZ ODOT #4356
Current SI Marking New IN-LBS
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 11
EVRAZ INC, NA PUEBLO, COLORADO ODOT #1621 (COILED REBAR #3-#6)
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 12
NUCOR-BAURBONNAIS (KANKAKEE) ODOT #4943 (BAR SIZE #3-#11)
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 13
CMC STEEL-DURANT OKLAHOMA #4-#11 STRAIGHT #3-#6 COILED ODOT #5138
Oregon DOT – QPL (July 2019) Oregon DOT – QPL (July 2019) Attachment “A” Approved Rebar Producers (English Units) Page A 14 ASTM A1035 CS (AAHSTO M334)
ChrǀmX 9100 SIZE #3-#8 PRODUCED BY: CASCADE STEEL ROLLING MILLS, INC. ODOT #3517
Oregon DOT – QPL (July 2019) Reinforced Concrete Section 5.1
Rebar Exercise
Mill: Size: Dia: Type: Grade:
Size & Shape
• Bar size • Bar length • Bar shape (correct radius) • Agrees with shop drawings
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REBAR MATERIAL TAG AB A. Quantity B. Size C C. Bend diagram D. Project D E. Bar ID or mark
→ Verify E
Doubled Up Horizontal Bars in Abutment?
January, 2020 17 Reinforced Concrete Section 5.1
Hooked Bar in Middle of Deck by Itself?
Rebar Condition
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Condition
• Look for any loose scale or rust, grease, oil, paint, or other foreign material that could harm the bond with the concrete. • Properly stored off the ground to avoid water and mud which can cause corrosion. • Do not use cracked or split bars (look at bends). • Look for epoxy damage.
Field Bent Bars?
January, 2020 19 Reinforced Concrete Section 5.1
Epoxy Damage
Rebar Jobsite Storage Total exposure time of epoxy-coated bar in storage or in place is not to exceed 2 months without covering. (530.40)
Epoxy breaks down under prolonged UV exposure – it gets chalky
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Faded Epoxy & Bare Ties?
View WCI Video
Jobsite Handling Epoxy Coated Rebar
January, 2020 21 Reinforced Concrete Section 5.1
Layout
• Number
• Spacing
• Alignment
Placement Tolerances according to “Manual of Standard Practice” 530.41
January, 2020 22
Reinforced Concrete Section 5.1
Effective Depth “d”
Distance from the compression face of the beam to the centroid of the reinforcement
Transverse Bar Alignment Shift?
January, 2020 23
Reinforced Concrete Section 5.1
Longitudinal Bar Alignment Shift?
Bar Supports
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Rail Stirrup Height Uneven?
Transverse Deck Bars Drop at Corner?
January, 2020 25 Reinforced Concrete Section 5.1
Bar Supports 00530.41(b) & (c)
2′ Centers (plans) Concrete blocks (Dobies) or other approved devices No rocks, broken brick, or wood
Bar Supports Plans, General Notes
Support the bottom mat reinforcing steel from the forms with precast mortar blocks at 24” max. centers each way. Support the top mat reinforcing steel from the bottom mat reinforcing steel with wire bar supports as shown in Chapter 3 of the CRSI Manual of Standard Practice (SBU, BBU or CHCU). Place wire bar supports at 24” max. centers.
January, 2020 26 14871 Contract Plans
195/468 Reinforced Concrete Section 5.1
Large Support Spacing Caused Epoxy Ties to Unzip
Ties
January, 2020 27 Reinforced Concrete Section 5.1
Top mat of Ties footings & 00530.41(b) decks: Tie 100% Epoxy coated ties for epoxy rebar If spacing < 6″ Tie 50%
Other locations: Tie 100% If spacing < 1′ Tie 50%
No Ties for Up to 10 Feet?
January, 2020 28 Reinforced Concrete Section 5.1
Missing Ties
Clearances
January, 2020 29 Reinforced Concrete Section 5.1
Concrete Cover Affects Rebar Corrosion
Concrete cover
Clearances • Within tolerances recommended in CRSI’s Manual of Standard Practice, Chapter 8 unless otherwise specified. (00530.41) • As specified on the plans. • Tolerance on top mat of reinforcement to the top of deck surface is (+/-) 1/4″. (00540.48(g))
January, 2020 30 Reinforced Concrete Section 5.1
Hooked Bar Laying on Form?
Transverse Bar on Chamfer Strip?
January, 2020 31 Reinforced Concrete Section 5.1
Transverse Deck Bar Under Drip Strip?
Transverse Bar Touching Fillet Form?
January, 2020 32 Reinforced Concrete Section 5.1
¾″ Clearance Under Deck Rebar Over Slabs?
Bottom Transverse Bars in Pilecap Touching Forms?
January, 2020 33 Reinforced Concrete Section 5.1
Bar Touching Form in Crossbeam?
High Stirrup in Crossbeam?
January, 2020 34 Reinforced Concrete Section 5.1
Watch Clearances on Rail Windows
½″ Clearance on Vertical Rail Bars to Window Form
January, 2020 35 Reinforced Concrete Section 5.1
How far are rail stirrups from the deck side form?
Clearance Exercise
Calculate the distance from the rail stirrups to the deck side form for standard F Rail.
______
January, 2020 36 Scoring joint, Scoring joint, 2-#4 Bars "Z" x panel length, 2" cl. required in all panels see bridge plans see bridge plans adjacent to ends and all joints except scoring joints. for location. Place for location. Place 1 1 1 1 Double tie to bars "A", "b" and #4 longitudinal bars 7 2" 7 2" 7 2" 7 2" 2"cl. at equal spaces 1 at equal spaces Type "B" Joint, for 12" each end. Bend as shown for 12" lap splice. 1 3 typ. " x " Type 'B' Joint with 4" Preformed 15'-0" max. between 2 4 15'-0" max. between Add 4 extra Bar "a" place at � interior C Place inside rebar cage and tie to back bars. Expansion Joint Filler. Place at � all other joints. scoring all all other joints. (or "A") front and back bents with B A faces above interior bents with continuous deck. A face plus 4 extra Bar "b" continuous deck Detail "C" Detail "A" top of deck Detail "B" Detail "A" each side of open or exp. joints and at rail ends.
Bars "a"
Finish Finish Bars "b" Grade Grade PLAN: BARS AT OPEN 2 extra Bars "A" and 2 extra Bars "a" and "b" at each side of 4 extra Bars "a" and OR EXPANSION JOINTS C 1" dia. hole through "b" at each side of #3 bolster "U" bar scoring joints, typ. A B "b" at each side of A barrier @ 10'-0" for scoring joints, typ. open or exp. joints AND RAIL ENDS anchorage connectors and at rail ends ELEVATION: CONCRETE BRIDGE RAIL (Slip Formed) ELEVATION: CONCRETE BRIDGE RAIL (Fixed Forms) 0.545 ft C.G. 1 3- 2" dia. x 1" long 1'-4" Roadway Width Csk galv. bolts A307 NOTE .
l 1'-0" 1 into resin-bonded Details shown are general details only and should be c 4 2" 1 1 7 " 1 1 4" 7 2" 4 8" 7
2 4 " " 2 " 1
1 anchors (front side modified as needed to fit specific project requirements. 4 4
1 1 3 0 of rail only) #4 Bar "A" @ 7 2" 2 8" 2
" " 4 - Provide 1" dia. hole 1
3 3 #3 BOLSTER #4 Bar "a" @ 7 2" 6 p. *** .ty 0 Max. Joint 3" 4" through barrier 1 "cl 3 12 "U" BAR 4" R. "
" 3
5 8" Steel Back @ 10'-0" for 4
Opening + 1"
- 1" dia. hole
' " n Cover Plate. anchorage connectors #3 bolster "U" bar @ 2
± through barrier 0 g
" 1
" 1 d
2 30" max. ctrs. and 1 2"cl. . @ 10'-0" for
2 - "J" 7-#4 Bars "C".
1 ' "J" = Joint Opening
0 typ. 1 D D "
1 each side of joints. 0 at mean temp. See Stop 2" clear at all anchorage connectors 6-#4 longit. bars. 0 2
1 1 1 r Project Plans. joints and rail ends. **2-#4 Bars "E" 4 " 4 2" Stop 2" clear at all
2 - b 7 '
3 " #4 Bar "a" "N" " Csk Screw joints and rail ends 1 4 5 8 " " Spanned distance #4 BAR "A" - @ 15" - ' 0 ' "
**2-#4 Bars "C" 2 10" R.
1 3 @ Mean Temp. 2 5 4 See Elevation for extra bars
" . * l 3 1 Traffic . 1 "J"+ " c at joints and rail ends. 4 2" 3" cl. 2 n " 4" 4" " 3 i **2-#4 " 2 6 4" " . 7 Direction 1 l m 1 1 s 1 c 1 e 3- " dia. . Finish Grade
2 Max. Joint " 8" 1 i * p 2 #4 Bar "b" @ 7 2" r 1 1 y Opening + 2" 3 a x 1 2" long t " Steel Front Cover Plate 1 8 V " cap screws into * 1 8" 4 2" 3 resin bonded * SECTION D-D #4 Bar "b" anchors (backside TYPICAL SECTION (Slip Formed) 1 @ 7 2" *** . of rail only) See TYPICAL SECTION (Fixed Forms) l Roughen construction joint EXPANSION JOINT COVER PLATE c "
and Elevation for details not shown, 2 3" 3 (When Required by Bridge Plans) 1 4" V-Groove
"Z" bars not shown for clarity. 1
1 " deep Expansion Joint or 12 GENERAL NOTES TYPICAL SECTION (Fixed Forms) ) 1 jt. (typ. " to 1" Open Joint scored 2 Rail designed and crashed tested to meet NCHRP 350 TL-4 requirements.
" (see Bridge Plans for 2 1 " ESTIMATED QUANTITIES Provide all reinforcing steel conforming to ASTM A706 or AASHTO M31 1 4 Exp. Joint width) 1 2'-8" Ht. 1" added Ht. (ASTM A615) Grade 60. Place all bars 2" clear of the nearest face of concrete unless shown otherwise. Concrete 2.23 ft.³/ft. 0.11 ft.³/ft. 1 3 1" radius 1" radius Provide Class 3300 - 1 2 or 4 concrete. 10.81 #/ft. (typ.) (typ.) Fixed Forms Bars "a" & longit. Provide steel cover plates conforming to AASHTO M183 (ASTM A36). Detail "C" Slip Forms Bars "A, C & E" 14.83 #/ft. Hot dip galvanize after fabrication. Section A-A Detail "A" At skewed bents up to 20° make joints parallel to the bent center line. Bar weight assume joints at 15'-0" ctrs. SCORING JOINT DETAIL OPEN OR EXPANSION JOINT DETAIL For skews greater than 20° make joints normal to rail.
(Slip-Formed) Accompanied by dwg. BR203
(Fixed Forms) . CALC. BOOK NO. BASELINE REPORT DATE 01-JULY-2016 ) d r e e
l 1"X3"X10"± polyfoam l m i NOTE: All material and workmanship shall be in accordance with r
F compression joint sealer NOTES
o the current Oregon Standard Specifications
f . e 1 t (Evazote or approved equal) * Place top of parapet 2'-8" above J r
1 2" deep scored 1 P The selection and use of this n 4" Preformed finish grade. Increase dimensions . "
joint (typ.), see o 3 1 OREGON STANDARD DRAWINGS 4 n i
i " wide x 1 " deep 1 1 Expansion Joint Filler 4 2 marked thus (*) by depth of ACWS. s
" Standard Drawing, while de- 1 2" (
Section A-A. n 8 m " 3 poured joint filler a
Appy Detail "C". deep 2 4" ** Continuous thru scoring joints, stop signed in accordance with p -
' 3 CONCRETE scored x 4" preformed 2" clear at ends and all other joints. 2 E " generally accepted engineer- " 2 BRIDGE RAIL 1 6 joint expansion joint filler B See dwg. BR203 for rail on end panel. ing principles and practices, " R TYPE "F" 3
2 *** See PLAN: BARS AT OPEN OR is the sole responsibility of Use when water drains towards rail 0 11 " EXPANSION JOINTS AND RAIL ENDS. Section C-C Section B-B 16 and no deck joint seal is used. the user and should not be 0 2018 Detail "B" Use joint fillers for length of used without consulting a DATE REVISION DESCRIPTION joint opening "J"+6". TYPE "B" JOINT DETAIL TYPE 'B' JOINT DETAIL Registered Professional En- (Slip-Formed) (Fixed Forms) DETAIL "D" gineer.
Effective Date: December 1, 2018 - May 31, 2019 BR200
Reinforced Concrete Section 5.1
Splices
No Splice?
January, 2020 37 Reinforced Concrete Section 5.1
Splices
• As permitted per plans • Splice bars No. 11 & smaller by Lapping or Approved Mechanical Splice. • Splice bars No. 14 and larger with an Approved Mechanical Splice Only. • Welded only with prior approval and with a certified welder.
Lap Splice 00530.42(b) • Place bars in contact. • Fasten with 3 ties/splice minimum. • Length as shown (General Notes). • Epoxy coated reinforcement requires longer splice length.
January, 2020 38 Reinforced Concrete Section 5.1
1 Tie on Splice?
January, 2020 39 Reinforced Concrete Section 5.1
1 Tie on Splice?
Mechanical Splice 00530.42(c) • Construct per Specifications and Manufacturers Recommendations. • Construct test splices in the presence of the Engineer. • Install splices in the presence of the Engineer. Splices made without the Engineer present will be rejected.
January, 2020 40 Reinforced Concrete Section 5.1
Mechanical Splice Installers 00530.30 • Provide qualified mechanical splice installers. • Construct test splices in the presence of the Engineer. • Construct 3 splice samples per type and size for each installer. • Do not begin splice installation until installers have been approved.
Spliced Bars Project Up?
January, 2020 41 Reinforced Concrete Section 5.1
Spliced Vertical Column Bars
Reinforcement Inspection
Inspection of the forms and reinforcement takes time. Check early and often to help assure they are doing things correctly and to avoid minimal rework. Do not wait until just before the concrete placement. Do a final check just prior to the concrete placement to assure everything still looks good.
January, 2020 42 Deck Rebar Checklist Project Information
Project Name (Section) Contract No.
Highway Federal Aid No.
Contractor or Subcontractor
Deck Placement Date: Inspected Date Item Yes No N/A Remarks (mm/dd/yyyy) 1 Bottom Mat Bar Size & Spacing
2 Bottom Mat Ties @ 50%
3 Bottom Mat Clearance
4 Epoxy Ties (if epoxy bars)
5 Supports @ 2' Centers
6 Clearance @ Drip Strip
7 Lap Splices have three (3) ties
8 Top Mat Bar Size & Spacing Top Mat Ties @ 100% 9a if spacing is greater than or equal to 6" Top Mat Ties @ 50% 9b if spacing is less than 6" Top Mat Bars directly over 10 Bottom Mat Bars Top & Bottom Mat Bars installed parallel 11 to skewed joint at both ends of deck 12 Side & End Form Clearances
13 Rail Stirrup Size & Spacing
14 Additional Rail Stirrups @ Joints Rail longitudinal bars cut at joint 15 except bottom two 16 Rail 1-1/4" inside Edge of Deck
17 Rebar Support @ Corners
18 Dry Run Clearance Check
Remarks
Inspected by Date
734-2837 (11-2010) http://www.oregon.gov/ODOT/HWY/CONSTRUCTION/hwyConstForms1.shtml 1 of 1