lesson 7 - CTQP Home Page Shaft Inspector/07 - 2015... · reinforcing steel will remain within allowable tolerances ... shafts until modifying the rebar cage support ... Lesson 7

Student’s Guide Lesson 7- Reinforcing Cage

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Lesson 7

REINFORCINGCAGE


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Learning Outcomes

• Describe cage construction

• Determine the circumference of a shaft and rebar cageand calculate the required number of side spacers.

• Explain how to assess the Contractor’s compliance withcage construction/placement requirements

• Verify CSL tube placement and condition

• Identify the applicable 455 Specifications


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Checklist


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455-14.2 Reinforcing Steel: Meet thereinforcing steel requirements of Section415. Ensure that reinforcing steel is inaccordance with the sizes, spacing,dimensions, and the details shown in theplans.

Reinforcing Steel


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455-16.1 Cage Construction and Placement:

Completely assemble and place as a unit the cage ofreinforcing steel, consisting of longitudinal bars, ties, andcage stiffener bars, immediately after the Engineerinspects and accepts the shaft excavation andimmediately prior to placing concrete. Tie all intersectionsof drilled shaft reinforcing steel with cross ties or “figure 8”ties. Use double strand ties or ties with larger tie wirewhen necessary. The Engineer will give final approval ofthe cage construction and placement subject tosatisfactory performance in the field.

455-16- Reinf. Steel Const. & Placement


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455-16- Reinf. Steel Const. & Placement


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Reinforcing Cage

C/L DRILLED SHAFT


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LongitudinalBars

Transverse or TieBars

Instrumentation

Reinforcing Cage


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Ties

Reinforcing Cage


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455-16.2 Splicing Cage: If the bottom of the constructedshaft elevation is lower than the bottom of the shaftelevation in the plans, extend a minimum of one half of thelongitudinal bars required in the upper portion of the shaftthe additional length. Continue the tie bars for the extradepth, spaced on 2 foot centers, and extend the stiffenerbars to the final depth. The Contractor may lap splice thesebars or use unspliced bars of the proper length. Do notweld bars to the planned reinforcing steel unless shown inthe Contract Documents.

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455-16.2- Splicing Cage


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455-16.2 Splicing Cage (cont’ed)……For drilled shafts supporting mast arms, cantilever signs,overhead truss signs, high mast light poles or othermiscellaneous structures, if the shaft cleaning operationsresult in excavating below the required tip elevation, thereinforcing steel cage does not need to be extended. Thereinforcing steel cage may be spliced to rest on the bottomof the excavation or suspended in place from the top.

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455-16.2- Splicing Cage


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Spliced Cages

Note the extended bars.


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Staggered splices

7-13

Spliced Cages

Mechanical Couplers


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7-14

455-16.3 Support, Alignment, and Tolerance: Tie andsupport the reinforcing steel in the shaft so that thereinforcing steel will remain within allowable tolerancesas specified in 455-20 and Section 415.

Use wheels or other approved noncorrosive spacingdevices within 3 feet of the bottom, within 6 feet of thetop, and intervals not exceeding 10 feet along the shaftto ensure concentric spacing for the entire length of thecage. Do not use block or wire type spacers. Use aminimum of one spacer per 30 inches of circumferenceof cage with a minimum of four at each level…

455-16.3- Support, Alignment & Tolerance


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Side Spacers

Cage

SpacersWithin 6 ft. of top,12 inch diameterspacers (recommended)

6”Cover

6”Min.

Shaft wall

Within 3 ft. of the bottom

Max. 10 ft. intervalsup the shaft

Bottom Spacers


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Side Spacers


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Typical Side Spacers


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7-18



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455-16.3 Support, Alignment,and Tolerance:

…..near the bottom, within 3 ft ofthe bottom, within 6 feet of the top,and intervals not exceeding 10feet along the shaft to ensureconcentric spacing for the entirelength of the cage.….. Use a minimum of one spacerper 30 inches of circumference ofcage with a minimum of four ateach level….

Number of Side Spacers

Need to Know

• Length of shaft

• Circumference of cage

To Determine

• Number of rows

• Number of spacersper row

Total of spacers=# rows x # spacers/row


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Circumference (C) = D

Where: C = circumferenceD = diameter = 2 times radius = 3.142

36” dia.

What is the circumference of the shaft in:

PROBLEM

C = D

C =

C =

Circumference of a Circle


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Circumference (C) = D Where: Diameter of cage = Shaft diameterminus 2 times the Concrete cover

D = diameter = 2 times radius = 3.142

What is the circumferenceof the reinforcing cage?

48” dia.

PROBLEM

6” Concretecover

Reinforcing cage

Circumference of a Cage


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7-23

How many side spacers are required for this shaft?

PROBLEM

56’

Number of spacers per row =

SAME CIRCUMFERENCE AS PREVIOUS PAGE

1.5’

11.5’

21.5’

31.5’

41.5’

51.5’

Rows

Number of Side Spacers


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455-16.3 Support, Alignment, and Tolerance:Continued

…. Provide spacers at the bottom of the drilled shaftreinforcing cage as required to maintain the properposition of the cage



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455-16.3 Support, Alignment, and Tolerance:Continued

Check the elevation of the top of the steel cage before andafter placing the concrete. If the rebar cage is notmaintained within the specified tolerances, correct it asdirected by the Engineer. Do not construct additionalshafts until modifying the rebar cage support in a mannersatisfactory to the Engineer.



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Typical Standoffs (Bottom Spacers)


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Typical Standoffs (Bottom Spacers)


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Side Spacers & Standoffs


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What are the side spacers used for?

What are the bottom spacers used for?

Learning Outcomes


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What percentage of intersections on the cage are to be tied?

How many side-spacers are required per row on the cage?

Learning Outcomes


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• Should not be stored in contact with soil• Keep away from oil or other deleteriousmaterials

• Adequate supports provided during storage & lifting

Reinforcement Storage


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Reinforcement Cage Handling


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Reinforcement Cage Handling


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Common Reinforcement Cage Issues


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Common Reinforcement Cage Issues


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Cross-hole Sonic Logging Tubes


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455-16.4 Cross-Hole Sonic Logging (CSL) Tubes:Install CSL access tubes full length in all drilled shafts from the tipof shaft to a point high enough above top of shaft to allow CSLtesting, but not less than 30 inches above the top of the drilledshaft, ground surface or water surface, whichever is higher.Equally space tubes around circumference of drilled shaft.Securely tie access tubes to the inside of the reinforcing cageand align tubes to be parallel to the vertical axis of the center ofthe cage. Access tubes from the top of the reinforcing cage to thetip of the shaft shall be NPS 1-1/2 Schedule 40 black iron orblack steel (not galvanized) pipe. Access tubes above the top ofthe reinforcing cage may be the same black iron or black steelpipe or Schedule 80 PVC pipe. Ensure that the CSL accesstubes are free from loose rust, scale, dirt, paint, oil and otherforeign material. Couple tubes as required with threadedcouplers, such that inside of tube remains flush. 7-37

455-16.4- CSL Tubes


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455-16.4 Cross-Hole Sonic Logging (CSL) Tubes:Continued

…. Seal the bottom and top of the tubes with threadedcaps. The tubes, joints and bottom caps shall be watertight.Seal the top of the tubes with lubricated, threaded capssufficient to prevent the intrusion of foreign materials.Stiffen the cage sufficiently to prevent damage ormisalignment of access tubes during the lifting andinstallation of the cage. Repair or replace anyunserviceable tube prior to concreting. Exercise care inremoving the caps from the top of the tubes afterinstallation so as not to apply excess torque, hammering orother stress which could break the bond between the tubesand the concrete….

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455-16.4- CSL Tubes


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…. Provide the following number (rounded up to the nextwhole number of tubes) and configuration of crosshole soniclogging access tubes in each drilled shaft based on thediameter of the shaft.

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455-16.4- CSL Tubes

Shaft DiameterNumber of Tubes

Required

ConfigurationAround the inside

Of Circular Reinforcing Cage

36 to 48 inches

Greater than48 inches

1 tube per footof shaft Diameter

4 90 degrees apart

360 degrees dividedby the number of tubes


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7-40


Insert simulated or mock probes in each cross-hole-sonic access tube prior to concreting to ensure theserviceability of the tube. Fill access tubes with cleanpotable water and recap prior to concreting. Repair orreplace any leaking, misaligned or damaged tubes asin a manner acceptable to the Engineer prior toconcreting.

455-16.4- CSL Tubes


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7-41


For drilled shafts supporting mast arms, cantilever signs, overhead truss signs, high mast light poles, or other miscellaneous structures, if the shaft cleaning operations result in excavating below the required tip elevation, the CSL tubes do not need to be extended. If the reinforcing steel cage is suspended in place from the top rather than resting on the bottom of the excavation, clearly mark the top of shaft location on each tube.

455-16.4- CSL Tubes


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455-16.4- CSL Tubes


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455-16.4- CSL Tubes


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700-010-84, Inspection Form

7-44

The Inspector is to compete the Drilled Shaft Log portion related to the Reinforcing Cage, which is located in the page 2 of the Drilled Shaft log. In addition, the inspector is to complete form 700-010-33, presented in the next slide. As mentioned earlier, the must check the constructed cage against the plans and if everything matches, you would check “Yes”. If not check “No” and place your comments in the “Comment” section below. Remember to check for: 1. Proper # Vertical Bars – does the number of bars and their size, match the plans? 2. Proper # Horizontal Bars- does the number of bars and their size match the plans? 3. Side Standoffs (spacers)- is the correct number (total and per row) in place? 4. Bottom Standoffs- does the number and the clearance from bottom of shaft to bottom of cage match the plans? 5Epoxy Condition- Epoxy is no longer used so that should be N/A. 6. Ties & Connections- are the ties (number or percentage) as specified in the plans. Use Comments section to provide any details.


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700-010-33, Inspection Form

7-45

Drilled Shaft Reinforcement/spacers/ log

In addition to do the checkings in form 700-010-84 the Inspector needs to compete the Drilled Shaft Reinforcement/Spacers/ Log to document CSL access tubes, spacers used, reinforcement diameters and length and extensions used. In this form the inspector documents the reinforcement, CSL and spacers observed. Items such as, bar size, lengths, CSL number of tubes, distances between spacers rows, etc, are recorded in this form.


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The “Cage”


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Learning Outcomes

• Describe cage construction

• Determine the circumference of a shaft and rebar cageand calculate the required number of side spacers.

• Explain how to assess the Contractor’s compliance withcage construction/placement requirements

• Verify CSL tube placement and condition

• Identify the applicable 455 Specifications


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ANY QUESTIONS ?

Questions?

TIN # Date:

Date:

1)

d1 = d6 = d11 =

d2 = d7= d12 =

d3 = d8 = d13 =

d4 = d9 = d14=

L l d5 = d10 = d15 =

3)

4)

5)

6) Number of longitudinal rebars =

7) Longitudinal Rebar Diameter =

8) L l = Longitudinal Rebar Length =

9) Transverse Rebar Diameter. =

Yes No

10)

IF YES:

(a) Number of Long. Bars Extended=

(b) Extension Length (ft) =

(c) Number of Additional Tie-bars =

11)

12)

13)

14) Yes No

cross ties or "figure 8" ties?

Note 1: In misc. shafts, explain here how the contractor provided the CSL access tubes extension for testing:

Comments:

CONSTRUCTION

700-010-33

Number of Spacers /Row =

(d) Extension above shaft provided (in) =

Were all the intersections tied with

Was Bottom of cage extended?

Anchor Bolts length=

d4

Anchor Bolts diameter=

d1

d2

d3

d5

CSL TUBES

Project Name:

FIN Project No.:

(c) Length of CSL Tubes (ft) =

(measure each after installation)

(Note 1)

Number of bottom spacers =

Number of Anchor Bolts=

2)

(a) Number of CSL Tubes Installed =

(b) Inside Diameter of CSL Tubes (in) =

Number of rows=

Bridge Structure #

(Project Admin Or Permit Manager)

Offset (ft)

Station

Page

Pier No.

Shaft I.D. or #

STATE OF FLORIDA DEPARTMENT OF TRANSPORTATION

DRILLED SHAFT REINFORCEMENT/SPACERS/LOG 10/13

Contractor:

Inspected by:

Cage Dia.

(in) =

Approved by:

Side Spacers

Bottom of CSL Tubes=Bottom of

Tie-Bars

1

1

TIN # Date:

Date:

1)

d1 = d6 = d11 =

d2 = d7= d12 =

d3 = d8 = d13 =

d4 = d9 = d14=

L l d5 = d10 = d15 =

3)

4)

5)

6) Number of longitudinal rebars =

7) Longitudinal Rebar Diameter =

8) L l = Longitudinal Rebar Length =

9) Transverse Rebar Diameter. =

Yes No

10) x

IF YES:

(a) Number of Long. Bars Extended=

(b) Extension Length (ft) =

(c) Number of Additional Tie-bars =

11)

12)

13)

14) Yes No

cross ties or "figure 8" ties? x

Note 1: In misc. shafts, explain here how the contractor provided the CSL access tubes extension for testing:

36"

Cage Dia.

(in) =

Approved by:

xxxxxx xxxxx

xxxxxx

STATE OF FLORIDA DEPARTMENT OF TRANSPORTATION

DRILLED SHAFT REINFORCEMENT/SPACERS/LOG 10/13

Contractor:

Inspected by:

Page

Pier No.

Shaft I.D. or #xxxxxx

Bridge Structure #

(Project Admin Or Permit Manager)

Offset (ft)

Stationxxxxxx

Number of bottom spacers =

Number of Anchor Bolts= NA

2)

4

1.5"

(a) Number of CSL Tubes Installed =

(b) Inside Diameter of CSL Tubes (in) =

Number of rows= 7

CSL TUBES

Project Name:

FIN Project No.:

164"

(c) Length of CSL Tubes (ft) =

(measure each after installation)

(Note 1)

Example

d1

d2

d3

d5

5

NA

NA

NA

NA

4

Were all the intersections tied with

Was Bottom of cage extended?

Anchor Bolts length=

d4

Anchor Bolts diameter=

NA

NA

10'

Comments:

CONSTRUCTION

700-010-33

NA

Number of Spacers /Row =

(d) Extension above shaft provided (in) =

10'

10'

10'

2' 10'

NA

14

#10

72.5

8' 1"

NA

NA

NA

76 NA

76

76

76

NA

NA

NA

NA

#5

NA

NA

NA

Side Spacers

Bottom of CSL Tubes=Bottom of

Tie-Bars

x

1