Transcript Rehabilitation of I

Rehabilitation of I-95 Bridges
11 Bridges Along I-95 Corridor
l Superstructure
Replacement
l Substructure
Repair
10
9
8
7
6
5
4
3
2
1
ROLLED BEAMS
l Existing deck is 7-1/2” thick
l Replacement deck creates
overstress in beams
l Category E fatigue detail at cover
plate ends
l Paint is in poor condition and lead
based
l Replace steel beams
Rehabilitation of I-95 Bridges
Bridge Widening
l Lombardy/CSX Bridge
12’ Shoulders (8’-8” Widening Each Side)
l Robin Hood Rd. Bridge
Ramp Extension (14’-8” Widening SBL)
l Sherwood Ave. Bridge
Ramp Extension (14’-8” Widening SBL)
Rehabilitation of I-95 Bridges
Superstructure Replacement
l Preconstructed
Composite Units (PCU)
PCU’s
Chosen option uses Pre-Constructed Units assembled in a casting
yard, trucked to site and lifted into place by cranes
PCU ready in Casting Yard
PCU Being Placed
during early test day
Construction Sequence
Construction Sequence
Construction Sequence
Setup of Maintenance of Traffic
Initiating MOT
Traffic Shifting
Moveable Traffic
Barrier Setup
Traffic waiting to
Shift
Construction Sequence
Preparation for PCU
Cut Deck and
Diaphragms and
remove Existing
Repair Bearing
Pads
Repaired Pier Cap
Construction Sequence
Preparation & Installation
Moving PCU to Pick up Point
Placement of PCU
Construction Sequence
Placing PCU
Aligning PCU & then Disconnecting
Rehabilitation of I-95 Bridges
l Match-Cast Longitudinal Joint
l Cast-in-Place Closure Pour
Highly Skew Bridges
Lombardy / CSX
Robin Hood
Hermitage
Westwood
Rehabilitation of I-95 Bridges
Substructure Repair
l Surface Repairs at Abuts. & Piers
l Pier Cap Replacement
5 Piers for Lombardy/CSX Bridge
l Pier Cap Strengthening
Infill Wall between Columns on Piers at
Boulevard Bridge
Rehabilitation of I-95 Bridges
Substructure Repair
l Cathodic Protection
Chloride Extraction (ECE)
Sealing Concrete Surfaces
Pier Caps
SCS’s Role in 11 Bridges
Corrosion Cost Progression
Cost of Maintenance
Potential Failure
Damage Accelerates Critical Point
First Visible
Damage
Internal
Damage
Condition of Structure
Temporary Piers
Corrosion Damage
Corrosion Damage
Evaluation
How much delam/spall existed at the time?
Chloride presence at various depths?
Future penetration & effects of chlorides?
Active corrosion occurring? How quickly?
Existing and future damage?
Presence and progression of ASR?
High risk of prescribing a poor solution
without proper diagnosis…
Boulevard - Structure Total
Rebar Cover Histogram
120
Frequency (# of Samples)
100
80
60
40
20
0
Rebar Cover (Inches to Top of Rebar)
Boulevard - Structure Total
Corrosion Potential
-750
-700
-650
Half-Cell Potential (mV)
-600
90% Probability of Active Corrosion
-550
Corrosion Threshold
-500
-450
-400
-350
Corrosion Potential
-300
-250
-200
-150
-100
-50
0%
10%
20%
30%
40%
50%
60%
Cumulative Frequency
70%
80%
90%
100%
Boulevard - Structure Total
Chloride Concentration Histogram
7
Frequency (# of Samples)
6
5
Threshold
4
Active Corrosion
Surface Sample
3
Rebar Sample
2
Behind Rebar Sample
1
0
Chloride Content (% Wt. Concrete)
Abutment Wall
Line
Scan 29
Line
Scan 28
GPR – Good Concrete
GPR – Delam. Concrete
Conclusions
Visible concrete damage – significant increase
Developed a concrete damage % for each
element
Average recorded cover – low
Majority of potential readings – active corrosion
High chloride readings behind rebars
Near future concrete damage will result
Significant weakening of the structure within
five years
Recommendations
Based on a unique methodology, we developed
recommendations for repair / replace /
life extension
Concrete repair on all bridges
ECE to lower the chloride concentration on
certain bridges
Sacrificial CP on the rest of the bridges
Sprayed Zinc – widely used, easy to apply
Structure
Replacement
cost
Repair
cost
Cost
Savings
Repair cost/
Replacement
cost, %
1
Boulevard
$1,931,202
$402,300
$1,528,902
21%
2
Hermitage Road
$3,240,312
$619,720
$2,620,592
19%
3
Laburnum Avenue
$1,730,258
$380,480
$1,349,778
22%
4
Lombardy/CSX
$5,821,420
$2,019,420
$3,802,000
35%
5
Overbrook Road
$1,147,005
$312,240
$834,765
27%
6
Ramp-A
$926,000
$146,440
$779,560
16%
7
Robin Hood Road
$1,877,817
$568,560
$1,309,257
30%
8
Sherwood Avenue
$1,595,045
$397,700
$1,197,345
25%
9
Upham Brook Run
$2,287,719
$429,620
$1,858,099
19%
10
Westwood Avenue
$3,592,000
$402,440
$3,189,560
11%
Total
$24,148,778
$5,678,920
$18,469,858
24%
S.
No.