By
PARIKH KALPESH
Overview
 Introduction
 Structural evaluation of the bridge deck, girders,
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abutment, and piers
Recommended non destructive tests
Short term solution
Long term solution
Detailing of the retrofit system
Construction Sequence
Cost benefit study
Summary and Conclusion
Introduction
 General description of the bridge
 Bridge location
 Structural systems
 Non-Structural systems
Introduction…..……..continued
General description of the bridge
 Bridge consist of two simply supported span, each of
50 ft. in length.
Bridge location
 Tioughnioga River Bridge is located over the mouth of
the river in the Cortland city.
Introduction…..……..continued
Introduction…..……..continued
Structural systems
Bridge deck
 Concrete deck with 7” thick with ordinary reinforcement.
 3-3/8”reinforced concrete layer at the top
Steel girder and diaphragms
 Steel Girder: A wide flange structural steel beam, W36x150
 Diaphragms: A steel member of 15” U @ 33.9”
Next Slide Shows the figure ……….
Introduction…..……………...continued
Introduction…..……………...continued
Introduction…..……………...continued
Pavement
Concrete Deck
Steel Girder
Bridge
Abutment
Steel Girder
Bridge
Pier
• Abutments
• Piers
Bridge
Abutment
Introduction…..…………...continued
 Non-Structural systems
 Asphalt- Placement of asphalt has increased the dead
load on the structural systems. It does not increase the
Moment Resistance
 Bridge Railings- Metal railings have been used at the
sides of the bridge deck
 Bridge bearings-Hinged Bearing at Pier
 Sliding Hinged Bearing at Abutment
 Construction Joints
Structural Evaluation of the Bridge Deck, Girders,
Abutment and Pier
Rating of Elements
Steel Railing
Rating – (5) Minor deteriorated
Reason: Corrosion result from the environment.
Curbs
Rating - (5) Minor deteriorated
Vertical cracking is noted at random locations throughout
Structural Evaluation of the Bridge Deck, Girders,
Abutment and Pier…………. continued
Concrete Deck
Rating - (3) Seriously deteriorated and not functioning
as originally designed.
Reason: Corrosion of the rebar.
 Top surface multiple transverse cracks
 Exposing the material of steel
 We deny adding additional dead load onto the deck .
Expansion Joints
Rating - (5) Minor deteriorated
Reason- Fatigue and dynamic loading
Structural Evaluation of the Bridge Deck, Girders,
Abutment and Pier…………. continued
Drainage Systems on Super Structures
Rating- (5) Minor deteriorated
Longitudinal Beams or Girders
Rating- (5) Minor deteriorated but functioning as
designed.
Reason- Corrosion
Bearing Assemblies (Include Misalignment)
Rating - (3) Seriously deteriorated
Reason – Corrosion of the plate
Structural Evaluation of the Bridge Deck, Girders,
Abutment and Pier…………. continued
Concrete Abutments
Rating– (3)
Reason- Seriously deteriorated.
Bridge Pier
Rating-(3)
Reason – Corrosion & deteriorated bearings.
Conclusion
 The bridge elements that received a “Poor” rating includ
concrete deck, the concrete abutments, steel plate girder
bearings and the bridge pier. The overall condition of the bridge
was rated as “
Seriously Deteriorated”.
Decision Making
Needs Rehabilitation!
Recommended Non Destructive tests
Non destructive test :
For Overall Load Rating
Static Load test
 Moving Load test
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Non destructive test for Steel girder
Magnetic-Particle testing
 Dye Penetrant test
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Recommended Non Destructive tests
… continued
Non destructive test for concrete deck
Sounding tests (Hammer tapping)
Cover meter and Rebar locator
Concrete Hardness test
Petro graphic Analysis- To Identify ASR
RECOMMENDED NON DISTRUCTIVE TESTING ……….. continued.
Conclusion for Non Destructive Test:
Existing Bridge condition & Inspection Reports suggest
that non destructive test is not required.
Repair Solution
 In 2001 evaluation and Inspection was made
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Long term solution opted
 In 2004 it should have been repaired
 It was decided to repair in Oct.2013.
 Can we keep the Bridge without short
term solution as it is now?
Answer is Definitely NO!
Short Term Solution & Long Term Solution are
Required
Short Term Repair Solutions
 Wrapping of Carbon Fiber Reinforced Polymer
(CFRP)
Short Term Repair Solutions contd..
Patching to exposed rebar in the deck
Short Term Repair Solutions contd..
Providing Steel Column Support near the
Abutment
Short Term Repair Solutions contd..
Galvanic protection for steel girder
Long Term Repair Solutions
Analysis and Design of a Retrofit System
1) Check for the adequacy of the existing bridge deck
It is safe
2) Check for the adequacy of the Existing Steel Girder
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Existing steel Girder is Grade 60
Mu = 3327.75 Kips-ft
Stress = 79.23Ksi. > Fu
Not safe and needs strengthening
Long Term Repair Solutions ……… continued
External Post tensioning System
 Tendons are placed on the outside the cross
section
 The forces transferred at the anchorages and at
deflectors
 No bond is present between the tendon and the
structure, except at anchorage and deflector
locations
Long Term Repair Solutions …………….continued
Analysis and Design of a Retrofit System
a) Design of post tensioning system
i) Assuming e = 12”
Fu = M/S + P/A
where, M = MDL + MLL – P*e
We obtain, Pu = 16228.432 Kips
# Of Tendons = 197 ( 0.6 in diam. with area 0.153 in2 & fpu =270 Ksi
Too large and hence increase eccentricity of the tendons
Long Term Repair Solutions …………….continued
ii) Assuming e = 57.95”
Fu = M/S + P/A
Pu = 208.24 Kips
# of tendons = 4
Long Term Repair Solutions …………….continued
iii) Check for axial compression and flexure
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Eccentricity = 57.95 in
A pre stressing force of Pu =208.24 Kips
The steel girder is adequate for the combined effects
of flexure and axial compression
Long Term Repair Solutions …………….continued
Final profile of the post tensioning system
Long Term Repair Solutions …………….continued
Long Term Repair Solutions …………….continued
Long Term Repair Solutions …………….continued
Long Term Repair Solutions …………….continued
b) Design of connection
H= 208.24 Cos 9.86 = 205.16Kips
V= 208.24 Cos 9.86 = 35.66 Kips
10 Bolts of A490X, 7/8 in diameter and nominal
tensile strength Fnt = 113ksi and nominal shear
strength Fnv = 75ksi, are enough
Long Term Repair Solutions …………….continued
"
The plates used are checked for
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12"
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Yielding failure mode
Fracture failure mode
Block shear failure mode
2"
8"
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2"
3"
Smallest of these values governs.
Design strength is
Φt Pn =1044.818 kips
2"
16"
205.16 Kips
Long Term Repair Solutions …………….continued
Design of the Bearings
Elastomeric Laminated Bearing for Structural
Movement
Size: 406 mm ×27 mm× 43 mm
Structural Resistance Maximum dead load + live load (zero rotation)
 Maximum dead load + live load (full rotation)
 Shear Movement Allowed
 Shear Stiffness KN/mm
 Rotation about longer axis (1rad/100 KN)
Construction Sequence
Bolts and Plate Fixing: Tightening, Can be Snug Tight
or Fully Tight.
Installation Dywidag Custom Make Holding Unit
by welding.
Installation of Dywidag System:
 Ducts Installation
 Stressing
 Grouting
Construction Sequence
Installation of
DYWIDAG
system for
Driscoll Bridge
Cost Benefit Study
Alternate Solution Proposal: Deck Reconstruction
Proposal Consist of:
 Construction Area : 6000 ft2
 List of Activates was Prepared
 Cost of Labor
 Cost of Equipment
 Cost of Engineers and Management
Cost Benefit Study…………….Continued
Miscellaneous Charges
 Security Charges
 Temporary Construction office Charges
 Commissioning Cost- 0.3% of the project
 Contingencies 3% of the project
 Small tools cost is 0.5% of project Cost
 After Job cleaning up is 0.3% of project Cost
Cost Benefit Study…………….Continued
The cost involved in the deck reconstruction makes the
post tensioning method preferable
Summary and conclusion
 The slab deck needs repair both for short
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term and long term
The abutments require an immediate
repair
The bearings shall be replaced
The Steel beam girder shall be post
tensioned using 4 tendons
Details and bill of quantities are included
in the report
QUESTIONS?