Direct Shear Test on Ottawa Sand
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Transcript Direct Shear Test on Ottawa Sand
By
PARIKH KALPESH
Overview
Introduction
Structural evaluation of the bridge deck, girders,
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
Non destructive test for Steel girder
Magnetic-Particle testing
Dye Penetrant test
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
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
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
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
12"
Yielding failure mode
Fracture failure mode
Block shear failure mode
2"
8"
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
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?