By PARIKH KALPESH

spyfleaUrban and Civil

Nov 25, 2013 (3 years and 8 months ago)

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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



Abutments



Piers

Introduction…..……………...continued

Steel Girder

Bridge

Abutment

Bridge

Abutment

Bridge

Pier

Concrete Deck

Pavement

Steel Girder

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, P
u

= 16228.432 Kips



# Of Tendons = 197 ( 0.6 in diam. with area 0.153 in
2

& f
pu

=270 Ksi


Too large and hence increase eccentricity of the tendons



Long Term Repair Solutions …………….continued



ii) Assuming e = 57.95”













F
u

= M/S + P/A




P
u

= 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 F
nt

= 113ksi and nominal shear
strength F
nv

= 75ksi,

are enough

Long Term Repair Solutions …………….continued

The plates used are checked for


Yielding failure mode


Fracture failure mode


Block shear failure mode

Smallest of these values governs.


Design strength is



Φ
t

P
n

=1044.818 kips



16"



"
12"
2"
2"
8"
3"
2"
205.16 Kips
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)



Long Term Repair Solutions …………….continued



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 ft
2




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


The

cost

involved

in

the

deck

reconstruction

makes

the

post

tensioning

method

preferable




Cost Benefit Study…………….Continued

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?