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TA 201-MmE
PROJECT REPORT
“Cantilever Bridge”
INSTRUCTOR: -Dr. J. Ramkumar
TUTOR: - Prof. Kallol Mondal
SECTION: - M1 / M2
GROUP NO. 9
Amit Kumar Y9073
Kumar Kislay Y9294
Mattam Pratap Naidu Y9327
Mohit Singh Y9343
Rohit Kumar Sinha Y9493
CONTENTS
Acknowledgements
General Description
1. Motivation
2. Innovations
Procedure
Processes Involved
Cost Estimation
Difficulties Faced
Scope for Improvement
ACKNOWLEDGEMENTS
We sincerely express our gratitude to our tutor Prof. Kallol Mondal,
our MME laboratory in charge Mr. G.P.Bajpai sir, and all the other
guides of the TA 201 MME lab for their valuable support and advice
in making this project possible. Without their moral and technical
support we would not have been able to complete this effortful task.
Overall we thank our instructor-in-charge Dr. J. Ramkumar for
providing us with the opportunity to make something creative along
with gaining hands-on-laboratory experience.
THANK YOU
GENERAL DESCRIPTION
A Cantilever Bridge is a bridge built using cantilevers, structures
that project horizontally into space, supported on only one end.
Large cantilever bridges are designed to handle road or rail traffic
using trusses built from structural steel. The steel truss cantilever
bridge was a major engineering breakthrough when first put into
practice, as it can span distances of over 1,500 feet.
MOTIVATION
The motivation for making this project was drawn from Newark Bay
Bridge. The Newark Bay Bridge (officially named the Vincent R.
Casciano Memorial Bridge) is steel through arch bridge connecting
the cities of Newark and Bayonne in New Jersey, USA. It was
completed on April 4, 1956
INNOVATIONS
We did some slight modifications in the original model to complete
the project effectively using the available lab facilities and in
constrained time.
Tapering of pillars to reduce weight of casting.
Providing large base area to the pillars for their stability.
Inclusion of a thicker sheet metal below the deck for its
proper welding with the pillars.
Deck is a rectangular box made by a thin sheet metal folding
instead of a thick metal slab to reduce the weight.
PROCEDURE
First of all casting of pillars was done using a thermocole
pattern, introducing designs on it for aesthetic taste. Simultaneously deck was made by forming thin sheet metal into
a box which was then locked by brazing. Then we moved on to shearing and bending of mild steel rods
for making arches and trusses for the bridge. After that the system of arches and side trusses was given
shape by welding and brazing, two parallel arch system were
made independently. At the same time the cast pillars were ground to improve
dimensional accuracy. The deck was fixed to a thicker sheet metal with the help of
brazing, and then the pillars welded on the thick sheet. Subsequently the two arch systems were welded to the deck. Two cars, made by sheet metal shearing, folding and resistance
welding were put on the deck to add life to the project. Then the two arch systems were connected via top trusses
which were fabricated by brazing. Finally, finishing touch was given to the pillars and the arch
systems by grinding with hand grinder. Oiling was also done to
prevent rusting.
PROCESSES INVOLVED
Casting:
Casting was used for making pillars of the bridge. Since pillars are
meant to bear the load of the whole structure, we preferred casting
process.
Welding and Brazing Process:
Primarily we used following joining processes
1. Brazing: For making the truss system as the truss rods
were very small in size and thus difficult to weld.
2. Gas Metal Arc Welding (GMAW): For joining pillars and
arch systems to the deck as strong joints were required
at these places.
3. Resistance Welding: For joining wheels made of GI sheets
to the cars.
Sheet Metal Forming:
We used sheet metal work for making the deck and two cars.
Metal Cutting:
To separate the runner from the cast with the help of all-cut
machine.
COST ESTIMATION
ITEM RATE QUANTITY AMOUNT Thermocole Rs. 15 per sq feet 0.50 sq feet Rs. 7.50/-
Fevicole Rs. 5/tube 1 tube Rs. 5/-
Pig Iron Rs. 50/kg 4.5 kg Rs. 225/-
Electricity used Rs. 4.80/unit 2 units Rs. 9.60/-
Mild steel sheet
(upto 3mm)
Rs. 40 per sq feet 0.28 sq feet Rs. 11.40/-
Mild steel rods Rs. 30/kg 1.15 kg Rs. 34.30/-
Mild steel sheet
(upto 1mm)
Rs. 16 per sq feet 0.62 sq feet Rs. 10/-
GI sheet (upto 1mm) Rs. 20 per sq feet 0.1 sq feet Rs. 2/-
Unskilled Labour Rs. 25 per hr 13 X 5 hr Rs. 1625/-
Skilled Labour Rs. 50 per hr 3 hr 150/-
Total Rs. 2080/-
Overhead charges: 10% = Rs. 208/-
Gross total = Rs. 2288/-
DIFFICULTIES FACED
Deck was made of thin sheet metal box. So, welding of pillars
to it was not possible.
Solution: We placed the box on a thick sheet metal which
could be welded with the pillars.
Unexpected bending of thick sheet metal during its welding
with the pillars, upsetting their levelling.
Solution: We connected the bases of the adjacent pillars
with square rods to provide proper levelling.
The whole arch system was to be kept in a plane while brazing.
Solution: We held the arch system with tong throughout
the process.
Due to insertion of thick sheet metal in the deck the dimension
of pillars did not match with the arch system.
Solution: We welded the arch system with the deck
instead of pillars.
SCOPE FOR IMPROVEMENT
.
For better performance we could have used tata GI sheet
which is not prone to rust easily.