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.