Engineering Mechanics: Bridge Design Project Report for ENS1101 Course

This project report details the design and construction of a bridge model as part of an Engineering Mechanics course (ENS1101). The project involved a team of students tasked with designing a bridge capable of spanning 1.5 meters and supporting specific concentrated loads. The report outlines the factors considered during the design phase, including material selection (wood, steel wire), structural integrity, and load-bearing capacity. It describes the technical procedures followed, from initial design sketches to the final construction, including the allocation of tasks among team members. The report also includes a technical justification of the proposed design, detailing the materials used and the steps taken to ensure the bridge met the required specifications. Furthermore, the report describes the specific materials, dimensions, and construction methods employed, along with the placement of supports and load-bearing members. The project aimed to meet the required load-bearing capacity while adhering to specific design constraints, providing a practical application of engineering principles.

ENGINEERING MECHANICS: PROJECT REPORT ON BRIDGE
DESIGN
Bridges play an important role in connectivity; it helps the people to commute between two
places in a fast and efficient way. Earlier when there were no bridges and tunnels people
needed several days to cover the distance which takes only hours now that too with ease and
access, also used to transport the goods. [1] There are several types of bridges such as stone
bridge, wooden bridge, arch bridge, suspension bridge, cantilever bridge, cable stayed bridge,
movable bridge, etc. The bridges are also categorised according to the material like stone,
wood, iron, steel, and other materials. Recently a technology was developed to use waste
plastic in the formation of road and bridges. [2]
Factors to consider before building a bridge
Building bridges are one of the most expensive projects in the field of construction. There are
set of parameters to be taken into action while designing or building a bridge. Some of them
are: geology of the area of project and its surrounding, type of traffic to be handled by the
bridge, to check for earthquake and flood probability, types of loads to be carried, etc. There
are different times of forces that act on the bridge like the compression and tension forces,
resonance, unbalanced loads and dynamic movements exerting force on the bridge. The high
wind pressures, vibrational disturbances due to construction nearby and the fact should also
be considered for the effect of accident or impact of vehicles to the bridge. It is very essential
to understand and encounter the topography of the environment as well as the situations that
generally occurs and that might occur. [3] Bridges were specially created to overcome natural
hurdles like rivers, valleys, huge natural trenches, distance between two cliffs, etc. They were
started building from 3rd century, the first major bridge made with iron was built in England
on river Severn, shows the evaluation of designing of bridges.
The Technical Procedure
At first, before starting the technical work the adequate knowledge of the project is very
necessary to be undertaken. All the constraints must be kept in mind before designing of
bridge like material, man power, electricity, equipment, proper design, money, evaluation
report of the site and requisite time expectation for the completion of project. Initial design
should be made after knowing all the required attributes to solve the requirement, all the
unique and new ideas should be entertained and rough sketches should be prepared. After the

all the sketches are considered and shortlisted one or two designs should be selected and
analysed. In the process of evaluation of design, these designs with appropriate measurements
are drawn in a software, simulated and analysed, the results are studied and then the design is
set to move in the action plan if not again new designs are to be prepared. Before the plan can
be executed it is important to make understand the action plan to all the engineers and
construction teams and responsibility should be given to different teams for different parts for
easy and effective construction of the bridge. Any changes if required for smooth
construction should be considered. Finally, the procedure should begin for the manufacturing
of parts and all the parts to be assembled in proper alignment. [4]
Technical justification of proposed design
According to the design proposed by the professor as shown in figure 1, our team will build a
suitable model of the bridge.
Figure 1: Proposed design model of bridge
As per the parameters set by the professor, the team needs to develop several suitable design
and experiment on them in order to succeed and stand on the expectation of the professor.
The task of this team is to build a bridge of 1500mm long pathway considering the aspects of
safety. The bridge must at least uphold the load of 15kg, for that the need to design the bridge
for minimum 20kg load bearing capacity, so it could not fall at the time of inspection. As the
guidelines provided the weights or loads will be placed at three points below the plank or
pathway i.e. first at the distance of 250mm, second at 500mm and 750mm from the left end,
let us consider the three points as 1, 2 and 3. The team members have decided to contribute

equal effort and work has been divided. All the team members finalised the design to be
taken into consideration.
Final Bridge design for submission
The final design as tested to be prepared by the team after a series of experimentation will be
concluded as shown in figure 2.
This will be how the bridge will look like after completion. Materials to be used are wooden
plank, wooden bars, steel wire, nut-bolts, wood glue, angles and hooks. First of all the,
required materials should be brought together. After that the team needs to measure and cut
wood blocks into required dimensions as shown in figure 3 and 4.

Procedure for Bridge Model building
Initially the wooden plank of dimension; length = 1500mm and breadth = 400mm is to be cut.
After that base structure is to be prepared for that we need 7 small square bars of wood of
dimension; sides = 20mm and length = 400mm, and 2 long square bars of length 1500mm
along with 4 base corner supports of dimension; sides = 50mm and length 750mm. The base
structure for support of plank also needs two central support pillars to withstand the weight of
15 kg at least. The 2 central supports are to be made cylindrical of diameter 100mm and
length 1500mm in which the steel wires will be tighten to provide strength to the support
structure. Now place all the parts according to the design, use super glue or wood glue for
placing parts inline, after that tightening of the joints with the help of nuts and bolts or
screws. Grooves must be made on the 4 base pillars to attach the upper support system made
for the plank or the pathway. Then at the centre of the system on both sides attach the
cylindrical pillar and tighten it with the help of aluminium or steel strip to the hooks or angles
at the support bars, and tighten the steel wires at the point indicated in figure 2. Finally check
all the connections and tighten all nuts and bolts to avoid miss happening. If needed can also
paint the bridge for eye catching appearance.
Task Allocation to team members
Member 1: Determination of correct quality of wood and purchasing.
Member 2: To bring required tools, wood saw, wood cutter, hammer, pliers, etc.
Member 3: To bring Wood glue, Steel wire, Wire cutter, screws, Nuts-Bolts and hooks.
Member 4: To design for bridge construction.
Member 5: To cut wood in desired shapes and sizes.
Member 6: Fixing screws, nuts-bolts and hooks at the points needed.
After all the parts are collected and prepared, all members of team, get together and start
assembling all the parts altogether, with precision because any misalignment could cause the
bridge to fall. If prepared correctly would be able to sustain about 25-30 kg of load easily.

REFERENCES
[1] "Bridge Types - Different Types of Bridges", Historyofbridges.com, 2019. [Online].
Available: http://www.historyofbridges.com/facts-about-bridges/types-of-bridges/.
[Accessed: 18- Sep- 2019].
[2] M. Tang, (2018) "Forms and Aesthetics of Bridges", Engineering, vol. 4, issue no. 2.
Available: 10.1016/j.eng.2017.12.013 [Accessed 12 September 2019].
[3] M. Latif and M. Saka, (2019) "Optimum design of tied-arch bridges under code
requirements using enhanced artificial bee colony algorithm", Advances in
Engineering Software, vol. 135, issue no. 102685. Available:
10.1016/j.advengsoft.2019.102685 [Accessed 12 September 2019].
[4] "Things engineers need to consider before building a bridge - bygging", bygging,
2019. [Online]. Available: https://bygging-uddemann.co.kr/things-engineers-need-to-
consider-before-building-a-bridge/. [Accessed: 12- Sep- 2019].