Sydney Harbour Bridge: A Case Study in Conceptual Design

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Assignment 1
The conceptual design phase for a project based on system engineering
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Contents
Introduction......................................................................................................................................3
Stakeholder needs............................................................................................................................4
Conceptual design process...............................................................................................................7
System requirements......................................................................................................................12
Conclusion.....................................................................................................................................14
References......................................................................................................................................15
List of figures
Figure 1 Sydney harbor bridge........................................................................................................4
Figure 2 Sydney harbor bridge at night...........................................................................................5
Figure 3 Inside view of Sydney harbor view...................................................................................6
Figure 4 Construction started from the end of the harbor and move towards the center of it.........7
Figure 5 7 designs submitted by the Dorman long..........................................................................8
Figure 6 proposed designs of Sydney harbor in 1900.....................................................................9
Figure 7 Location plan of Sydney Harbor Bridge.........................................................................10
Figure 8 Terminological view of Sydney Harbor Bridge..............................................................11
Figure 9 Sydney harbor bridge under construction.......................................................................12

Introduction
The report is about to develop an understanding of the conceptual design phase of an engineering
project. The selected case study is on the Bridge that is “Sydney Harbor Bridge”. Basically, the
conceptual design phase basically refers to the advancement and improvement in the concept
plans which were developed during the scoping phase. The design of the bridge includes various
steps that are a preliminary phase, conceptual phase, and the final phase. The Sydney harbor
bridge was designed by a British firm Dorman Long and Co ltd., under the guidance of John
Bradfield. The Hell Gate Bridge, New York, acts as an, influencer for the design of this bridge.
This is the 6th longest spanning-arch bridge. It is also named as “coat hanger” due to the arch-
based design. Bridges are helpful to minimize the distance and provide a pathway across two
distinct places which cause less time in traveling. The report will include the stakeholder needs,
conceptual design and the requirement of the system.

Stakeholder needs
Stakeholders require the bridge to connect the north shore and Sydney central business district.
Bridge should be able to carry the bicycle, vehicle, rail, and pedestrian traffic. In 1929, the
Australian government found that the economy is shrinking and unemployment is increasing.
This is a backdrop for the Sydney harbor bridge construction.
Figure 1 Sydney harbor bridge
It was insisted by Dr. Bradfield that bridge should support car streaming over the harbor. It was
also insisted by him that it can be a section or part of the integrated transport system which is
connected with the city circle underground railway (eTool, 2012). It is required by the
stakeholder that additional crossing should be constructed. The Sydney Harbor Bridge opened
the harbor's southern part, allowing Sydney to grow northward. Passing the harbor before the
bridge was constructed implied getting a ferry boat. The bridge implied that individuals and
products could make the trip much faster. In the Sydney region, the bridge enhanced
communications – a simpler flow of products and individuals helped increase the area based
economy. The better infrastructure development improves the social value and that can be
developed by using minimum time and cost. The bridges are helpful to reduce the distance
between two places and offer a pathway (Bridgesdb.com, 2019).

Figure 2 Sydney harbor bridge at night
The main requirement of the construction of this bridge is to connect the North shore and Sydney
central business district. The need is to implement the specific and affordable design of bridge
using the experienced architecture that is Hell Gate Bridge. The requirement of the stakeholder
before the construction of the bridge is to test the load effect on the structure with the various
vehicle types. The next requirement is to determine the connection or connectivity systems that
are using bolts and plates. Another consideration from the stakeholder side is to define and
describe the material that will be used and the structure description along with all the elements.
The stakeholder needs the structural analysis of the design of a bridge. Another need is to the
documentation of the specification of bridge load which includes wind load, compression,
tension and live load of the Sydney Harbor Bridge (Glazier, 2015).

Figure 3 Inside view of Sydney harbor view

Conceptual design process
The Sydney harbor bridge is 440 ft. tall and length is 3,7770 ft. The width of the bridge is 160 ft.
primarily. In 1932 the bridge made using reinforced concrete which was a new technique at that
time. Steel-frame based construction is also referred to as modern technology. The design of the
bridge is new and ancient both. The design of the bridge is an arch bridge that distributes the
weight of the bridge structure across the distance by using dispersion. In all the traditional arch
bridges, the arch is situated under the bridge but in case of Sydney Harbor Bridge, the deck
crosses through the arch. Thus, the base arch is below the deck (Ellmoos and Murray, 2015).
Figure 4 Construction started from the end of the harbor and move towards the center of it
The feasibility study of the Sydney harbor bridge consists of several main points like there must
be exact and accurate dimensions for structure for the proper survey and assessment of the
location. If the exact measurement is not possible then it is compulsory to do assessment and
survey of condition. It is also important to make the analysis and assumption about the pathway
in the process of design. In the construction process, it is also mandatory to consider the safety
and health risks of the workers and society. The material should be selected according to the
strength and durability (Institution of Civil Engineers (ICE), 2018). The assessment of the
condition includes some of the major points such as measurement and investigation of the size
of elements and the thickness of elements should be measured using the ultrasound thickness.
The condition assessment also includes a sketch that is showing the site and the bridge
measurement. The limitations and assumptions include that the limited survey on the study of
dimensions and assessment of the condition is enough. The size of bolts, plates, and elements
are determined on the basis of assumption to have at least approximate value (Kajewaski, 2019).
The analysis should be done to check the fracture, lack of rivets and cracks in the bridge
structure. 20 designs were received from the 6 companies. The selected design was designed by
the Dorman Long and Co Ltd.

Figure 5 7 designs submitted by the Dorman long

Figure 6 proposed designs of Sydney harbor in 1900
In the year 1914, John Bradfield appointed as Chief engineer of Sydney Harbor Bridge and
metropolitan railway construction. A cantilever bridge was at the preference at the start and the
NSW legislative Assembly passed such idea for this type of construction. But the legislative
council denied the idea by saying that the money would be better spent in the war. After this,

Bradfield traveled overseas to find out tenders (McCallum and Advocate, 2016). After returning
from the travels it has been analyzed by Bradfield that the arch design is also suitable for this.
Figure 7 Location plan of Sydney Harbor Bridge

Figure 8 Terminological view of Sydney Harbor Bridge
The arch design was affordable and cheap than the cantilever bridge design. This also makes it
suitable for the expected heavy loads. The task to see the complete bridge design and the process
of building was done by Bradfield and the staff. While, others are associated, to carry out the
detailed design and the process of erection of the Sydney harbor bridge. The structure of the
Sydney Harbor Bridge is aligned with the structure of underground railways that is known as the
city circle is present. The design of the bridge was in such a way that it carries the 6 lanes of the
traffic. There are two railway tracks on each side of traffic lanes and a pedestrian way or footpath
(Muscato, 2019). These railway tracks are connected with the underground railway station by
symmetrical tunnels and ramps

System requirements
Width of the Sydney harbor bridge is 49 m. and supported by the cross girders that are based on
steel material that is hung on the 134-meter-high arch hangers in tandem with huge granite-faced
structures built on rock. Over the course of the centuries, the Bridge has been prepared to
smoothly increase its ability by offering eight paths for vehicles transporting around two million
vehicles every day, along with a cycleway, two rail lines, and the pedestrian way that is
upgraded, and the ability to grow again. The length of the bridge is 1.149 m. Thus, the Sydney
harbor bridge requires 52,800 tons of steel and 6 M hand-driven rivets for the construction of a
bridge including 8 traffic lanes. During the construction of the bridge, 5 tone locomotive cranes
based on steam, erecting the timber trestle for the support of steelwork. The total cost of the
Sydney harbor bridge AU£6.25 million. There was a bigger 25-ton crane based on electronics
behind each tiny crane that raised the steel into the correct location. Construction is done using
reinforced concrete. To create the arch of the bridge, creeper cranes were used, one the height of
the tower reaches to the 47m from the level of the ground.
Figure 9 Sydney harbor bridge under construction
An operational requirement of the system includes some of the main points such as
documentation of the types of equipment and structure that consist of electrical and mechanical
aspects of the structure. Another operational requirement includes the frequency inspection in the
main road and transport aspect. The schedule for the maintenance should be there this includes
repainting, patching, filling the cracks, etc. 30,000 liters of paint is required to paint the bridge.
The maintenance work is divided into two sections and each section includes two-phase. The
first phase refers to the removal of the existing corrosion and paint that is based on lead with the
help of blasting types of equipment. Part two refers to the repainting and repairing of the bridge.