Conceptual Design Analysis Of Sydney Harbour Bridge

In this group assessment, you are required to write a report which critically analyses the conceptual design phase of a systems engineering project. Projects might include designing a bridge, a dam, an environmentally-conscious building or a mechatronic system. You might not have been involved in the project personally, but some connection with the project would make the analysis more meaningful. The report should analyse the following:

• Needs definition
• Conceptual system design

Design and Construction of Sydney Harbour Bridge

This paper involves the assessment of the conceptual design of Sydney Harbour Bridge by considering the needs definition, maintenance and support, feasibility study, system operation requirement, functional analysis, system planning, and construction process, performance measurement. The Sydney Harbour Bridge is a through arch bridge made of steel through the Sydney Harbour that conveys pedestrian bicycles, traffic, vehicles, and rails between Sydney central business district and the North Shore. The design and construction were performed by Dorman Long and Co Ltd of Middleborough which is a British firm under the course of Dr John Bradfield of the New South Wales Department of Public Works and opened in 1932.

The design of the Sydney Harbour Bridge was prejudiced by the Hell Gate Bridge in New York City and became the tallest steel bridge in the world and the sixth longest spanning-arch bridge globally measuring 134m from the top to the level of water. The bridge was also the widest long-span bridge in the world until the new Port Mann Bridge was constructed in 2012. The construction of the Sydney Harbour Bridge was under the supervision of the Bradfield together with three other seriously involved people who were involved in the construction and design of the include Sir Ralph Freeman, Edward Judge, and Lawrence Ennis (Brinckerhoff, 2012).

The major reason from the design and construction of the Sydney Harbour Bridge back in 1815 was to connect the south and north shores of Sydney Harbour. This is because initially, the only way to make this trip was to make a ferry across the Harbour or travel the approximately 12 miles journey around the shore. The time wasted and the cost involved in following these routes resulted in the need for designing and construction of the bridge. There was a letter written in The Australian newspaper stating the Sydney Harbour Bridge would provide an clue of magnificence and strength that would reflect glory and credit on the Mother Country as well as the colony (Cash, 2012).  

The conceptual design of the Sydney Harbour Bridge involves assessment of the high-level and early life cycle activity of the Dartmouth Dam with an aim of establishing, committing, and predetermining the development form, schedule, form, and function of the bridge as well as its components. The conceptual design of the Sydney Harbour Bridge basically considers the requirement analysis of the bridge during its maintenance, construction process, performance measurement, system operation requirement, functional analysis, and feasibility study (Crew, 2009). There were two proposed designs for the Sydney Harbour Bridge construction, these two designs are explained below:

Proposed Designs for Sydney Harbour Bridge Construction

In 1840, Robert Brindley who was a naval architect suggested that a floating bridge is constructed. Engineer Henderson came up one of the ancient known sketches of a bride through the Harbour. A proposal for a high-level bridge and truss bridge was made in the year 1879 approximated at $850,000 was recommended in 1880. A truss bridge is a bridge whose lead nearing structure is made of a truss which is a stricture of joined components normally forming units that are triangular in shape. Trusses are presumed to be pin coupled where the constituents that are straight meet for the analysis purposes. This hypothesis means that the truss members such as diagonals, vertical, and chords will act only in compression or tension (Ellyard, 2010).

The inclusion of the elements used in the design and construction of the bridge are hugely engineering decisions based upon the economics being balanced between the cost of labour, machinery availability, on-site erection, component transportation, off-site fabrication, and the cost of materials. The figure below shows the design of a typical truss bridge:

Figure 1: Truss dam design (Ellyard, 2010)

In the truss bride above, the inner diagonals are in tension, the top members, and top members are in compression, the lower horizontal members are in bending, shear, and tension, while the vertical members are in tension.

A through an arch bridge which is also referred as a half-through arch bridge and it is a bridge that is made of constituents like reinforced concrete or steel, in which the arch structure base is beneath the deck but the upper upsurges overhead it. Therefore, the deck is within the arch, and the beams or cables that are in tension hang the middle section of the deck from the arch. With the availability of the concrete or iron as structural materials, it became possible to design and construct the Sydney Harbour Bridge which is a through the arch bridge where the deck does not have to be lifted over the top of the arch. The analysis of the Sydney Harbour Bridge is assessed below (Ernest, 2015).

There have been ideas to construct a bridge back in 1815 when the noted architect and convict Francis Greenway supposedly proposed to Lachlan Macquarie who was Governor, that the bridge from the southern to the northern shore of the Harbour. Nothing came of the suggestions of the Greenway, however, the proposal stayed alive and numerous other proposals were made during the 19^th century. Robert Brindley who was a naval architect recommended that a floating bridge is constructed 1840. Engineer Henderson came up one of the ancient recognized sketches of a bride through the Harbour. A proposal for a high-level bridge and a truss bridge was made in 1879 and a approximated at $850,000 was recommended in 1880 (Holder, 2011).

Elements Used in Design and Construction

The plans to design and construct the bride gained momentum following World War 1. Bradfield persisted with the scheme, fleshing out the specifics of the financing and specifications for his proposal of cantilever bridge and on his return from his travels, he made a decision that an arch design would be the most appropriate bridge design. The government approved the Act stipulating the design and construction of an arch or a high-level cantilever bridge through the harbour between Milsons and Dawes Point in 1922, together with electric railway lines and essential approaches. The government received 20 tendering proposals from six companies as a result of inviting tenders for the project (James, 2010).

Bradfield and his staffs were involved overseeing the whole process of construction and design of the bridge, while Ralph Freeman who was an engineer in the Dorman Long and Co.’s Consulting carried out erection and detailed design of the Sydney Harbour bridge. The contractor’s architects were from Scotland from the John Burnet and Partners. The bridge was designed to accommodate a footpath, two railway lines, and six lanes of road traffic (Lalor, 2011).

The construction of the Bridge was under the supervision of Bradfield together with three other individuals who were involved heavily, namely Sir Ralph Freeman, Edward Judge, and Lawrence Ennis. The official formality to mark the beginning of the construction process took place in 1923 on the north shore on the Milson Point where two workshops to help in the construction of the bride were to be built. Approximately 469 structures on the north shore, both commercial operation and private were destroyed to permit erection process to commence with no or little compensation being paid. As the erection of the approaches commenced, effort was also underway on the preparation of the required foundation's weight of loadings and arch. Granite and concrete faced support towers were built with the foundation angled into either of the sections (Luck, 2012).

Figure 2: Construction process of Sydney Harbour Bridge (Mallard, 2010)

After the construction of support structures have sufficiently progressed, a creeper crane was raised to both sides of the harbour. The cranes were fixed with a support and then used to raise materials and men into place to enable steelwork erection. Tunnels were also quarried on both shores with cables of steel passed through them and then held to upper units of both half-arch to halt them from crumpling as then stretched out so as to stabilize works while constructing the arches. The construction of Arch itself started in 1928 October with the cranes creeping along the arches as they were built, ultimately meeting up at the centre. The binary arch halves for the first time connected in less than two years in 1930, August. The workers joined both the bottom and top segments of the arches together, and the arch became self-sustaining, permitting the removal of cables of support (Moy, 2011).

Traffic and Transportation on the Bridge

The normal day-to-day traffic includes 1650 bicycles, 204 trains, and 160,435 vehicles in 2010. From the CBD in Sydney, motor vehicles can access to the bridge usually through Western Distributor, Cahill Expressway, Kent Street, Clarence Street, or Grosvenor. The bridge initially had for wider traffic lanes occupying the middle section and was later increased to six lanes. The construction of tunnel later began to complement the bridge in 1988 since the bride could no longer maintain the amplified flow of traffic. The bridge is also incorporated with the operation of tidal flow, enabling the flow direction on the Sydney Harbor bridge be changed to properly accommodate the evening and morning rush patterns of traffic (Nicholson, 2012).

The traffic paths of vehicles on the bridge operate as a toll road. The toll paid does not depend on the time of the duration in which the motor vehicle is allowed to pass through the toll plaza. There is also footway for pedestrian-only which is positioned on the east section of the Sydney bridge. Accessing the footway on the north section entails ascending flight of stairs that can easily be spotted on the eastern section of the Sydney Harbour Bridge at the Broughton Street. The cycleway for bikes only is also another function of Sydney Harbour Bridge and this way is situated on the west section of the bridge. Entrance from the north section entails pushing or carrying a bicycle up a stairs composed of 55 footsteps, situated on the west section of the bridge at Burton Street. The bridge also has railway lines since it lies between Wynyard and Milson's railway stations situated on the south and north shore with binary paths running alongside the western section of the Sydney Harbour bridge (Pages, 2018).

The arch is made of double arch trusses each with 28 panels and height varying from 18m at the middle of the arch to 57m at the terminals next to the pylons. The arch has a summit of 134m and a span of 504m above the average sea level. The bridge is held in position by hand-driven rivets at a cost of six million and made in Australia delivered by the McPherson Company. The practice of riveting huge structures of steel, and not welding was at that period an understood and proven technique of construction while structural welding had not at that phase been sufficiently established to the application on the bridge. Each stands a pair of high concrete pylons of 89m faced with granite (Phillips, 2009).

The abutments at the pylon base assist in supporting the weights from the arch and position firmly its span in position, however, the pylons have no purpose structurally themselves. The operation of the Sydney Harbour Bridge is made possible due to the functionality of the road, tidal flow, tolls, pedestrian way, cyclist way, and railways. The normal day-to-day traffic includes 1650 bicycles, 204 trains, and 160,435 vehicles in 2010 (Spearritt, 2011).

The Sidney Harbour Bridge needs frequent maintenance and other inspection works to protect it from corrosion and to keep it safe for the public. Some of the people employed on the bridge for the purposes of maintenance include riggers, plumbers, carpenters, plasterers, electricians, fitters, boilermakers, ironworkers, and painters. The most conspicuous work of maintenance of the bridge entails painting. The bridge’s steelwork which requires to be painted is 120 acres with each coat on the bridge needs 30,000L of paint. The Roads and Traffic Authority started repainting process of southern approach spans of the bridge in 2003 and the process involved the removal of the initial paint and then repainting the 22 acres of steel beneath the deck (Tozer, 2009).

The technical performance of the design 2 of the Sydney Harbour Bridge is the quantitative values of estimated, predicted, and measured which describes the performance of the Sydney Harbour Bridge. The figure below shows the evaluation of the performance measure of the Sydney Harbour Bride:

Technical Performance Measure	Quantitative Requirement	Current Benchmark	Relative Importance (%)
Design Type	Through arch bridge	Cantilever bridge.	8
Size	Total Longest span 503 m, Height 134m, Width 48.8, and length 1,149m (Ellyard, 2010)	Total length 2,200 m, Width 56.3 m, Height 180 m, and Longest span 600 m	32
Operations	The average daily traffic include 1650 bicycles, 160,435 vehicles, and 204 trains	The average daily traffic include 1800 bicycles, 210,200 vehicles, and 410 trains	24
Process Time	Construction started July 1923 and ended January 1932 (Nicholson, 2012)	Timeline of 6 years	16
Maintainability	Minimum of 2 times per month	Monthly	14
Human factors	Less than 12% error rate per year	Less than 8% error rate per year	6
			100

Conclusion

This is an assessment paper of the conceptual design of Sydney Harbour Bridge by considering the needs definition, maintenance and support, feasibility study, system operation requirement, functional analysis, system planning, and construction process, performance measurement. The major reason from the design and construction of the Sydney Harbour Bridge back in the year 1815 was to connect the south and north shores of Sydney Harbour. With the availability of the concrete or iron as structural materials, it became possible to design and construct the Sydney Harbour Bridge which is a through the arch bridge where the deck does not have to be lifted over the top of the arch. A through an arch bridge which is also known as a through-type arch bride or a half-through arch bridge is a bridge that is made of materials such as reinforced concrete or steel, in which the arch structure base is beneath the deck but the top upsurges above it.

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