Construction and the Design of Southern Cross Station - Case Study Example

Construction and the Design of Southern Cross Station Name Institution name Southern Cross station Southern Cross station is located at western edge of the central business district on Spencer Street and occupies about 60,000m2. The station is served by 16 platforms and 22 tracks. it has over 120 passenger information screens , comfortable air conditioning waiting areas, a 30 bay coach terminal secure parking for about 800 cars, direct factory out let with 120 speciality shops and food courts public facilities such as toilets, internet services and telephones as well as retail outlets including safe and restaurants. The aspects of the station design were performance ease of passenger movement. It currently provides about 15 million passengers a year. Fully sheltered, high quality ticketing, baggage-handling, waiting and retail services with comfortable seats light and passenger information systems characterises the uniquely characterises the station. The interior has a big and spacious hall with uninterrupted vista in every direction. This facilitates ease understanding of the interconnection of different streets surrounding the building (Designbuild-network.com, 2014). The figure below shows the structure of the Southern Cross station. Figure 1: Overview of the Southern Cross Station: (Southerncrossstation.net.au/) The type of foundation used The kind of foundation used is pier foundation also known as pillar foundation and founding level. All piers on suburban platform constructed with founding that is below RL+2 AHD (Department of infrastructure, 2002, p. 34). In simple terms, a pier foundation is an individual footer supporting a structural post or a beam. Some piers are normally are normally placed on footings to support the elevated structure. The type of footing affects the foundation performance. Piers on top of a continuous grade beams offer greater resistance to lateral loads. The footing and grade beam are normally reinforced to resist the force at base of pier due to lateral loads. Footing and pier are type of shallow foundations sued in situation where the subsoil is required to support the foundation load. In design of footing, the minimum depth of footings depends on the soil characteristics or the profile. consider the following when determining the depth of foundations, how deep is the top soil, depth of poor surface, location of ground water table, and depth of the adjacent footing (Som and Das, 2003, p. 164). While there are, piers that are drilled deep into the ground. For deep foundation use of piers among other like piles and pile groups are used to resist heavy loads that come from big structures (Kameswara Rao, 2011, p. 309). The construction of Southern Cross station used the drilled piers or drilled caissons. The drilled piers or caissons may consist of a shaft with or without a bell and a cap. Kameswara Rao, (2011, p. 328) argue that drilled piers are also called drilled shafts or drilled caisson. They can also be termed as large diameter piers. They are cylindrical in nature and are normally filled with concrete. They differ with piles because of the greater diameter of above 750 mm. These holes are normally drilled with casing or without casing. When casing are used are they are normal left as part of the structure or removed as concreting takes place. The bottom of the pier can be enlarged, under-reamed or belled out manually or by use of machine. This will facilitate a larger bearing area and this therefore means that the bearing capacity will be higher (Kameswara Rao, 2011, pp. 328-329). The types of drilled piers are shown below, Figure 2 : Drilled Piers (Kameswara Rao, 2011, p. 329) Reasons for the foundation chosen Som and Das, (2003, p. 65) argues that foundation is the critical part of the structure or building. It t offers support to the structure and any other loads .The foundation was determined by a number of factors such as duration, which in the initial proposal the requirement was that the design should provide a 100-year design life suitable for all types of permanent structures and the characteristics of the site which is corrosive. Kearney, (2013) argues that Melbourne’s soil can be classified according to its properties into classes. A and S having low reactivity to moisture, class M reacts moderately to water because it is sandy loam and clay mixture, class H highly reactive to moisture, class E extremely reactive and class p which is problematic of all characterised by land slide and coastal erosion. The soil on which the current structure lies is highly corrosive and weak. Having this in mind and the need to prevent effects of vibrations drilled piers were chosen. Drilled piers are used where the soil is week and the loads are too large. They are also used in situations where vibrations have to be avoided (Kameswara Rao, 2011, pp. 329). The engineers therefore took into consideration the geotechnical conditions of soil in the area and allowance for expandability, which will allow for addition of new tracks and platforms below the existing facility. Ghosh, 2010, p.12) argues that the soil engineering that primarily determines and addresses the properties and soil behaviour is termed as geotechnics. These properties determine the type of foundation and underground structures. Newman, (2013, p.15) argues that the foundation of a building is directly proportional to the soil properties and is only good as the soil can support it. It is important for anyone wishing to design foundation to understand the soil properties. This is because the root cause of many failures lies in this understanding by the designers. The overall weight of the structure is enormous, since piers support heavy weight it was for the structure. Drilled piers and caissons offer strong foundation for heavy loads and high horizontal thrust. Drilled pier derives its supporting power from two main pats, the skin friction and the bottom bearing. However, most of the weight is taken by the stratum beneath the pier (Raj, 2008, p. 605-606). This kind of foundation allows for expansion. This was in accordance to the regulation of the state government reason being. The public transportation system is evolving and expanding continuously and flexibility in design is required in order to incorporate any future alteration to the rail infrastructure. State government stressed that there are a number of projects that may impact the new facility, therefore developments need to consider these public transport projects and to provide flexibility. In other word the construction company needed to the sub-structure facility systems that will provide the require clearances for the future rail infrastructure. The projects the state eyed were Melbourne Airport link; the transit will link Melbourne airport and the Southern Cross station in a form of enhanced bus form which might later on change to rail transport mode. Therefore engineers needed to come up with design that will facilitate and be flexible enough to incorporate the in its design the provision of facilities such as check in, handling of baggage and dedicated lounges. Another project was establishment of very high speed train that will link Brisbane, Sydney, Canberra and Melbourne. Room for the facilities of this project should also be needed to be incorporated into the design. This includes check in, handling of baggage and dedicated lounges. The state also intended to have city loop expansion flexibility and expansion in order to meet the future needs, from the current four underground rail loop tunnel due to expected increase in capacity (Department of infrastructure, 2002, p. 4). Benefits of this foundation Compared to other types of foundations piers have very distinct advantages. Sometimes when piles penetration is, difficult piers are used. This is because they of their high penetrating capability. It does not cause vibration and soil during pier installation, this useful when adjacent structure is on spread footings or under short piles. Most equipment’s that are used in drilled pier are less noisy. It is therefore suitable to be used near places affected by loud noise such as hospital. In pier, it is possible to test the soil or rock condition at the bottom of the pier, problems of soil shifting and lifting is not witnessed here since there is little displacement of soil, they resist high lateral stress and require use of light construction equipment. What will happen if other foundation were used Foundation is important to every design. Its strength is greatly influenced by soil underneath. Shallow foundation types could not have worked for the structure simply because of the weight of the material on top. This means that the structures could have easily collapsed (Raj, 2008, p. 536). Using shallow foundation techniques are also affected by soil corrosive characteristics considering the fact that geotechnical report on soil showed that the soils is corrosive. Use of other deep foundation could have achieved the great depth achieved by drilled foundation; this implies that weak foundation due to the shallowness of the supporting matter could have weekend the whole structures (Raj, 2008, p. 605). The main purpose of using this pier was to incorporate the changes suggested by the state government such as need for flexibility to support emerging projects dependent on this, using other foundation structures no matter how strong they could have been it would still be difficult to achieve or fulfil this equipment (Department of infrastructure, 2002, p. 34). References Department of infrastructure, S. (2002). Spencer Street Station Redevelopment Annexure I : Project Brief. 1st ed. [ebook] Available at: https://www.tenders.vic.gov.au/tenders/contract/download.do?id=11655&docIndex=2 [Accessed 19 May. 2014]. Designbuild-network.com, (2014). Southern Cross Station, Melbourne, Victoria - Design Build Network. [online] Designbuild-network.com. Available at: http://www.designbuild-network.com/projects/southerncrossstation/ [Accessed 19 May. 2014]. Ghosh, K. (2010). Foundation Design in Practice. 1st ed. New Delhi: PHI learning private limited. Kameswara Rao, N. (2011). Foundation design. 1st ed. Hoboken, N.J.: Wiley. Kearney, J. (2013). Soil Tests for the Melbourne Residential Market: What Do They Mean, and Why Do You Need to Know?. [online] The Sloping Block Professor. Available at: http://blog.slopingblocksolutions.com.au/soil-tests-for-the-melbourne-residential-market-what-do-they-mean-and-why-do-you-need-to-know/ [Accessed 19 May. 2014]. Newman, A. (2013). Foundation and anchor design guide for metal building systems. 1st ed. New York: McGraw-Hill. Raj, P. (2008). Soil mechanics and foundation engineering. 1st ed. New Delhi: Dorling Kindersley. Som, N. and Das, S. (2003). Theory and Practice of Foundation Design. 1st ed. New Delhi: Prentice-Hall of India. Southerncrossstation.net.au, (2014). Southern Cross Station. [online] Southerncrossstation.net.au. Available at: http://www.southerncrossstation.net.au/ [Accessed 19 May. 2014]. Read More

While there are, piers that are drilled deep into the ground. For deep foundation use of piers among other like piles and pile groups are used to resist heavy loads that come from big structures (Kameswara Rao, 2011, p. 309). The construction of Southern Cross station used the drilled piers or drilled caissons. The drilled piers or caissons may consist of a shaft with or without a bell and a cap. Kameswara Rao, (2011, p. 328) argue that drilled piers are also called drilled shafts or drilled caisson.

They can also be termed as large diameter piers. They are cylindrical in nature and are normally filled with concrete. They differ with piles because of the greater diameter of above 750 mm. These holes are normally drilled with casing or without casing. When casing are used are they are normal left as part of the structure or removed as concreting takes place. The bottom of the pier can be enlarged, under-reamed or belled out manually or by use of machine. This will facilitate a larger bearing area and this therefore means that the bearing capacity will be higher (Kameswara Rao, 2011, pp. 328-329). The types of drilled piers are shown below, Figure 2 : Drilled Piers (Kameswara Rao, 2011, p. 329) Reasons for the foundation chosen Som and Das, (2003, p. 65) argues that foundation is the critical part of the structure or building.

It t offers support to the structure and any other loads .The foundation was determined by a number of factors such as duration, which in the initial proposal the requirement was that the design should provide a 100-year design life suitable for all types of permanent structures and the characteristics of the site which is corrosive. Kearney, (2013) argues that Melbourne’s soil can be classified according to its properties into classes. A and S having low reactivity to moisture, class M reacts moderately to water because it is sandy loam and clay mixture, class H highly reactive to moisture, class E extremely reactive and class p which is problematic of all characterised by land slide and coastal erosion.

The soil on which the current structure lies is highly corrosive and weak. Having this in mind and the need to prevent effects of vibrations drilled piers were chosen. Drilled piers are used where the soil is week and the loads are too large. They are also used in situations where vibrations have to be avoided (Kameswara Rao, 2011, pp. 329). The engineers therefore took into consideration the geotechnical conditions of soil in the area and allowance for expandability, which will allow for addition of new tracks and platforms below the existing facility.

Ghosh, 2010, p.12) argues that the soil engineering that primarily determines and addresses the properties and soil behaviour is termed as geotechnics. These properties determine the type of foundation and underground structures. Newman, (2013, p.15) argues that the foundation of a building is directly proportional to the soil properties and is only good as the soil can support it. It is important for anyone wishing to design foundation to understand the soil properties. This is because the root cause of many failures lies in this understanding by the designers.

The overall weight of the structure is enormous, since piers support heavy weight it was for the structure. Drilled piers and caissons offer strong foundation for heavy loads and high horizontal thrust. Drilled pier derives its supporting power from two main pats, the skin friction and the bottom bearing. However, most of the weight is taken by the stratum beneath the pier (Raj, 2008, p. 605-606). This kind of foundation allows for expansion. This was in accordance to the regulation of the state government reason being.

The public transportation system is evolving and expanding continuously and flexibility in design is required in order to incorporate any future alteration to the rail infrastructure. State government stressed that there are a number of projects that may impact the new facility, therefore developments need to consider these public transport projects and to provide flexibility.

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