Case study on the design of a contemporary Civil Engineering project Essay - 1

Case study on the design of a contemporary Civil Engineering project - Essay Example The bridge is a natural expression of structural engineering and architecture but a city center footbridge is equally about people and the environment; in short a piece of public architecture. The bridge gives the pedestrians unique views of London, free from traffic and high above the Thames. In September 1996, a competition was organized by a London-based newspaper the Financial Times and London Borough of Southwark to design a new Footbridge across the River Thames. The idea behind the competition was to get the best design in every aspect therefore the teams participating in the design were structured to have an engineer, an architect and an artist. More than 200 teams participated and the competition was won by Arup (engineer), Foster (architect) and Sir Anthony Caro (Sculptor). The height restrictions and the view behind the bridge required an innovative design which was provided in the form of a design which included some unusual practices; the suspension design had supporting cables below the deck level. This innovative design was given the name ‘blade of light’ by its designers. The structure of the Millennium Bridge is innovative and complex but it has been designed to achieve an apparent simple form. The design of the Millennium Bridge is based on the following considerations: An evolved support system in which the majority of the bridge stiffness is created by shallow cable profile derived tension. This allows a light bridge deck structure. A modular design in which several structural members and components can be repeated in the structure, thus reducing the fabrication costs. This can also simplify the maintenance after the construction and allows easy execution of the construction phase. The distribution of the forces on the foundations should be such that they do not disturb the existing structures on the north bank and also the foundations of the existing bridges. The aesthetics of the bridge at night were also a big concern and a l ight pipe system illumination was proposed to create a ‘blade of light’ across the river at night. The river traffic analysis is also important while designing a bridge at such a location. A major issue was the provision of planning advice for gaining the necessary approvals to construct a new river crossing in the heart of London. Moreover ways of generating the finances for the bridge were also to be considered while designing the bridge. Superstructure Design The bridge design is a shallow suspension bridge in which the view behind the bridge is facilitated by keeping the suspension cables below the bridge deck. The bridge is supported on two river piers through two groups of four 120mm diameter locked coil cables which span from one bank to the other. The three spans of the bridge have different lengths. The middle span which lies between the two piers is 144m long. The north span is 81m long while the south span is 108m in length. Fabricated steel box sections whic h are known as the transverse arms span between the two