The Millennium Bridge in the UK - Essay Example

History and development As the world approached the new millennium nine years back, before 2000, various projects were undertaken to mark this special occasion in different parts of the world. The United Kingdom or UK also saw various projects; the most prominent ones being the Millennium Dome and the Millennium Bridge. So decision was taken that London would have a suspension bridge between Southwark and Bankside. To be precise this bridge connected the Tate Modern Gallery which is at the Bankside with the St. Paul Cathedral at London. The goal was to build something which would establish UK's scientific and technological prowess strongly in the minds of experts and general populace, all around the world and which would also become one of the most significant tourist spots for the UK and London. For this a competition was held which was organized under the purview of the Southwark Council in the year 1996, on an international level to select the best design-concept. The Best design was chosen amongst the various entries from all over the world. The bridge was opened up to the public in the month of June in 2000 and the construction process had begun in 1998. The exclusivity of this bridge, apart from its design and engineering marvel was the fact that it was a pedestrian bridge and also meant for cyclists. The cost of construction and the project as a whole was $36,000,000. It is 325 m in length. The structure is made of steel. Before this the last 'river crossing bridge' in the city of London was way back in 2894 and that was the Tower Bridge. In spite of the engineering knowhow and constructional knowledge behind the project, when it was opened to the public, on 10th June 2000, the bridge 'wobbled' from side to side and there was uproar in the media and amongst the general public as well as the government. It was closed after this incident and it was refurbished from different technical perspectives, after which it was again opened up for use in 2002. Survey of literature and reports Various reports are there which focus on the engineering and structural knowhow behind this project; how it was built, what went right or wrong and what were the ensuing modifications which were done as a part of the corrective measures, after the bridge was closed down following its initial opening. The Millennium Bridge was built from the point of view of ushering in a new era into the London cityscape with the bridge's unique design and engineering precision and which would eventually act as a prominent structure for London and UK leading to an increased status all over the world. The Millennium Bridge rests on two huge and heavy piers which are made of concrete. These piers are in the middle of the river which primarily supports this comparatively low hanging suspension bridge. The bridge has got on its both sides; four cables which run simultaneously and these bear partial weight of this huge structure. These are coil cables and they span throughout the whole length of this bridge. These coil cables are 120 mm in diameter. These cables have for support steel boxes which fabricated ones made of steel and are found at an interval of 8m along the length of the cables. The deck of the bridge is manufactured out of aluminum, making it lighter but strong. The cables have been strongly anchored onto the banks for stability. This suspension bridge is comparatively shallow than the normal ones. In fact these cables have a suspension of only 2.3 m which is significantly lower than what is normally found in other bridges of the similar nature. The two main piers are V shaped and they congregate at the bottom to add to strength to the basic structure. These cables are very important as they get their stiffness from the cables. Along the straight axis of the Millennium Bridge the dead load has been calculated to be 2ton/linear m whereas the total dead load in context of cable tension has been calculated to be 22.5MN. The lateral stiffness for this bridge has been kept at same levels of what is found in footbridges all over the world normally. The bridge's design has been chosen to be such that it allows for maximum view and therefore quite unconventionally the parallel cables are spread wide into and over the sea, beyond the basic breadth of the bridge's deck. This particular design has actually accentuated the torsinal stiffness of the structure. This ensures that when there is disparity in the load factor on the bridge, the resulting torsinal deflection is controlled and brought under manageable levels. This structural specification accentuates the interplay of aerodynamic performance for the structure. Specific type of sliding joints was inculcated into the bridge at particular points on a regular basis over the length of the structure, which absorbs and minimizes excessive cable movements. The piers constitute some of the most crucial element of the whole bridge from an engineering and technological perspective. The Thames river and the movement of ships in it accounted as a major reason behind the particular designing and technological process which was used to build these piers. The structure of the piers had to be such that they could withstand this resultant force of these movements. The steel brackets which are V shaped had been into concrete base. Studies and surveys were initiated to calculate the river traffic and its possible effects on the structure of the bridge and the probable design at that time. To add more stability to the overall structure the , the abutments on both the north and south have been have strong cables which are anchored deep into the concrete bases or ramps over there. The specific technique which is used here is known as 'strut & tie' in engineering parlance. The main two piers are acting as the primary 'pillars of support' for this huge structure. A single pier has ''''''''to be cntd'.. Read More