The President of Expoagua, Roque Gistau, says that in no other building in Spain has piling gone so deep.
The most advanced technology verifies that the piles can withstand 7,000 tonnes.
“In our country there is no other building where the piles reach such depth as in the Bridge Pavilion” These are words from the President of Expoagua, Roque Gistau, who brought a specific technology from England called the ‘Osterberg Cell’ to verify the foundations of this peculiar engineering project, designed by the architect Zaha Hadid.
Its intention was to assure that the central piles embedded up to 72.5m in depth into the river-bed are able to withstand the 7,000 tonne weight of this colossal Gladiolus-shaped, steel structure, which shall remain crossing the River Ebro after the World Fair, as if it were a suspended boat.
The Director of Infrastructures at The World fair, Miguel Ángel Soria, reaffirmed “the record in depth we have reached with the foundations for the Bridge Pavilion, which started in March, are now finished” he also reminded us that it had been a very complex operation that the man in the street could not appreciate but had been fundamental to settle the foundations in one of the most expensive and charismatic buildings in this international exhibition.
Gistau also went into great detail regarding the technical difficulties the foundations of this building had imposed, all the more since the flow of the water in the river washes away the sand and soil. He also added that the problems did not finish with the foundations but would continue with the structure as the “Bridge Pavilion would act as if it were a steel boat supported on three columns”.
On the other hand, the engineer, Guillermo Capellá, member of the team Arenas y Asociados, which is constructing the Third Millennium Bridge in Zaragoza, with piles up to 52m deep, stressed that in Spain the maximum which drill depth in bridge construction had averaged 50m. “Definitely, the World fair has wanted to guarantee a good foundation going down to 72.5m in the case of the Bridge Pavilion and also testing the resistance capacity with a special system they brought from England”.
At the end of July, specialists from Loadtest Europa, which has its central offices in London, and responsible for carrying out load tests in large public works, were in the Ranillas Meander to test the strength of the central piles of the Pavilion Bridge which are 270m long.
Although its foundations are supported on 22 piles, 10 of them are installed on the central isle in the River Ebro, and which bear half of the load of this structure to be built shortly. Roque Gistau explained that the loads on the central support are very high, and therefore, it was not sufficient to place piles to bear loads by friction, but to find bedrock”. The remaining piles are shared between the right bank of the River Ebro and eight others on the left bank.
Sources from Expoagua explained that a special pile driver had to be brought to place the columns, which bear the structure, 70m into a compact, chalky soil. Roque Gistau explained that the 2m diameter embedded piles “have been done with a sleeve or sheath which protects the shuttering of the borehole so that the walls do not collapse inwards. A pile cap is placed on top and subsequently the Bridge Pavilion, once construction starts, awarded by the executive commission of Expoaqua last 17 July to Dragados and Urssa.
The Director of the Infrastructures of the World Fair, Miguel Ángel Soria, advanced that the construction of the Bridge Pavilion was about to begin, that on the right bank it would be narrower being 5m initially and progressively widening until reaching 30m on the left bank when inside the World Fair Exhibition Site.
The Construction Foreman, Eduardo Ruiz de Termiño, described the Works as if you were to construct a “tube two thirds from the right bank to one from the right bank”. The isle constructed by Dragados, to be able to do the foundations, will have to be connected by a platform so as to be able to carry out the structural works of the Bridge Pavilion, which shall begin shortly and will last until May 2008. In February this year, according to the Expoagua calendar, the installation of the thematic contents shall begin, titled “Water, a unique resource” and will therefore become the only fitted-out bridge in Spain one of few in the world with these characteristics. Its special character was one of the reasons behind the Expoagua’s jury decision to choose it amongst 41 other projects presented.
Miguel Ángel Soria also mentioned the technical differences between the Third Millennium Bridge and the Bridge Pavilion. Whilst the first is a incrementally launched bridged the second is a launched bridged which means “its structure is constructed in pieces which will be connected on one of the banks and when the steel tube passes the flow of the river, just so it does not pitch, it will be connected by some cables and will be launched to the central support”.
The Director of the Infrastructures of the World Fair, stated that the Works were going at a good pace, although things had slowed down somewhat in August, but on this point he said “December is a month where we must get a move on and work to the maximum”
Currently, there are around 500 workers grafting away in the Ranillas meander, the majority dedicated to rebar and concreting. Miguel Ángel Soria stated “it will be at the end of the year or the beginning of next when we shall need far more people for the installations”