Miscalculations led to Montuiri bridge collapse

THE design of the Montuiri bridge, which spectacularly collapsed last month, was right for the job it had to do.
Its collapse onto the Manacor road on November 4 was due to an error in calculations during its construction, as when the cylindrical steel structure was filled with concrete, a series of factors came into play related to the rigidity of the upper wings of the structure. The report, which was made public by the Council of Majorca's Public Works Department, concludes that the upper wings of the structure were not strong enough to take the weight when it was filled with concrete. At the same it says that the metal casing was lacking ”certain structural elements” to enable it to resist the torque. On this subject, the director of the Roads Department, Gonzalo Aguiar, said that if, while filling the structure with concrete, ”they had supported the structure with a crane”, the bridge would not have collapsed and, once the concrete was dry, ”they could have put it in place without any problems”. In fact, the confidence which the construction company UTE and the administration has in this type of structure is such that the reconstruction of the bridge will be made with the same mixed system of steel and concrete. Aguiar said that ”it will be the same design but, of course, with structural corrections”. Aguiar had made it clear right from the moment the bridge collapsed that this would not mean any extra expenditure for the Council of Majorca, as it was the UTE's responsibility because they were carrying out the widening of the Manacor road, which was opened on December 2. The report also says that the UTE put the project in the hands of an experienced engineer ”for a better guarantee of success”. This experienced engineer is a Professor at the School of Superior Engineering Techniques in Madrid and co author of the recommendations for the design of the bridge. To find out the cause of the collapse of the bridge, the construction materials were analysed and virtual simulations made of all the steps in the construction.