A Creative solution for two bridges: widening the span of two existing bridges by eliminating three

The engineering thinking behind the development of creative designs for two bridges is described. The main stages are included, from the initial and alternative designs to the selection of the best solution for the construction.

An important expressway in Buenos Aires had to be widened. The traffic flow is intense (greater than 250,000 vehicles/day) and because there are no alternative routes it was impossible to replace the existing structures. The three central supports of 2, six-span continuous prestressed concrete overpasses had to be removed.

At least four lanes had to be kept open to traffic flow in each direction at all stages of the construction work. This was a requirement imposed on the designers.

To deal with these heavy constraints steel over-bridges were designed from which the existing structures were suspended.
Some details of complex structural problems that derived from the interaction between the old and the new superstructures are described.

Jorge Fontán Balestra, Structural Engineer – Partner: Del Carril – Fontán Balestra y Asoc., Buenos Aires, Argentina

Tomás del Carril, Structural Engineer – Partner: Del Carril – Fontán Balestra y Asoc., Buenos Aires, Argentina
Member of the National Academy of Engineering, Buenos Aires, Argentina