BRIDGES OVER THE RIVERS JEMSEG AND SAINT JOHN IN CANADA

These two viaducts for the Fredericton-Monton Highway in the New Brunswick province were identically designed with strict box systems and double composite action of the constant edge. Both viaducts were designed to be launched from both ends together with semi-bridges which joined at the centre of the main spans set in the centre of the river. An abacus system would have to be employed in these main spans using composite elements encased in the concrete shafts of the main piers.

In this way the launched constant depth system would extend the entire length of the section and once in final position, the joints between the abacus and the deck would provide the necessary areas of variable depth to cross the central span and the two adjacent lateral spans. These spans be substantially greater than those of the standard approach spans