Pile Coffering
The Pont du Val Benoit, Liege, is a long stone bridge of five arches supported on four piers and two abutments, the footings of which, in poor soil, are anchored by means of a series of wooden piles, the heads of which project into the masonry. It was found, however, that the stream, especially at periodical flood time, produced disturbing scour, which was undermining the bridge supports. To remedy this, these supports have been enclosed in a type of cofferdam carried out thus : Reinforced concrete piles were moulded, 12 in. by 12 in. and 25 yd. long, which were driven close together round the footings, with a slight inward inclination. Owing to the unevenness of the ground a rather irregular enclosure was formed, but where the breach was considerable, the opening was blocked with flat bags of cement. - Le Constructeur de Ciment Armé. No. 56, 1924.