economical and permanent, and that they might be used very largely to
the exclusion of cribwork, which, after a decade or so, becomes a source
of constant maintenance charges, besides never presenting an attractive
appearance. Finally, in bridges requiring the most rigid foundations,
these caissons might readily be used as substitutes for open wooden
caissons, sunk on a prepared foundation of whatever nature, and still be
capable of incorporation into the finished structure.




DISCUSSION


WILLIAM ARTHUR PAYNE, M. AM. SOC. C. E. (by letter).--On the arrival of
the first barge load of brick, to be used in building a residence on the
estate to which this pier belongs, a severe northwest wind blew for two
days, after the boat was moored alongside, directly against the head of
the pier and the side of the boat. The effect on the pier was to crush
the fender piles and cause a settlement of one of the caissons at the
pier head on the west end. The caisson was knocked slightly out of
alignment, and a settlement toward the west was observable.

The writer believes that this was caused by the pounding of the brick
barge on the sand bottom on which the caissons rest, during half tide,
the boat being raised from the bottom on a roller, and striking when the
roller had passed. In order to protect the pier and avoid the bumping of
barges against it, three groups of piles were driven about 8 ft. beyond
the end, a secondary platform was built between these and the stringer
of the pier, and arranged so that it would slide on the stringer in case