float and boat landing. After the first bids were received, the owner
wished to reduce the cost, and every other caisson in the pier head was
omitted, so that, as built, the pier contains eight caissons and five
53-ft. trusses. The caissons supporting the trusses are 8 ft. wide and
12 ft. long, and those in the pier head are 12 by 12 ft. On account of
the shoal water and the great height of the outer caissons in comparison
with their cross-section, it seemed advisable to mould them in two
sections. The reinforcement in the side walls consisted of round 1/2-in.
rods horizontally, and 3/8-in. rods vertically, spaced as shown on Fig.
1, together with cross-diaphragms as indicated.

The caissons were reinforced for exterior pressures, which were to be
expected during the launching and towing into position, and also for
interior pressures, which were to be expected at low tide, when the
water pressure would be nothing, but the filling of the caissons would
be effective. The corners were reinforced and enlarged. In order to
secure a proper bedding into the sand foundation, a 12-in. lip was
allowed to project all around the caisson below the bottom. In the
bottom there was cast a 3-in. hole, and this was closed by a plug while
the lower section was being towed into place.

The question of the effect of sea water on the concrete was given much
thought. The writer is unable to find any authoritative opinions on this
subject which are not directly controverted by equally authoritative
opinions of a diametrically opposite nature. He thinks it is a question
that this Society might well undertake to investigate promptly and
thoroughly. There can be no question that there are many distressing
instances of failures due to the action of sea water and frost on
concrete, and that many able and experienced engineers in charge of the
engineering departments of the great transportation companies have