66 THE KANSAS CITY BRIDGE.

tions of the well walls were torn away, to secure a por bond between the
masonry and the filling of beton.

The layer of boulders had been the cause of considerable delay, while it
had also been productive of some additional expense ; but the character of the
larger stones, which, by their roughness, showed that they were seldom, if ever,
disturbed by the water, indicated the perfect security of a foundation put in at:
this depth ; and the mere presence of such material was equivalent to three feet
of riprap protection around the base of the pier.

The false-works were stripped, the trusses taken down, and on the 26th of
March nothing remained above the lower platform. A fifth section was added
to the caisson as a security against any rise in the river ; a derrick was mounted
on the platform on the north side of the pier; on the 2d day of April the
laying of masonry was resumed and the pier was built up at once.

This foundation, which from its situation might fairly be regarded as much
the most difficult on the work, became, in its final execution, the most success-
ful of all, and was put down in a less time than was consumed on any other
deep foundation. The plan here adopted is believed to admit of wide applica-
tion ; and, while it is more expensive than the simple foundations which are
used in ordinary streams, it becomes a cheap method of founding in deep and
unstable bottoms. By slight modifications it can be combined with the pneu-
matic process, in such a way as to allow extraordinary obstacles to be removed.
by men, while the entire sand excavation is made by machinery. It is also
applicable to foundations of extraordinary depth, where the pneumatic process
must fail from the inability of the men to stand the air pressure ; it could be
carried to a depth double that to which pneumatic tubes or caissons have been
sunk, with the occasional use of the air chamber for a very short time ; and if
this be entirely dispensed with, it may even be extended to a depth of several
hundred feet in clean sand, or with machinery sufficiently heavy to remove
obstacles.*

 

* A patent for this method of founding has been applied for by the authors of this volume.