Arizona republican., 1909-06-28
MGsSPS. Davis and knipe Have
Finished Their Investigation
FOR BRIDGE FOUNDATION
The Structure According to
Their Plans Will Be 5000
Feet Long and Will Be
Supported by Forty Piers
of the Mushroom Type.

The work of making sound.ngs in
the river for the Center street bridge
was begun a week ago and was fin
ished yesterday. The work was un-
dertaken by B. L. Davis of San Fran
cisco. one OF the engineers who ap-
peared before the board of super
visors last Monday. L. G. Knipe, the
architect, is associated with him in
the enterprise.
A large force of men has been
employed and a large amount OF mon
ey has been spent in making sound
ings and cross sections and in ex-
ploring the river for a long distance
above and below the center line Of
the proposed bridge. These explora-
tions have been made for the pur-
pose of ascertaining where the old
channels were and whether there was
a possibility of coaXing the river into
a permanent channel in the center
of the river by means of dykes erect
ed above IN this part of the work
the investigators have been assisted by
several old residents VINO have told them
where the main and smaller chan
nels were at different times. These
explorations have convinced Messrs.
Davis and Knipe that the river can
not be coaNed but that it will have
to be controlled, or built against.
The soundings have shown that the
pile system -ifaPFsetieable. 1t was
found impossible to sink the sound
ing rod below a depth Of seventeen
feet and Of course it would be i'm
possible TO drive a pile so far The
v.-rfpa In Enf
viii adopt the mushroom pier which
they are sure viii answer every pur-
pose
The mushroom pier is so called
from the fact that it is of a triangular
shape, slopinE from the foot of the
visible pier. up and down the river.
The slope up the river is longer and
the base of the triangle will have a
length Of forty-two feet The pier
of course will he of concrete. The
engineers say this style of constrUc-
tion Will be absolutely safe-just as
safe at "A depth of twenty four feet,
the proposed depth. as if it were car
ried down sixty feet, which is the
oretically below the securing zone.
As a matter of fact no evidences of
securing were discovered below
depth of six feet. It is reasoned that
if at a depth Of twenty-four feet
there should he any securing it could
not extend i'm any period of high
water more than eight or ten feet
under the upper side of the pier. II
could never reach the center of the
pier on which the weight rests. After
the subsistence of the water, if there
has been any securing, the hole may
be filled up and the pier will be left
i'm the same shape il was before.
The plans of Messrs. Davis and
Knipe involve a bridge 5000 feet long
instead Of POO feet as has been pro-
posed There will be fortyfour piers.
The element of cost has been con-
sidered carefully also and it may be
stated that the result comes within
the amount Of money proposed to be
raised A well known construction
company has co-operated in the work
Of sounding and making estimates.
This is said to be the first inves-
tigation OF the river that has ever
been made. 1t has never before been
sounded and no cross section work
has ever been done until now.
Both Mr Knipe and Mr.. Davis have
had extensive experience in cOnstruc-