The morning call., 1895-02-17

springing line of the arches, i e.. three feet six
inches below the city base to the point shown |
on the plan, one foot above the city base, the |
piers and concrete arches and vaults shall be |
constructed OF concrete OF Portland cement to
be mixed under the direction of the chief engi- |
neer OF the Harbor Commissioners, in the pro-
portion OF one barrel of cement to eighteen cubic
feet OF rock and four cubic feet of sand. The
rocA LOT TINS work must not be larger than one
inch at its greatest dimension. The vaulting
Is to be constructed in alternate bay l. e., every
other bay or vault shall be built in and allowed
to set thirty days before the alternate bay is
bu1lt IN. This procedure should be under the
direct supervision and direction of the chief
engineer of the Harbor Commissioners"
Our investigation has not shown any differ
ence in the formula used for that of the piers
and that of the arches. In the matter OF alter
nate bays we find that the thirty-day clause
has been disregarded. We further find that in
the dumping OF concrete from the chute, on
the crown OF the arch, the continual play
ing OF the hose on the same carries the cement
to the outer edges OF the arch, thereby ma
terally weakening that portion which should
nave the greatest strength. We recommend
that this particular portion of the work should
be more strictly executed and supervised.
CEMENT PLAsTERING-The specifications say
that the soffits of all the arches, vaults, ETC.,
are to be thoroughly plastered with cement
cement to one part of sand. This plastering is
to be applied in one coat one-fourth of an inch
In thickness when finished. 1t shall be trow-
eled smooth and allowed to dry thoroughly be-
fore being exposed to the salt water Said
cement plastering is to be wet every day with
fresh water and kept covered from the sun and
protected from the salt water in the manner
as specified for the concrete piers and arches.
We find that the above has not been complied
car no
piled with for the reason that the exterior of
the work in all cases has set and being ex-
posed to salt water and the rise and fall of the
tide, carrying with it vast amount of greasy
substance, as is the case around all large sea-
ports where sewage and other oily substances
are discharged in the water, the same has COW
cred the entire interior surfaces with Shiny
mass, thereby making itimpossible to make any
material adhere to the same.
DRILL ExPERIMENTs-Hav drilled into sew
eral piers with l-inch drill to depth of from
sixteen to twenty-eight inches we find that in
the latter depth we encountered nothing but
sand and cement with very small proportion
of rock. This proves conclusively that the ma
terials have not been properly incorporated
and further confirms our belief that too much
water has been used, therefore proving that the
sides of the piers received the greatest portions
of the cement, which proves it cannot be a
homogeneous mass, as called for And as for
making tensile or hydraulic test of any por-
ton thereof it was impossible to do SO unless
we could tunnel to procure the desired sample,
which, in our opinion, must be done. We were
prevented from selecting samples of such por-
tions of the work we desired, but were in
formed by the contractor that we could take
samples from certain piers pointed out by him.
Samples of boring are now in the hands of
qualified chemist, who will shortly make his
report to you direct.
PILEs-Specifcations say that all piles must
be fresh cut frst-quality Oregon pine piles,
80 feet inches long, 16 inches in diameter at
the butt and not less than z inches in diameter
at the top and driven 20 feet inches below
that the majority of the piles in sight are more
nearly II inches il diameter than 16 inches as
specified. In our judgment we recommend
that it would be wise to adopt some method of
an inspection of the piling. This, we think, is
/ of paramount importance. Let the concrete
claimed be ever so good, since it is on sus-
| pended piles, or, rather, piles hung in soft
muck, since they have not reached hard pan,
no one can make calculation as to what their
| carrying strength may be and what the factor
of safety might be.
In concluding this report we respectfully
recommend that more searching untram-
| meled investigation be made, and that future
operations be more closely guarded and in
spected, which, in our Judgment, would be of
lasting benefit to the State. Yours most
| respectfully, P. ]. DoNAHoE,
S. K. DOYLE.