The morning call. [volume] (San Francisco [Calif.]) 1878-1895, 1895-02-07
State Engineer Il. G. Holmes
Makes Reply.
PRAISES THE PILING PLAN.
The Sticks Are Eighty Feet Long and
Are Not Spliced.
4. PAGE BROWN In A BAD HUMOR.
As an Architect He Designed the FOun.
datiOn Which Is an Engineers
Problem.
4. PAGE BROWN In A BAD HUMOR.


to be charitable toward the sweeping criti-
cisms made upon the foundations of the
new ferry depot by G. Z. Allardt, Civil
Engineer, as published in THE CALL of
yesterday.
Il don't know whether Mr.. Allardt is a
fool or a knave," he said, "but his criti-
cism proves him to be either one or the
other. The proof of pudding is in the
eating and we have the absolute proof Of
experience that piles driven in the mud of
the water front is a better foundation than
the stone wall he recommends. He is alb
soluteiy wrong in almost every proposition
he puts forward. He is wrong IN his state
ment of what purports- to be facts and
wrong in his deductions and theory, and so
palpably so that If it was not matter in
which the public is interested and which is
not supposed to be up in technical engi-
neering, would not bother about answer
ing 1t. But III run over the main points
which Mr., Allardt tries to make.
He says the danger lies not so much in
the liability of the vertical weight causing
the foundation to sink as in its sliding out
into the sea because of the movement of
the made land in that direction caused by
the weight OF buildings on it, and because
the piles do not reach solid ground and
consequently offer no resistance in that
direction. A ocktiling in the mud would
be absolutely safe, he thinks. In support
of his theory he states as fact that the sea-
wall, which he claims was built upon his
plan of rock filing, has stood immovable
for thirty years and that piling at Mare
Island and Oakland have gone out, as he
fears ours will.
His facts and theory were both wrong,
as 1 said. The seawall has not moved out
an inch in twenty years, as I recently
proved by recent surveys over the tracks
OF the original surveys. But it has sunk
repeatedly at different points Why, I
have seen large section of the wall wholly
disappear in a single night. That fact
alone, for it is fact of which we have the
records here, is a complete answer to all he
has said. But there are very many other
equally eloquent facts, chief of which is
that the ferry slips, wholly built of piles
which are driven into the surface of this
mud, mind you, have stood for eighteen
years and have not advanced one inch to-
wards the bay. They have been eaten and
worn, to be sure, and replaced, but that
fact only strengthens it as a witness, for it
has become a solid mass of piles in the
mud, so that were there any pressure be-
hind them they would receive the whole
force of it.
81 know nothing of the work at Mare
Island, but do know why Edison Adams
failed to bind up his Oakland marshes. In
fact, 1 told him his plan would fail before
he tried it, and therefore it is not likely
: lo4 -, IL
lines. He drove piles in the mud and
then dug the mud from the bay side and
threw it On the inside. The balance was
quickly upset and the piles went out be-
fore the weight behind them. 1t was not
because there was general movement
into the bay.
There is no general movement into the
bay and will be none. And if there was,
how would a lot of broken stones sus-
pended in the mud make better resist
ance than a great number OF piles sus-
pended there, as Mr.. Allardt is pleased to
put 1t? l cannot see. The plan Allardt
suggests is that Of the seawall, which, as
say, has sunk repeatedly. 1t contemplates
digging a trench and piling broken stone
into 1t until it ceases to sink. He cannot
mean to dig the trench down to solid
ground, for no dredger can work lower
than forty feet, and he admits the mud is
100 feet deep. The fact is it is $50 feet deep
IN front Of Market street. Would not his
stone filling be suspended in it? If there
was to be rushing down of a steep place
snto the sea, what would prevent this
lot of stone going with it?
"But on the other hand if this rock was
TO be piled into the mud until it Quit sink
ing when would We get to work on the
building? The mud, remember, is $50 feet
dee p, and If the rock sinks into it as has
the seawal by its own weight there would
be nothing to do but fill in until it rose as
much above the surface as might be
deemed practicable, allow it to settle and
then I'LL in again, repeating this until it
remained stationary. What then? Build
big and costly and very heavy building
upon. it? What guarantee have we that
the added weight of the building will not
cause the broken rock to do some more set
ting, and would not that be Just what
might be expected?
snow, SIR" continued Mr.. Holmes, get
ting more interested in his subject as he
progressed, sit is a principle so familiar in
engineering that should not have to call
it to the attention of so old an engineer as
NJ r. Allardt that the skin friction, as it is
called, of the individual pile has value
of its own above that of broken tone as a
support.
'sFor instance, by way of illustration,
a square pier be built in the mud.
1t would have only the friction of its four
sides TO check its progress down
ward and there is no telling how far it
would sink. A great number of piles being
driven within the area that the square pier
occupies each of them has the clutch of the
earth about it, the skin friction to hold
it, and the longer it stays there the firmer
the clutch. A pile you were driving to-day,
for instance, drops several inches at each
blow of the hammer, leave it and return
tomorrow and you will find that it takes
several blows of the hammer to start 1t go
ing. These piers are built upon strong
of piIing driven ninety feet into
The mud and cut off q feet 6 inches be- |
low base Mr.. Allardt must know that all
the brig buildings in the area of the made |
ground that he speaks of as likely TO slide |
9ut are built upon piles and they are all |