The herald., 1896-02-22
A Good Piece OF Work by City
Clerk Luckenbach
THE NEW SYSTEM ADOPTED
By Which Danger Of Error Is Completely
Done Away With
The Amended Specifications for Cement Side
walks and Curbs az Adopted by the
Board of Public Works

The necessity for a thorough revision of
all the specifications for public improve
ments, such as street paving and cement
pavement work, has long been apparent,
and yesterday Clerk Lu:kenbach appeared
before the board of public works and pre-
sented the revised specifications for the
construction of cement sidewalks and
curbs in the city limits, which were adopt
ed by the board and will be presented to
the council for approval at the meeting on
Monday next.
The specifications as adopted heretofore
have been simply designated by numbers,
as No. -, for instance, and when amend
ed in any particular were designated by
the same number, with the prefix 'amend-
ed" In case second or third amend
ment was adopted, there was nothing to
indicate that such was the case, and in
consequence there was always danger of
valuable contract being shocked out
through some misunderstanding as to
which of the amended specifications COW
cred the case. AT any rate, it left the
specifications ambiguous, and it was to
remedy this trouble that the revision and
reclassification was had. Under the new
system when a set of specifications is
adopted it will be numbered and lettered,
commencing with A. Should they be
amended they will still carry the same
number, but with the letter B, and so on
down the alphabet. BY this means all
danger of a mistake is done away with,
and the specifications can be designated
definitely. Following are the specifica-
tions for cement sidewalks and curbs
adopted yesterday. and which are desig-
mated n enari ifiratiOUa M. 1O-A.
CONSTRUCTION AND DIMENSIONS
The curbing shall be six inches on top by
eighteen inches deep by twelve inches on
the bottom, having batter of three inches
on each side. The excavation for curb
ing on both sides.
The curb shall be composed Of concrete
of the proportion hereinafter specified.
and finishing coat composed of one
part of cement to one part sand,
one-half inch thick on top, and on
the face to a depth of two inches below
that given by the city engineer for the
depth of the curb face.
Sidewalks shall be three and one-half
inches thick, built on a foundation con-
structed as follows: All soft or spongy
material is to he removed and replaced
with sand gravel of quality that will pack
when moistened, and then tamped or
three and one-half inches below the fin
ished surface of the walk.
Upon the foundation thus prepared shall
be spread layer of concrete of the proper
ton hereinafter described, which shall be
three inches thick after being we'll tapped.
This concrete base shall receive finishing
coat composed of one part OF cement to
one part of sand one-half inch thick, and
the surface shall be srnoothed surfaced,
polished and marked off into blocks.
After the concrete has been laid in the
curb, good strong grout, consisting of
one part cement to four parts water, shall
be applied to the top of the curb, and
where no cement walk joins the curb, for
at least two inches down on back or inside
of curb; said surface 80 grouted to be COW
er6d with cement mortar one-half inch
thick, composed of one part of cement to
one part of sand.
Where the cement sidewalk is not the
full width of the walk the earth or other
material must be removed to the grade of
the finished work on the portion not occlI-
pied by cement work. Where filling is re-
quired, suitable material must be placed
on the unoccupied portion, so as to make
the whole width of walk from curb to
property line one continuous plane.
The material removed, if eft in the road
way, must be placed where the street su-
perintendeut may designate. or if required
by him to be removed entirely from the
6tC60ts tn9 Same UnuSU D0 QOIl6 al tl6 eN-
pense of the contractor.
The material to be supplied in case of
fill must be of good sound earth and built
up in layers of not to exceed one foot in
thickness, each layer to be we'll packed by
rolling or tamping, and if the fill shall ex-
ceed two and a half feet in height 1t shall
be rolled when completed with a roller
weighing not less than 25O pounds to the
linear inch.
All sidewalks and curbs must be pro-
tected from the sun and thoroughly wa.
tered for ten days after completed.
MATERIALS
All cement used shall be of the best
Portland cement. Sand and gravel shall
be clean and sharp, free from loan, vege-
table matter, silt or dirt. No gravel stone
ehall be larger in diameter than that which
will pass through a ring two incl
diameter.
CEMENT TESTS
The city engineer shall make, or cause
to be made, any tests that may be desired
to satisfy him (the city engineer) as to the
strength and quality of the cement, and he
shall reject any and all parcels that do not
conform, to the following conditions and
tests:
All tests shall be made by the methods
and under the conditions prescribed by the
committee of the American Society of
Civil Engineers, and shall be open to con-
tractors.
Fineness-No less than 90 per cent by
weight of the cement must pass through
sieve of fifty meshes to the inch; not less
than S5 per cent by weight of the cement
must pass through sieve of 100 meshes
to the inch.
Time of setting-Initial set in not less
than fifteen minutes when mixed with the
smallest possible amount of water at the
temperature at which it flows from the tap
in the testing room provided by the city of
Los Angeles.
Tensile strength - After twenty-four
hours (briquettes to remain in air until
hard set; to be submerged in water during
the rest of the twenty-four hours), neat,l25
pounds per square inch; after seven days
(briquettes to remain in air one day, III wa
ter six days., neat, 800 pounds per square
inch; three parts sand to one part cement,
100 pounds per square inch. After twenty
eight days (briquettes to remain in air one
day. in water twenty-seven days., neat,
400 pounds per square inch; three parts
sand to one part cement, 125 pounds per
square inch.
The contractor shall give at least one
weeks notice to the city engineer, SO that
he may test the cement it is proposed to
use on the work. No cement shall be
hauled on the work that has not been tested
and accepted by the city engineer.
CONCRETE, PROPORTIONS, MINING
Concrete shall consist of one part by