HomeMy WebLinkAbout1036; Laguna Riviera Park Volleyball Ct/Comfort Station; Laguna Riviera Park Volleyball Court/Comfort Station; 1976-08-17BENTON ENGINEERING, INC.
APPLIED SOIL MECHANICS FOUNDATIONS
PHILIP HENKING BENTON
PRESIDENT - CIVIL ENGINEER
City of Carlsbad
1200 Elm Avenue
Carlsbad, California 92008
6717 CONVOY COURT
SAN DIEGO, CALIFORNIA 92111
August 17, 1976 TELEPHONE (714) 565-1955
Attention:
Subject:
Mr. Ed Smertelny
Engineering Department
Project No. 76-7-27DF
(Your Contract No. 1036)
Results of Field Density
And Expansion Tests
Volleyball Court and
Comfort Station
Laguna Riviera Park
Park Drive and Kelly Drive
Carlsbad, California
RECEIVED
AUG20 1976
CITY OF CARLSBAD
Engineering Department
Gentlemen:
This is to report the results of two field density tests taken in subgrade soils for the new volleyball
court at Laguna Riviera Park in Carlsbad, California. An expansion test was also performed on a
sample of soil obtained at the site of the proposed comfort station and recommendations and
precautions are presented for construction on this soil.
The results of the field density tests taken in the volleyball court area on July 28, 1976 are
presented as follows:
Test
No.
1
2
Approx-
imate
Location
West Side
of Court
East Side
of Court
Depth
of Test
Below
Existing
Grade
in Inches
4-10
0- 6
Field
Moisture
% dry wt
7.6
5.4
Dry
Density
Ib/cu ft
124.9
115.1
Approx-
imate *
Maximum
Dry
Density
Ib/cu ft
130.1
130.1
•
Percent
Compaction
95.6
88.4
Based on one laboratory compaction test conducted at the approximate optimum
moisture content.
Project No. 76-7-27DF s^ -2- ^ August 17, 1976
City of Carlsbad ^ ^
LABORATORY TEST RESULTS
Compaction tests were performed on representative samples of the soils to establish compaction
criteria. The soils were tested according to the A.S.T.M. D 1557-70 method of compaction
which uses 25 blows of a 10 pound rammer dropping 18 inches on each of 5 layers in a 4 inch
diameter 1/30 cubic foot mold. The results of the tests are presented as follows:
Maximum Optimum Mois-
Soil Dry Density ture Content
Location Description Ib/cu ft % dry wt
Volleyball Court Gray brown fine to coarse sand 130.1 ** 9.6
Comfort Station Dark brownish gray silty clay 112.2 14.7
** Value determined by performing one compaction test at the approximate optimum
moisture content.
In addition to the above laboratory tests, an expansion test was performed on the sample of soil
obtained in the area for the proposed comfort station to determine its volumetric change character-
istics with change in moisture content. The recorded expansion of the sample is presented as
follows:
Percent Expansion
Under Unit Load of
500 Pounds per Square
Soil Foot from Air Dry
Description to Saturation
Dark brownish gray silty clay 14.81
(Molded to 91 percent of maximum dry density)
Recommendations for Comfort Station
It is concluded from the results of the laboratory expansion test that the silty clay soil encountered
in the area for the proposed comfort station would be considered as a critically "expansive" soil.
Therefore, in order to minimize possible detrimental effects caused by this potentially "expansive"
soil, the following special design and precautions are recommended:
10 Use continuous interconnected reinforced concrete footings throughout
and place these at a minimum depth of 2.0 feet below the lowest
adigcentexterior final groundjsurface^
2. Reinforce and interconnect continuously with steel bars all interior and
exterior footings with a minimum of one "j bar at 3 inches above the
bottom of aJJ footings..qnd.pne *5 bar placed 1 1/2 inches below the top
of the stems of the footings.
BENTON ENGINEERING. INC.
Project No. 76-7-27DF - -. -3- ^ > August 17, 1976
City of Carlsbad V^ vy
3. Reinforce the concrete floor slab with a minimum of 6 x 6 - 6/6 welded
wire fabric and provide a base Jayer of at least 4 inches of 3/4 to 1 inch
size crushed rock beneath the slab._ If desirable, a moisture barrier could
be provided above the crushed rock and then 2 inches of sand placed over
the moisture barrier and below the bottom of the slab in order to prevent
moisture from penetrating through the floor slab.
Moisten the subgrade soils to a depth of 3 feet below finished subgrade to
a moisture content of at least three percent greater than optimum prior to
pouring the footings and floor slab.
5. Provide positive drainage away from all perimeter footings with a vertical
fall of at least 5 inches in a horizontal distance of 5 feet outside the
perimeter of the building.
Respectfully submitted,
BENTON ENGINEERING, INC.
By
R. C. Remer
Reviewed by
Philip H. Benfon, Civil Engineer
R.C.E. No. 10332
Distr: (3) Addressee
RCR/PHB/ew
BENTON ENGINEERING, INC.