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ER-5863 - Slope Block Inc.
LEGACY REPORT
Business/Regional Office
#
5360 Workman Mill Road, Whittier, California 90601
#
(562) 699-0543
Regional Office
#
900 Montclair Road, Suite A, Birmingham, Alabama 35213
#
(205) 599-9800
Regional Office
#
4051 West Flossmoor Road, Country Club Hills, Illinois 60478
#
(708) 799-2305
ICC Evaluation Service, Inc.
www.icc-es.org
Legacy report on the 1997 Uniform Building Code
ER-5863
Reissued March 1, 2006
Copyright © 2006
Page 1 of 4
ICC-ES legacy reports are not to be construed as representing aesthetics or any other attributes not specifically addressed, nor are they to be construed as
an endorsement of the subject of the report or a recommendation for its use. There is no warranty by ICC Evaluation Service, Inc., express or implied, as to
any finding or other matter in this report, or as to any product covered by the report.
DIVISION: 02SITE CONSTRUCTION
Section: 02830Retaining Walls
SLOPE BLOCK WALL SYSTEM
SLOPE BLOCK INC.
280 ASTA AVENUE
NEWBURY PARK, CALIFORNIA 91320
1.0 SUBJECT
Slope Block Wall System.
2.0 DESCRIPTION
2.1
General:
The Slope Block Wall System utilizes a concrete revetment-
type block for construction of gravity retaining walls. The wall
system is assembled in running bond without mortar, grout,
or reinforcement. Type S1 concrete block is 13.8 inches (350
mm) deep, 5.9 inches (150 mm) high, and 11.8 inches (300
mm) wide, and weighs 66 pounds (30 kg). The blocks may be
assembled in a closed (solid) configuration, open
(checkerboard pattern) arrangement, alternate (one course
closed alternating with one course open in a continuous
pattern), or a mixed arrangement. All configurations except
the solid permit planting in the 5.9-inch-wide (150 mm) gap
between Type S1 units and the 3.9-inch-wide (100 mm) gap
between Type S2 units. Type S2 concrete block is 13.8
inches (350 mm) deep, 5.9 inches (150 mm) high, and 7.9
inches (200 mm) wide, and weighs 43 pounds (20 kg).
The units must comply with UBC (1997 Uniform Building
Code) Standard 21-4 and have a minimum 28-day
compressive strength of 4,000 psi (27.6 MPa) when tested in
accordance with ASTM C 140 using Type I or Type II portland
cement complying with ASTM C 150-94. Dimensional
tolerances are as follows: depth, ±
1
/
8
inch (3.2 mm); width, ±
1
/
8
inch (3.2 mm); height ±
5
/
64
inch (2 mm).
2.2
Design:
2.2.1
General: The Slope Block Wall System depends upon
its weight and geometry to counteract lateral earth pressure
or other lateral forces. A soils investigation determines the
soil properties and values for design. The effects of
surcharges must be considered. The lateral earth pressure is
determined using the Coulomb theory, and the angle of wall
friction is assumed to be two-thirds the angle of internal
friction.
2.2.2
Structural Analysis:
2.2.2.1 General: Structural calculations must be submitted
to the building official for each wall system. The structural
analysis shall be based on accepted engineering principles
and Section 2107 of the UBC for unreinforced, mortarless
working stress design, except where otherwise specified in
this report. When they are requested, the engineer of record
is to provide stability analysis calculations for seismically
active areas. All contact surfaces of the units must be
maintained in compression; a net resultant tension force is
not permitted in any portion of the retaining wall. The
compressive stress is limited to 100 psi (689 kPa). The
coefficient of friction between blocks is 0.6. A drawing of each
block size is to be included with the design description,
indicating the portion of the contact surfaces providing
resistance to sliding block to block. Walls must be designed
to provide a minimum safety factor of 1.5 against sliding
between units. Foundations must be designed to provide a
minimum safety factor against overturning and sliding equal
to 1.5. See Figure 1 for additional details.
2.2.3
Wall Revetment: For walls having an angle of
inclination equal to or greater than 27 degrees from the
vertical, the Slope Block Wall System only functions as
cladding or erosion control. Calculations for overturning are
not required for stability analysis. A soils investigation is
optional. Figure 2 provides additional details.
The resistance to sliding is determined by the following
equation:
F =
W
Pp
Pa
*
tan +
where:
F
= Factor of safety against sliding.
P
a
= Equivalent active pressure resultant, pounds (N).
P
p
= Equivalent passive pressure resultant, pounds (N).
W = Total weight of wall, pounds (N).
*
= Angle of wall (external) friction.
The value of F must be at least 1.5.
2.3
Assembly:
The minimum angle of wall inclination is 10 degrees from
vertical toward the backfill. For walls having an angle of
inclination equal to or greater than 27 degrees, wall
calculations for overturning are not required for stability
analysis. For walls having an angle of inclination from 15 to
27 degrees, the lateral earth pressure determined by the Page 2 of 4
ER-5863
Coulomb theory is multiplied by a factor of 1.2. A blanket of
cohesionless backfill is placed behind the wall. The width of
the backfill blanket is determined by the soils engineer. The
groundwater table must be a minimum distance of 3 feet (914
mm) below the bottom of the footing. If soils are found to have
poor drainage qualities, a perforated drain line system is
installed to prevent a hydrostatic pressure buildup behind the
wall. The in-place wall must be constructed to a maximum
cumulative tolerance of ±
3
/
4
inch (19.1 mm) from
specifications, measured every 10 feet (3048 mm) along both
wall height and width. Each block course must be placed to
a tolerance of ±
1
/
4
inch (6.4 mm).
The top course of the retaining wall system is always a
closed assembly set in mortar. The bottom course of block is
also a closed assembly set in the wet footing concrete, Type
S mortar, or epoxy grout using a template to assure the
correct angle of inclination (tilt) of the wall. The footings may
be eliminated when calculations show that the resulting
bearing pressure due to wall weight and overturning does not
exceed the allowable bearing pressure for the soil supporting
the wall.
Type S1 block may be assembled in a curved layout with a
minimum radius of 9 feet (2743 mm) measured from the back
face (earth face) of the bottom course of block and the
outside face (exposed face) of the top course of block. Type
S1 outside face gap is limited to 5.9 inches (150 mm),
maximum, for curved open arrangement with a minimum
bearing contact width of 2.5 inches (63.5 mm), measured
from either side of the gap. Type S2 outside face gap is
limited to 3.8 inches (97 mm), maximum, for curved open
arrangement with a minimum bearing contact width of 2
inches (51 mm), measured from either side of the gap.
2.4
Special Inspection:
Continuous special inspection in accordance with Section
1701 of the UBC is required. The special inspectors duties
include observing that proper back-filling tolerances and the
angle of wall inclination are attained. In lieu of continuous
special inspection, periodic special inspection in accordance
with Section 1701.6.2 of the UBC is permitted provided that
the installers are certified by Slope Block Inc.; that structural
observation in accordance with Section 1702 of the UBC is
conducted; and that the following verifications are made,
subject to the building officials approval:
a. Footing details conform to plans and specifications.
b. The first course of the Slope Block Wall System, including
the wall inclination, is in conformance with the plans and
specifications.
c. The backfill is as required by the plans and specifications.
d. At the completion of wall installation, the wall inclination
does not deviate more than one degree from the specified
inclination, and finish grading is in place.
2.5
Identification:
Each shipping pallet is identified with the name and address
of Slope Block, Inc., the manufacturers name and address,
the words Slope Block and the evaluation report number
(ER-5863).
3.0 EVIDENCE SUBMITTED
Descriptive literature, calculations and a quality control
manual.
4.0 FINDINGS
That the Slope Block Wall System complies with the 1997
Uniform Building Code (UBC), subject to the following
conditions:
4.1
The Slope Block units are verified as complying with
the mix design, compressive strength and
dimensions noted in this report.
4.2
The system is identified and installed in accordance
with this report and the manufacturers instructions.
4.3
Special inspection is required in accordance with
Section 2.4.
4.4
Specific retaining walls must be designed in
accordance with recognized engineering principles
and the design parameters in this report. The design
must be approved by the building official.
4.5
A soils investigation, providing information outlined
in Section 1804 of the UBC, must be provided for
each project site, except as permitted in Section
2.2.2. The report must specify allowable soil
pressures for design by the project engineer.
4.6
The Slope Block units are manufactured by Orco
Block Co., at their manufacturing facility located at
600 North Hathaway Street, Banning, California.
This report is subject to re-examination in two years. Page 3 of
4
ER-5863
PROPERTY
CLOSED
OPEN
W
all
W
eight
(psf)
138
94
l
1
(inches)
12
4
Area (inch
2
) =
b
1
x
l
1
1