HomeMy WebLinkAbout11-01-1990 - Re: Design of Timber Retaining Walls IEFERICKSON
. ENGINEERING
Consulting Engineers
November 1, 1990
Jim Speich
Aspen Landscape Inc.
P.O. Box 834
Wayzata, MN 55391
RE: Design of Timber Retaining Walls at the Walker Residence in Orono, MN
Dear Mr. Speich:
I have completed the design of the retaining walls for the project referred to above. There are three
cross-sectional drawings enclosed. Two of the drawings are for traditional header-and-deadman
timber walls and one is for a timber wall reinforced with earth anchors. Also enclosed is a detail
drawing showing how to connect the earth anchors to the timbers that make up the face of the wall.
This design specifies Minuteman 650I earth anchors. If you decide to substitute Duckbill earth
anchors instead, the equivalent model is 138-DB 1. Please check with me before substituting any
other type or model of earth anchor. All of the hardware used to construct this wall should be hot-
dip galvanized steel.
The design specifies that the first two feet of soil behind the wall must be clean, free-draining sand.
This will help prevent the buildup of water behind the wall, one of the major causes of wall
failures. The design also specifies that a 6-inch layer of high-clay content soil should be placed on
the top of the backfill. This will help keep water from entering the soil behind the wall. It is
extremely important that the backfill soil be thoroughly compacted. I recommend that you use a
vibrating plate compactor and compact the soil in lifts of not more than 1 foot.
Finally, if you have any questions at all about this design,please feel free to call me at 929-6791.
Thank you very much for allowing Erickson Engineering to provide the engineering design on this
project.
Sincerely,
ERICKSON ENGINEERING COMPANY
oseph A. Arsenault
Enc.
Erickson Engineering Company 3340 Republic Avenue St. Louis Park, Minnesota 55426 (612)929-6791
6"HIGH-CLAY CONTENT \ \ N. N.
(� ��]}�' \ • 4'4'\' ' ' ' ' ' .
SOIL CAP ML Y \ \ 1'A'4'\'\f\' \'4'\'\'4
6:1 fff / FFJf { fff / Ifff / ff
\
N. N. \ \ \ ,' ,' \ \ \ N. N. N. 4 N. N. N.
{ f f f f { { f f f { / / / f { { f {
f f / / I J / / / i f f I f f / J f /
\
S. S. S. S. 4 \ 4 4 \ \ \ 4 ♦ S. \ \ 4
f I f f f f I f / { f f
N. N. \ N. 4 N. N. \ \ \ \ N. N. ♦ \ \ N. N.
f { f f f f / f / { f J f f f f f f
\ \ 4 4 4 \ \ \ \ N. N. ♦ \ \ \ \
f / J 1 1 / / / / f
N. \ N. 4 \ N. \ \ 4 \ \ \ \ 4 \ N.
f f / f I f f I
4 \ \ \ \ \ 4 \ \ \ N. 4 4 \ N. \
f f f f f
\ \
MINUTEMAN EARTH ANCHOR 650I(TYPICAL)
0
0.5"MINIMUM DIAMETER
= GALVANIZED STEEL CABLE
_is_ __ 2.0'MINIMUM,CLEAN
_ FREE-DRAINING SAND
6.0' _
_V 0—
BE
EARTH ANCHORS SHALL
SPACED A MAXIMUM
HORIZONTAL DISTANCE
_ OF 8 FEET ON CENTER
A , 0—
V
• 5.0'
• 6.5' .-
ASSUMPTIONS:
1. ONSITE SOIL IS A SANDY CLAY WITH A FRICTION ANGLE OF 27°.
2. BAITER OF THE WALL IS 1 INCH PER FOOT.
3. MINIMUM FACTOR OF SAFETY FOR WALL AS SHOWN IS 1.6.
I HEREBY CERTIFY THAT THIS PLAN WAS PREPARED WALKER RESIDENCE: 6.0'WALL,EARTH ANCHORS
BY ME OR UNDER MY DIRECT SUPERVISION AND THAT
I AM A DULY REGISTERED PROFESSIONAL ENGINEER E R I C KS O N
UNDER THE LAWS OF THE STATE OF MINNESOTA. ENGINEERING
Consulting Engineers
Brian D.Walter,P.E.
3340 Republic Avenue
/ ///7O /-3c7(' St. Louis Park, MN 55426
Date Reg.No. (612) 929-6791
/ { / .
4 4 4 4 4
6"HIGH-CLAY CONTENT e]U�`
\ \ ♦/4/4/\/4/4/4/\'\'
ML Y 4 4 4/ ! / / { {414f\{4f 414f 411{4.
SOIL CAP 6' / / / { / / f f / / / / / / / / ! e /
\ \ \ \ t 4 4 \ 4 4 4 4 \ N. N. N. 4
f f f / / f f f ! / f f ! f ! f { !
\ \ \ \ 4 4 4 4 4 4 4 4 4 \ \ 4 4
f f f { { f ! f ! / {
4 4 4 1 4 4 \ \ t ♦ 4 4 4 4 t \ 4
f l ! / f
\ 4 4 4 ♦ 4 4 4 4 4 4 4 4 \ 4 4 4
4 4 4 \ \ N. 4 4 4 4 4 4 4 4 4 4
! ! ! f { { ! / ! f { f f f f { {
4 4 4 4 4 4 4 4 4 4 4 4 \ 4 4 4
/ ! !
N. N. 4 \ 4 4 4 1 N. N. 4 \ 4 4 4
r /
A
4 4 4 4 4 4 ♦ 4 \ 4 ♦ \ \
f f !
\ 4 4 4 4 4 4 4
•////: ef,./ ///
4 4
- 2.0'MINIMUM,CLEAN
FREE-DRAINING SAND
tyl;
•
7.0' ♦ r
• /F./
A
EMBERS
1111==1111—=— ,� ALL TREATED TIMBERS
ASSUMPTIONS: X 8'
ASSUMPTIONS:
1. ONSITE SOIL IS A SANDY CLAY WITH A FRICTION ANGLE OF 27°.
2. BATTER OF THE WALL IS 1 INCH PER FOOT.
3. MINIMUM FACTOR OF SAFETY FOR WALL AS SHOWN IS 2.5.
I HEREBY CERTIFY THAT THIS PLAN WAS PREPARED WALKER RESIDENCE: 7.0-FOOT WALL
BY ME OR UNDER MY DIRECT SUPERVISION AND THAT
I AM A DULY REGISTERED PROFESSIONAL ENGINF.FR E R I C KS O N
UNDER THE LAWS OF THE STA lE OF MINNESOTA. ENGINEERING
Consulting Engineers
Brian D.Walter,P.E. G~/
3340 Republic Avenue
/�X /3S,7( St. Louis Park, MN 55426
Date Reg. No. (612) 929-6791
6" HIGH-CLAY CONTENT
4 S. \ S. \ \ \ \f
SOIL CAP1VI8X
6.1 F F F F F F f F F f f { F F F { F F F {
4 \ \ \ \ \ \ 4 \ \ \ \ \ 4 4 \ \ \ \
F F F F F J J f f F f f f f F { F F f
4 \ \ 4 \ \ \ \ \ \ \ \ \ \ \ \ \
F J J F F { F F F F F J F f f f f f
\ \ \ \ \ \ \ 4 4 S. \ \ \ \ \ \ \ \
{ F f F f F F f F F F F F J F F F F F
\ \ \ \ \ \ 4 \ \ \ \ \ 4 4 4 4 \ \
f / f f f f F f f
\ 4 \ \ \ 4 \ 4 \ \ \ \ \ \ \ \
F f f f f f f F f F J F F f f F {
f F F J f F F f F F f f F F F f F f
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \IV \
f f f f F F J f f f F F f f F f f
4 \ \ \ \ \ \ \ \ \ \ \ \ \
F { f F f { { f f F F
3111A.
•
6.0 I / //:///_
•
2.0'MINIMUM,CLEAN
♦ FREE-DRAINING SAND
• / ///
•,://
Alk/
ALL MEMBERS ARE 6" X 6"X 8'
(111=1111- TREATED TIMBERS
ASSUMPTIONS:
1. ONSITE SOIL IS A SANDY CLAY WITH A FRICTION ANGLE OF 27°.
2. BATTER OF THE WALL IS 1 INCH PER FOOT.
3. MINIMUM FACTOR OF SAFETY FOR WALL AS SHOWN IS 2.5.
I HEREBY CERTIFY THAT THIS PLAN WAS PREPARED WALKER RESIDENCE: 6.0-FOOT WALL
BY ME OR UNDER MY DIRECT SUPERVISION AND THAT E R I C KSO N
I AM A DULY REGISTERED PROFESSIONAL ENGINEER
UNDER THE LAWS OF THE STA I'h OFOF/MINNESOTA. EEa ENGINEERING
,,Gt.///Z Consulting Engineers
Brian D.Walter,P.E.
3340 Republic Avenue
/,) -74( St. Louis Park, MN 55426
Date Reg.No. (612) 929-6791