8/18/2019 ACI 318-08 Design of Retaining Wall With
Counterfort_Rev1.0_08-Apr-2014
1/2Page 1 of 2
Retaining Wall with Counterfort Check of Stability &
Calculation of Internal forces
And design sections According ACI 318-08 Rev1.0
Project :- Designed by:- M. Abu Shady
Building :- Checked by:- M. Abu Shady
Element:- Retaining Wall with Counterfort Date:-
Location:- M.A.S.
General Input :
fc'=25 N/mm2 fy=420 N/mm2
ɣC=25 KN/m3tw= 0.90 m LL=20.0 KN/m2 277.10 m
µ= 0.58
qall=150 KN/m2 Active Soil
Cover=100 mm ɣs=22KN/m3
Ignore Passive Soil YES Ka= 0.500
Ignore Soil wet W 5 YES
H=2.70m
275.00 m
Passive Soil
Hp=0.60m Kp= 3
tb= 0.60 m 274.40 m
0.90m 0.90m
b= 2.70 m tc= 0.20 m
d=0.49m
Lc= 1.75 m
tc= 0.20 m
1-Check Stability of Wall: Elevation
a- Check of Retaining Wall Overturning:
Calculation of ∑W & Stability Moment ∑M
Description of loads Loads W kN/m'Dist. From load
to point O (m)
Moments M @
O KN.m/m'Weight of stem
W147.25 1.350 63.79 = 10.00
Weight of base slab W2 40.50 1.350 54.68 = 40.10
Weight of earth over
Heel slab W341.58 2.250 93.56 = 0.00
Weight of Counterfort
W4 using(ɣc-ɣs)1.62 2.100 3.40 = 49.59
Weight of earth over
Toe slab W50.00 0.450 0.00
∑W=130.95 ∑M=215.42
= 4.34
b- Check of Retaining Wall Sliding:
= 50.10
= 75.95
= 1.52
c- Check of Retaining Wall bearing Capacity:
finding eccentricity e, take moments @ point O
= 1.27 m = 0.08 m = 0.450 m
09-Feb-16
> 1.5, OK SAFE
> 1.5, OK SAFE
OK SAFE < qall
57.51 KN/m2
39.49 KN/m2
45.50 KN/m2
51.50 KN/m2
54.77 KN/m2
Plan
co
ℎ =ɣ
2
2
ℎ =
⁄
C , , &
⁄. ′
= ∑/
⁄
⁄ ′
µ∑ ⁄ ′
= µ∑ /∑ℎ
=
± = ∑
1∗ ± ∗∑
�∗3
2
= ∑
± 6∗∑
= ∑
(1 ± 6
)
= ∑
(1 +
6
)=
M@o= 0 = −∑ ∗ x + ∑ − ,∴ ,
= ∑
(1 −
6
)=
, =
, =
, /6
, =
ℎ =ɣ
2
2
= ℎ ∗ +ℎ* - ℎ*
⁄
∑ ℎ = ℎ+ ℎ- ℎ
e ≤ /6 to ignore tension stress
l o n g i t u d i n a l d i r e c t i o n
Transverse direction
-
8/18/2019 ACI 318-08 Design of Retaining Wall With
Counterfort_Rev1.0_08-Apr-2014
2/2Page 2 of 2
Retaining Wall with Counterfort Check of Stability &
Calculation of Internal forces
And design sections According ACI 318-08 Rev1.0
Project :- Designed by:- M. Abu Shady
Building :- Checked by:- M. Abu Shady
Element:- Retaining Wall with Counterfort Date:-
Location:- M.A.S.
09-Feb-16
2-Internal Forces of Retaining Wall:
a- Toe Slab Moment and Shear:
finding net stress on Toe Slab42.5 KN/m2 Upward 39.8
KN/m2 Upward
36.5 KN/m2 Upward
24.6KN.m/m BOT. RFT. Use 5 T 18 /m' Tension RFT.
Q Toe max Ult. @d dis. From b = 25 KN/m < ΦVc =
312 KN/m Where
ACI318-08 , Eq 11-3
b- Heel Slab Moment and Shear:
finding net stress on Heel Slab
-18.9 KN/m2 Downward
-24.9 KN/m2 Downward
-24.7 KN/m2 Downward
-13.1KN.m/m TOP RFT. Use 6 T 16 /m' Tension RFT.
M heel longitudinal Ult. @d -Ve = -11.4KN.m/m TOP RFT. Use 6 T
16 /m' Tension RFT.
M heel longitudinal Ult. @d +Ve = 9.5KN.m/m BOT. RFT. Use 6 T 16
/m' Tension RFT.
Q Heel max Transverse Ult. @d = 32 KN/m < ΦVc
= 312 KN/m
Q Heel max longitudinal Ult. @d = 33 KN/m <
ΦVc = 312 KN/m
C- Stem Slab Moment and Shear:
33.10 23.48 10.00 KN/m2
M stem vertical Ult. @c cant -ve = -15.3KN.m/m Use 9 T 16 /m'
Tension RFT.
M stem longitudinal Ult. @z -Ve = -10.8KN.m/m Use 15 T 12 /m'
Tension RFT.
M stem longitudinal Ult. @z +Ve = 9.0KN.m/m Use 15 T 12 /m'
Tension RFT.
M stem longitudinal Ult. @z0 -Ve = -4.6KN.m/m Use 15 T 12 /m'
Tension RFT.
M stem longitudinal Ult. @z0 +Ve = 3.8KN.m/m Use 15 T 12 /m'
Tension RFT.
Q Stem max Cantilever Ult. @c = 43 KN/m < ΦVc
= 504 KN/m
Q Stem max longitudinal Ult. @z = 31 KN/m <
ΦVc
d- Counterfort Moment and Shear:
= 0.83 m = 1.40 m = 0.70 m
= 0.55 m = 0.28 m
3.4KN.m/m Use 1 T 22 Tension RFT.
17.3KN.m/m Use 1 T 22 Tension RFT.
58.5KN.m/m Use 2 T 22 Tension RFT.
65 KN/m < ΦVc = 91 KN/m use 5T10/m E.F
48 KN/m < ΦVc use 5T10/m E.F
M heel Transverse Ult. @c -ve =
OK SAFE
MToe Transverse max Ult. @b =
, = = =
=
=
heel Slab behaves as:
1- a cantilever from point c to x with length Lc/2, supported by
stem.
2- a continuous beam from point x to d in longitudinal direction
of Retaining wall
supported by counterforts
=
Stem Slab behaves as:
1- a cantilever from point c at heel top to point z with length
Lc/2, supported by heel Slab.
2- a continuous beam above point z in longitudinal direction of
Retaining wall supported by
counterforts slab.
@ = , @= , @ =
on active side
on active side
on passive side
on active side
on passive side
Counterfort Slab behaves as:
a Tee Beam its flange (is heel & stem slabs) with effective
depth dctf, subjected to
1- max. moment MCfort@c at c point produced from horizontal
earth pressure
2- max horizontal shear VHal Cfort@c at c point produced from
horizontal earth
pressure
stress @ on stem slab multiplied by counterfort
spacing.
3- max Vertical shear VVal Cfort@d at d point produced from
Vertical net stress
dctf
MCfort@c =
VHal Cfort@c =
VVal Cfort@d =
hz1 hz2
MCfort@z2
MCfort@z1
dctf @z1dctf @z2
