HomeMy WebLinkAboutSTRUCTURAL CALCS - 21-00160 - 1354 Clover Ct - New SFRSTRUCTURAL CALCULATIONS
PIERCE RESIDENCE
RETAINING WALL
1354 CLOVER CT.
REXBURG, IDAHO 83440
IDAHO FALLS
OFFICE:
3153 MCNEIL DRIVE
IDAHO FALLS, ID 83402
PHONE: 208.542.6120
FAX: 208.932.4046
LICENSED IN:
UTAH
WASHINGTON
for
NEWPEAK HOMES
May 12, 2021
ARIZONA
CALIFORNIA
HAWAII
MONTANA
NEVADA
OREGON
IDAHO
WYOMING
5/12/2021
5/12/2021
5/12/2021
5/12/2021
UltraWall
Project: Pierce Residence
Location: 1354 Clover Ct. Rexburg, ID
Designer: KA
Date: 5/12/2021
Section: 4 Block
Design Method: NCMA_09_3rd_Ed, Ignore Vert. Force
Design Unit: UltraBlock
SOIL PARAMETERS φ coh γ
Reinforced Soil: 35 deg 0psf 120pcf
Retained Soil: 35 deg 0psf 120pcf
Foundation Soil: 35 deg 0psf 120pcf
Leveling Pad: Crushed Stone
GEOMETRY
Design Height: 9.83ft (8.33ft Exp.) Live Load: 0psf
Wall Batter/Tilt: 0.00/ 0.00 deg Live Load Offset: 0.00ft
Embedment: 1.50ft LL2 Width: 0ft
Leveling Pad Depth: 0.50ft Dead Load: 0psf
Slope Angle: 14.0 deg Dead Load Offset: 0.0ft
Slope Length: 12.0ft Dead Load Width: 0ft
Slope Toe Offset: 0.0ft
Vertical δ on Single Depth
FACTORS OF SAFETY
Sliding: 1.50 Pullout: 1.50
Overturning: 2.00 Uncertainties: 1.50
Bearing: 2.00 Connection: 1.50
Shear: 1.50 Bending: 1.50
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 1
RESULTS
FoS Sliding: 3.60 FoS Overturning: 4.80
Bearing 1,672 FoS Bearing: 12.92
Pullout 1.81
Total Pullout 4,644 FoS Total Pullout 3.88
Top FoSot: 3.93 FoS Connection: 1.74
ID Height Length Geogrid.Tallow EP(Pa)LL (Pql)DL (Pqd)TMax FS Str Tal Cn FS Pk Cn FS PO/[Tmax]FS Sldg [fndn]Grid Embed
2 4.92 7 5XT 1637 605 0 0 605 4.06 702 1.74 1.81/[605]13.48 1.23
1 2.46 7 5XT 1637 581 0 0 581 4.23 725 1.87 6.12/[581]7.60 [3.60]2.88
Column Descriptions:
Ta: allowable geogrid strength
Rc %: percent coverage for geosynthetics
EP (Pa) internal active earth pressure
LL (Pql) earth pressure due to live load surcharge
DL (Pqd) earth pressure due to dead load surcharge
Tmax maximum earth pressure on geosynthetic layer
FSstr factor of safety on geogrid strength (Ta/Tmax)
Ta cn allowable tension on the connection
FS Pkcn, factor of safety on the connection (Ta cn/Tmax)
FS PO, factor of safety on pullout (Ta pullout/(Tmax - LL)
Grid Embedment, depth of embedment beyond the theorectical failure plane.
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 2
GEOGRID REINFORCING
STRUCTURAL PROPERTIES: Mirafi
GEOGRID PROPERTIES
Name Tult RFcr RFd RFid Ci Cd Alpha Ltds
5XT 4700 1.45 1.10 1.20 0.90 0.90 0.80 2456
CONNECTION STRENGTHS
Geogrid Slope 1 Intercept 1 Peak Break Slope 2 Intercept 2 Max Normal Rup Conn Conn Creep Tlot (%)Tlot
5XT 18.00 536 1571 3.00 964 2361 False 1.45 100 4700
8XT 19.00 946 4834 3.00 2357 7745 False 1.45 100 7400
10XT 22.00 1464 -1 0.00 0 4999 False 1.45 100 9500
20XT 26.00 1825 4746 0.00 4140 6936 False 1.45 100 13705
SHEAR STRENGTHS
Slope 0 deg
Intercept 3500psf
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 3
CALCULATION RESULTS
OVERVIEW
UltraWall calculates stability assuming the wall is a rigid body. Forces and moments are calculated about the
base and the front toe of the wall. The base block width or bottom reinforcement length is used in the calculations.
The concrete units, granular fill over the blocks or reinforced zone soils are used as resisting forces.
EARTH PRESSURES
The method of analysis uses the Coulomb Earth Pressure equation (below) to calculate active earth
pressures. Wall friction is assumed to act at the back of the wall face. The component of earth pressure is assumed to
act perpendicular to the boundary surface. The effective delta angle is delta minus the wall batter at the back face
(assumed to be vertical). If the slope breaks within the failure zone, a trial wedge method of analysis is used.
INTERNAL EARTH PRESSURES
Effective internal Delta angle (2/3 phi)delta =23.3 deg
Coefficient of active earth pressure ka =0.291
Internal failure plane ρ = 56.0 deg
EXTERNAL EARTH PRESSURES
Effective external Delta angle delta =35.00 deg
Coefficient of active earth pressure ka =0.298
External failure plane ρ = 55.0 deg
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 4
FORCES AND MOMENTS
UltraWall resolves all the geometry into simple geometric shapes to make checking easier. All x and y
coordinates are referenced to a zero point at the front toe. The wall image can be exported to CAD for a more
detailed output.
Loads for Overturning about the FRONT TOE of the structure
Name Factor γ Force (V)Force (H)X-len Y-len Mo Mr
Face Blocks(W1)1.00 3384 --1.23 ----4160
Soil(W3)1.00 5357 --4.73 ----25336
Slope(W5)1.00 309 --4.67 ----1440
Pa_h 1.00 --1762 --3.65 6439 --
Sum (V, H)1.00 9050 1762 Sum Mom 6439 30936
W0: leveling pad W6: Rectangle zone in broken back
W1: facing units W7: Live load over the mass
W2: soil wedge behind the face W8: Dead load over the mass
W3: rectangular area in MSE area W9: Force Pa
W4: the wedge at the back of the mass W10: Surcharge load Paq
W5: slope area over the mass W11: Dead Load Surcharge Paqd
X-Len: is measured from the center of the base (+) Driving, (-) Resisting.
Pa_h: horizontal earth pressure Pa_v: vertical earth pressure
Pq_h: horizontal surcharge pressure Pq_v: vertical surcharge pressure
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 5
BASE SLIDING
Sliding at the base is checked at the soil-to-soil interface between the reinforced mass and the foundation
soil.
Forces resisting sliding = (SumVr- W0 - W1 - W7)
9,050 - 0 - 3,384 - 0 SumVr = 5,666ppf
Resisting force = SumVr x tan(35) + c x L + Base Shear Rf1 =6,337
where L is the base width
where Base Shear = N tan(35.0) * 0.8 1,895.77
Driving force is the horizontal component of Pah + Pqh+ Pdh Df = 1,762
Factor of Safety = Rf/Df FSsl =3.60
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 6
OVERTURNING ABOUT THE TOE
Overturning at the base is checked by assuming rotation about the front toe by the block mass, soil retained
on the blocks or within the reinforced zone. Allowable overturning can be defined by eccentricity (e/L) or by the ratio
of resisting moments divided by overturning moment (FSot).
Moments resisting overturning = Sum(M1 to M6) + MPav + MPqv Mr =30,936ft-lbs
Moments causing overturning = MPah + MPqh Mo =6,439ft-lbs
Factor of safety = Mr/Mo FSot =4.80 OK
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 7
ECCENTRICITY AND BEARING
Eccentricity is the calculation of the distance of the resultant away from the centroid of mass. In wall
ReinDesign the eccentricity is used to calculate an effective footing width, or in rigid structure, it is used to calculate
the pressure distribution below the base.
Calculation of Eccentricity
e = (SumMr + M7 + SumMo)/SumV
Mr = -6,945.07
Mo = 14,123.71
e = (-6,945.07 + 0.00 + 14,123.71) /9,050.22)e =0.793
Calculation of Bearing Pressures
Qult = c*Nc + q*Nq + 0.5*gamma*(B')*Ng
where:
Nc =46.12
Nq =33.30
Ng =48.03
c =0.00psf
q =180.00psf
B' =5.41ft
Calculate Ultimate Bearing, Qult Qult =21,593.81psf
Applied Bearing Pressures = (SumVert / B' + (2B + LP depth)/2 * LP depth *gamma)
sigma =1,671.76psf
Calculated Factors of Safety for Bearing Qult/sigma =12.92
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 8
TENSION CALCULATIONS
Tmax is the maximum tension in the reinforcing based on the earth pressure and surcharge loads applied.
In the NCMA design method, earth pressures are calculated using the Coulomb Earth pressure equation. Infinite
surcharge loads are applied as q x ka. In designs were there is a broken back slope, or the surcharge is not uniform
over the area, a tie-back wedge analysis method is used.
FS = (Tal * FS_tn) / Tmax
TABLE OF RESULTS
Elevation[ft]ka z sv Name[ft]Tult[ppf]Ta[ppf]Rc %Tmax[ppf]FS
4.92 0.291 3.07 6.14 5XT 4,700 1,637 100 605 4.06
2.46 0.291 7.37 2.46 5XT 4,700 1,637 100 581 4.23
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 9
PULLOUT CALCULATIONS
Pullout is the amount of resistance of the reinforcing has to a pullout failure based on the Tmax applied and
the depth of embedment (resistance). In an NCMA design the failure place is defined as the Coulomb failure plane
which varies with face batter, backslope angle, and surcharge loads applied. All failure planes begin at the tail. of the
facing units.
For AASHTO calculations, the live load surcharge is not included in the Tmax value for pullout.
Failure Plane Angle (ρ) = 56.0 Deg
NOTE: The pullout capacity is limited by the LTDS of the reinforcing layer, not the ultimate pullout capacity calculated.
F* = 0.67 x tan(φ) = 0.67 x 0.70 = 0.47
Le = embedment length = Li - block depth - hi * Tan(90 - ρ)
La = Li - Le
sv = geogrid spacing
Rc = % coverage
α = scale effect correction
Pullout = 2 x Le x F* x sv x α x Rc
TABLE OF RESULTS
Elevation[ft]Normal[lbf]Ci % Coverage Tmax[ppf]Le[ft]La[ft]Pullout_[Pr][ppf]FS PO
4.92 866.50 0.90 100 605 1.23 5.77 1092 1.81
2.46 2818.18 0.90 100 581 2.88 4.12 3552 6.12
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 10
CONNECTION CALCULATIONS
Connection is the amount of resistance of the reinforcing has to a pullout failure from the facing units based
on the Tmax applied and the normal load on the units. In an AASHTO LRFD design, creep on the connection may be
applied for frictional and mechanical connections. In NCMA or AASHTO 2002, a frictional failure is based on the
peak connection capacity divided by a factor of safety. For a rupture connection the capacity is the peak load divided
by a creep reduction factor and a factor of safety.
Frictional Connection
Peak Connection = N(ppf) tan(slope) + intercept
Rupture Connection
Connection Capacity = [N(ppf) tan(slope) + intercept] / RFcr
RFcr can be a value obtained from long-term testing or by default could be the creep reduction factor of the
geogrid reinforcing.
Tal_cn = Allowable connection capacity = Tult_cn / FScn
Rc = % coverage
FS = Tal_cn * FScn/Tmax
TABLE OF RESULTS
Elev[ft]Name Tmax[ppf]Rc %N[ppf]Tult_cn Tac[ppf]FS
4.92 5XT 605 100 1692 1158 702 1.74
2.46 5XT 581 100 2538 1197 725 1.87
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 11
UltraWall
Project: Pierce Residence
Location: 1354 Clover Ct. Rexburg, ID
Designer: KA
Date: 5/12/2021
Section: 3 Block
Design Method: NCMA_09_3rd_Ed, Ignore Vert. Force
Design Unit: UltraBlock
SOIL PARAMETERS φ coh γ
Reinforced Soil: 35 deg 0psf 120pcf
Retained Soil: 35 deg 0psf 120pcf
Foundation Soil: 35 deg 0psf 120pcf
Leveling Pad: Crushed Stone
GEOMETRY
Design Height: 7.38ft (6.88ft Exp.) Live Load: 0psf
Wall Batter/Tilt: 0.00/ 0.00 deg Live Load Offset: 0.00ft
Embedment: 0.50ft LL2 Width: 0ft
Leveling Pad Depth: 0.50ft Dead Load: 0psf
Slope Angle: 14.0 deg Dead Load Offset: 0.0ft
Slope Length: 12.0ft Dead Load Width: 0ft
Slope Toe Offset: 0.0ft
Vertical δ on Single Depth
FACTORS OF SAFETY
Sliding: 1.50 Pullout: 1.50
Overturning: 2.00 Uncertainties: 1.50
Bearing: 2.00 Connection: 1.50
Shear: 1.50 Bending: 1.50
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 1
RESULTS
FoS Sliding: 4.49 FoS Overturning: 7.77
Bearing 1,148 FoS Bearing: 16.75
Pullout 2.92
Total Pullout 3,122 FoS Total Pullout 4.78
Top FoSot: 14.32 FoS Connection: 2.71
ID Height Length Geogrid.Tallow EP(Pa)LL (Pql)DL (Pqd)TMax FS Str Tal Cn FS Pk Cn FS PO/[Tmax]FS Sldg [fndn]Grid Embed
2 4.92 7 5XT 1637 218 0 0 218 11.24 541 3.71 2.92/[218]31.22 1.23
1 2.46 7 5XT 1637 388 0 0 388 6.33 702 2.71 6.40/[388]12.57 [4.49]2.88
Column Descriptions:
Ta: allowable geogrid strength
Rc %: percent coverage for geosynthetics
EP (Pa) internal active earth pressure
LL (Pql) earth pressure due to live load surcharge
DL (Pqd) earth pressure due to dead load surcharge
Tmax maximum earth pressure on geosynthetic layer
FSstr factor of safety on geogrid strength (Ta/Tmax)
Ta cn allowable tension on the connection
FS Pkcn, factor of safety on the connection (Ta cn/Tmax)
FS PO, factor of safety on pullout (Ta pullout/(Tmax - LL)
Grid Embedment, depth of embedment beyond the theorectical failure plane.
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 2
GEOGRID REINFORCING
STRUCTURAL PROPERTIES: Mirafi
GEOGRID PROPERTIES
Name Tult RFcr RFd RFid Ci Cd Alpha Ltds
5XT 4700 1.45 1.10 1.20 0.90 0.90 0.80 2456
CONNECTION STRENGTHS
Geogrid Slope 1 Intercept 1 Peak Break Slope 2 Intercept 2 Max Normal Rup Conn Conn Creep Tlot (%)Tlot
5XT 18.00 536 1571 3.00 964 2361 False 1.45 100 4700
8XT 19.00 946 4834 3.00 2357 7745 False 1.45 100 7400
10XT 22.00 1464 -1 0.00 0 4999 False 1.45 100 9500
20XT 26.00 1825 4746 0.00 4140 6936 False 1.45 100 13705
SHEAR STRENGTHS
Slope 0 deg
Intercept 3500psf
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 3
CALCULATION RESULTS
OVERVIEW
UltraWall calculates stability assuming the wall is a rigid body. Forces and moments are calculated about the
base and the front toe of the wall. The base block width or bottom reinforcement length is used in the calculations.
The concrete units, granular fill over the blocks or reinforced zone soils are used as resisting forces.
EARTH PRESSURES
The method of analysis uses the Coulomb Earth Pressure equation (below) to calculate active earth
pressures. Wall friction is assumed to act at the back of the wall face. The component of earth pressure is assumed to
act perpendicular to the boundary surface. The effective delta angle is delta minus the wall batter at the back face
(assumed to be vertical). If the slope breaks within the failure zone, a trial wedge method of analysis is used.
INTERNAL EARTH PRESSURES
Effective internal Delta angle (2/3 phi)delta =23.3 deg
Coefficient of active earth pressure ka =0.291
Internal failure plane ρ = 56.0 deg
EXTERNAL EARTH PRESSURES
Effective external Delta angle delta =35.00 deg
Coefficient of active earth pressure ka =0.300
External failure plane ρ = 54.0 deg
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 4
FORCES AND MOMENTS
UltraWall resolves all the geometry into simple geometric shapes to make checking easier. All x and y
coordinates are referenced to a zero point at the front toe. The wall image can be exported to CAD for a more
detailed output.
Loads for Overturning about the FRONT TOE of the structure
Name Factor γ Force (V)Force (H)X-len Y-len Mo Mr
Face Blocks(W1)1.00 2538 --1.23 ----3120
Soil(W3)1.00 4022 --4.73 ----19021
Slope(W5)1.00 309 --4.67 ----1440
Pa_h 1.00 --1070 --2.84 3037 --
Sum (V, H)1.00 6869 1070 Sum Mom 3037 23581
W0: leveling pad W6: Rectangle zone in broken back
W1: facing units W7: Live load over the mass
W2: soil wedge behind the face W8: Dead load over the mass
W3: rectangular area in MSE area W9: Force Pa
W4: the wedge at the back of the mass W10: Surcharge load Paq
W5: slope area over the mass W11: Dead Load Surcharge Paqd
X-Len: is measured from the center of the base (+) Driving, (-) Resisting.
Pa_h: horizontal earth pressure Pa_v: vertical earth pressure
Pq_h: horizontal surcharge pressure Pq_v: vertical surcharge pressure
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 5
BASE SLIDING
Sliding at the base is checked at the soil-to-soil interface between the reinforced mass and the foundation
soil.
Forces resisting sliding = (SumVr- W0 - W1 - W7)
6,869 - 0 - 2,538 - 0 SumVr = 4,331ppf
Resisting force = SumVr x tan(35) + c x L + Base Shear Rf1 =4,810
where L is the base width
where Base Shear = N tan(35.0) * 0.8 1,421.83
Driving force is the horizontal component of Pah + Pqh+ Pdh Df = 1,070
Factor of Safety = Rf/Df FSsl =4.49
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 6
OVERTURNING ABOUT THE TOE
Overturning at the base is checked by assuming rotation about the front toe by the block mass, soil retained
on the blocks or within the reinforced zone. Allowable overturning can be defined by eccentricity (e/L) or by the ratio
of resisting moments divided by overturning moment (FSot).
Moments resisting overturning = Sum(M1 to M6) + MPav + MPqv Mr =23,581ft-lbs
Moments causing overturning = MPah + MPqh Mo =3,037ft-lbs
Factor of safety = Mr/Mo FSot =7.77 OK
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 7
ECCENTRICITY AND BEARING
Eccentricity is the calculation of the distance of the resultant away from the centroid of mass. In wall
ReinDesign the eccentricity is used to calculate an effective footing width, or in rigid structure, it is used to calculate
the pressure distribution below the base.
Calculation of Eccentricity
e = (SumMr + M7 + SumMo)/SumV
Mr = -5,303.83
Mo = 8,800.50
e = (-5,303.83 + 0.00 + 8,800.50) /6,868.90)e =0.509
Calculation of Bearing Pressures
Qult = c*Nc + q*Nq + 0.5*gamma*(B')*Ng
where:
Nc =46.12
Nq =33.30
Ng =48.03
c =0.00psf
q =60.00psf
B' =5.98ft
Calculate Ultimate Bearing, Qult Qult =19,235.91psf
Applied Bearing Pressures = (SumVert / B' + (2B + LP depth)/2 * LP depth *gamma)
sigma =1,148.28psf
Calculated Factors of Safety for Bearing Qult/sigma =16.75
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 8
TENSION CALCULATIONS
Tmax is the maximum tension in the reinforcing based on the earth pressure and surcharge loads applied.
In the NCMA design method, earth pressures are calculated using the Coulomb Earth pressure equation. Infinite
surcharge loads are applied as q x ka. In designs were there is a broken back slope, or the surcharge is not uniform
over the area, a tie-back wedge analysis method is used.
FS = (Tal * FS_tn) / Tmax
TABLE OF RESULTS
Elevation[ft]ka z sv Name[ft]Tult[ppf]Ta[ppf]Rc %Tmax[ppf]FS
4.92 0.291 1.85 3.69 5XT 4,700 1,637 100 218 11.24
2.46 0.291 4.92 2.46 5XT 4,700 1,637 100 388 6.33
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 9
PULLOUT CALCULATIONS
Pullout is the amount of resistance of the reinforcing has to a pullout failure based on the Tmax applied and
the depth of embedment (resistance). In an NCMA design the failure place is defined as the Coulomb failure plane
which varies with face batter, backslope angle, and surcharge loads applied. All failure planes begin at the tail. of the
facing units.
For AASHTO calculations, the live load surcharge is not included in the Tmax value for pullout.
Failure Plane Angle (ρ) = 56.0 Deg
NOTE: The pullout capacity is limited by the LTDS of the reinforcing layer, not the ultimate pullout capacity calculated.
F* = 0.67 x tan(φ) = 0.67 x 0.70 = 0.47
Le = embedment length = Li - block depth - hi * Tan(90 - ρ)
La = Li - Le
sv = geogrid spacing
Rc = % coverage
α = scale effect correction
Pullout = 2 x Le x F* x sv x α x Rc
TABLE OF RESULTS
Elevation[ft]Normal[lbf]Ci % Coverage Tmax[ppf]Le[ft]La[ft]Pullout_[Pr][ppf]FS PO
4.92 506.25 0.90 100 218 1.23 5.77 638 2.92
2.46 1970.43 0.90 100 388 2.88 4.12 2483 6.40
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 10
CONNECTION CALCULATIONS
Connection is the amount of resistance of the reinforcing has to a pullout failure from the facing units based
on the Tmax applied and the normal load on the units. In an AASHTO LRFD design, creep on the connection may be
applied for frictional and mechanical connections. In NCMA or AASHTO 2002, a frictional failure is based on the
peak connection capacity divided by a factor of safety. For a rupture connection the capacity is the peak load divided
by a creep reduction factor and a factor of safety.
Frictional Connection
Peak Connection = N(ppf) tan(slope) + intercept
Rupture Connection
Connection Capacity = [N(ppf) tan(slope) + intercept] / RFcr
RFcr can be a value obtained from long-term testing or by default could be the creep reduction factor of the
geogrid reinforcing.
Tal_cn = Allowable connection capacity = Tult_cn / FScn
Rc = % coverage
FS = Tal_cn * FScn/Tmax
TABLE OF RESULTS
Elev[ft]Name Tmax[ppf]Rc %N[ppf]Tult_cn Tac[ppf]FS
4.92 5XT 218 100 846 892 541 3.71
2.46 5XT 388 100 1692 1158 702 2.71
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 11
UltraWall
Project: Pierce Residence
Location: 1354 Clover Ct. Rexburg, ID
Designer: KA
Date: 5/12/2021
Section: 2 Block
Design Method: NCMA_09_3rd_Ed, Ignore Vert. Force
Design Unit: UltraBlock
SOIL PARAMETERS φ coh γ
Retained Soil: 35 deg 0psf 120pcf
Foundation Soil: 35 deg 0psf 120pcf
Leveling Pad: 35 deg 0psf 135pcf Crushed Stone
GEOMETRY
Design Height: 4.92ft Live Load: 0psf
Wall Batter/Tilt: 0.00/ 0.00 deg Live Load Offset: 0.00ft
Embedment: 0.50ft Live Load Width: 0ft
Leveling Pad Depth: 0.50ft Dead Load: 0psf
Slope Angle: 14.0 deg Dead Load Offset: 0.0ft
Slope Length: 12.0ft Dead Load Width: 0ft
Slope Toe Offset: 0.0ft Leveling Pad Width: 3.46ft
Vert δ on Single Dpth
FACTORS OF SAFETY
Sliding: 1.50 Overturning: 1.50
Bearing: 2.00
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 1
RESULTS
FoS Sliding: 2.01 (lvlpd) FoS Overturning: 3.92
Bearing: 818.43 FoS Bearing: 13.67
Name Elev.[dpth]ka Pa Paq Paqd (PaC)PaT FSsl FoS OT %D/H
1 2.46[2.46]0.291 106 0 0 0 106 --14.35 100%
1 0.00[4.92]0.291 422 0 0 0 422 2.01 3.92 50%
Column Descriptions:
ka: active earth pressure coefficient
Pa: active earth pressure
Paq: live surcharge earth pressure
Paq2: live load 2 surcharge earth pressure
Paqd: dead surcharge earth pressure
(PaC): reduction in load due to cohesion
PaT: sum of all earth pressures
FSsl(lvl Pad): factor of safety for sliding at each layer. (FS sliding below the leveling pad)
FSot: factor of safety of overturning about the toe.
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 2
RETAINING WALL UNITS
STRUCTURAL PROPERTIES:
N is the normal force [or factored normal load] on the base unit
The default leveling pad to base unit shear is 0.8 tan(φ) [AASHTO 10.6.3.4] or
may be the manufacturer supplied data. φ is assumed to be 40 degrees for a stone leveling pad.
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 3
FORCE DETAILS
The details below shown how the forces are calculated for each force component. The values shown are not
factored. All loads are based on a unit width (ppf / kNpm).
Layer Block Wt Soil Fill Wt Soil Wt
1 846 0
2 846
Block Weight (Force v (Block Wt + Infill Soil)) = 1692ppf X-Arm = 1.23ft
Soils Block Weight (Force v) = 0ppf X-Arm = 0.00ft
Active Earth Pressure Pa = 422ppf
Pa_h (Force H) = Pa cos(δ - batter) = 422 x cos( 23.3 - (0.0 )) = 388ppf
Y-Arm = 1.64ft
Pa_v (Force V) = Pa sin(δ - batter ) = 422 x sin( 23.3 - (0.0 )) = 167ppf
X-Arm = 2.46ft
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 4
CALCULATION RESULTS
OVERVIEW
UltraWall calculates stability assuming the wall is a rigid body. Forces and moments are calculated about the
base and the front toe of the wall. The base block width is used in the calculations. The concrete units and granular fill
over the blocks are used as resisting forces.
EARTH PRESSURES
The method of analysis uses the Coulomb Earth Pressure equation (below) to calculate active earth
pressures. Wall friction is assumed to act at the back of the wall face. The component of earth pressure is assumed to
act perpendicular to the boundary surface. The effective δ angle is δ minus the wall batter at the back face. If the
slope breaks within the failure zone, a trial wedge method of analysis is used.
EXTERNAL EARTH PRESSURES
Effective δ angle (2/3 retained phi)δ =23.3 deg
Coefficient of active earth pressure ka =0.291
External failure plane ρ = 56 deg
Effective Angle from horizontal α =90.00 deg
Coefficient of passive earth pressure: kp = (1 + sin(φ)) / (1 - sin(φ)) kp =3.69
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 5
FORCES AND MOMENTS
The program resolves all the geometry into simple geometric shapes to make checking easier. All x and y
coordinates are referenced to a zero point at the middle of the base block for eccentricity calculations.
LOADS FOR OVERTURNING ABOUT THE TOE
Name Factor γ Force (V)Force (H)X-len Y-len Mo Mr
Face Blocks(W1)1.00 1692 --1.23 ----2080
Pa_h 1.00 --388 --1.64 636 --
Pa_v 1.00 167 --2.46 ----411
Sum V / H 1.00 1859 388 Sum Mom 636 2491
W0: stone within units W1: facing units
W2: soil wedge behind the face
X-Len: is measured from the center of the base (+) Driving, (-) Resisting.
Pa_h: horizontal earth pressure Pa_v: vertical earth pressure
Pq_h: horizontal surcharge pressure Pq_v: vertical surcharge pressure
BEARING LOADS: NCMA
Name Factor γ Force (V)Force (H)X-len Y-len Mo Mr
Face Blocks(W1)1.00 1692 --0.00 ----0
Pa_h 1.00 --388 --1.64 636 --
Pa_v 1.00 167 ---1.23 -----206
Sum V / H 1.00 1859 388 Sum Mom 636 -206
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 6
BASE SLIDING
Sliding at the base is checked at the block to leveling pad interface between the base block and the leveling
pad.
Forces Resisting sliding = W1 + Pav
1692 + 167 N =1859ppf
Resisting force at pad = (N * 0.8 * tan(slope) + intercept x L)
1859 x0.8 x tan(35.0) + 0.0 Rf =0
Driving force is the horizontal component of
Pah
388Df =388
FSsl = Rf / Df FSsl =2.01
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 7
OVERTURNING ABOUT THE TOE
Overturning at the base is checked by assuming rotation about the front toe by the block mass and the soil
retained on the blocks. Allowable overturning can be defined by eccentricity (e/L). For concrete leveling pads
eccentricity is checked at the base of the pad.
Moments Resisting Overturning = M1 + MPav
2080 + 411 Mr =2491ft-lbs
Moments causing Overturning = MPah
636Mo =636ft-lbs
FSot = Mr / Mo
FSot =2491 / 636 FSot =3.92
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 8
ECCENTRICITY AND BEARING
Eccentricity is the calculation of the distance of the resultant away from the centroid of mass. In wall design
the eccentricity is used to calculate an effective footing width.
Calculation of Eccentricity
SumV = + W1 + Pav
+ 1692 + 167 SumV = 1859
Moment Resisting Mr = -206
Moment Driving Md = 636
e = (SumMr + SumMd)/(SumV)
e = (430 /0.00)e =0.231ft
Calculation of Bearing Pressures
Qult = c * Nc + q * Nq + 0.5 * γ* (B') * Ng
where:
Nc =46.12
Nq =33.30
Ng =48.03
c =0.00psf
q = 120.00psf(soil weight above base of leveling pad)
B' = B - 2e + lvlpad = 2.50ft
Gamma =120pcf
Calculate Ultimate Bearing, Qult Qult =11186psf
Bearing Pressure = (SumVert / B') + (LP width * gamma) sigma = 818.43psf
Calculated Factors of Safety for Bearing Qult/sigma =13.67
Note: Calculations and quantities are for PRELIMINARY ANALYTICAL USE ONLY and MUST NOT be used for final
n or construction without the independent review, verification, and approval by a qualified professional engineer.
UltraWall 5.1.24.19 9