Report -0a5so
110-3 C6tj (pP PRAir
GeoPtng ne nno,Inc.
Real-World Geotechnical Solutions
• Investigation • Design • Construction Support
October 2, 2013
GeoPacific Project No. 01-7231
Way W. Lee General Contractor, Inc.
5210 SE 26th Avenue
Portland, OR 97202
Fax (503)234-0593
Copy: AKS, Trevor Synkelma <trevors@aks-eng.com>.
Via e-mail with hard copies mailed
Subject: SUPPLEMENTAL GEOTECHNICAL ENGINEERING REPORT- ULTRA BLOCK WALLS
LEE OFFICE BUILDING
TIGARD, OREGON
Reference: Foundation Investigation, Lee Office Building, City of Tigard, Oregon, report dated
July 3, 2001.
In accordance with your request, GeoPacific Engineering, Inc. (GeoPacific) prepared this report
containing results of retaining wall analyses for the subject project. These services were
performed as an addendum to our existing contract for geotechnical services on the project. This
letter report presents wall stability calculations, and also includes geotechnical recommendations
for wall construction.
GeoPacific previously performed a geotechnical engineering study for the project, results of which
are presented in the above-referenced report. Soil parameters used in this analysis were based on
results of our previous geotechnical studies.
DESIGN CONSIDERATIONS
The subject Ultra Block wall will generally extend along the west half of the south side of the
proposed limits of grading (see Figure C071). The wall supports an access road; therefore traffic
surcharge will need to be considered in design and construction. Ultra Block walls may also be
constructed in other areas of the site.
Exposed wall height ranges up to about 7 feet as indicated on the plans. Over much of the wall
alignments, the maximum wall height requires no more than 3 vertical rows of blocks. We
understand the finish grade above the tops of the walls will generally be nearly level to slightly
sloping.
14835 SW 72nd Avenue Tel(503)598-8445
Portland,Oregon 97224 Fax(503)941-9281
October 2, 2013
Project No. 01-7231
Wall stability calculations are attached to this report. Walls were designed as gravity structures.
For the purpose of the design recommendations presented below, it was assumed that wall
• foundation soils will have an allowable bearing pressure of 2,000 psf. Calculations were
performed for both static and seismic conditions, using pseudostatic methods and an appropriate
peak horizontal acceleration to simulate earthquake loading.
Subgrade soils should consist of stiff native silt or engineered fill. The wall should be founded on a
crushed rock leveling pad a minimum of 6 inches thick and should be embedded a minimum of 12
inches (Figure 1). Wall backfill materials (if needed) should consist of clean granular materials or
crushed rock compacted to at least 95% of Standard Proctor(ASTM D698), extending a horizontal
distance behind the wall equivalent to the wall height. Beyond that zone, backfill soils may consist
of any engineered fill materials as recommended in the project geotechnical report.
Based on the attached calculations, the proposed walls will have adequate factors of safety against
sliding, overturning, bearing capacity failure, and facing failure provided that our recommendations
for wall construction are followed. GeoPacific should perform observe construction of the designed
Ultra Block walls including subgrade inspection, overexcavation requirements (if needed),
embedment, wall batter, and backfill compaction.
CONSTRUCTION RECOMMENDATIONS
The Ultra Block walls have been analyzed as vertical, with no wall batter or tilt. This should
enhance constructability, as it can be difficult to construct Ultra Block wall curved sections and
corners where wall batter is specified.
It should be noted that portions of the walls extend through zones identified as being underlain by
soft organic soils. The above-referenced geotechnical report should be consulted for additional
information such as estimated organic soil zone extents and depths. Wall keyway soils should be
observed by GeoPacific. Where soft soils are encountered, they should be overexcavated and
backfilled as recommended by GeoPacific in the field. Once the organic soils are removed,
localized removals of soft subgrade and/or stabilization measures may be necessary to stabilize
localized areas. Proof-rolls and/or hand probe surveys of the subgrade should be performed and
observed by GeoPacific to verify subgrade strength prior to fill placement.
Engineered fill should be compacted in horizontal lifts not exceeding 8 inches using standard
compaction equipment, compacted to at least 90% of Modified Proctor(ASTM D1557). To avoid
bulging of the wall facing, self-propelled drum roller compactors up to 5 tons in weight should not
be used within 2 feet of blocks and compaction against the back of wall should be achieved using a
hand held vibratory plate compactor.
Adequate drainage behind and beneath the wall is important for wall performance. A subsurface
drain consisting of 4-inch diameter, perforated pipe should be placed at the back of the wall as
shown on the attached detail. The drain pipe and surrounding drain rock should be wrapped in
non-woven geotextile (Mirafi 140N, or approved equivalent)to minimize the potential for clogging
7231 -1..ee Office Ultra Block Walls Suppl 2 GEOPACIFIC ENGINEERING,INC.
October 2, 2013
Project No. 01-7231
and/or ground loss due to piping. Water collected from the drains should be outlet to the natural
area below the walls, or may also be connected to the storm drain system if practical.
It should be noted that gravity walls such as those planned for the project will generally experience
some minor wall movement. As a result, structural foundations should be set back from the
retaining walls a horizontal distance of at least 1.0H, where H is the total height of the wall plus any
retained slope behind the wall. Also, where patios or other settlement-sensitive improvements are
located within the influence zone of the wall, they may be impacted by wall movement. For
example, patio slabs located near the wall may settle and/or pull away from the structure at cold
joints.
UNCERTAINTY AND LIMITATIONS
We have prepared this report for the owner and their consultants for use in design of this project
only. This report should be provided in its entirety to prospective contractors for bidding and
estimating purposes; however, the conclusions and interpretations presented in this report should
not be construed as a warranty of the subsurface conditions. Experience has shown that soil and
groundwater conditions can vary significantly over small distances. Inconsistent conditions can
occur between explorations that may not be detected by a geotechnical study. If, during future site
operations, subsurface conditions are encountered which vary appreciably from those described
herein, GeoPacific should be notified for review of the recommendations of this report, and revision
of such if necessary.
Sufficient geotechnical monitoring, testing and consultation should be provided during construction
to confirm that the conditions encountered are consistent with those indicated by explorations.
Recommendations for design changes will be provided should conditions revealed during
construction differ from those anticipated, and to verify that the geotechnical aspects of
construction comply with the contract plans and specifications.
Within the limitations of scope, schedule and budget, GeoPacific attempted to execute these
services in accordance with generally accepted professional principles and practices in the fields of
geotechnical engineering and engineering geology at the time the report was prepared. No
warranty, expressed or implied, is made. The scope of our work did not include environmental
assessments or evaluations regarding the presence or absence of wetlands or hazardous or toxic
substances in the soil, surface water, or groundwater at this site.
7231-Lee 01 flee Ultra Block Walk Suppl 3 GEOPACIFIC ENGINEERING,INC.
October 2, 2013
Project No. 01-7231
We appreciate this opportunity to be of service.
Sincerely,
GEOPACIFIC ENGINEERING, INC.
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E!(PIRES:06/30/201
James D. Imbrie, P.E., G.E.
Principal Geotechnical Engineer
Attachments: Figure C071 —Grading and Demolition Plan by AKS Engineering & Forestry
Figure C072 —Retaining Wall Spot Elevation Plan and Detail
Figure 1 —Gravity Ultra-Block Wall Typical Construction Detail
Retaining Wall Calculations
" 7231-Lee Office Ultra Block Walls Suppl 4 GEOPACIFIC ENGINEERING,INC.
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114' X1.41 RETAINING WALL SPOT Pt 41.11401 St .
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ELEVATION PLAN AND 4. -
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DETAIL TIGARD OREGON
••••J f--, ,4„,„,11 ..,%.,
14835 SW 72nd Avenue GRAVITY ULTRA-BLOCK WALL
Gimp Portland, Oregon 97224
tne,ntt, ine Tel: (503)598-8445 Fax:(503)941-9281 TYPICAL CONSTRUCTION DETAIL
4 BLOCKS MAXIMUM HEIGHT
Granular Backfill Compacted
to 95%of Standard Proctor
9 ft. Maximum Maximum Density
Wall Height(H)
Limit of Excavation
(Contractor Responsible
for Stable Backcut)
Minimum Embedment +,•"
Depth= 12 in •r: rr:r:r:r:r:r
4"Perforated PVC Drain Wrapped in Mirafi 140N
Fabric or Approved Equivalent
Competent Native Materials or Engineered Fill
6-in.-thick Crushed Aggregate
Leveling Pad
Notes:
1. GeoPacific should review subgrade soils. Base of wall should be supported on
stiff native soils or engineered fill.
2. Use Ultra-block or similar product, 2.5 x 2.5 x 5-foot blocks.
3. Leveling pad and any additional drainage materials should consist of 3/4"-0
crushed aggregate.
4. Backfill behind the wall should consist of 3/4"-0 crushed aggregate or other
granular materials pre-approved by GeoPacific.
Project: Lee Office Building Project No. 01-7231 FIGURE 1
Tigard, Oregon
U TR i BLOCK,i C.
I v3.1 Build 13133
Project: 68th Parkway
- Location:
Designer: JDI
Date: 10/1/2013
Ilk
Section: Section 7
Design Method: NCMA 09_3rd_Ed, Ignore Vert. Force
Design Unit: Ultrablock Full Double eio
Seismic Acc: 0.140 i
92
SOIL PARAMETERS cP coh y .
Retained Soil: 28 deg 0 psf 120 pcf f id
Foundation Soil: 30 deg 0 psf 120 pcf
Leveling Pad: Crushed Stone
Crushed Stone Interface is true, cp = 34deg
GEOMETRY
Design Height: 8.00 ft Live Load: 250 psf
Wall Batter/Tilt: 0.00/0.00 deg Live Load Offset: 0.00 ft
Embedment: 1.00 ft Live Load Width: 100 ft
Leveling Pad Depth: 0.50 ft Dead Load: 0 psf
Slope Angle: 0.0 deg Dead Load Offset: 0.0 ft
Slope Length: 0.0 ft Dead Load Width: 100 ft
Slope Toe Offset: 0.0 ft Leveling Pad Width: 5.92 ft
Vertical 6 on Single Depth
FACTORS OF SAFETY(Static/Seismic)
Sliding: 1.50/ 1.125 Overturning: 1.50/ 1.125
Bearing: 2.00/ 1.5
RESULTS(Static/Seismic)
FoS Sliding: 2.21 (fnd)/3.19 FoS Overturning: 2.86/3.93
Bearing: 1926.27/ 1637.33 FoS Bearing: 4.40/ 5.17
Name Elev. ka kae Pa Pae Pir -PaC FSsl FoS OT siesFSsl FoS SeisOT
1X -7.38 ' 0.321 0.354 8 „,-,. 8 0 0 100.00 83.97 100.00 fad 00
1X 4.92 0.321 0.354 183 202 0 0 43.59 3.85 93.11 9,93
2X 2.46 0.567 ' 0.615 1045 1133 122 0 14.95 4.65 20.71 5.66
2X 0.00 0.478 0.520 1834 1996 244 0 2.3512.211 2.86 3.19(2.88) 3.93
Note: Calculations are for Preliminary use only and should
not be used for construction without the review of a qualified professional,
Page
U. TR 'BLOCK.1 C.
�i
DESIGN DATA
• TARGET DESIGN VALUES (Factors of Safety-Static/Seismic)
Minimum Factor of Safety for the sliding along the base FSsI =1.50/1.125
Minimum Factor of Safety for overturning about the toe FSot=1.50/1.125
Minimum Factor of Safety for bearing (foundation shear failure) FSbr=2.00/1.500
MINIMUM DESIGN REQUIREMENTS
Minimum embedment depth Min emb =1.00 ft
INPUT DATA
Geometry
Wall Geometry
Design Height, top of leveling pad to finished grade at top of wall H =8.00 ft
Embedment, measured from top of leveling pad to finished grade emb =1.00 ft
Leveling Pad Depth LP Thickeness=0.50 ft
Face Batter, measured from vertical i =0.00 deg
Slope Geometry
Slope Angle, measured from horizontal (3 =0.00 deg
Slope toe offset, measured from back of the face unit STL_offset=0.00 ft
Slope Length, measured from back of wall facing SL_Length =0.00 ft
NOTE: If the slope toe is offset or the slope breaks within three times the
wall height, a Coulomb Trial Wedge method of analysis is used.
Surcharge Loading
Live Load, assumed transient loading (e.g. traffic) LL=250.00 psf
Live Load Offset, measured from back face of wall LL offset=0.00 ft
Live Load Width, assumed strip loading LL width = 100.00 ft
Dead Load, assumed permanent loading (e.g. buildings) DL =0.00 psf
Dead Load Offset, measured from back face of wall DL offset=0.00 ft
Dead Load Width, assumed strip loading DL:width = 100.00 ft
Soil Parameters
Retained Zone
Angle of Internal Friction tp =28.00 deg
Cohesion coh =0.00 psf
Moist Unit Weight gamma=120.00 pcf
Foundation
Angle of Internal Friction cp = 30.00 deg
Cohesion coh =0.00 psf
Moist Unit Weight gamma =120.00 pcf
Note: Calculations are for Preliminary use only and should
not be used for construction without the review of a qualified professional.
Page
U TR BLOCK,I C.
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(cp)[AASHTO 10.6.3.4]or
may be the manufacturer supplied data. cp is assumed to be 40 degrees for a stone leveling pad.
Unit Designation: Full
Unit Dimensions:
Height = 2.46 ft Depth=2.46 ft
Width =2.46 ft Density= 140.00 pcf
Weight=2079.94 lbs
Unit to Unit Shear Unit to Leveling Pad Shear
T = N tan(0.00)+ 17796.00 ppf T= N tan(34.00)+0.00 ppf
Unit Designation: Double
Unit Dimensions:
Height=2.46 ft Depth =4.92 ft
Width =2.46 ft Density= 140.00 pcf
Weight=4159.88 lbs
Unit to Unit Shear Unit to Leveling Pad Shear
r = N tan(0.00) + 17796.00 ppf T = N tan(34.00)+0.00 ppf
Note: Calculations are for Preliminary use only and should
not be used for construction without the review of a qualified professional.
Page
U TR BLOCK,1 C.
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 b angle is b 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 6 angle (3/4 retained phi) 6=25.5 deg
Coefficient of active earth pressure ka =0.478
External failure plane p = 58 deg
Effective Angle from horizontal Eff. Angle =72.92 deg
Coefficient of passive earth pressure: kp = (1 + sin(cp))/(1 -sin(cp)) kp =3.00
cos(.i+i)2
Ka
2
( ) s Sig
C090.) cos Si_i1 1 + �i
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 of the base block.
UNFACTORED LOADS
Name ;Factory Force(V) Force(HyX-len; V-len Mo Mr
Face Blocks(W1)e' 1.00 5076 -- 2.05 - 10400
Soil Wedge(W2) 1.00 181 -- 2.61 — -- 472
LvIPad(W18) 1.00 336 -- -- -- -- —
Pa_h 1,00 -- 1350 — 2.67 3601 —
b ti
Pay1.00 1241 — 4.10 -- -- 5084
Pq_h 1.00 — 703 - 4.00 2813 —
Sum v 1.00 7 646 - 3.69 -- — 2383 �_ �` P
Pq—v 1.00q
144 2054 Sum Mom 6414 18339 ," \
Note: live load forces and moments are not included `s Pa
in SumV or Mr as live loads are not included as resisting forces.
L �.
Note: Calculations are for Preliminary use only and should
not be used for construction without the review of a qualified professional.
Page
U TR • BLOCK. INC.
BASE SLIDING
Sliding at the base is checked at the block to leveling pad interface between the base block and the leveling
- pad. Sliding is also checked between the leveling pad and the foundation soils.
Forces Resisting sliding =W1 +W2 + Pay + Pqv
5076 + 181 + 1241 + 646 N =7144 ppf
Resisting force at pad =(N tan(slope) + intercept x L)
7144 x tan(34.0) +0.0 x 4.9 Rf1 =7144
where L is the base block width
Friction angle is the lesser of the leveling pad and Fnd cp =30.00 deg
N1 includes N(the leveling pad)+ leveling pad (LP)
7144 + 336 N1 = 7480 ppf
Passive resistance is calculated using kp =(1 + sin(30))/(1 -sin(30)) kp = 3.00
Force at top of resisting trapezoid, dl = 1.00 Fp1 =360.00
Force at base of resisting trapezoid, d2 = 1.50 Fp2 =540.00
Depth of trapezoid depth =0.50
Pp = (Fp1 + Fp2)/2 *depth 225.00
Resisting force at fnd =(N1 tan(phi) +c L) + Pp
7480 x tan(30)+0 x 5.2 + 225 Rf2 =4544
where LP=lvl pad thickness*130pcf* L +Ivi pad thickness/2
Driving force is the horizontal component of
Pah+ Pqh
1350 + 703 Df=2054
FSsl = Rf/Df FSsI =2.35/2.21
Note: Calculations are for Preliminary use only and should
not be used for construction without the review of a qualified professional.
Page
•
U_;TR"BLOCK, 1 C.
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 eccentricity=M1 + M2 + MLvIPad +MPav + MPqv
10400 + 472 + 5084 + 2383 Mr=18339 ft-lbs
Moments causing eccentricity=MPah + MPq + MPqv
3601 +2813 Ma=6414 ft-lbs
e = L/2-(Mr-Mo)/N1
e =4.92/2-(18339-6414)/7480 e =0.79
e/L =0.16
FSot= Mr/Mo
FSot=18339/6414 FSot=2.86
Note: Calculations are for Preliminary use only and should
not be used for construction without the review of a qualified professional.
Page
U TR BLOCK,I C.
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 +W2 + LL + Pa_v+ Pq_v)
e =U2-(SumMr+ M_LL-SumMo)/(SumV+ LL)
e =4.92/2 -(11925/7144.13) e=0.789 ft
Calculation of Bearing Pressures
QuIt=c* Nc+q *Nq +0.5 *y*(B)*Ng
where:
Nc=30.14
Nq =18.40
Ng =22.40
c =0.00 psf
q = 180.00 psf
B' =B-2e + Ivlpad = 3.84ft
Gamma =120 pcf
Calculate Ultimate Bearing, Qult Qult=8471 psf
Bearing Pressure= (SumVert/B') +(LP width *gamma) sigma=1926.27 psf
Calculated Factors of Safety for Bearing Quit/sigma =4.40
Note: Calculations are for Preliminary use only and should
not be used for construction without the review of a qualified professional.
Page
•
U TR• BLOCK, I C.
SEISMIC CALCULATIONS
The loads considered under seismic loading are primarily inertial loadings. The wave passes the structure
putting the mass into motion and then the mass will try to continue in the direction of the initial wave. In the
_ calculations you see the one dynamic earth pressure from the wedge of the soil behind the reinforced mass, and then
all the other forces come from inertia calculations of the face put into motion and then trying to be held in place.
Design Ground Acceleration A=0.140
Horizontal Acceleration [kh =N2] kh =0.048
Vertical Acceleration kv =0.000
INERTIA FORCES OF THE STRUCTURE
Face(Pif) = (W1)*kh(ext) = 5076.46*0.048
Pif=244.44 ppf
SEISMIC THRUST
Kae Kae =0.520
D_Kae = Kae- Ka = (0.520 - 0.000) D_Kae =0.042
Pae =0.5*gamma*(H)^2*D_Kae Pae =161.89 ppf
Pae_h = Pae*cos(i ) Pae_h =119.20 ppf
Pae_v = Pae*sin(0) Pae_v =109.54 ppf
TABLE OF RESULTS FOR SEISMIC REACTIONS
Name Force(V) Force(H) X-!en Y-!en Mo M —
Face Blocks(W1) 5076.458 -- 2.049- -- 10399.69
Face Soil(W2) '-180.517- -- 2.612- -- 471.57
Pa_h -- 1350.3 ' -- 2.667 3600.8 -
Pa_v 1240.871; -- 4.097- - 5084.12
P 1 244.44 4.8 1173.31
I Pae_h 1 -- 119.199 ' -- 4.8 572.15
1 Pae_v 1 109.539 1 -- 4.097' - -- 448.81
Note: Calculations are for Preliminary use only and should
not be used for construction without the review of a qualified professional.
Page
U TR'BLOCK, INC.
SEISMIC SLIDING
The target factor of safety for seismic is 75% of the static value. Live loads are ignored in the analyses
based on the basic premise that the probability of the maximum acceleration occuring at the exact same instant as
the maximum live load is small.
Details are only shown for sliding at the base of blocks, a check is made at the foundation level with the
answer only shown.
The vertical resisting forces is W1 +W1 + Pay+ Paev SumVs =6607
Resisting force=SumVs *tan(phi) + intercept x L FRe =6607 ppf
Driving force = Pa_h + Pae_h + Pif
=1350 +119 +244 FDr=1714 ppf
FOS = FRe/FDr [leveling pad/foundation] FoS =3.19/2.88
SEISMIC OVERTURNING
Overturning is rotation about the front toe of the wall. Eccentricity is also a check on overturning
Resisting Moment = M1 + M2 + MPav + MPaev SumMrS =16404 ft ppf
Driving Moment= MPav + MPaeh +MPif SumMoS = 5346.27 ft ppf
Factor of Safety= SumMrS/SumMoS FoS = 3.93
SEISMIC BEARING
Bearing is the ability of the foundation to support the mass of the structure.
Qult=c*Nc +q*Nq +0.5*gamma*(B')*Ng
where:
Nc=30.14
Nq = 18.40
Ng =22.40
c=0.00 psf
q = 180.00 psf
Calculate Ultimate Bearing, Qult(seismic) Qult= 8471.46 psf
eccentricity (e) e=0.607
Equivalent Footing Width, B' = L-2e + Ivl pad B' =4 ft
Bearing Pressure = sumVs/B' sigma =1637 psf
Factor of Safety for Bearing = Qult/Bearing FoS=5
Note: Calculations are for Preliminary use only and should
not be used for construction without the review of a qualified professional.
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