Report (3) OFFICE COPY
CIq4f Geopier Northwest
GEopIER ®
40 Lake Bellevue,Suite 100
APR Bellevue,Washington 98005
9 z��� Tel. 425.646.2995-Fax 425.646.3118
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www.geopier.com
REVISION ?0"'Dl lG Dwi3Ot
April 9, 2020
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TO: Corbett Stewart 7y SV 72'D err
Essex
General Construction Inc..
SUBJECT: Design Submittal
Geopier-Impact Ground Improvement
Dartmouth Apartments—Tigard, OR
Dear Mr. Stewart:
This letter and the attached documents represent our design submittal for Geopier® soil
reinforcement at the site of the Dartmouth Apartments Project located in Tigard, OR. The
following paragraphs document our design of the patented Geopier-Impact reinforcement system
for support of the building footings. Our approach does not include support of the building slab.
Geopier Reinforcement Design
Subsurface information, as documented in the geotechnical report completed by GeoDesign on
February 18, 2019, has been used as a basis for our design. The subsurface conditions below
the existing grades consist of medium stiff to very stiff silts. Groundwater was encountered at
depths of approximately 8 to 20 feet below ground surface during explorations.
In view of the medium stiff silts coupled with a high groundwater table, the Geopier-Impact
system or "displacement process" will be used to install the Geopier elements. The Geopier-
Impact system which we propose to utilize consists of a hollow mandrel with an internal
compaction surface which is driven into the ground using a powerful static down force
augmented by dynamic vertical impact energy. After driving to the design depth, the hollow
mandrel serves as a conduit for aggregate placement. As the mandrel is raised and re-driven
downward thin lifts of compacted aggregate are formed and compacted both vertically and
laterally. The process is repeated until the rammed aggregate pier is constructed.
We envision the Geopier soil reinforcement will be installed from near existing grades following
rough grading of the site. Our Geopier-Impact elements will be installed to a depth of 30 feet or
refusal whichever occurs first. The refusal criteria will be less than 6 inches of mandrel
advancement in 30 seconds. The Geopier elements will be installed and constructed to ground
surface. Our Geopier elements will be installed directly beneath the footings and shear wall
mats. Currently, our design consists of the construction of 1,214 Geopier elements which can
provide an allowable bearing capacity of 5,000 psf with a '/z increase for short term duration
loads. Our pier count and spacing is designed based off the loads provided by the design team.
Foundation Settlement
For our analysis, settlements are first calculated for a zone extending from the bottom of the
footing to the depth of the reinforcement. Additional settlement may occur in the "lower zone" or
in the unimproved soil beneath the reinforced zone. The lower zone settlement is calculated
using an elastic or consolidation approach depending on the soil type. Based on our analyses,
we estimate that total settlement (static) will be less than one inches and differential settlement
will be less than one-half inch between columns. Please see our attached calculations for
additional information.
Geopier'and Rammed Aggregate Pier'are registered trademarks of Geopier Foundation Company,Inc_
Dartmouth Apartments April 9, 2020
Tigard, OR Page 2
Geopier Installation
The installation of the Geopier reinforcement, including a downward modulus test, will be
completed in general accordance with the specifications. The installation and the modulus test
will be conducted under the supervision of an experienced geotechnical engineer from Geopier
Northwest. The modulus test will consist of loading the Geopier element in increments to 150%
of the design load while measuring deflections to verify the design parameters. The modulus
test will also incorporate a creep test at 115% of the design load.
We appreciate the opportunity to work with you on this project. If you have any questions or
require further information, please call.
Sincerely,
Geopier Northwest Inc.
PROF
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`SNDER 80U
Exams: tt/3t /Loll
Alex Bogue P.E. David Van Thiel, P.E., G.E.
Attachments: Geopier Foundation Plan and Construction Notes, and Geopier Capacity and Settlement
Calculations
GEOPfERd Foundation Company GEOPIER®
Project:land&DartDartmouthrou
No.:Near boring B-1
Engnr:AB SQUARE FOOTINGS
Date: Version 3.0.6 August 2013
INPUT PARAMETER VALUES: TOP OF PIER STRESS-SQUARE FOOTINGS
'Parameter Symb Val. Parameter Symb Equation F8 F10
RAP diameter(in) d 22 Column load(kips) P 300 405
Depth to groundwater(It) dgw 10 Required fooling width(It) Br sgd(P/gall) 7.75 9.00
Total unit weight of soil(pcf) g 115 Selected footing width(It) B 8 10
Sod frict.angle(decof 26 Footing beating pressure q P!(BB) 4.69 4.05
Max.hor.pressure(psf) pmax 2500 Required No.RAP elems Nr Moen 7.5 10.1
From Table 4.2: Selected No.RAP atoms N 8 10
RAP cell cap.(kips) Ogee 40 Area replacement ratio Ra hi-Ad/CBS) 0.330 0.284
Footing bearing press.(ksf) gall 5 Stiffness ratio Rs kg/km 12.0 12.0
RAP stern.modulus(po0 kg ISO Stress al top of GP(ksf) qg q'Rx/(Rs'Ra-Ra+1) 12.15 12.45
Soil stiffness modulus(poi) km 12.5 Load at top of GP(kips) Qg gg'Ag 32.1 32.9
SHAFT LENGTH REQUIREMENTS
Depth of Embedment Df 2.0 2.0
Trial shaft length(ft) Hs 21.0 21.0
Dril depth(ft) Hdrill Df+Hs 23 23
Frictional resistance force(kips) an fs"pr d"Hs 130 130
Allowable tensile resistance(kips)Qsall Qs/2 65 65
Allowable end-bearing rest.(kips) Qeb Qeb 3 3
Is shaft long enough? Qs+Qeb>Pcdem4 ok ok
INPUT PARAMETER VALUES: UPPER ZONE SETTLEMENT-SQUARE FOOTINGS
Upper Zone Elastic Parameters Parameter Symb Equation
Parameter Sym Val UZ Settlement Approach 1Stiffne$s,2-Modulus 2 2
Pier Modulus Layer 1(kat) Egi 2800 Thickness of UZ sublayer((It) H.) 5.0 5.0
Pier Modulus Layer 2(kW') Egg 2500 Thickness of UZ sublayer 2(ft) H,,, 5.0 5.0
Pier Modulus Layer 3(ksQ Eg3 1400 Thickness of UZ sublayer 3(ft) H„n 5.0 5.0
Pier Modulus Layer 4 Bad) Eg4 1400 Thickness of UZ sublayer4(ft) Ha, 5.0 5.0
Pier Modulus Layer 5(ksf) Eg5 2500 Thickness of UZ sublayer 5(ft) H.s 3.0 3.0
Soil Modulus Layer l(ksf) Emi 200 Total UZ Thickness OK? Hoz a Hs+d ok ok
Soil Modulus Layer2(ksf) ErrQ 75 Composite Modulus Layer 1(ksf) Eea„a, Eg1Ra+Emt(1-Ra) 1058 886
Soil Modulus Layer 3(ksf) Emi 50 Composite Modulus Layer 2(ksf) E„.„re Eg2Ra+Ern2(1-Ra) 875 715
Soil Modulus Layer 4(ks) Ern4 150 Composite Module,Layer 3(ksf) E.a„as Eg3Ra+Em3(1-Ra) 495 408
Soil Modulus Layer 5(ksf) Ems 175 Composite Modulus Layer 4(ksf) Eaa,„a, Eg4Ra+Ern4(1 Ra) 562 480
Composite Modulus Layer 5(ksf) Ero„1a E95Ra+Emb(1-Ra) 942 789
Sett.of LZ sublayer 1(n) s,a, 00110 orsfunas'WEcemp 0.23 0.25
Sett.of LZ sublayer 2(n) 4az q1u-2"H,d/E,a„,,0 0.12 0.16
Sett.al LZ sublayer 3(it) s,as q1u-3'H,m//EE,a„,as 0.10 0.14
Sett_of LZ eublayer 4(n) a,a, g1n-4'H,aq/E,a„,at 0.05 0.07
Sett.al LZ sublayer5(n) s,, q1u-51N,s/Eaa„,., 0.01 0.02
Total Upper Zone Settlement(in) s,a s,a,+s,).+s,as+R,,+K.,, 0.50 0.64
INPUT PARAMETER VALUES: LOWER ZONE SETTLEMENTS-SQUARE FOOTINGS
Parameter Symb Val. Parameter Symb Equation FB F10
Plowable and-bearing(kips) Qeb 3 Dpih to bottm of LZ from fig(It) X'B X'B 32 a 40
E or 4 for LZ sublyr I E,/e, 0.015 Upper zone thickness(ft) H. Hs+d 22.8333 22.8333
E or cr for LZ sublyr 2 Ey/c,a Lower zone thickness(ft) Ha H2b-Hlz 9.2 17.2
E or for LZ sublyr 3 Es/ca Thickness of LZ sublayer TO Ha, 9.2 172
E or co for LZ sublyr 4 Ea/ca, Thickness of LZ sublayer 2(ft) HI.
E or 4 for LZ sublyr 5 EaIca Thickness of LZ sublayer 3(ft) Has
Cale.settlement to XB X 4 Thickness of LZ sublayer4(ft) Ha,
Thickness of LZ sublayer 5(ft) H(a
Total IS thickness ok7 ok ok
E or;for LZ subyrl E,/c„ E(ksf)orc, 0.015 0.015
E or for LZ sublyr 2 Er/c„ E(ksf)orc, 0 0
E orq for LZ sublyr 3 Es/ou E(kef)dr4 0 0
E or c,for LZ sublyr 4 E,/co. E(ksf)orc, 0 0
E or for LZ sublyr 5 Es/cos E(ksf)orc 0 0
Initial stress for sublyr 1(ksf) P., 2.172 2.383
Initial stress for sublyr 2(ksf) P. 2.414 2.835
Initial stress for sublyr 3(ks1) P'a, 2.414 2.835
Initial stress for sublyr 4(ksf) Pa 2.414 2.835
Initial stress for sublyr 5(ksf) Pa 2.414 2.835
Fig stress on sublyr I(hat) API q1 0.18 0.19
Fig stress on sublyr 2(ksf) AP2 q1 0.14 0.12
Fig stress on sublyr 3(ksQ APS q'1 0.14 0.12
Flg stress on sublyr 4(ksQ AP4 q1 0.14 0.12
Fig stress on sublyr 5(ksf) APS q1 , 0.14 0.12
Sell of LZ sublayer 1(in) ski r.,wa,m.Sec,.oa,yvap 0.06 0.10
Sett.of LZ sublayer 2(in) Ka wn.aaltan(nz.ortyraa) 0.00 0.00
Sett of LZ sublayer 3(in) Ka o 5lm t((rms.on),m) 0.00 0.00
Sett.of LZ sublayer 4(in) K. wmwxrtlnoo'onyaen 0.00 0.00
Sett.of LZ sublayer 5(in) se o.ereaswe(lr.n.onyrm) 0.00 0.00
Total lower zone sett.(in) so Sa,+Sa,+sas,S,+Sas 0.1 0.1
Total UZ+LZ settlement(in) 5 0.6 0.7
Note:When"No LZ"Is displayed-thicknesses of lower zone should equal 0
p9 1 of 1
GEOP7ER® Foundation Company GEOPIER®
Project:72nd S Dartmouth
No.:Borings B2-84
Engnr:AB SQUARE FOOTINGS
Data: Version 3.0.6 August 2013
INPUT PARAMETER VALUES: TOP OF PIER STRESS-SQUARE FOOTINGS
Parameter Symb Val. Parameter Symb Equation F6 F8 FIO i
RAP diameter(in) d 22 Column load(kips) P 130 295 482
Depth to groundwater(ft) dgw 10 Required fooling width(ft) Br sgrl(P/gall) 5.10 7.68 9.82
Total unit weight of soil(pet) g 115 Selected looting width(ff) B 6 6 10
Soil Pod.angle(degr) f 26 Footing bearing pressure q P/(B"B) 3.61 4.61 4.82
Max,hot.pressure(psi) max 2500 Required No.RAP elems Nr Ware' 2.4 5.4 8.8
From Table 4.2: Selected No.RAP ebbs N 3 6 9
RAP cell cap.(kips) Qoet 55 Area replacement ratio Ra N'Ag/(B`B) 0.220 0,247 0.238
Footing bearing press.(kaQ qall 5 Stiffness ratio Rs kg/km 10.0 10.0 10.0
RAP stiffn.modulus(pci) kg 200 Stress at lop of GP(ksQ qg q`Rs/(Rs'Ra-Ra+1) 12.12 14.28 15.36
Sot stiffness modulus(pci) km 20 Load at top of GP(kips) Og gg'Ag 32.0 37.7 40.5
SHAFT LENGTH REQUIREMENTS
Depth of Embedment Df 2.0 2.0 2.0
Trial shaft length(ft) Hs 21.0 21.0 21.0
Da depth(ft) Hdr6 Of+Hs 23 23 23
Frictional resistance force(kips) Os fs'pi'd'Hs 130 130 130
Allowable tensile resistance(kips)Orel Qs/2 65 65 65
Allowable end-bearing rest.(kips) Qeb Qeb 3 3 3
Is shaft long enough? Qs+Qeb>Pcdem? ok ok ok
INPUT PARAMETER VALUES: UPPER ZONE SETTLEMENT-SQUARE FOOTINGS
Upper Zone Elastic Parameters Parameter Synl, Equation
Parameter Gym Val UZ Settlement Approach 1S5ftnesa,2-Modulus 2 2 2
Pier Modulus Layer 1(ksQ Eg1 2800 Thickness of UZ sublayer 1(ft) Hm, 5.0 5.0 5.0
Pier Modulus Layer2(ksQ Eg2 2800 Thickness of UZ sublayer2(ft) H,m 5.0 5.0 5.0
Pier Modulus Layer 3(ksQ Eg3 2500 Thickness of UZ sublayer 3(ft) Hm, 5.0 5.0 5.0
Pier Modulus Layer 4(red Eg4 2500 Thickness of UZ sublayer 4(ft) Hm 5.0 5.0 5.0
Pier Modulus Layers(kat) Eg5 3000 Thickness of UZ sublayer 5(ft) H,os 3.0 3.0 3.0
Sol Modulus Layer 1(loaf) Em1 200 Total UZ Thickness OK? Huz.Ha+d aR ok ok
Soil Modulus Layer2(Vast) Em2 200 Composite Modulus Layer 1(red) Low Eg1Ra+Em1(1-Ra) 772 843 818
Soil Modulus Layer 3(ksQ Em3 150 Composite Modulus Layer 2(ksQ Em,,5 Eg2Ra+Em2(1-Ra) 772 843 818
Soil Modules Layer 4(hst) Em4 150 Composite Modulus Layer 3(lost) E,r,,,ya Eg3Ra+Em3(1-Ra) 667 732 708
Soil Modulus Layer 5(kaQ Ems 200 Composite Modulus Layer 4(lei) Ea,,,yy Eg4Ra+Em4(1.Ra) 667 732 708
Composite Modulus Layers(kV) Em,ys Eg5Ra+Eno(1-Ra) 816 893 865
Sett.of LZ sublayer l(in) s,y, Vika or glo-s'yEuo np 0.21 0.28 0.32
Sett,of LZ sublayer 2(in) s,m q'lo-2'H,m/Emy,5 0.07 0.12 0.17
Sett.of LZ sublayer 3(in) im q'17-3'H,s/E„y,5 0,03 0.06 0.10
Sett.of LZ sublayer 4(in) som q'lo-a'H,yt/E,,,,,yy 0.02 0.03 0.06
Sell,of LZ sublayer 5(in) s,es q`17311m/Ew,,,s 0.01 0,01 0.02
Total Upper Zone Settlement(in) ay: s,a,+ym+s,m+s,m+s,m 0.34 0.51 0.66
INPUT PARAMETER VALUES: LOWER ZONE SETTLEMENTS-SQUARE FOOTINGS
Parameter Symb Val.J Parameter ,crab Equation _L F6 FB Fin
Allowable end bearing(kips) Qeb 3 Dpth to bottm of LZ from ftg(11) X'B X'B 24 32 40
E or o,for LZ subyr 1 Er I cm 0.015 Upper zone thickness(ft) Ha Hs+d 22.8333 22.8333 22.8333
E or c,for LZ sublyr 2 Ea/c,a Lower zone thickness(ft) Hp H2b-Hlz 1.2 9.2 17.2
E or c,for LZ subyr 3 Es/&s Thickness of LZ sublayer 1(ft) Her 1.2 9.2 17.2
Eor&for LZ subyr 4 E,I;, Thickness of LZ sublayer 2(ft) Hot
E or c,for LZ subyr 5 Es/dry Thickness of LZ sublayer 3(ft) Hm
Cele.settlement to X'B X 4 Thickness of 12 sublayer 4(h) Hp,
Thickness of LZ sublayer 5(ft) Hps
Total LZ thickness ale? ok ok ok
E or;for LZ subyyr 1 E,/co E(WI)or; 0.015 0.015 0,015
E or for LZsublyr 2 Eaf zo E(kat or 0 0 0
E or 0,for LZ subyyr 3 Esr4, E(ksf)or c, 0 0 0
Eor e,forLZsubyr 4 Elf c„ E(kst)or; 0 0 0
E orc,for LZ subyr 5 Es/c,s E(kaQ or ce 0 0 0
Initial stress for subyr 1(kaQ P',t 1.962 2.172 2.383
Initial stress for subyr 2(Rd) P'm 1.993 2,414 2,835
Initial stress for subyr 3(ksQ Pee 1.993 2.414 2.835
Initial stress for subyr 4(ksQ P'm 1.993 2,414 2.835
Initial stress for subyr 5(kaQ P',s 1.993 2.414 2.835
Ftg stress on subyr 1 Oaf) AP1 91 0.11 0.18 0,22
ftg stress on subyr2(ksQ AP2 91 0.10 0.13 0.14
Ftg stress on subyr 3(lost) Ap3 91 0.10 0.13 0.14
Ftg stress on subyr 4(ksQ AP4 q'I 0.10 0.13 0.14
Ftg stress on sublyr 5(ksQ AP5 q'I 0.10 0.13 0.14
Sett.of LZ sublayer l(n) set mr'eurlwyy,,.onvrorl 0.01 0.06 0.12
Sett.of LZ sublayer2(in) sm mremsoarez.onyv.,zr 0.00 0.00 0.00
Sett,Of LZ sublayer 3(el) on, ermmeptvm.o»yywl 0.00 0.00 0.00
Selo.of LZ sublayer 4(n) sp, awwea 591 eu„owyeor 0.00 0.00 0.00
Sett.of LZ sublayer 5(in) spa 0005 kagrm.ovsuwsr 0.00 0.00 0,00
Total lower zone sett.(In) sp sp,+sm+spy+sp,+spa 0.0 0.1 0.1
Total UZ+LZ settlement(in) s 0.3 0.6 0.8
Note:When"No LZ"is displayed,thkknesses of lower zone should equal 0
pg 1 oft