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Home My WebLink AboutRetaining wall info . �� aYS�� 2u� H A, u G Q ZI�13--01041 _ . September 22,2014 Project Number: 14-681 Mr. Ethan Kindseth Gonyea Homes 10850 Old County Road 15,Suite 200 Plymouth, MN 55441 RE: Soil Evaluation,Boulder Retaining Wall,75 Bay 'de Trail,Orono,MN Dear Mr. Kindseth, This letter summarizes the results of the soil borings a laboratory analysis completed to aid in evaluating construction of the boulder retaining wall a the above referenced address in Orono, Minnesota. Our services were completed as requested by you and included; completing hand auger soil borings, laboratory Proctor tests, moisture content nd organic content tests and preparing a brief summary letter of our findings with soil parameters or wall analysis and design. Project and Site Des iption Two boulder landscape retaining walls were recently co tructed at 75 Bayside Trail in Orono, MN along with the newly constructed single family home. W 111 was a relatively long wall (approx 135 feet)that generally extends southward from the Deck nea the southwest corner of the home. Wa111 is a tiered wall, about 4 feet tall,stepped back about 31/z et and then another 4 foot tall wall. Wall 2 is a single wall about 51/z feet tall that extends about 1 feet to the east off the northeast corner of the home. We understand that the walls were constructed wit out any engineering design documents. Because of that the City of Orono requested that an engi eering analysis of the as-built condition of the wall be completed. We further understand that defec s, if any,would be required to be repair or the wall replaced to meet code requirements. Results Wall Observations We observed the general conditi of the wall and estimated the average boulder/rock width to range from about 24 to 32 in hes, the average boulder thickness was estimated to be 20 inches and the batter was estimated to range from about 9 to 12 inches. We excavated below a few of the boulders and estimated the verage burial depth to range from about 6 to 8 inches. Soil Conditions Six hand auger borings were complete for this project. Hand auger borings HAP- 1, HAP-2 and HAP-3 were taken near Wall 1 and hand auger borings HAP-4, HAP-5 and HAP-6 Page � 2 taken near Wall 2. The hand auger boring extended to d pths ranging from about 2 to 5 feet below the ground surface. Hand auger boring HAP-1 encountered about 1 1/z feet cl y fill overlying about 21/z feet of granular fill underlain by native clay soils. Borings HAP-2 and H -3 encountered about 1 to 31/2 feet of clay or clayey sand fill overlying native clays. Hand auger boring HAP-4,taken"behind" Wa112 encou tered about 5 feet of clay fill. Hand auger borings HAP-5 and HAP-6 taken at the base of Wall 2 encountered about 3 feet of organic clay. Laboratory organic content test(s) of the clay resulted ' an average organic content of about 9 1/z percent which classifies the soil as"organic". A Log of Boring sheet for each boring is attached. Soil ata boundaries were estimated based on changes in the samples recovered and the auger cu 'ngs. The strata boundaries are only approximate and the boundaries will likely occur as gra ual rather than abrupt transitions. Strata boundaries should also be expected to vary away from th boring location. The approximate boring locations are shown on the S '1 Boring Location Sketch, attached. The sketch was prepared by HGTS using a "Certificate of Su ey" of the property prepared by Sathre- Bergquist, Inc. as a base. Groundwater Conditions Groundwater was not encou ered in the hand auger borings. We made water level measurements in the borings at the times an under the conditions stated on the boring logs. The period of observation was relatively short and uctuations in the groundwater level may occur due to rainfall, flooding, irrigation, spring thaw, drainage, and other seasonal and annual factors not evident at the time the observations were mad . Design drawings and specifications and construction planning should recognize the possibility of uctuations. Discussion Based on the results of the hand auger brings completed or Wa111, it appears that the boulder wall is supported on native clay soil or clay fill that was judge to be generally suitable for wall support. We observed a layer of granular soil in boring HAP-1 tak n"behind" Wall 1 but did not observe the granular layer in boring HAP-2 which was also taken be 'nd Wall 1. It appears imported sand was used as a drainage layer,although it appears inconsistent. Draintile was not observed day-lighting through the wal or encountered in the hand auger probes. Based on conversations with the contractor, draintile w s installed and routed through the yard, day-lighting near the pond. Based on conversations with the contractor, we underst d Wall 2 is going to be reconstructed to retain less than 4 feet,and therefore it will not require to e engineered. 1 3570 GROVE ORIVE �'�78! APLE GROVE, M1� 5531 1 Page � 3 Recommendatio s Soil Bearing Capacity Based on the result of our soil bo ings it is our opinion that the wall can be supported on the native lean clay or sandy lean clay or compacted engineered fill following removal of the organic clays. It is further our opinion th t a net allowable soil bearing pressure up to 2,000 pounds per square foot(ps�can be used for wall esign. Wall Drainage We recommend backfill adjacent to the w 11(s) with sand having less than 50 percent of the particles by weight passing the #40 sieve and les than 5 percent of the particles by weight passing the #200 sieve. The sand backfill should be plac d within at least 1 foot horizontally of the wall. We recommend using a friction angle of 32 degree and a unit weight of 120 pound per cubic foot(pc fl for this material. Soil Backfill Standard Proctor tests were performed o samples of the on-site soils. Result of the Proctor tests yielded maximum dry densities ranging fr m about 98 to 115 pounds per cubic foot (pc fl with corresponding wet (total maximum) densit es of 115 to 129 pcf, respectively. We recommend using a friction angle of 28 degrees and a u it weight of 125 pcf for the on-site clayey soils for wall design. Compaction Since the walls are strictly landscaping wal it is our opinion that the wall backfill can be compacted to a minimum of 90 percent of its standard Proctor density (ASTM D 698). Fill should be placed within 5 percentage points above and 1 perc ntage point below its optimum moisture content as determined by the standard Proctor. All 'll should be placed in thin lifts and be compacted with a vibratory compactor. Summary The soils below Wa111 appear suitable for the recommen bearing capacity of 2,000 psf. The backfill soil observed generally appeared to meet the recommend d 90 percent compaction. We understand Wall 2 with be reconstructed to be le s than 4 feet tall and therefore, it is not required to be engineered. General The hand auger borings were completed using a 3 inch d meter bucket type auger. The hand auger was advanced in 3 to 6 inch increments. The sampl recovered were visually and manually classified in accordance with ASTM Test Method D 2488. chart explaining the classification system is attached. Haugo GeoTechnical Services does not practice in the fi d of surveying therefore the locations and elevations referenced or described above should be consi ered approximate. 1 3570 GROVE DRIVE �'278! APLE GR�VE� MN 5531 1 Page � 4 Haugo GeoTechnical Services LLC has used the degree o skill and care ordinarily exercised under similar circumstance by members of the profession curre ly practicing in this locality. No warranty expressed or implied is made. Thank you for the opportunity to assist you on this pr ject. If you have any questions or need additional information please contact Joe Westphal at 61 -269-4027 or Paul Gionfriddo at 763-954- 1101. Sincerely, HAUGO GEOTECHNICAL SERVICES,LLC /�1� ;9, ' �. , , , ' � -� - Paul S.Gionfriddo,P.E. Senior Engineer Professional Certification I hereby certify that this plan,specification or report was prepared by me or under my direct supervision and that I am a duly licensed professional engineer under the laws f the State of Minnesota. ��,� < .�QN �- wE�'�, ;. ,,,.......,.S)•A � :� '� Joe Westphal,P.E. ��i� _ Project Engineer �� License Number 49833 :NJ� ��3 � Expires June,2016 '��`+.�, y �� '��F MINN��: '��` Attachments: Soil Boring Location Sketch Soil Boring Logs,HAP-1 thru HAP-6 Terminology of Soil Characteristics Proctor Tests,P-1 thru P-2 1 3570 GROVE �RIVE �'278! APLE GROVE� MN 5531 1 ,� IR" .. .. .._. .. ' � --�----' , � - _ J>A� ' � ii 1 _ 5.:� (! ___ 7�_ - . 96 � -f I 1 I;7A � !'_".'_.; - , � �� 1 s.S� �'-� �► . �1. I - , N . 1 � � �` � -� � �.�..J �l�?' /'1 � _�� ,�y�' A ! '�� / (j � L �� -- _ �v,J`.4 �- r 9p5 •.� -;� ��"- ��._1,Y � .4 �� 1 * r �1. �' _ — .�.• ,..yYi-'1.. i �_._ _, M / yA ,�� -ii+ls� ; / ;��--- ,��.. ;:�i�: '� �� l � `1 ; t � n'b` _ � �49•E i ', � � f � ��o � �;� zss ti, .9�e�__j ' `�,,;`� � ", , �y�;,`�i� �,1 �:s� �_^ Zn 99�� ! •a4 . a, �- �v�'= ' ' W , �, ,4� � i� ' ,.. ��'t "' o t, t.-`" p� 4�y� I � ; `�t�1 � ; / ��' `� HAP-1 • �,� .,o ' �• ; � YY ,,� � �i � • '.1;,` ... yy�j q•' , � ' 1 . . ° y � � � ; .; �;. -� � � � rv�4 4 ��r ~�� ` HAP-5 �Y'' i ' 4,t .g ' -..i ^ �r O �; � /1 .� �. � , � � � 1 � _ u •^ `p ' ' � . . { , J! g a�ILyy � i �;-.,�. �; .. •aq: 99�6� � " � �A' UD) , ��e �. � M ti, � �' � . m s �r a ,� W � � ,�� '�,1- ti HAP-4 ��-�. I '\ � .:,C.`. ^ I �y Q'jp y� _�a .�1`,'c, . \ � 6L Gf' 1� ,:r �' h • ;f: � r I f.. ; ,y�� 33'. .:.�r. 1t • /. .. . , � HAP-3 0- �l- o ''-`y , << 1 ��''' �� } �, m',� *� - � y �v, t: i .q� ,.1 I y. � t z,y:• ° s,, '`v �� `" `` Y� � ��9S � '� 1 � � � � °'1' 'ti-. �'n�� , �. r i .,,, �� ,Q . M, ,t ,,.; HAP-6 �� , i \ � i ��-iFi� I *E � „ �' '� r \ 3~� ' ., `' _,ar±F , � � �. .�,= 1 � '�.�. � •� �~ �•,�,�r, /� ! , I � dtltptl ��r.. . � / ��i s HAP-2 , , � `Jr�„ '� ` y ,j /� � ' '--�y � 7 O / � I � ,�wr, '9Q:.i � ST 4°�S.�f �/ ? , . . , . � � � \ � I � �9��r�� ^ry 1,�.� � o �`� -a �aP P, •Ht�� -+ � �/,J ��/1/ � t', � � 'i,, ,l f,� �, ___ ,y�,, � , s g ��, �a .,; �'C��---�-ar-x----t�-�-'------',�-- —�-�-------ti: _—��7 ��s \ r'�''� � ,, ` " / .�' / ,�-;` g ' / /'khn /� ��c;n � f � f//g . /� 4Ml 9 5 D � ---�-- � � 5 6 % ' 1 HMl 47ts N / � � . � � �` � � �� — — — -- — — ..._,.. ,_.. � •-- — -� —: .A�1�:1 d . . � � . . � �. � =Approximate Soil Boring Location '�t' �r� r Haugo GeoTechnical Soil Boring Location ketCh Figure#: 1 Services. Retaining Wall Eval ation Drawn By: MJS Date: 9/17/2014 2825 Cedar Ave 75 Bayside Tra I Scale:None Minneapolis, MN Orono, Minnes a Project#: 14-681 BORING NUMBER HAP-1 HA� Haugo GeoTechnical Services PAGE 1 OF 1 2825 Cedar Avenue S Minneapolis, MN 55407 CLIENT Gonyea Homes _ PROJE T NAME 75 Bayside Trail __ PROJECT NUMBER 14-681 PROJE T LOCATION _Orono,Minnesota DATE STARTED 9/11/14 COMPLETED 9/11/14 GROUN ELEVATION HOLE SIZE _3 inches DRILLING CONTRACTOR HGTS GROUN WATER LEVELS: DRILLING METHOD Hand Auqer Probe A TIME OF DRILLING —Not Encountered LOGGED BY DH CHECKED BY A END OF DRILLING --Not Encountered _ NOTES From Top of Wall#1 A ER DRILLING --Not Encountered w �� U a� J� U �p MA ERIAL DESCRIPTION WQ�' a= (n �J Q Z � (� � �.� Lean Clay,organic,brown and black.(FILL) AU AU � AU J � � � �.7 __ _...._— —.__" _-- o AU Pooriy Graded Sand with Silt,brown,damp.(FI L) � r a m AU � 2.5 �o -- � ' AU � � � � AU a F z � AU J 4.O Z (CL)Lean Clay,brown,wet,medium.(Possibl FILL) m AU CL �n 4.5 z (CL)Sandy Lean Clay,brown,wet,medium.( lacial Till) � � AU � 5.0 CL 0 � I' AU 5.3 � Bott m of borehole at 5.3 feet. a h � w m � U v 0 � 0 c N N m F � � m Q J N � � F � F Z � J W � 'a � _ m J � W Z W ('J BORING NUMBER HAP-2 AUG❑ Haugo GeoTechnical Services PAGE 1 OF 1 2825 Cedar Avenue S Minneapolis, MN 55407 CLIENT Gonyea Homes __ PROJE T NAME 75 Bayside Trail__ PROJECT NUMBER 14-681 PROJE T LOCATION Orono,Minnesota DATE STARTED 9/11/14 COMPLETED 9/11/14 GROU ELEVATION HOLE SIZE 3 inches DRILLING CONTRACTOR HGTS GROU WATER LEVELS: DRILLING METHOD Hand Auqer Probe A TIME OF DRILLING —Not Encountered _ LOGGED BY DH CHECKED BY A END OF DRILLING --Not Encountered NOTES From Top of Wall#1 A ER DRILLING --Not Encountered __ w _ �� U W a� �g v �p M ERIAL DESCRIPTION w" a� vi �� ° Q z � c� � 0.0 Clayey Sand,dark brown to brown,moist,med um dense.(FILL) AU AU � I AU J � H o AU � a m AU � 2.5 � ` AU � � U w � AU _ 3.3 F (CL)Lean Clay,brown,wet,medium.(Possibl FILL) � A� CL w 4.0 Z (CL)Sandy Lean Clay,brown,wet,medium.( lacial Till) W II AU CL � 4.5 w Bott m of borehole at 4.5 feet. � � U O 0 U m � a � � w � � U v 0 ro 0 v N N � H � � m Q J � � � � N r z c� J W � a � _ m J � W Z W � FIAUG❑ Haugo GeoTechnical Services BORING NUMBER HAP�3 � 2825 Cedar Avenue S PAGE 1 OF 1 Minneapolis,MN 55407 CLIENT Gonyea Homes PROJE T NAME 75 Bayside Trail ____ PROJECT NUMBER 14-681 PROJE T LOCATION Orono,Minnesota DATE STARTED 9/11/14 COMPLETED 9/11/14 GROU ELEVATION HOLE SIZE 3 inches DRILLING CONTRACTOR HGTS GROU WATER LEVELS: DRILLING METHOD Hand Auger Probe A TIME OF DRILLING —Not Encountered __ LOGGED BY DH CHECKED BY A END OF DRILLING --Not Encountered NOTES From Bottom of Wall#1 A ER DRILLING --Not Encountered w }� U 2 iav W C0 � �p M ERIAL DESCRIPTION o a� ¢z � c� � 0.0 Lean Clay,brown,wet,soft to medium.(FILL) AU AU __ 1 A --- --- (CL)Sandy Lean Clay,brown,wet,medium.( lacial Till) � AU J � CL � o AU m 2.0 'a Bott m of borehole at 2.0 feet. m � � � � a � � U w O � a F z c� i w J H Z W m N H Z W � � U O � U J m � a N � w N � U v 0 � 0 v N N m � � (� ai a J � � 0 F � F Z � J W � a � x m J � W 2 W � BORING NUMBER HAP-4 AUG❑ Haugo GeoTechnical Services PAGE 1 OF 1 2825 Cedar Avenue S Minneapolis,MN 55407 CLIENT Gonyea Homes PROJE T NAME 75 Bayside Trail PROJECT NUMBER 14-681 PROJE T LOCATION Orono,Minnesota ____ DATE STARTED 9/11/14 COMPLETED 9/11N4 GROUN ELEVATION __ HOLE SIZE 3 inches DRILLING CONTRACTOR HGTS GROUN WATER LEVELS: DRILLING METHOD Hand Auqer Probe A TIME OF DRILLING —Not Encountered LOGGED BY DH CHECKED BY A END OF DRILLING --Not Encountered NOTES From Top of Wall#2 __ A ER DRILLING --Not Encountered w �� U w v J� Q p MATE IAL DESCRIPTION � Qz � � 0.0 Lean Clay,slightly organic,dark brown,soft to mediu .(FILL) ' AU ' AU � AU J � F o AU � > — a °�,° i AU � 2.5 �o � � AU � U w I � AU G z � AU J Z m AU � � z � ' AU � 5.0 5.0 o Bottom of borehole at 5.0 feet. U J m � a � K w � � U v 0 co 0 v N N m r 0 c� m a J � � � H � H Z � J J W 3 a � x m J � w Z W � �IAUG❑ Haugo GeoTechnical Services BORING NUMBER HAP-�J � 2825 Cedar Avenue S PAGE 1 OF 1 Minneapolis, MN 55407 CLIENT Gonyea Homes ______ _ PROJE T NAME 75 Bayside Trail __ PROJECT NUMBER 14-681 PROJE T LOCATION Orono,Minnesota DATE STARTED 9/11/14 COMPLETED 9/11/14 GROUN ELEVATION HOLE SIZE _3_inches DRILLING CONTRACTOR HGTS GROUN WATER LEVELS: DRILLING METHOD Hand Auqer Probe A TIME OF DRILLING —Not Encountered LOGGED BY DH CHECKED BY A END OF DRILLING --Not Encountered __ NOTES From Bottom of Wall#2 A ER DRILLING --Not Encountered w �� U S ~" w C0 v a p MA ERIAL DESCRIPTION w� a� ui �� Q Z � c9 N 0.0 _ (OL)Organic Clay,dark brown to black,wet,s .(FILL) AU AU � AU J � - OL _ � — o AU = � a m AU — � 2.5 � — �o — � AU — � — 3.0 W Bott m of borehole at 3.0 feet. 0 � a F z � � w J F Z W m N H Z W � � U O 0 U � m 7 a � � w N � U e 0 ro 0 v N N m H � (� m 5 � � 0 � � � Z � J W 3 a � x m J � W Z W � BORING NUMBER HAP-6 A- GO Haugo GeoTechnical Services PAGE 1 OF 1 2825 Cedar Avenue S Minneapolis, MN 55407 CLIENT Gonyea Homes _ _ PROJE T NAME 75 Bayside Trail PROJECT NUMBER 14-681 PROJE T LOCATION Orono,Minnesota ____ DATE STARTED 9/11/14 COMPLETED 9/11/14 GROUN ELEVATION HOLE SIZE 3 inches___ __ DRILLING CONTRACTOR HGTS GROUN WATER LEVELS: DRILLING METHOD Hand Auqer Probe A TIME OF DRILLING _-_Not Encountered __ LOGGED BY DH CHECKED BY A END OF DRILLING --Not Encountered NOTES From Bottom of Wall#2 A ER DRILLING --Not Encountered w _ �� U w a x J� v �p MA ERIAL DESCRIPTION wo�- a� vi qQ� ¢Z � c� � 0.0 (OL)Organic Clay,dark brown to black,wet,s . (FILL) AU AU � ' AU J — � OL � o AU N } -- — Q m AU � 2.5 — � -- �o — ' AU — � — 3.0 w Bott m of borehole at 3.0 feet. 0 � a G z c� i w J F Z W m N F- Z W � � U O 0 U m � a � � w N � U v 0 � 0 c N N � H � � m Q J N 7 � F N F Z � J W 3 a � x m J � W Z W (� ' � D scriptive Terminology of Soil d Standard D 2487 • 00 ,ju'�/ Classification of Soils for Engineering Purposes , . .., (Unified Soil Classification System) Crrtena�or Assi n�n Grou S mbols e�d Sods Classlfiution PaAitle Siie IdentifiCat�on 9 9 P Y ---T-------- – Group Names Usmg LaDoratory Testt' roup Hcultlers uver 12- S mbal� Group Name` CoDb�es 3 to 12' � � Gravels Clean Grsvels C,�4 a�o�S C�< 3� yy y��i_ Gravei � g�aoea g�avei – o Mae tnan SC:.o� 5� c;r iess 4nes� -- ��« 3�� 0 3' ,°� � � caarse fracl�on __ C,��anCfor� a C >J` P � v�,iy g�aaea qravN' F,n� No �ro 3�,' � � � retained o� Grsvels with Fines F mes class� as Ml�a MH M S,R yLavei ' � Sand c N No 4 s�eve More IAan�2°<hr�es' Fmea Uass�h as CL o�CH C Cla e �ravei''� Coar� No 4 to No �0 Q,�� Sands hAedwm No �D to No 40 Clean Sands C�2 6 and� �,C� S�` W Wplt•gra0ed sana Fme No a0 ro No 200 d q o 50%or more or 5°•or Ipss hnes' c � = Z coa�se�raaw� G�<6 an0/or t >C�>J P Poony graoed sand S�1 �No 200 PI<�or � °' Sands with Fines F��s class�ly as ML or MN �t M beiow�A�une � � passes Sdry sand'�' Clay <No 200 P12 1 and E No a S�ve � hlcre than 12`e' f�nes c�ass�fy as Cl or CH C Cla e sanC� on or above A' h�e � PI>7 and piots an or aDore'a ur�e� L ! lean Ga ' _ -- SiNa snd Clays �norganK --- --- Relative Densi o( a Pi<a or ptocs bebw'A ime� L 0 o a+ Lpwd I�mi S�tl' (Y '� � ' � L wd��mrt oven qr�J � O� amc c�a Cohesionless Soils � q g� i �ess than 57 OrganK p r p 75 9 Y� c a o � l uw i�mi� noi dr� � Oigamt 5�8' - Very�oose 0 to e BPF w QN —� PI p�ots on or above`A'une N i Fa;clay' �0�� S lo tU BPF o,E Sltts and clays InorganK e PI prots oelow A"r��e H � Med�um oense t i to 30 BPf b � Z LiQuitl umrt ' E�astic 5�1.' c -- Dense 3�to 50 BPF 50 a more li0wd bmrt-ov2n tlr�f Or anK r.ta ii�` � OrganiG � � p;5 i H 9 Y 1Aery dense ovef 50 BPF � � L� uKl limR�npltlnetl H Or arnc sitt' " Highly Organ�c Solls Pn�rdy argamc matler CarM m cobr antl orgamc odor T Peat ConeiStency of Cot►esive SOilf e fS85POM:11C'ndllrWG��'�G�••� '''rY��SlvE V2(YSOh '�1OI BP� r n r�e�a samok coMw�ea:dw�es o ..� .F,s a odr ,on w nn��Y a ooutars a eom w qroyb�s�P Soh 2 to 3 BPF c C = Dk:D., C =�u�� RathBr soN S l0 5 BPF p. .Dt Medwm 6 to b BPF y M soa corrans2 t 5'�santl aw w.M san0��rywF�e Rather shR 4 l0 12 BPf c G/aveN wtn�ic'7'4'nes rrX.re a.a�Y�nbds �� S1tM 13 l0 14 BPF GvµGM wa;i qrewa poVe�we^s.r, i VEry SUH 17 t0 30 BPF Gw GC well�yrsdq,�r�rp�wM n!r H8/0 over 30 BPf GP.GM uoo��r asoeo��r.,m.,�� GP-GC Goati 9raaeC yra.e�wqr.day } M��+es cvss��»Cl Mt ..x aw'svmDcw GC-GM w SC SM g M�neaaravpa^c aCc��maqan,c�,n�y:ooroup^sms i n n so��conq�ns 2 t5x q�a.e� soa rm+�rare� ro praq^amE � , $�vJs+v�n S to 17 w�r+es n�x.�re n�s>f mppy sw sM w!�QU4lO 5iM w1�Sd' Orilling Notes SNCSf. �.ec�qsoea sr�c we�cuti Stacda�o pe��:etrabon tesi oonngs were a0vancetl by 3 1!1 cr 6 tl�� SP'S�'n °°°"��'°�°'a�'°`"""r IL'hWl�w-srem augers��nless noted olherw+se Jelhng wa�e�was usetl SP sC wa�r c�sa.a.a��a+�n car to Gean out auger prp� to sampl�ng only where mC�cafed on logs � tl Aneiperp�wnrts O�a�n N�cI�M A w fo��s a Cl Ml a+ny ua� ► pa.w�wn,c,c2�koR.sr�:;�G aoa��msrq�« wrtrq�a�e�wn�vers;r000mrw� Stantlard penelrai�on test bonnps are oesignated by tne pre/a �ST- � u sai cems�a.�ws No:�o v.aa^.wvr�s.�a aaa sarwti royraq nr�,e ISD��tuCeJ An samp�es were taken w+In the standaro 2'00 spl�1-lube m MsWcdAen5230'+bCV7Nc:oo�eea+�.w�ropa�e:aoa�r�veuy waouo�,a�+�e i. sam �er ex� n Pt 2 4 ano piots on ar at�ore A �w�e li P ..eW whe�E notCtl c Pi<�a pias Oebw R �me Powe�auger bo�mga were ativancea by 4 or 6 d�amele�conhnuous- � =��rns o�a aoo�e a �-e fl�ght so1W-s�em augers Sa1 cfeud�cstw�s anA strata aepths were in- v ��c ca>ae� n � ierrea trom a�s�u�betl sampies augered to the suAace ana are theretore 60 somewhat approwmate Pp,�r auger bwrtigs are deapnated by 1ne � D�eha'B I 50 ; _ '' Mantl auger bor�ngs were advancetl manually wdn a 1 trZ or 3 1!�' ! �. � aameter auper antl were brrHtetl to t�e deplh from wh�ch t�e euper couW � :J ' � �;c be manuilly wifhOrawn Na�d au9a bonngs are md�cated Dy tnc prefi: a 40 i I _ H x I O� � � �� G�` BPF: NumDers mdicate blows per tppt reCorCeO m slanCartl penelra[qn � 30 j � !es! aiso knpwn as'N velue The samplet wa5 set 6 mto untlisturbed �. � � I � s�i be�ow Me hdlpw•atem auyer Orrv�np resistarxe�were�hen countetl '� � � +e�second and tn�rd 6"mcrements and a0tletl to pet BPF Where they ' ' �' oinereC s� nAecan the are re np � 20 --�-- 9 uY Y P«1ed m Ihe lolbwi brm 2rt 2 for the � I � �� { secona ara tMro 6 mcrements �especuvely a ,' G�' MH or OH ' WH: WH rnC�Ca�es Ih!Sampler penetr8letl s0U urN7er we�ht ol hammer 10 -- --- . i ---+ � a„d rotls alo�e tlnvinq not requrrea 7 _ ' � c� ,M� � ML or OL � I � � I WR VdR�ntl�cates Me sampie�penetrate0 aa�unCer we�ght o1 roCs � . � 1 � ' d�ane �amner we�ghl anC Ohwng nol rgpuired 0 10 16 20 30 s0 50 60 7Q BO 90 100 1 0 TW,no�Wtes tn�n.watletl Iuncf�swrbeC>tube sample Lipuid Um�t�LL► Laboratory Tests No�e. Au rests aere run�n ge�era�accoroance v�nm apW�ce��e ASTM s�a�uaros OD [1 y dE�;s�h Cc' OC Org3n�c Can(?nI ` WD We�oens�q pcl S Percem o�saturet�on < MC Nawrai�+o�sture contem SG Soec��c gravrtv lL L�o�wtl iimd `�� C CQneS�on pgf PL Plashc umn � (� Ang1e Of internai tncRon Pi Plast�c�sy ��tler , qu U�conGnec!compress�ve strength,psl P200 �< passmg 200 s�eve qp Pockel �nCtromellr Str@ngth tSt Rer 1,C i PROCTOR TEST EPORT 99 ZAV for , Sp.G._ _ -- — -- _- -- — — �- - - — -- -- 2.65 98 0 97 U a T .N C N � T � 96 95 94 13.5 15 16.5 18 19.5 21 22.5 Water content,°/a Test specification: ASTM D 698-07 Method A Standard Elev/ Classification Nat. %> %< Depth USCS AASHTO Moist. Sp.G. LL P� �q No.200 CL/SC 2.65 2.4 5 L 1 TEST RESULTS MATERIAL DESCRIPTION -------- - _ _ __ -_ Maximum dry density=97.7 pcf Sandy Lean CLAY,Brown Optimum moisture= 18.5% — --_ -----__ _— Project No. 14-681 Client: Gonyea Homes ,Remarks: Project: 75 Bayside I Assumed Specific Gravity 2.65 'OLocation:95'S of North End of Wall Sample Number: P-1 Haugo GeoTechnical Services, LLC Maple Grove, Minnesota Figure Tested By: Matt Sandhoefner , � PROCTOR TEST EPORT 117.5 I �— ' -— 1 1° 1 1 115 — ZAV for Sp.G._ 2.65 112.5 U a T N C N � ! � � 110 107.5 105 7.5 9 10.5 12 13.5 15 16.5 Water content, o Test specification: ASTM D 698-07 Method A Standard Elev/ Classification Nat. %> %< Depth USCS AASHTO Moist. Sp.G. LL P� #q No.200 SC 2.65 4.6 29.1 TEST RESULTS MATERIAL DESCRIPTION Maximum dry density— 115.1 pcf Clayey SAND,Dark Brown Optimum moisture= 12.1 % Project No. 14-681 Client: Gonyea Homes Remarks: Project: 75 Bayside Assumed Specific Graviry 2.65 OLocation:44'S ofNorth End of Wall Sample Number:P-2 Haugo GeoTechnical Services, LLC Ma le Grove Minnesota . _. Figure Tested By: Matt Sandhoefner . . �� s1G(�. Ti�a � 1 � 2.� (3 - 0104I I hereb certify that this plan, specification or report was pre ared by me or under my direct supervision September 23, 2014 and tha I am a duly licensed professional engineer under t e laws of the Sta of�jl'yhnesota. �/ I Gonyea Homes 10850 Old County Rd 15, Suite 200 Nick anson Date: 9-23-14 Plyl'1'lOUtfl, MN 55441 Minnes ta Registration No.46665 Attn: Ethan Kindseth Subject: Boulder Retaining Wall Assessment 75 Bayside Trail, Orono, MN Hanson Group Project: 4.292 To Whom It May Concern: The purpose of this letter is to report the findings of a tructural engineering review of an existing boulder retaining wall at the above address. ASSIGNMENT The Hanson Group has been retained to provide a stru tural engineering assessment of the existing tiered boulder retaining wall constructed at 7 Bayside Trail in Orono, MN, as directed by Ethan Kindseth of Gonyea Homes. BACKGROUND The above referenced boulder retaining wall at a singl family residence was recently constructed without prior engineering design docume ts. The City is requesting an engineering review of the boulder retaining walls be conducted. DESCRIPTION Two different walls were constructed at the address n ted. A tiered boulder wall was approximately 135 feet long that is 4 feet tall, steps b ck 3.5 feet, and extends upward another 4 feet. The second wall in question is approximately 5 5 feet tall. It is reported that the second wall will be re-graded to a height below 4 feet and thu will not require engineering and excluded from the scope of this report. • Gcnyea Homes �� Hanson Group Project: 4.292 September 23, 2014 Page 2 OBSERVATION AND COMMENTS 1. Nick Hanson, PE of The Hanson Group perform d a site visit on September 18, 2014 to verify existing boulder geometry and construction. Tested soils information by Haugo Geotechnical Services provided on September 2, 2014 was provided for use in the design of the retaining wall. The Hanson Grou has reviewed the obtained and provided information and the following is note : a. The boulders used in the field are fields one and were approximately 24 to 32 inches wide with an average of 20 inch s in depth. The batter of the walls varied from 9 inches to 12 inches. The above i formation was also confirmed by Haugo. Haugo reportedly observed bur al depths of approximately 6 to 8 inches of the bottom boulders during the bear ng compaction testing. b. Haugo lists the soil design recommenda ions on Page 3 of their report and are based on the actual site obtained and I boratory tested soils information. These soil parameters were the basis for the s ructural stability design of the tiered retaining wall. c. It should be noted that draintile could n t be observed by The Hanson Group or Haugo due to the presence of filter fabr c directly behind the soils. It is reported by the Builder that each tiered wall had a layer of draintile and drainage medium directly behind the boulders that daylig ted and were routed into a nearby pond. Haugo's findings indicated that reas of drainage medium were found at locations but were inconsistent in locati n and geometry. 2. The following information is noted in regard to the above observed conditions: a. A boulder retaining wall of this nature r lies on the self-weight of the boulder material in conjunction with a slight bat er to resist lateral soil pressures through gravity. A small amount of passive resi ance is relied upon at the bottom buried portion at the base. b. The geotechnical soil properties for uni weight, angle of friction, and bearing capacity listed in Haugo Geotechnical S rvices report were used for the design of the wall (refer to this report for all soil i formation). The existing tiered wall was checked for stability including overturni g, sliding, and bearing capacity failures based on the lateral pressures of the pr vided soils information. c. Boulder retaining walls do have the pot ntial for movement from a number of items including, but not limited to, fros heave, groundwater fluctuation, improper drainage, creep from prolong d rainfalls, etc. Movement may occur in this wall as a result of any number of re sons. Boulder retaining walls do have the ability to accommodate some mino differential movement as a result of their flexible construction and practices The Hanson Group does not guarantee that some movement will not occur. � Gc�nyea Homes Hanson Group Project: 4.292 September 23, 2014 Page 3 PROFESSIONAL OPINION 3. It is our professional engineering opinion that t e existing tiered boulder retaining wall at the rear of the single family residence noted appears in acceptable condition and structurally capable of resisting the required la eral soil loads. GENERAL 4. The observations and opinions expressed in thi report are based on our professional engineering judgment and professional practic , as well as limited visual observations of exposed materials only. No testing or removal f materials was performed by The Hanson Group to determine physical condition nd state of structural components, nor compliance with the present Building Code. Co tact The Hanson Group should evidence contrary to the above observations and finding noted be found during construction. 5. No other engineering was performed or reques ed for this project. This document pertains to the general structural assessment a d condition of the exposed existing tiered boulder retaining wall at the rear of the esidence located above only. All drainage, as well as means and methods of con truction, are the responsibility of the Builder and/or contractor. This report is limite to the elements exposed only. 6. All construction is assumed to be in accordanc with this document, standard industry practice, and the requirements of the Code unl ss further information is supplied by the contractor or City inspector regarding the cons ruction of the foundation system. 7. The conclusions are based on preliminary and I mited examination and analysis. We reserve the right to supplement and/or amend these findings and/or opinions should new information become available. Concealed discrepancies and/or defects limit the accuracy and scope of this report. No warrant , either expressed or implied, for any portion of the structure is given. If you have any questions, please contact us. Sincerely, The Han on Group �/� /�f"" 'i Nick Hanson, PE �