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Home My WebLink Aboutboulder wall � � �" , , , , �/ickery �,n�ineerin� F,• onsultin .��, LLC 14�4�4�I ��i��.��e�+'��ooc�ti�rive,�t�en Prairie,M� 55i4i-�5�9 �hone: ?�2-4r5-SZ'2 �:�x: 9;�2-42r-19�1 ivi c ke ryFavi c�:e ry c nY�.com March 21, 2014 Project VEC 14-067 Mr. Brian Butterfield B. Butterfield Landscape Company ��r,n I^ � 3925 Watertown Road �/"'�y XJU/ l. Orono, MN 55359 �� Dear Mr. Butterfield: �� Re: Boulder Wall Observations and Evaluations, 3625 Eileen St, Maple Plain, Minnesota As you requested, Vickery Engineering and Consulting, LLC, (VEC), has completed the observations and evaluation of the boulder retaining walls at the referenced location. We are writing this letter to present the findings of our observations and evaluation. Background Information Three boulder retaining walls were constructed at the referenced site. Boulder Wall Plans were not prepared as part of this project. Observation Results On February 14, 2014, VEC performed observations of the boulder retaining wall at the site. Site observations included visual observations of the boulder retaining wall and measurement with a tape measure only. Survey measurements or use of other instruments were not performed. The results of the visual observations performed are summarized below: • The boulder wall has positive batter. � Filter fabric was placed behind the boulders. • The walls ranged from about 1 foot to 5 feet tall(total height), with an additional 1/2- to 1-foot of wall below grade. • The boulder sizes ranged from about 2 1/2 feet deep (perpendicular to the wall face) at the bottom to about 1 1/2-foot deep at the top. Evaluation The tallest cross-section of each boulder wall was evaluated. The evaluation was based on the Federal Highway Administration design methodology shown in their publication "Rockery Design And Construction Guidelines - FHWA-CFLTD-06-006" published in 2006. The results of the evaluation are attached. As noted, the boulder walls meet the required factors of safety. �n�ineerin��jolutions�or-an(�nsta�ile wo�d Boulder Retaining Wall Evaluation Project VEC 14-067 March 21, 2014 Page 2 of 2 Conclusions Based on the visual observations, it appears the boulder retaining wall was constructed in general accordance with industry standards and appear to be performing adequately at the time of the observations. The evaluation of the tallest cross-sections indicate the required factors of safety have been met. General Services performed by VEC personnel on this project have been conducted with that level of care and skill ordinarily exercised by members of the profession currently practicing in this area. No warranty, express or implied, is made. Thank you for using the services of VEC. If you have any questions about this letter, please call me at 952-465-8272. I hereby certify that this plan,speci�cation, or report was prepared under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. Ronalcf'��Vickery, PE President/Principal Engineer Registration Number: 24065 March 21, 2014 �/ickery �n�ineerin�� Consultins�.r,LLC 1444-I �i��:it�e Wao�s l�rivc,�c�en�rairfe.M�j 55�4J-150� � ��onr: �'?L-4<5-82?Z f :�x: q52-^FZ6-19J1 ivickr ri��ic ke rycn�.com Boulder Wall Calculations - 5-foot Total Wall Height Project VEC 13-037 - March 20, 2014 3625 Eileen Street, Maple Plain, MN - Garage Walls Page 1 of 2 Desiqn Parameters: Retained Soil Friction Angle, �sr:= 28dcg Soil Unit Weight, �ys:= 125pcf Crest Slope, (3:= Odeg Foundation Soil Friction Angle, �sf:= 28deg bl := 3 �sr S1 = 18.667�deg Rock Unit Weight, -yr:= 150pcf Surcharge Load, qs := Opsf Exposed Height, He:= 4.5ft Wall Embedm ent, Hb :_ .Sft Total HeigM, Hr:= He+ Hb Hr= Sft Top of Wall Width, Wc:= 1.5ft Base of Wall Width, Wba:= 2.3ft a:= 83deg �:= 90deg - a � = 7•deg v = tan(�sf) v = 0.532 Calculate Wall Weiqht: Wl :_ .5•(Wba— Wt)•He•�yr•lft Wl = 2701bf W2 := Wt•He•�yr•lft W2 = 1.013x 1031bf W3 := Hb•Wba•rys•lft W3 = 143.751bf Ww:= W1 + W2 + W3 Ww= 1426.31bf Active Earth Pressue Coefficient(Ka): (cos(�sr+ �)) 2 Ka :_ Z Ka= 0.274 (cos(�))��(cos(S1 — �;))��1 + �(sin(�sr+ S1))�(sin(�sr— (3))� [(cos(S1 — �))�(cos(�— �))] Total Horizontal Force: Wt HorizOntal ForCe From SOiI, Fah:= .5•^�s•Ka•Hr•Hr•cos(S1 —�)•Ift Fah= 419.SIbf Horizontal Force From Surcharge, Fs:= qs•Ka•Hr lft Fs = 0 Total Horizontal Force, Fh:= Fah+ Fs Fh= 419.5 lbf 2 H� Frictional Resistance: Vertical Force From Soil, Fav:_ .5•-ysKa•Hr•Hrsin(S1 - �)•lft Fav= 86.61bf 1 Fu:= v•(Ww+ N'av) Fu= 804.41bf Factor of Safetv, Base Slidinq: 3 Hb FOS Sliding, FOSs := F" FOSs = 1.917 �� wb �ngineerin��jo/utions fo�an Unsta6/e Wo�d �/ickery �n�ineerin�£� Consultin .��,LLC i 9�79� ��ii�a,oe Wooc�s�rivc,�c�en�rairic,�v�1 V 5�54 j-I 509 Pl�one: n5Z-465-8Z'2 f":�x: 95L-4Z6-197� rvic�cen�Lavickeryent�.com Boulder Wall Calculations - 5-foot Total Wall Height Project VEC 13-037 - March 20, 2014 3625 Eileen Street, Maple Plain, MN - Garage Walls Page 2 of 2 Calculate Overturnina Moment: Drlving Moment, Mo:= L0.5•Ka�ys�Hr�Hr cos(S1 — �)•�HrJJ +Lqs•Ka•H•�Hll Mo= 699.21bf 3 2�� Calculate Resistinq Moment: Resisting Moment is calculated by taking the sum of the weights times the moment arms for each section of wall above 2 W1�(Wba— W[)� — M1 :_ � M1 = 1441bf lft W2•�(Wba— Wt) + W�� M2:= 2 M2= 1569.41bf (lft) WZ �Wba� M3 := 2 M3 = 1164.41bf lft Resisting Moment, Mr:= M1 + M2 + M3 Mr= 2877.81bf Factor of Safetv, Overturninq: FOS Overturning, FOSot:= Mr FOSot= 4.1 16 Mo I hereby certify that this plan, specification, or report was prepared under my direct supervision and that I am a duly Licensed Professional FnninaPr unclar thP laws�f ihP StatP �f Minnasnta r �� Ronald . ickery, PE Registration Number: 24065 March 20, 2014 �nJPineerin�Yso�utions�oran unstab�e wor�� /ickery �,n�ineerin�Fy Consultin��.,LLC 1444�I �ii�n�e�ti��,c�c�s�rive.�c�en�r�irie.M�j 5534J-I 50� f'�one: 952-4e5-82J2 { :ix: 952-426-1971 rvic kr rt�C�vic�Ccrt�en�.com Boulder Wall Calculations - 5-foot Total Wall Height Project VEC 13-037 - March 20, 2014 3625 Eileen Street, Maple Plain, MN - Driveway Wall Desiqn Parameters: Page 1 Of 2 Retained Soil Friction Angle, �sr:= 28dcg Soil Unit Weight, ^�s:= 125pcf Crest Slope, p:= Odcg Foundation Soil Friction Angle, �sf:= 28deg � bl := 3 �sr S1 = 18.667�deg RoCk Unit Weight, �yr:= 150pcf Surcharge Load, qs := Opsf Exposed Height, He:= 4.5ft Wall Embedm ent, Hb:_ .Sft Total Height, Hr:= He+ Hb Hr= Sft Top of Wall Width, Wt:= 1.5ft Base of Wall Width, Wba:= 2ft a:= 83deg � := 90deg - a � = 7•deg v := tan(�sf� v = 0.532 Calculate Wall Weiqht: Wl :_ .5•(Wba- Wt)•He•7r•lft Wl = 168.751bf W2 := Wt�He•7r�lft W2 = 1.013x 1031bf W3 := Hb•Wba•^ys 1 ft W3 = 1251bf Ww:= W 1 + W2 + W3 Ww= 1306.31bf Active Earth Pressue Coefficient(Ka): Ka= (cos(�sr+ '�)) 2 2 Ka= 0.274 (cos(�))��(cos(S1 - �;))��1 + «sin(�sr+ Sl))�(sin(�sr- (3))] [(cos(S 1 - �))•(cos(-�j;- (3))] Total Horizontal Force: Wt Horizontal Force From Soil, Fah:= .S��ys•Ka•Hr•Hr�cos(S1 — �)•lft Fah= 419.51bf Horizontal Force From Surcharge, Fs := qs•Ka•Hr•lft Fs= 0 Total Horizontal Force, Fh:= Fah+ Fs Fh= 419.5 lbf 2 H� Frictional Resistance: Vertical Force From Soil, Fav:= .5•�ys�Ka•Hr•Hr�sin(S1 — �)•lfr Fav= 86.61bf 1 Fu:= v•(Ww+ Fav) Fu= 740.61bf Factor of Safetv, Base Slidinq: 3 Hb FOS Sliding, FOSs:= FU FOSs= 1.765 � wb �ngineerrngso/utions�o�an unsta6/e wor�d vickery �n�ineerin�£� Consu�tin.��,LLC I�144 I �i��crn�c��ooc�s�rivc,�c�cn�rainc,M�� 55 i9 j'I 50,9 �hone: 7tiL-4o5-8Z7? f-`nx: )52-42r-1971 rvickcrc�E�vic�cen�en�.com Boulder Wall Calculations - 5-foot Total Wall Height Project VEC 13-037 - March 20, 2014 3625 Eileen Street, Maple Plain, MN - Driveway Wall Page 2 of 2 Calculate Overturninq Moment: Driving Moment, Mo:= L0.5•Ka•^ys•Hr•Hr�cos(S1 — �)�I HrJJ +Lqs Ka•H I HJJ Mo= 699.21bf ` 3 `2 Calculate Resistinq Moment: Resisting Moment is calculated by taking the sum of the weights times the moment arms for each section of wall above W]�(Wba— Wt)•�� M1 := 3 M1 = 56.251bf lft W2•L(Wba— Wt) + Wt� ? M2:= M2= 1265.61bf (lft) W2 �Wbal I M3 :_ � � M3 = 1012.5 lbf lft Resisting Moment, Mr:= M1 + M2+ M3 Mr= 2334.41bf Factor of Safetv, Overturninq: FOS Overturning, FOSoc:= Mr FOSor= 3.338 Mo I hereby certify that this plan, specification, or report was prepared under my direct supervision and that I am a duly�icensed Professional FnninPPr iinciPr thP laws nf ihP StatP nf Minnasnta_ Ronald . ickery, PE Registration Number: 24065 March 20, 2014 -��ngineering�jo/utions�o�an unsta6/e wor�d