The URL can be used to link to this page

Home My WebLink AboutCDP 2017-0074; STAINBACK RESIDENCE; CITY COMMENT RESPONSE LETTER; 2019-10-03[\)p t.::> ,,., ,.. 0:, '1 'i '$1 '1 ◄r.-4ei1 Geotechnical Exploration, Inc. SOIL AND FOUNDATION ENGINEERING • GROUNDWATER • ENGINEERING GEOLOGY 03 October 2019 Ms. Darcy Eaton 5360 Los Robles Drive Carlsbad, CA 92008 Subject: City Comment Response Letter Eaton-Stainback Residence 5360 Los Robles Drive Carlsbad, California Dear Ms. Eaton: Job No. 17-11606 In response to an email from Mr. David Rick, associate engineer with the City of Carlsbad dated September 10, 2019 (refer to Appendix A), Geotechnical Exploration, Inc. is responding to comments and concerns regarding the horizontal and vertical limits of excavations required to remediate the existing undocumented fill soils within the proposed new building pad area and the evaluation of the temporary slope cuts required for these excavations adjacent to the neighboring properties foundations. In addition, Mr. Rick has requested the production of a geologic cross section through exploratory excavation HP-2. SCOPE OF SERVICES In order to properly address the remaining concerns expressed by the City reviewer, our firm has prepared a new site Plot Plan (Figure No. I) utilizing the preliminary grading plan prepared by BHA, Inc., dated May 22, 2019, as our base map. The Plot Plan shows the horizontal limits of the remedial grading required for the proposed new building pad and shows the site-specific geologic and soil units encountered. In addition, two geologic cross sections for the subject project (Figure Nos. II and II) have been prepared with their locations shown on the Plot Plan . The geologic cross sections display the anticipated distribution of fill soils underlying the project site and the anticipated limits of the required remedial grading required for the proposed building pad, both horizontally and vertically. CONCLUSIONS AND RECOMMENDATIONS As our geologic cross sections demonstrate, the 45° descending zone of influence for the vertical foundation loading of the northwestern and southeastern neighboring 7420 TRADE STREETO SAN DIEGO, CA. 92121 • (858) 549-7222 G> FAX: (858) 549-1604 "' EMAIL: geotech@gei-sd.com Eaton-Stainback Residence Carlsbad, California Job No. 17-11606 Page 2 properties is well below the anticipated limits of the required fill soil excavations. The maximum depth of fill removals required adjacent to these properties is approximated at 4½ feet. Additionally, keeping 1 foot inside and parallel to the subject property line/fence as stated in the city comment email, will still allow for relatively stable temporary slope cuts at the recommended maximum slope inclinations. The recommendations for temporary slopes cuts are as follows below. 1. Temporary Slopes Cuts: Temporary and continuous slope cuts of a maximum 5 feet in height and at a slope cut ratio no steeper than 0.5:1.0 (horizontal distance:vertical distance) are recommended for the required fill soil excavations. For fill soil excavations greater than 4 feet in height, a slotting method should be utilized. The excavation slots should not exceed 7 feet in width, parallel to the 1-foot setback off the property line fence. These slot cuts should also adhere to the 0.5: 1.0 maximum slope inclination steepness. It should be noted that these limits of vertical fill soil excavations have been made based on our field exploration hand pit data and on the assumption of a wedge-shaped distribution of fill soils underlying the subject lot. A representative of our firm should be present at the start of grading operations to confirm actual field conditions. Should conditions be different than what is anticipated, additional recommendations for shoring may be warranted. Should you have any questions regarding this letter, please contact our office. Reference to our Job No. 17-11606 will help expedite a response to your inquiry. Respectfully submitted, GEOTECHNICAL EXPLORATION, INC. )~ R.C.E. 34422/G.E. 2007 Senior Geotechnical Engineer ... LEGEND ~ HP-3 Approximate Location of Exploratory Handpit j f' Approximate Location of Cross Section Artificial Fill Qaf Qvop 6 Very Old Paralic Deposits ( Unit 6) r --, ._ -..J Approximate Limits of Remedipl Gradi(19 £/aSTIHG I" C.S. V.C.P. MIJHCJta. Sl'l!DPE11 OIIC, 141-& SHr.10 ':t \ \ 'I, roll£ t.FGRADm ro ,. '-°'51WCWA1rR.liE1lR~ ~cJorno~ ' NA <'' "·"' t>.~A:Jr£·.,.....,= e!t!.\ ~11511~~ IUlrt"I." ~.;",oo•-ua1 It" w l 17-f1eotJ.p2.aJ ~'( ,,.,.. .. <; ,, N'PR(JJ(..L0CA1IOHOF-DCIS'lWGS/4"C4SI.N IQSD(:11£1/»H(l 15.JIU-IIOHd(RElD """J.OC.4""" ,_.,. - APN \ ,,, ~~., ~ NO.t•)f jiff ,~ \ \ 'I, /jQ!r._ DOD.Ol'E1t ltl OST~ POl6iT ntOI/ CAJILS84D PARKS AHO RrO!t"AJIOH 10 llflloK' MD mm llt~ M.IIIUC RA t , '"""" .... "' ~ sa.:,;zfflll \ NOTE: This Plot Plan Is not to be used for legal purposes, Locations and dimensions are approximate. Actual property dimensions and locations of utilities may be obtained from the Approved Building Plans or the ·As-Bulh• Grading Plans. ,.,~ 42.4'E \ \ APN 2-10-112--/1 llHCf'MIOCi'UIJCUIIJrY~r DOC. HQ. 71242. li£C. l,M/SI II "1124. PAIX. 114, OJl :,_,w:~ rottfMl'OtUl'AI.L 11HGOIO!l£AD ~ -- -,;;;r,..""" 210-1/2-10 """ '""''""'-'£ APN 2/0-112-05 @ 16 5' O' 10' 20'. Scale: l " = 20' (approximate) REFERENCE: This PLOT PLAN was prepared from an existing undated GRAOtNG PLAN by BHA, INC. and from on-site field reconnaissance performed by GEi. ,,, PLOT PLAN Eaton-Stainback Residence 5360 Los Robles Drive Carlsbad, CA. Figure No. I Job No. 17-11606 gt Geotechnical Exploration, Inc. October 2019 ___ , .. 17-11606-M ~ ~ ~ j < C ,g 0 > i\!l 2 0 E "[ ~ A 90 80 70 so Existing Neighboring Residence Wood Fence/Pl PL I GEOLOGIC CROSS SECTION A-A' Eaton-Stainback Residence PROPOSED NEW RESIDENCE oar 5360 Los Robles Drive Carlsbad, CA. Proposed Patio Proposed Wall Proposed Patio Proposed Residence Hallway PL Wood Fence/ PL Proposed Fence Proposed Patio I I I I I I Proposed: Sidewalk I --?---?--?-? Qvop • Proposed l 1 /2 to 1 1... ____________ Adjacent Foundations 45° Zone of Influence -----------' (H-V) Temporary Cuts into RIIAreas Relative Horizontal Distance (feet) Scale:1" = 10' (Horizontal and Vertlcol) Existing Neighboring Residence ?- Proposed 1/210 1 (H-V) Temporary Cuts into Fill Areas 40-+-----~---~----~----~---~----~----~---~----- 0 NOTE: Thi• Cron Section ii not to be UMd for legol ~ locotiona ond dim.n:aions ore o~xi-mot .. Acwol property dimeMlorl• Gnd locot10n• of utaiUea may be Obtained from the ~OYed Building Plans or the ·AII-Bu~t• Crodlng Pion-. 10 20 30 40 Oar Artificial RI! Ovop Very Old Parolic Deposits • (unit 6) Approximate Geologic Contoct so 60 70 80 ·90 A' Figure No. II JobNo.17-11606 al. Geotechnlcal Exptoratlon, Inc. ~ October 2019 .. -. B 90 I 80 -1 ai ~ ....I V) 70 -I~ Q) > 0 .0 < C: ,g 0 60 -I ~ w ~ a E ">< e a. 50 -l .'t Existing PL and I Proposed Grades Proposed I New Grade ? HP-1 (3'toNW) I GEOLOGIC CROSS SECTION B-B1 ? Oaf Ovop 8 Eaton-Stainback Residence 5360 Los Robles Drive Carlsbad, CA. East End of Existing ---- Residences PROPOSED NEW RESIDENCE ? ? ? HP-2 (4' to SE) Oaf Qvop 8 i Proposed limits of Existing FIi Soii Removal I ? Existing and Proposed Grades Proposed New Planter Box ? HP-3 (27' to SE) ? Qaf Ovop 8 B' PL I I -- 40+----.--------r-----,----.------.----..,.------.-----.-----r----r-----.----,------.------,-----, 0 10 20 NOTE: Thie Croa S.ction is not to ti. u .. d for 1e901 purpoau. l.ocotiona ond dimenaion• o,.. o~oxi-mote. Actual propert)' di!Mtllions ond locotlONI ~~~~iPlo':f or~ lh~~~eu~rt~mG~i:'Pi:~ 17-l 160lr88 30 40 50 60 70 80 Relative Horizontal Distance (feet) Scale:1" = 10' (Horizontal and Vertical) 90 100 110 Oaf Artificial Fill Ovop Very Old Paralic Deposits s (unlt6) 120 Approximate Geologic Contact 130 140 Figure No. Ill JobNo.17-11606 150 .-, Exploration, Inc. Gai-~ ~ Octaber2019 ~