Loading...
HomeMy WebLinkAboutCDP 08-13; GREEN DRAGON COLONIAL VILLAGE; GEOTECHNICAL PLAN REVIEW; 2009-10-23I cpr oc'I?, 1Mr \\ ) /1 2 Geotechnical e Geologic e Coastal 0 Environmental 5741 Palmer Way Carlsbad, California 92010 • (760)438-3155 FAX (760) 931-0915 October 23, 2009 W.O. 5892-A-SC Mr. Bruce R. Bartlett do Esbensen Architecture 6150 Yarrow Drive, Suite H Carlsbad, California 92009 Attention: Mr. Dennis Moore Subject:. Geotechnical Plan Review, Green Dragon Tavern and Museum, 6115 Paseo Del Norte, City of Carlsbad, San Diego County, California Dear Mr. Bartlett: In accordance with a request from Esbensen Architecture, and in response to plan check comments from the Esgil Corporation ([Esgil], 2009 [see the Appendix]), GeoSoils, Inc. (GSI) has performed a review of our geotechnical report (GSI, 2009), the foundation plans and details prepared by Esbensen & Associates ([E&A], 2009), and the grading and improvement plans prepared by O'Day Consultants ([ODd, 2009a, 2009b) for the purpose of evaluating if the plans are in general conformance with the intent of the geotechnical report (GSI, 2009). GSI's scope of services included a review of the referenced reports and plans, analysis of data, and preparation of this summary letter. The conclusions and recommendation presented in GSI (2009) are considered valid and applicable with respect to the subject site, and should be properly incorporated into the design and construction phases of site development, unless specifically superceded in the text of this review document. PLAN REVIEW Grading Plans Based on our review, our recommendations (GSI, 2009) generally appear to have been properly incorporated into the plans (O'Day, 2009a). As such, the plans generally appear suitable from a geotechnical standpoint, with the following comments, and/or additional recommendations. For Clarity, Engineer's Note No. 6, shown on Sheet 1 of O'Day (2009a) should include the work order and date of the geotechnical report as follows: "as described in the retaining wall section of the soils report by GeoSoils," (add) work order 5892 A-SC, dated June 30, 2009. Section C-C, D-D, E-E, and F-F, shown on Sheet 2 of O'Day (2009a) should also indicate that the "gravel" shall be encapsulated in a filter fabric (mirafi 140 N, or equivalent). The gradational requirements for the gravel should also be indicated. "Engineered Soil," indicated on Sections C-C, D-D, E-E, and F-F of O'Day (2009a) should consist of a relatively permeable, granular soil with a minimum sand equivalent (SE) of 25 and be compacted to a minimum relative compaction of 90 percent per ASTM D-1 557. As onsite soils contain variable amounts of clay, a select import, or stockpiling of available, select onsite soil (if any) should be anticipated. The gravel underdrain systems (see Sections C-C, D-D, E-E, and F-F on Sheet 2 of O'Day [2009a]) should remain above a 1:1 projection down and away from any adjacent, settlement sensitive improvement. Alternatively, the affected improvement may be deepened to at least 6 inches below the gravel layer, or to the top of formational soil, whichever is deeper. "Enhanced pavements" shown on Sheets 1 and 3 of O'Day (2009a) were indicated on these plans as being a part of the landscape plans for the project. At this time, the landscape plans were not available for review by this office. A geotechnical review of the "enhanced pavement" sections should be performed prior to construction, and preferably in the planning stage. Grading Note #36, shown on Sheet 2 may be completed as follows: "The Soils Report Titled" Preliminary Geotechnical Investigation, Proposed Green Dragon Colonial Village (Formerly Hadley's), Paseo Del Norte, Carlsbad, San Diego County, California "Prepared By" GeoSolls, Inc. Work Order No. 5892-A-SC. "Dated" June 30, 2009 The "Note:" indicated with respect to preliminary pavement sections, shown on Sheet 4 of O'Day (2009a) should be revised to indicate that actual pavement thickness to be determined by R-value tests performed upon the completion of grading. Bus pads and trash enclosures should be designed and constructed per the minimum City Standards. Mr. Bruce Bartlett W.O. 5892-A-SC 6115 Paseo Del Norte, Carlsbad October 23, 2009 FHe:e\wp9\5800\5892a.gpr Page 2 GSI has assumed that trench re-surfacing during the improvement of Paseo Del Norte will be performed per City Standards, and pavement section minimally matched in kind. Therefore, no further pavement design/laboratory testing is deemed necessary, based on this condition. Improvement Plans Based on our review, our recommendations (GSI, 2009) generally appear to have been properly incorporated into the plans (O'Day, 2009b). Again, the plans generally appear suitable from a geotechnical standpoint, with the following comments, and/or additional recommendations. Water note #7, shown on Sheet 1 of O'Day (2009b) discusses "soil tests" as they relate to soil corrosion potential. Testing to evaluate the corrosion potential of site soils has been performed, and is presented in GSI (2009). Additional testing of site soil may be performed if requested. GSI assumes that cathodic protection of utilities as indicated on the plans, is a requirement of the City, and was thus not discussed in our geotechnical report. Foundation Plans and Details Based on our review, the plans reviewed (E&A, 2009) generally appear suitable from a geotechnical standpoint, with the following comments, and/or additional recommendations. Per Plan Check Comment #23 (structural), seismic design data to be provided on the plans is included in GSI (2009). In order to reduce any misunderstanding between the plans and the content of the geotechnical report, our report (GSI, 2009) should be referenced on the plans (EM, 2009). Foundation Note 7 indicates a minimum slab thickness of 4 inches. This should be revised to a minimum of 5 inches per GSI (2009). Foundation Note 7 should also include a reference to GSI (2009). The current edition of the California Building Code (California Building Standards Commission, 2007) should be cited on the plans. The "existing" footing depths indicated, and/or implied on the plans (see Sheet S7, Detail 51, 52, and Sheet S8, Detail 67) were not provided by GSI. The plans should cite the applicable reference regarding existing footing depths/widths. If existing footing depths are generally unknown at this time, all depths indicated for new Mr. Bruce Bartlett W.O. 5892-A-SC 6115 Paseo Del Norte, Carlsbad October 23, 2009 Fi1e:e:\wp9\5800\5892a.gpr Page 3 foundations on the plans are considered minimums and may need to be deepened, based on the conditions exposed during construction. The stab designer should review the "Soil Moisture Considerations" section in GSI (2009) for further criteria with regard to moisture transmission and stab underlayment. If moisture sensitive areas within the structure are planned, a retrofit of the existing stab may be considered. This may include removal and replacement of slabs, and/or stab surface treatments, as necessary, if a lower level of moisture vapor transmission is desired. The foundation depths shown on the plans are considered as minimums only. New footings to be located in areas where remedial grading is not performed (i.e., existing building interior, etc.) will likely need to be deepened to encounter suitable bearing soil, based on the soil conditions exposed within the foundation excavation. Underpinning may be performed on the existing foundation where new structural loads are significantly higher than for existing, and the bearing capacity would be exceeded. Underpinning should be reviewed when column toads are provided. The underpinning should be performed in sections (per the designer) such that the un-supported condition of the existing footing may be tolerated by the existing foundation system, without distress. The methods used or planned should be provided by the designer. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSl at each of the following construction stages: During grading/recertification. During significant excavation (i.e, higher than 4 feet). During placement of subdrains, toe drains, or other subdrainage devices, prior to placing fill and/or backfill. - After excavation of building footings, retaining wall footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. Prior to pouring any slabs or flatwork, after presoaki n g/p resatu ration of building pads and other flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor retarders (i.e., visqueen, etc.). Mr. Bruce Bartlett W.O. 5892-A-SC 6115 Paseo Del Norte, Carlsbad October 23, 2009 Fi1e:e:\wp9\5800\5892a.gpr Page 4 During retaining wall subdrain installation, prior to backfill placement. During placement of backfill for area drain, interior plumbing, utility line trenches, and retaining wall backfill. During slope construction/repair. When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. When any improvements, such as flatwork, spas, pools, walls, etc., are constructed. A report of geotechnical observation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. This report presents minimum design criteria for the design of slabs, foundations and other elements possibly applicable to the project. These criteria should not be considered as substitutes for actual designs by the structural engineer/designer. The structural engineer/designer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness and deflections in the various slab, foundation, and other elements in order to develop appropriate, design-specific details. As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer/designer should consider all applicable codes and authoritative sources where needed. If analyses by the structural engineer/designer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. It is considered likely that some, more restrictive details will be required. If the structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or otherwise transmit their requests to GSI. ADDITIONAL PLAN REVIEW Any additional revisions to the plans reviewed herein, or any new plans, should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. Mr. Bruce Bartlett W.O. 5892-A-SC 6115 Paseo Del Norte, Carlsbad October 23, 2009 File:e:\wp9\5800\5892a.gpr Page 5 LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty is express or implied. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this portion of the project. The opportunity to be of service is greatly appreciated. If you have any questions concerning this report, or if we may be of further assistance, please do not hesitate to contact any of the undersigned. Respectfully subm GeoSoils, Inc. r1 Robert G. Crisman Engineering Geolc RGC/ATG/J PF/jh ' 't 1 9 4 l- Crtifl9d 5ngrieerIng Geologist - r'J ,2oESs:0, Wo.GE A44/41 32D - ) * ,'Andrew T. Guatelli Attachment: Appendix - References Distribution: (4) Addressee Mr. Bruce Bartlett W.O. 5892-A-SC 6115 Paseo Del Norte, Carlsbad October 23, 2009 FHe:e:\wp9\5800\5892a.gpr Page 6 APPENDIX REFERENCES California Building Standards Commission, 2007, California building code. Esbensen & Associates, 2009, Foundation plan and details for: Green Dragon tavern and museum, colonial village, 6115 Paseo Del Norte, Carlsbad, Ca. 92011, 1/8 inch scale, Sheets S2, S5, S6, S7, and S8, Cup 08-08, CDP 08-13, no job No., dated September 11. Esgil Corporation, 2009, Plan Check Comments for: Proposed Green Dragon Colonial Village (Formerly Hadley's), Paseo Del Norte, Carlsbad, San Diego County, California, City of Carlsbad Plan Check 091499, dated September 28. GeoSoils, Inc., 2009, Preliminary geotechnical investigation, proposed Green Dragon Colonial Village (formerly Hadley's), Paseo Del None, Carlsbad, San Diego County, California, W.O. 5892-A-SC, dated June 30. O'Day Consultants, 2009, Grading plans for: Green Dragon Colonial Village, 20 scale, Sheets 1 through 4, Job No. 081240, print dated September 10. 2009b, Improvement plans for: Green Dragon Colonial Village, 20 scale, Sheets 1 through 5, Job No. 081240, print dated September 10.