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Home My WebLink AboutFLOOD ZONE - 4810 W Sixth St Unit# 2 - PlanBldg #101122162 APPROVALS: PLNG - C. Santana BLDG - J. Lo POLICE - B. Martin PUBLIC WORKS - B. Sarlak FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 PR O J E C T A D D R E S S #DATE REVISION REVISIONS SHEET DESCRIPTION TITLE 24 SHEET # T24.1 DATE PROJECT # RESIDENTIAL TITLE 24 DOCUMENTS & HVAC DESIGN SERVICES LITTLE TREE ENERGY CONSULTING, LLC D.B.A. TITLE 24 ASAP 23546 COMMUNITY ST WEST HILLS, CA 91304 LINA@TITLE24ASAP.COM CALL/TEXT (833) 482-4362 TITLE 24 ASAP FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 PR O J E C T A D D R E S S #DATE REVISION REVISIONS SHEET DESCRIPTION TITLE 24 SHEET # DATE PROJECT # RESIDENTIAL TITLE 24 DOCUMENTS & HVAC DESIGN SERVICES LITTLE TREE ENERGY CONSULTING, LLC D.B.A. TITLE 24 ASAP 23546 COMMUNITY ST WEST HILLS, CA 91304 LINA@TITLE24ASAP.COM CALL/TEXT (833) 482-4362 TITLE 24 ASAP T24.2 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 PR O J E C T A D D R E S S #DATE REVISION REVISIONS SHEET DESCRIPTION TITLE 24 SHEET # DATE PROJECT # RESIDENTIAL TITLE 24 DOCUMENTS & HVAC DESIGN SERVICES LITTLE TREE ENERGY CONSULTING, LLC D.B.A. TITLE 24 ASAP 23546 COMMUNITY ST WEST HILLS, CA 91304 LINA@TITLE24ASAP.COM CALL/TEXT (833) 482-4362 TITLE 24 ASAP T24.3 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 SANTA ANA CITY COUNCIL Mayor vamezcua@santa-ana.org Mayor Pro Tem, Ward 1 tphan@santa-ana.org Ward 2 bvazquez@santa-ana.org Ward 3 jessielopez@santa-ana.org Ward 4 pbacerra@santa-ana.org Ward 5 jryanhernandez@santa-ana.org Ward 6 dpenaloza@santa-ana.org Valerie Amezcua MAYOR PRO TEM Thai Viet Phan COUNCILMEMBERS Phil Bacerra Johnathan Ryan Hernandez Jessie Lopez David Penaloza Benjamin Vazquez CITY OF SANTA ANA Planning and Building Agency 20 Civic Center Plaza ● P.O. Box 1988 Santa Ana, California 92702 www.santa-ana.org CITY MANAGER Alvaro Nuñez CITY ATTORNEY Sonia R. Carvalho CLERK OF THE COUNCIL Jennifer L. Halll August 8, 2024 Also sent via email to: westindevelopment@yahoo.com Michael Vu 7291 Garden Grove Blvd Suite J Garden Grove, CA 92841 Subject: Address Assignment for a new detached Accessory Dwelling Unit (ADU) (APN: 100-581- 14) in Santa Ana, CA Dear Mr. Vu, The City of Santa Ana Planning and Building Agency (PBA) is the responsible agency for legal addressing within the City of Santa Ana’s jurisdiction. This letter confirms the address assignment for new detached ADU proposed at 4810 W. Sixth Street (APN: 100-581-14). Notice is hereby given that the following assigned address(es) shall be posted onsite per the approved address plan, attached hereto as Exhibit A. Address(es) to be Activated/Posted 4810 W. Sixth Street, Unit 2 To subdivide commercial and/or residential units into multiple units, a building permit (and all other associated permits), plans, and inspection approvals by the PBA are required. Address(es) will be verified during inspections by the Building Safety Division. Please update your records accordingly. Should you have any questions, feel free to contact me by phone at 714-667-2728 or by email at CSantana@santa-ana.org. Sincerely, Cristian Santana Cristian Santana Assistant Planner I Exhibit A – Address Plan FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Address Letter for 4810 W. Sixth Street Page 2 of 2 c: Vencent Quaglia, United States Post Office Chris Tuiolosega, United States Post Office Cipriano Corona, Marketing Manager, United States Post Office Alex Alvarez, Postmaster Santa Ana, United States Post Office Federal Express, Administration Cathy Joseph, Garden Grove Unified School District Christine Hy, Garden Grove Unified School District Cathy Slader, Orange Unified School District Orin Williams, Santa Ana Unified School District Yvette Miranda, Santa Ana Unified School District Cristina Bernal, Tustin Unified School District Orange County Fire Authority Neal Kelly, Registrar of Voters Members, Board of Supervisors Southern California Gas Company Southern California Edison Company Claude Parrish, County Assessor's Office SAG, AT&T UPS, Administration City Manager’s Office Beverly Martin, Police Community Services Specialist Boris Duran, Police Systems Manager Jennifer Mendoza, Police Communications Manager Chris Hubbard, Police Systems Support Analyst Alejandra Gutierrez, Treasury & Customer Services Manager Hector Jimenez, Revenue Supervisor Alfonso Chavez, Utilities Customer Services Supervisor Judson Brown, Housing & Neighborhood Development Manager Rudy Rosas, Principal Civil Engineer Zdenek (Zed) Kekula, Principal Civil Engineer Jason Kwak, Building Safety Manager Evelyn LaRocca, Permit Supervisor Kathy Hernandez, Permit Technician Julie Amsden, Permit Technician Ali Pezeshkpour, Planning Manager Jerry Guevara, Senior Planner Yvette Portugal, Code Enforcement Principal Sergio Verino, Code Enforcement Principal FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Exhibit A FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 O R A N G E C O U N T Y F I R E A U T H O R I T Y Plan Submittal Criteria Form Required for Single Family or Duplex Residences (Use Commercial form for lots with 3+ dwelling units or new residential tracts) Complete the Project Information and Questionnaire below, then sign and date the Applicant Certification. Project Information  New Single Family Residence/Duplex  Addition/Remodel  ADU  Other Address: Unit #: City or Unincorporated County Area: ZIP: Scope of Work: Existing Area to Total Resulting Stories: Area Added in Past 2 Years Yes No Questionnaire OCFA Plan Type if “Yes” 1.   New – Is this a new single family residence or duplex? *(PR160) Residential Site with Water Availability 2.   ADU – Is this a new Accessory Dwelling Unit (ADU) on the same property as a house that already has (PR400-402) Fire Sprinkler   Addition – Is this (A) an addition to a currently sprinklered building, or (B) an addition requiring a fire sprinkler retrofit based on a threshold set by local ordinance? (PR400-402) Fire Sprinkler 4.   Distance – Is the most remote portion of the addition, ADU or other detached structure greater than *(PR160) Residential Site 5.   Total Area – Will the addition result in a total area of greater than 3,600 square feet (sf) for non- sprinklered buildings, or greater than 6,200 sf for sprinklered buildings, including the area of all *(PR160) Residential Site with Water Availability 6.   Remodel – Is this a remodel of a sprinklered building with a scope of work that includes adding or removing any interior walls? Note: If “Yes”, then project must be evaluated by a C-16 licensed (PR400-402) Fire Sprinkler   Detached Structure – Is this a new detached utility or accessory structure (not an ADU), such as a garage, workshop, game room, pool house, barn, etc., requiring fire sprinklers based on a threshold *(PR160) Residential Site (PR400-402) Fire Sprinkler 8.   Gate – Is a gate being installed across a driveway or road that is designated as a fire department access roadway, or a driveway or road that serves more than a single home/duplex? (PR180) Gate 9.   Methane – Is project located in or less than 100’ from a “Division of Oil, Gas, and Geothermal Resources” (DOGGR) field boundary or well (active or abandoned), less than 300-feet from an oil/gas seep, or less than 1000-feet from a landfill? (Note: For projects in Yorba Linda, this requirement only applies to new homes, enclosed accessory structures, addition to existing structure greater than 1000 *(PR160) Residential Site *(PR172-174) Methane Test/Mitigation Plans 10.   Vegetation – Is the property/structure (A) on the perimeter of a community containing, or adjacent to slopes or hills, or (B) adjacent to an open space or wildland area containing non-irrigated vegetation, or (C) in a State Responsibility Area or Local Responsibility Area “Fire Hazard Severity Zone”, as *(PR125) Fuel Modification (PR182) Accessory Structure *OCFA approval required before issuance of a grading/building permit. All other plans types may be deferred submittals. Applicant Certification I certify, under penalty of perjury, under the laws of the State of California, that the information above is true: Print Name:_______________________________________ Signature:___________________________________________ Date:______________ Phone Number:_____________________________________________ Email:_____________________________________________________________ Attention Building Department Staff – After you’ve verified all questions were answered accurately as “No”, then you may accept this signed form as a written release that an OCFA review is not required. If any questions were answered as “Yes”, then the plan type on the right side may be required. ______If all answers are “No” and the Building Department still requires the applicant to have their plans reviewed by OCFA, or if any answers are “Yes” and the Building Department prefers for OCFA to determine if a review is required, please initial this line and provide an explanation on the Plan Referral Form (on the reverse), to be submitted along with the appropriate plans to OCFA for a determination. For questions and submittal information, please visit ocfa.org, or call OCFA at (714) 573-6100 SFR FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 FLOOD ZONE - 4810 W Sixth St Unit# 2 5/5/2025 Page 1 of 1 EXISTING ONE & TWO FAMILY DWELLINGS ELECTRICAL SERVICES UNDERGROUND EXCEPTION CEC 2022 ELC-04 All new utility connections are required to be installed below grade by Santa Ana Municipal Code 41- 626(b). There is a standing exception for one and two family dwellings. This exception applies only when the new electrical service is designed to be fed from below grade as well as overhead. This diagram is a typical unit. The utility is able to feed this cabinet from the top or the bottom without interfering with the distribution wiring. All the circuit breakers and branch circuits are contained in the circuit breaker side of this cabinet. Only listed combination overhead and underground feed service boxes may be used to connect to an overhead utility drop. This exception to an underground fed service applies only to existing single family and two family residences. Planning & Building Agency Permits & Plan Check Section 20 Civic Center Plaza P.O. Box 1988 (M-19) Santa Ana, CA 92702 (714) 647-5800 Rigid Conduit Service Entrance Conductor Riser Underground Service Lateral METER Rev. 1/21/2020 FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 GEOTECHNICAL INTERNATIONAL LAN & ASSOCIATES Land Survey & Civil, Structural & Geotechnical Engineering 13139 Harbor Boulevard, Garden Grove, CA 92843 Tel: (714) 414-9215, Fax: (714) 537 – 7974, Email: Lanpham9@hotmail.com Project No. SA-03-09-24 September 16, 2024 Michael Vu WESTIN DEVELOPMENT 714-878-7430 westindevelopment@yahoo.com SUBJECT: Soil Report for Proposed New Detached ADU, 4810 W. 6th Street, Santa Ana, CA 92703. Dear Mr. Vu: In accordance with the requirements of the City and per your request and authorization, this soil report has been prepared for the proposed project. It is noted that Geotechnical International was the project geotechnical consultant of many similar projects in the City of Santa Ana. Therefore, we are familiar with the geotechnical conditions of the site. Follow is a summary of our findings and conclusions and recommendations for this project. Site Description and Proposed Development The subject property is located on the southerly side of W. 6th Street, south of Hazard Avenue, north of W. 5th Street (north of W. 1st Street), east of Rosita Street (east of N. Euclid Street), west of N. Newhope Street, within a developed residential area. A one-story house with an attached garage exists at the site. Based on the Site Plan prepared by the designer, we understand that the proposed new detached ADU will be located in the rear yard area. Note to the geotechnical report reviewer: Please see the actual full-scale plans prepared by the architect/designer/civil engineer which are separately submitted to the City for review, for clarification/details of the proposed development, as needed. The site is relatively flat; and we understand that additional raw cut/raw fill is not proposed for the site. FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 2 Geotechnical Conditions Based on the published geologic map prepared by the California Division of Mines and Geology (CDMG), the site is located within a broad flat alluvium and colluvium area. Based on the State of California SEISMIC HAZARD ZONES Map, Newport Beach Quadrangle, the subject site is located within a potential liquefaction zone. For conservative purposes, we assume that the site will be subjected to the liquefaction; and to mitigate the potential adverse effects due to potential liquefaction, as for other recent near-by projects, a strengthened foundation system is recommended to be used for the proposed new structure. To verify the near ground surface soils, a 5 ft. deep test hole has been drilled using a hand-held drilling tool and soil samples were collected for laboratory testing. The approximate location of the test hole is depicted on the Site Plan / Geotechnical Map. The geotechnical boring log and summary of results of the laboratory testing are included in Appendix B. Based on the data of our test hole, the near ground surface earth materials generally consisted of silty fine sand with minor clay and some gravel, damp to moist, medium dense and have a very low expansion potential. Groundwater Free standing groundwater was not encountered in our test hole. Based on the “Historically Highest Ground Water Contours and Borehole Log Data Locations, Newport Beach Quadrangle”, Plate 1.2 of the Open-File Report 97-08 prepared by California Division of Mines and Geology (CDMG), Department of Conservation, the historically highest groundwater level at the subject site is about 4.5 ft. below the ground surface. Free standing ground water was not reported to be an issue at the site and in the vicinity. Deep footings/excavations are not proposed for the site; therefore adverse effects due to groundwater are not anticipated for the proposed development. Note: it is not anticipated; however, if wet soils are encountered, removal of the wet soils and replacement with drier soils/cement slurry can be performed. In addition, if needed, crushed rock and or geogrids for bridging, etc. can also be used. This will be determined by the geotechnical consultant based on the exposed conditions during the excavations at the site. FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 3 Seismicity The subject site is located in Southern California, which is a major earthquake-prone zone. Therefore, the owner(s) of this property should be aware of the seismic risks associated with being located in this zone. The Soil Site Class D Default can be used for the soils underlying the subject site. The Seismic Design Category D can be used for the site. The following seismic parameters obtained from the computer program https:// seismicmaps.org prepared by SEAOC [Structural Engineers Association Of California] in conjunction with California’s Office of Statewide Health Planning and Development [OSHPD] ) in accordance with ASCE7-16 can be used for the site. • Fa = 1.2 • Fv = null* • Mapped Spectral Accelerations Values: Ss = 1.33 (for the short period of 0.2 second) S1 = 0.474 (for the 1-second period) • Maximum Considered Earthquake Spectral Response Accelerations: SMs = FaSs = 1.596 (for the short period of 0.2 second) SM1 = FvS1 = null* (for the 1-second period) • Design Spectral Response Accelerations: SDs = 2/3 SMs = 1.064 (for the short period of 0.2 second) SD1 = 2/3 SM1 = null* (for the 1-second period) • PGA = 0.568 Please see ASCE 7-16, Section 11.4.8. Please see APPENDIX C for additional seismic parameters, as needed. Note: In general, the structural consultant of record for this project should review the seismic parameters provided in this report and the 2022 CBC to evaluate the seismic design. Final selection of design coefficients should be made by the structural consultant based on the local laws and ordinances, expected structure response, and the desired level of conservatism. FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 4 The civil/structural design engineer should consult with the project geotechnical consultant, if additional geotechnical information is needed for structural seismic design. Faults No active faults are known to exist within or near the site. The probability of primary surface rupture or deformation at the site is, therefore, considered very low. The site is not designated to be located within the Special Studies/Earthquake Zone under the Alquist-Priolo Special Studies Act. Liquefaction Potential As previously mentioned, for conservative purposes, the subject site is assumed to be subject to the liquefaction. Therefore, the owner(s) of this property should be aware of the risks associated with the potential liquefaction such as structural distress due to the potential differential settlement caused by the potential liquefaction. As previously mentioned, for conservative purposes, a strengthened / stiffened foundation system (having thicker slabs with more reinforcements and deeper and wider footings with more reinforcement as recommended in this report) should be used for support of the proposed structure. Potential Consequences of Liquefaction or Secondary Liquefaction Included Hazards Potential consequences of liquefaction or secondary liquefaction included hazards generally consist of differential settlement (vertical deformations), lateral movement/lateral spreading (horizontal deformations), oscillation, and reduction in foundation soil-bearing capacity (bearing failure). A sloping condition or drainage or stream channel does not exist at the site; therefore, lateral movement/lateral spreading, oscillation, etc. due to potential liquefaction are not anticipated to be credible hazards for the proposed new structure. We believe if the area would be “liquefied” in the future due to a very strong earthquake, the potential damage to the proposed new structures which will be properly structurally designed in accordance with the new up-to-date codes would be much less severe than the existing on-site structures and surrounding existing houses which have been previously structurally designed based on old codes (which are much less stringent than the current new codes). However, the owner(s) of this property should be aware of the potential damage to the new structures due to liquefaction. In summary, it should be recognized that structural mitigation may not reduce the potential of the soils to liquefy during an earthquake; and there will remain some risk that FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 5 the new structures could still suffer damage if liquefaction occurs, during a very strong earthquake. For conservative purposes, a strengthened / stiffened foundation system as recommended in this report should be used for support of the proposed structure. Slope Stability The site is a flat area; therefore, slope instability is not a concern for the proposed development. CONCLUSIONS AND RECOMMENDATIONS General Conclusions Construction of the proposed structure at the subject site is considered geotechnically feasible, provided the recommendations outlined in this report are implemented. Note: The conclusions and recommendations of this report are based on information as interpreted from our limited subsurface investigation. It is not anticipated but they should be revised accordingly if geotechnical conditions to be exposed during site preparation/ grading and construction significantly differ from our findings and interpretations. In general, a conventional shallow foundation can be used for support of the proposed structure. The following recommendations are considered minimum and may be superseded by more restrictive requirements of the architect, civil/structural engineer, building codes, or governing agencies. Geotechnical Impact on Neighboring Properties Adverse geotechnical impact of the proposed development on the neighboring properties is not anticipated, provided the recommendations outlined in this report are properly implemented. Site Preparation/Grading To create a relatively uniform new engineered compacted fill layer for a proposed new structural slab-on-grade area, over-excavation and recompaction of about 3 ft. deep (measured from the existing ground surface) of the existing on-site soils should be performed. The lateral limits of the over-excavation should be minimum equal to depth of removal (3 ft. in this case) beyond the outside perimeter of the proposed new structure. FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 6 For the proposed new exterior concrete slabs including new driveway, if any, the overexcavation and recompaction should be minimum 1 ft deep and 1 ft. outside of the new slab areas. Deeper remedial removal is not anticipated; however, this will be determined in the field by the project geotechnical engineer, based on the actual conditions to be exposed at the time of the site grading/preparation. The fill/backfill materials, if any, should be free of organic matter and oversized materials, 4 inches or greater in diameter, placed in near-horizontal loose lifts not to exceed eight inches in thickness, and moisture conditioned to slightly over optimum moisture content prior to compaction. Imported soils, if any, should have a very low expansion potential and should be geotechnically observed/tested and accepted by the geotechnical consultant prior to using at the site. In general, grading at the site, if any, should be performed in accordance with the requirements of the City and under the geotechnical observation and testing of the project geotechnical consultant. The compaction criterion for fill and backfill materials is a minimum of 90% of the maximum density determined in accordance with ASTM Test Method D1557. Temporary Excavations In general, temporary excavations should be performed in accordance with OSHA requirements. In general, care should be taken during excavation near an existing structural object, if any to ensure no damage is done to the existing object. For this project, the detached ADU will be located far away from the existing building. Therefore, impact of the proposed temporary excavation to the existing building is not anticipated. BUILDING FOUNDATION DESIGN GUIDELINES Geotechnical Parameters For Structural Design For conservative purposes, the following “lowest” code values should be used for structural design, as needed. a. Allowable vertical bearing earth pressure: 1,500 psf. An increase of one-third is permitted when using the alternative load combinations that include wind or earthquake loads. FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 7 b. Lateral bearing passive earth pressure: 100 psf. per foot into competent materials below the finished ground surface. An increase of one third is permitted when using the alternative load combinations that include wind or earthquake loads. c. Lateral Sliding Resistance: cohesion = 130 psf. The cohesion value is to be multiplied by the contact area. In no case shall the lateral sliding resistance exceed one-half the dead load. d. Soil unit weight: 120 pcf. New Building Footings In general, the foundation system for the proposed structure must be properly designed by the civil/structural design engineer of record for this project and reviewed and approved by the city prior to construction. New building footings should be embedded minimum 24-inches below the adjacent lowest finished grade. Minimum widths for isolated columns/pad footings, if any, should be 24-inches, and for continuous wall footings should be 15-inches for one-story and 18- inches for two story portions, if any. Minimum reinforcement for new continuous footings should be two #5 re-bars at top and two #5 re-bars at bottom. Settlement Distress to the existing house due to settlement of the underlying soils was not observed/reported. Therefore, deep-seated settlement of the soils underlying the site is not considered to be a concern for the proposed development. In general, based on our experience, the conventional total settlement of ½ inch and a differential settlement of ¼ inch over a horizontal distance of 30 feet are anticipated for the proposed new structure and would occur during the construction stage. New (Interior) Building Slabs-on-Grade New (interior) building slabs-on-grade should be minimum 5 inches thick, reinforced with #4 re-bars at 12 inches on centers, or equivalent, placed at mid-height of the slab. New slabs should be underlain by a 2-inch thick layer of clean sand. For moisture sensitive floor areas, the new slabs should be underlain by a 10-mil polyethylene moisture barrier membrane (such as Visqueen). The moisture barrier membrane should FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 8 be properly lapped and sealed at joints and around any breaks such as openings for utility conduits. Note: CAL Green Code, and/or other applicable codes/City’s requirements should govern and be followed. The entire slab-on-grade system including the capillary break / vapor/moisture retarder should be properly designed by the project civil /structural design engineer of record (but not by the geotechnical engineer) and reviewed and approved by the City prior to construction. New Exterior Slabs-on-Grade To reduce the potential for excessive cracking, new exterior concrete slabs-on-grade, if any, should be minimum 4 inches thick, provided with construction or weakened plane joints at frequent intervals (e. g., every 6 feet or less). Provision of a 2-inch thick layer of crushed rock, gravel, or clean sand to be placed beneath the slabs and/or reinforcement, such as #3 re-bars at 24 inches on-centers, or equivalent, placed at the mid-height of the slab should be considered. The subgrade soils for the exterior slabs should be properly re- compacted. Slab Subgrade Pre-Saturation The conventional pre-saturation of subgrade soils to minimum 140% of the optimum moisture content to minimum 24 inches deep is not considered necessary for this project. However, spraying with water should be performed prior to concrete pour. Other Recommendations for Reducing Slab Cracking While not a geotechnical issue, the potential for slab cracking may also be reduced by careful control of water/cement ratio and slump of concrete. The contractor should take appropriate curing precautions during the pouring of concrete in hot weather to reduce cracking of slabs. A slip sheet (or equivalent) can be utilized if grouted tile, marble tile, or other crack- sensitive floor covering is planned directly on concrete slabs. New Driveway The minimum section required by the City can be used for a new driveway, if any. If there is no minimum requirements by the City, a 5-inch thick concrete slab (PCC), reinforced with #4 rebar (placed at mid-height of slabs) at 18 inches on-centers both ways, or 5-in. thick asphalt concrete (AC), or equivalent, over a 6-inch thick layer of aggregate base (AB) can be used. The aggregate base and subgrade should be properly compacted to a minimum of 95% and 90%, respectively, of the maximum density determined in accordance with ASTM D1557 prior to placement of the concrete slab. Spraying the compacted subgrade soils with water should be performed prior to concrete pour. FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 9 If pavers are to be used, they must be properly designed by the civil engineer of record for this project and approved by the city prior to construction. Additional geotechnical data can be provided for design, if requested. Site Drainage In general, proper surface drainage should be checked, improved as needed, and maintained to ensure surface water flows away from all structures. Requirements by the city and applicable CBC (2022 CBC) should also be followed. Roof gutters should be properly provided. Roof drains, gutters and downspouts should be maintained to function as intended. Outlet drains should be kept open. Irrigation at the site, if any, should be kept to a minimum required to support plant life. In the future, sources of uncontrolled water, such as leaky sewer, water (domestic, irrigation) or drainpipe, should be repaired if identified. Seismic Design We recommend the proposed new structure be structurally designed to meet the applicable building codes and requirements of the controlling governmental agencies. The seismic parameters provided in the “Seismicity” section of this report can be used. The civil/structural design engineer should consult with the project geotechnical consultant, if additional geotechnical information is needed for the seismic design. Cement Type For Concrete in Contact with On-Site Earth Materials Our previous tests performed on the soils of many lots in the City of Santa Ana which are similar to the on-site soils show negligible water-soluble sulfate contents. Sulfate attack on concrete was not observed for the existing on-site house and other houses in the surrounding areas. It appears sulfate attack on concrete is not considered to be a problem for this project. However, for conservative purpose, Type V cement with a maximum water/cement ratio of 0.45 and a minimum concrete strength, f'c of 4,500 psi is recommended to be used for concrete in contact with the on-site soils. Additional water- soluble sulfate content testing can be performed for the soils at the site, as needed. The test can be conducted during and/or after completion of site preparation/grading. The applicable California Building Code (2022 CBC) and other requirements by controlling governmental agencies should be followed. Corrosion To Ferrous Metals and Copper For conservative purposes, the on-site soils can be considered severely corrosive to ferrous metals and copper. Underground/buried ferrous metals or copper are not planned FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 10 to be used for this project. However, if underground/buried ferrous metals or copper are planned to be used at the site, they should be properly protected. A corrosion specialist can be consulted. Testing can be performed for verification of the potential corrosion of the soils at the site to ferrous metals and copper, if needed. The test can be performed during and/or after completion of grading. Geotechnical Review of Grading and Foundation Plans Based on the City’s requirements, the project geotechnical consultant should review, “approve” and sign the project grading and foundation plans with details/specifications, if any, indicating conformation to applicable geotechnical recommendations. We will corporate with the civil/structural design engineers who prepare the plans to ensure our geotechnical recommendations are properly incorporated into the plans. Geotechnical Observation and Testing During Construction We recommend that a qualified geotechnical consultant be retained to provide geotechnical engineering services, including geotechnical observation/testing, during the construction phase of the project. This is to verify the compliance with the design, specifications and/or recommendations, and to allow design changes in the event that subsurface conditions differ from those anticipated. Geotechnical observation/testing can be performed at the following stages:  During ANY grading operations, including excavation, removal, filling and backfilling, etc.  During and after excavation for footings to verify the adequacy of underlying materials.  After pre-saturation of slab subgrade earth materials, if any, prior to pouring concrete.  After compaction of subgrade soils and/or aggregate base for exterior slabs and or driveway, if any.  During backfill of drainage and utility line trenches, if any, to verify proper compaction.  When/If any unusual geotechnical conditions are encountered. Note: If Geotechnical International is not provided the opportunity to perform the geotechnical observation/testing during the construction phase, Geotechnical International will take no responsibility for the conclusions and recommendations contained in our report in the event that subsurface conditions differ from those interpreted and anticipated during our preliminary investigation phase prior to the start of construction. FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 11 CLOSURE The conclusion and recommendations contained in this report are presented based on geotechnical data as described herein which are believed representative of the total project area. However, earth materials can vary in characteristics, both laterally and vertically, and those variations could affect the conclusions and recommendations contained herein. As such, observation and testing by a qualified geotechnical consultant during the construction phase of the project are essential to confirming the basis of this report. This report has been prepared consistent with that level of care being provided by other professionals providing similar services at the locale and time period. The contents of this report are professional opinions and as such, are not to be considered a guaranty or warranty. This report should be reviewed and updated after a period of one year or if the lot ownership or site conditions / proposed development change from that described herein. The following are attached and complete our report: Appendix A – References Appendix B – Geotechnical Log of Test Hole and Laboratory Test Results Appendix C – Seismic Data Figure 1 – Vicinity Map Figure 2 – Site Plan/Geotechnical Map If you have any questions or require clarification, please contact this office. This opportunity to be of service is sincerely appreciated. Very truly yours, Lan N. Pham, P.E. Chief Geotechnical Engineer RGE686, Exp. 3/31/25 FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 12 APPENDIX A REFERENCES FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 13 REFERENCES 1.California Division of Mines and Geology (CDMG), the Resources Agency, Dept. of Conservation, 1981, “Geology Map of Orange County Showing Mines and Mineral Deposits”, scale 1:48,000, 1” = 4000’, or 1” = 0.76 miles, prepared in corporation with County of Orange EMA, compiled by P.K. Morton and R.V. Miller, dated 1981. 2.California Division of Mines and Geology (CDMG), Department of Conservation, 1997, 1998, “Seismic Hazard Zones, Newport Beach Quadrangle”, Scale 1:24,000 (1” = 2,000 ft or 1” = 0.38 miles), Liquefaction Zone Released April 17, 1997, Landslide Released: April 15, 1998. 3.California Division of Mines and Geology, 1997, “Seismic Hazard Zone Report for The Anaheim and Newport Beach 7.5-minute Quadrangle, Orange County, California,” Seismic Hazard Zone Report 03,” revised 2006. FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 14 APPENDIX B GEOTECHNICAL LOG OF TEST HOLE AND LABORATORY TEST RESULTS FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 15 GEOTECHNICAL LOG OF TEST HOLE Date: September 6, 2024 TEST HOLE No. 1 Project No. Michael Vu Job No.: SA-03-09-24 Hole Diameter: 4 + inches Equipment: Hand-Auger DEPTH DESCRIPTION 0’ - 2’+ (Grass). Medium grey silty fine sand with minor clay, damp to moist, medium dense. 2’- end Medium gray silty fine sand, moist to very moist, medium dense. Total Depth: 5 ft. + No Caving No Free-Standing Groundwater Hole backfilled with onsite soils FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 16 EXPANSION INDEX TEST RESULTS Sample Compacted Moisture Content Expansion Expansion Location Dry Compacted Final Index Potential Density (pcf) (%) (%) Classification TH-1 @ 0’ – 3’ sandy: non-expansive. Test Method: ASTM D4829 FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 17 ATTERBERG LIMITS TEST RESULTS Sample Location Liquid Limit Plastic Limit Plasticity Index TH-1 @ 0’ - 3’ sandy: could not perform the tests. Test Method: ASTM D4318 FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 Page 18 APPENDIX C SEISMIC DATA FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 USGS web services were down for some period of time and as a result this tool wasn't operational, resulting in timeout error. USGS web services are now operational so this tool should work as expected. 4810 W 6th St, Santa Ana, CA 92703, USA Latitude, Longitude: 33.7495904, -117.9326922 Date 9/10/2024, 8:48:32 PM Design Code Reference Document ASCE7-16 Risk Category II Site Class D - Default (See Section 11.4.3) Type Value Description SS 1.33 MCER ground motion. (for 0.2 second period) S1 0.474 MCER ground motion. (for 1.0s period) SMS 1.596 Site-modified spectral acceleration value SM1 null -See Section 11.4.8 Site-modified spectral acceleration value SDS 1.064 Numeric seismic design value at 0.2 second SA SD1 null -See Section 11.4.8 Numeric seismic design value at 1.0 second SA Type Value Description SDC null -See Section 11.4.8 Seismic design category Fa 1.2 Site amplification factor at 0.2 second Fv null -See Section 11.4.8 Site amplification factor at 1.0 second PGA 0.568 MCEG peak ground acceleration FPGA 1.2 Site amplification factor at PGA PGAM 0.682 Site modified peak ground acceleration TL 8 Long-period transition period in seconds SsRT 1.33 Probabilistic risk-targeted ground motion. (0.2 second) SsUH 1.444 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration SsD 1.943 Factored deterministic acceleration value. (0.2 second) S1RT 0.474 Probabilistic risk-targeted ground motion. (1.0 second) S1UH 0.514 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration. S1D 0.67 Factored deterministic acceleration value. (1.0 second) PGAd 0.797 Factored deterministic acceleration value. (Peak Ground Acceleration) PGAUH 0.568 Uniform-hazard (2% probability of exceedance in 50 years) Peak Ground Acceleration CRS 0.921 Mapped value of the risk coefficient at short periods CR1 0.921 Mapped value of the risk coefficient at a period of 1 s CV 1.366 Vertical coefficient 9/10/24, 8:48 PM U.S. Seismic Design Maps https://www.seismicmaps.org 1/2 FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 DISCLAIMER While the information presented on this website is believed to be correct, SEAOC /OSHPD and its sponsors and contributors assume no responsibility or liability for its accuracy. The material presented in this web application should not be used or relied upon for any specific application without competent examination and verification of its accuracy, suitability and applicability by engineers or other licensed professionals. SEAOC / OSHPD do not intend that the use of this information replace the sound judgment of such competent professionals, having experience and knowledge in the field of practice, nor to substitute for the standard of care required of such professionals in interpreting and applying the results of the seismic data provided by this website. Users of the information from this website assume all liability arising from such use. Use of the output of this website does not imply approval by the governing building code bodies responsible for building code approval and interpretation for the building site described by latitude/longitude location in the search results of this website. 9/10/24, 8:48 PM U.S. Seismic Design Maps https://www.seismicmaps.org 2/2 FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 VICINITY MAP FIGURE 1 4810 W. 6th STREET SANTA ANA, CA 92703 SITE FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025 4810 W. 6th STREET SANTA ANA, CA 92703 SITE PLAN/GEOTECHNICAL MAP FIGURE 2 Approximate Location of Test Hole TH-1 TH-1 TH E E N T I R E S I T E I S U N D E R L A I N B Y A L L U V I U M A N D C O L L U V I U M REDUCED SCALE FLOOD ZONE - 4810 W Sixth St Unit# 25/5/2025