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Home My WebLink About5604 W Highland St & #2 - 101119017-18 - PlanBLDG # 101119017-18 APPROVALS BLDG - CSG Consultants PLNG - ASevilla POLICE - BMartin 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 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 5604 W Highland St & #2 - 101119017-1811/19/2024 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 Michael Vu WESTINDEVELOPMENT CO. 7291 Garden Grove Blvd. Suit J Garden Grove, CA 92841 714-878-7430 5604 W Highland St & #2 - 101119017-1811/19/2024 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 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 Case No.: 22-09-0801ADate: LOMA Federal Emergency Management Agency Washington, D.C. 20472 Page 1 of 2 April 12, 2022 APPROXIMATE LATITUDE & LONGITUDE OF PROPERTY:33.737257, -117.942233 SOURCE OF LAT & LONG: LOMA LOGIC COMMUNITY AND MAP PANEL INFORMATION LEGAL PROPERTY DESCRIPTION COMMUNITY AFFECTED MAP PANEL FLOODING SOURCE: EAST GARDEN GROVE WINTERSBURG CHANNEL; SANTA ANA RIVER CITY OF SANTA ANA, ORANGE COUNTY, CALIFORNIA Lot 102, Tract No. 3821, as described in the Grant Deed recorded as Document No. 2017000131032, in the Office of the Recorder, Orange County, California DATUM: NAD 83 DETERMINATION DOCUMENT (REMOVAL) LETTER OF MAP AMENDMENT DETERMINATION STREET FLOOD ZONE LOWEST LOT ELEVATION (NAVD 88) BLOCK/ SECTION SUBDIVISIONLOT OUTCOME 1% ANNUAL CHANCE FLOOD ELEVATION (NAVD 88) LOWEST ADJACENT GRADE ELEVATION (NAVD 88) WHAT IS REMOVED FROM THE SFHA 102 --54.8 feet--X (shaded) Structure5604 West Highland Street Tract 3821-- Special Flood Hazard Area (SFHA) - The SFHA is an area that would be inundated by the flood having a 1-percent chance of being equaled or exceeded in any given year (base flood). ADDITIONAL CONSIDERATIONS (Please refer to the appropriate section on Attachment 1 for the additional considerations listed below.) PORTIONS REMAIN IN THE SFHA LEVEE PROTECTED ZONE A STATE LOCAL CONSIDERATIONS This document provides the Federal Emergency Management Agency's determination regarding a request for a Letter of Map Amendment for the property described above. Using the information submitted and the effective National Flood Insurance Program (NFIP) map, we have determined that the structure(s) on the property(ies) is/are not located in the SFHA, an area inundated by the flood having a 1-percent chance of being equaled or exceeded in any given year (base flood). This document amends the effective NFIP map to remove the subject property from the SFHA located on the effective NFIP map; therefore, the Federal mandatory flood insurance requirement does not apply. However, the lender has the option to continue the flood insurance requirement to protect its financial risk on the loan. This determination is based on the flood data presently available. The enclosed documents provide additional information regarding this determination. If you have any questions about this document, please contact the FEMA Mapping and Insurance eXchange toll free at (877) 336-2627 (877-FEMA MAP) or by letter addressed to the Federal Emergency Management Agency, LOMC Clearinghouse, 3601 Eisenhower Avenue, Suite 500, Alexandria, VA 22304-6426. 5604 W Highland St & #2 - 101119017-1811/19/2024 Case No.: 22-09-0801ADate: LOMA Federal Emergency Management Agency Washington, D.C. 20472 Page 2 of 2 April 12, 2022 LETTER OF MAP AMENDMENT DETERMINATION DOCUMENT (REMOVAL) ATTACHMENT 1 (ADDITIONAL CONSIDERATIONS) PORTIONS OF THE PROPERTY REMAIN IN THE SFHA (This Additional Consideration applies to the preceding 1 Property.) Portions of this property, but not the subject of the Determination/Comment document, may remain in the Special Flood Hazard Area. Therefore, any future construction or substantial improvement on the property remains subject to Federal, State/Commonwealth, and local regulations for floodplain management. LEVEE PROTECTED (This Additional Consideration applies to the preceding 1 Property.) The subject property is located in an area protected from the 1-percent annual chance flood (base flood) by a levee or other structure subject to possible failure or overtopping by a flood larger than the base flood. ZONE A (This Additional Consideration applies to the preceding 1 Property.) The National Flood Insurance Program map affecting this property depicts a Special Flood Hazard Area that was determined using the best flood hazard data available to FEMA, but without performing a detailed engineering analysis. The flood elevation used to make this determination is based on approximate methods and has not been formalized through the standard process for establishing base flood elevations published in the Flood Insurance Study. This flood elevation is subject to change. STATE AND LOCAL CONSIDERATIONS (This Additional Consideration applies to all properties in the LOMA DETERMINATION DOCUMENT (REMOVAL)) Please note that this document does not override or supersede any State or local procedural or substantive provisions which may apply to floodplain management requirements associated with amendments to State or local floodplain zoning ordinances, maps, or State or local procedures adopted under the National Flood Insurance Program. This attachment provides additional information regarding this request. If you have any questions about this attachment, please contact the FEMA Mapping and Insurance eXchange toll free at (877) 336-2627 (877-FEMA MAP) or by letter addressed to the Federal Emergency Management Agency, LOMC Clearinghouse, 3601 Eisenhower Avenue, Suite 500, Alexandria, VA 22304-6426. Patrick “Rick” F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 5604 W Highland St & #2 - 101119017-1811/19/2024 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 5604 W Highland St & #2 - 101119017-1811/19/2024 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-01-01-23 January 02, 2023 Peter Mac 714-312-8184 c/o David Tran DELTA CONSTRUCTION 714-987-0787 deltaconstructionco@gmail.com SUBJECT: Soil Report for Proposed New Detached ADU, 5603 W. Highland Street, Santa Ana, CA 92704. Dear Mr. Tran: In accordance with the requirement 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 for many similar projects located in the City of Santa Ana; therefore, we are very familiar with the geotechnical conditions of the site. Follow is a summary of our findings, conclusions and recommendations. Site Description and Proposed Development The subject property is located on the northerly side of Highland Street, south of McFadden Avenue, north of Edinger Avenue, west of Euclid Street, and east of Ward Street, within a developed residential area. Based on the Site Plan prepared by the architectural designer, we understand that the proposed new 800 square-foot one-story wood-framed detached ADU will be located in the rear yard area of the lot. The existing primary dwelling with attached garage will be kept in place. 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. 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 2 The site is relatively flat; and we understand that major raw cut/raw fill is not proposed for the site. 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. A 5 ft. deep test hole was drilled and sampling and laboratory testing were performed. The geotechnical log of the boring is included in Appendix B and the laboratory test results are included in Appendix C. Based on the data of our test hole and laboratory testing, the on-site near-ground surface subgrade soils generally consisting of silty fine sand, damp and medium dense, and have an expansion index of zero (very low). It is noted that the subject site is a previously graded lot which was previously approved by the city for construction of the existing house. Distress to the existing house due to deep-seated settlement of the underlying earth materials was not observed and or reported. Therefore, deep-seated settlement is not anticipated to be a problem for the proposed new structure; and therefore, drilling deeper test hole(s), substantial sampling, and consolidation testing for verification of potential deep-seated settlement are not considered necessary for this project. In addition, for conservative purposes, the lowest Code values (2019 CBC, Table 1806.2 Material Class 5) including the lowest bearing capacity of 1,500 psf. are recommended to be used for the proposed new structure. Therefore, direct shear testing is not considered necessary for this project. Ground Water Free standing groundwater was not encountered in our 5 ft. deep test hole. 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/gravel/base materials 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. Seismicity 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 3 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 conservatively 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 & 2019 CBC can be used for the site. • Fa = 1.2 • Fv = null* • Mapped Spectral Accelerations Values: Ss = 1.338 (for the short period of 0.2 second) S1 = 0.478 (for the 1-second period) • Maximum Considered Earthquake Spectral Response Accelerations: SMs = FaSs = 1.605 (for the short period of 0.2 second) SM1 = FvS1 = null* (for the 1-second period) • Design Spectral Response Accelerations: SDs = 2/3 SMs = 1.070 (for the short period of 0.2 second) SD1 = 2/3 SM1 = null* (for the 1-second period) • PGA = 0.573 *Please see ASCE 7-16, Section 11.4.8. Note: In general, the structural consultant of record for this project should review the seismic parameters provided in this report and the 2019 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. The civil/structural design engineer should consult with the project geotechnical consultant, if additional geotechnical information is needed for structural design. 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 4 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 Based on the State of California SEISMIC HAZARD ZONES Map, Anaheim Quadrangle, the subject site is located within a potential liquefaction zone. 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. (A strengthened foundation system has been recommended to be used for the proposed new structure to reduce the potential effects due to the potential seismic settlements). 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 structure 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 structure 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 the new structure could still suffer damage if liquefaction occurs, during a very strong earthquake. Note: In accordance with the California Geological Survey (CGS), Special Publication (SP) 117A, a detailed site-specific liquefaction study is not required for this project, since the proposed new dwelling structure is not exceeding two stories and is not part of a development of four or more dwelling units. 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 5 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 re-compaction of 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. For the proposed new exterior concrete slabs including new driveway, if any, the over-excavation and re-compaction 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 new fill/backfill materials 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, 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 6 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 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. The above temporary excavation recommendations can be changed by the geotechnical consultant based on conditions to be exposed in the field during excavations. BUILDING FOUNDATION DESIGN GUIDELINES Geotechnical Parameters For Structural Design For conservative purposes, the following “code” values (2019 CBC, Table 1806.2 Material Class 5) can 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. 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 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 7 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 12-inches for one-story and 15- inches for two story portions, if any. Minimum reinforcement for new continuous footings, if any should be two #4 re-bars at top and two #4 re-bars at bottom. Settlement Distress to the existing house due to settlement of the underlying soils was not observed. 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 16 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 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, 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 8 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 a minimum of 2 ft. deep is not considered necessary. However, thorough spray 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. 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 (2019 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. 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 9 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 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 a problem in the City. Therefore, Type V cement with a maximum water/cement with a maximum water/cement ratio of 0.45 and a minimum concrete strength, f’c of 4,500 psi is not considered necessary. Cement type and concrete strength designed by the civil/structural design engineer such as 2,500 psi can be used. 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 (2019 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 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. 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 10 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. 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. 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 11 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 & Laboratory Test Results 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. 3/31/23 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 12 APPENDIX A REFERENCES 5604 W Highland St & #2 - 101119017-1811/19/2024 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 07, 1997, Landslide Released: April 15, 1998. 3. CDMG, 1997, Seismic Hazard Zone, Report 03, Seismic Hazard Zone Report For The Anaheim And Newport Beach 7.5 – Minute Quadrangles, Orange County, California", dated 1997. 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 14 APPENDIX B GEOTECHNICAL LOG OF TEST HOLE & LABORATORY TEST RESULTS 5604 W Highland St & #2 - 101119017-1811/19/2024 Page 15 GEOTECHNICAL LOG OF TEST HOLE Date: December 22, 2022 TEST HOLE No. 1 Project Name: Peter Mac-DELTA Job No. SA-01-01-23 Hole Diameter: 4 + inches Equipment: Hand-Auger DEPTH DESCRIPTION 0 – 4 +’ Grey silty fine sand, damp, medium dense. 4 ’ – end Light grey silty fine sand, damp, medium dense. Total Depth: 5 ft. + No Caving No Free Standing Groundwater Hole back-filled with on site soils 5604 W Highland St & #2 - 101119017-1811/19/2024 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’ 107.5 10.0 17.1 zero very low Test Method: ASTM D4829 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024 5604 W Highland St & #2 - 101119017-1811/19/2024