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HomeMy WebLinkAboutSDP 00-06; DAYBREAK COMMUNITY CHURCH; UPDATE OF COMPACTION REPORT FOR PROPOSED DAYBREAK COMMUNITY CHURCH SITE; 2000-06-07VINJE & MIDDLETON ENGINEERING, INC. Job #00-248-F 2450 Vineyard Avenue, #102 Escondido, California 92029-1229 Phone (760) 743-1214 Fax (760) 739-0343 June 7, 2000 Daybreak Community Church Attention: .Mr. William Fink, President Building Committee 5741 Palmer Way, Suite "A" Carlsbad, California 92008 UPDATE OF COMPACTION REPORT FOR PROPOSED DAYBREAK COMMUNITY CHURCH SITE, LOT #8, MAP # 13434, SW CORNER OF AMBROSIA AND POINSETTIA LANES. CARLSBAD In accordance with your request, this report is written to bring the foundation recommendations put forth in that report into current standards, and to discuss remedial grading that will be required prior to construction of the proposed church site. I. REFERENCES The following documents have been reviewed in order to provide this Update Report: Unsigned grading plan prepared by Rick Hill Engineering, Inc., dated January 5, 2000. "As-Graded Geotechnical Report, Aviara Phase II, Carlsbad, California" prepared by Geotechnics Incorporated, dated June 25, 1998. II. SITE INFORMATION Grading observations and compaction testing were conducted periodically during construction of this site from September 5, 1996 through June 30, 1998. A final as graded compaction report with compaction results and limited foundation recommendations was issued as indicated above. A review of the "As-Graded Report" as it pertains to Lot #8 grading, indicates that the grading of this "cut" lot was conducted in substantial conformance with the Grading Ordinance for the City of Carlsbad. All inspections and testing were conducted under the supervision of Geotechnics Incorporated. In our opinion, all excavations were constructed in substantial conformance with the approved grading plan for the previous grading operations, and are acceptable for their intended use. Update Compaction Report Proposed Church Site June 7, 2000. Page 2 A site inspection was made by a representative from this office on June 6, 2000, and found the site to be visually the. same with respctto ad elevation, location of, and height of slopes. Therefore, the building site remains substantially s reported in the subject report. ic' ,4p ,j,t 7 4& It is our understanding that a proposed building consisting of a wood frame and stucco structure supported on shallow stiff concrete footings with slab on grade is planned. Ill. RECOMMENDATIONS A. Remedial Grading Remove all vegetation prior to the start of the grading operations. Prior to placement of any fill, the upper 6 to 12 inches of the existing surface shall be scarified, re-moisture conditioned to near optimum moisture content, and recompacted to a minimum of 90% of ASTM Method D-1 557-91 under the observation of the project geotechnical engineer. Field density testing shall be conducted in order to confirm minimum compaction requirements. A review of the grading plan indicates that there will be a daylight (cut/fill) line crossing the westerly portion of the building. Therefore, provide a minimum of 3 feet of compacted fill beneath the building area plus a 10 foot perimeter, to mitigate the potential for concrete cracking along the cut/fill line. The westerly third of the lot may require deeper removals. Depths to be determined by exploratory excavations dug and monitored by a representative of the project geotechnical engineer during the beginning of the grading operations. The existing "desilting basin" will require removals of approximately 3 feet from existing grades prior to backfilling under the direction of the *project geotechnical engineer. B. Foundations, Slab On Grade, Monolithic Pour System The following minimum foundation recommendations for medium expansive (Expansion Index less than 51) soils, classified using the "Unified Soil Classification VINJE & MIDDLETON ENQINEERINQ, INC. 2450 V&novd Avenue, #102, Escondido, Califovnuz 92029.1229 • Phone (760) 743.1214 • Fax (760) 739.0343' QEOTECHNICM. INVESTIGATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIGATIONS Update Compaction Report Proposed Church Site June 7,.2000 Page System or USCS" as SM, should, be adhered to, and incorporated into the foundation plans. It is suggested that the foundation plans be submitted to our office for review and approval prior to construction. Please note (**) items for revised recommendations since the issuance of Geotechnic's report dated June 25, 1998. The following recommendations are to be confirmed by appropriate laboratory testing at the completion of the grading operations. Changes to these recommendations may be necessary and should be anticipated. ** 1. Continuous strip foundations should be a minimum of 24 inches deep measured below the lowast adjacent ground surface not including the sand under the slab. Continuous strip foundations should have a minimum width of 12 inches for one story and 15 inches for two story structures. Spread pad footings should be at least 24 inches by 24 inches wide and 18 inches deep, for one and two story structures. Exterior continuous footings should enclose the entire building perimeter. 2. Use four #4 reinforcing bars in all interior and exterior stud bearing wall footings. Place tvm bars 3 inches below the top of the footing, and the other bars 3 inches above the bottom of the footing. Reinforcement for isolated square footings should be designed by the project structural engineer. ** 3. All interior slabs must be a minimum of 5 inches in thickness reinforced with #3 reinforcing bars spaced 18 inches on center each way, placed midheight in the slab. Use 4 inches of clean sand (SE 30 or greater) beneath all slabs. A six-mil plastic moisture barrier must be placed midheight in the sand. ** Provide re-entrant (±2700 corners) reinforcement for all interior slabs as generally shown on the enclosed "Isolation Joints and Re-Entrant Corner Reinforcement' detail. Re-entrant corners will depend on slab geometry and/or interior column locations. 4. The minimum steel reinforcement provided herein is based on soil characteristics only, and is not intended to be in lieu of reinforcement necessary for structural considerations. ** 5. The clayey soil should not be allowed to dry before pouring the concrete. The soil should be 3% to 5% above the optimum moisture content at 18 inches below VINJE & MIDDL.ETON ENGINEERING, INC. 2450 Vinyard Avenue, p102, Escondido. California 92029.1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATIONS Update Compaction Report Proposed Church Site June 7, 2000 Page slab subgrade.. This office should be notified 72 hours prior to pouring the footings and slab to inspect the footing trenches and to verify the moisture conditions. ** 6. Provide "soft-cut" contraction/control joints consisting of sawcuts. spaced. 10 feet on center maximum each way for all interior slabs. Cut as soon as the slab will support the weight .of the saw, and operate without disturbing the final finish, which is normally within 2 hours after final finish at each control joint location, or when the compressive strength reaches 150 to 800 psi. The "soft-cur must be a minimum of 1 inch in depth and must not exceed I 1h inch in depth or the reinforcing may be damaged. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipment across cuts for at least 24 hours. 7. All underground utility trenches under slabs should be compacted to a minimum of 90% of the maximum dry density of the soil. Care should be taken not to crush the utilities or pipes during the compaction of the trench backfill. 8. Exterior Flatwork and Driveways: Walkways, patios, etc. adjacent to the building must be a minimum of 4 inches in thickness reinforced with 6x6/1 Oxl 0 welded wire mesh placed two inches below the top of the slab. Provide contraction joints consisting of savuts spaced 10 feet on center (not to exceed 12 feet maximum) each way within 24 hours of concrete pour. The sawcuts must be a minimum of 3/4 inch in depth and must not exceed 11/4 inch in depth or the reinforcing may be damaged. Exterior slabs placed against the perimeter footings should be doweled to the footing using #3 reinforcing bars spaced 18 inches on center, extending 20 inches into the slab at mid-height, and into the footing to the elevation of the bottom reinforcing bar. Pavement/concrete thickness and sub/basegrade recommendations will be provided at the completion of the grading operations based on R-Value testing. 9. This office is to be notified to inspect or test the following prior. to foundation concrete pours: VINJE & MIDDLETON ENQINEERZNQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029.1229 • Phone (760).743-1214 • Fax (760) 739-0343 PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS QEOTECHNICAL. INVESTIGATIONS QRADINQ SUPERVISION Update Compaction Report Proposed Church Site June 7, 2000 Page Inspect the plumbing trenches beneath slabs after the pipes are laid and prior to backfilling. Test the plumbing trenches beneath slabs for minimum compaction requirements. Inspect the footing trenches for proper width, depth, reinforcing size and placement. Inspect the slabs for proper • thickness, reinforcing, size and placement, sand thickness and moisture barrier placement. 10. The following allowable foundation and lateral pressures may be used for design of foundations on certified soils for structures which have continuous footings having a load of less than 2,000 plf and isolated footings with loads of less than 50,000 lbs. a) Per tests and calculations by Geotechnics Inc. an allowable bearing capacity of 2,000 psf for continuous and isolated footings embedded into properly compacted fill soils may be used. The allowable soil bearing pressure provided herein is for dead plus live loads and may be increased by one-third for wind and seismic loading. ** b) An allowable lateral bearing pressure of 150 psf per foot of depth may also be used for all structures except retaining walls. The lateral bearing earth pressure may be increased by the amount of the The value for each additional foot of depth to a maximum of 1,500 psf. C. Retaining Walls, Lateral Load Parameters 1. The following earth pressures based on the anticipated finish grade soils, should be used for design of retaining walls. These values will need to be confirmed at the completion of the grading operations: Use a coefficient of friction of 0.35 for concrete on soil. Use an active pressure of 35 pcf equivalent fluid pressure for cantilever, unrestrained walls with level backfill surface. Use a active pressure of 45 pcf equivalent fluid pressure for cantilever walls with a 2:1 (horizontal tovertical) backfill. . VINJE'& MIDDL.ETON ENQINEERINQ, INC: 2450 Vineyard Avenue, #102, Escondido, California 92029.1229 • Phone (760) 743.1214 • Fax (760) 739.0343 QEOTECHNICAI. INVESTIQATIONS qRADINQ SUPERVISION PERC TESTING ENVIRONMENT/ti. INVESTIGATIONS Update Compaction Report Proposed Church Site June 7, 2000 Page i) Use an allowable bearing capacity of 2000psf as described above. Expansive clayey soils should not be used for backfihling of any retaining walls. Retaining walls should maintain at leasta 1:1 (horizontal.to vertical) wedge of granular non-expansive soil backfill measured from the base of the wall footing to the ground surface. All retaining walls should be provided with a drain along the backside as generally shown on the enclosed "Retaining Wall Drain" detail. Specific drainage provisions behind retaining wall structures must be inspected by this office prior to backfilling the wall. All backfill soils must be compacted to a minimum of 90% of the corresponding maximum dry density, ASTM 1557-91. NOte: Because large movements must take place before maximum passive resistance can be developed, use a minimum safety factor of 2.0 for wall sliding stability where structures or improvements are planned near or adjacent to the top of the wall. When combining passive and frictional resistance, the passive component should be reduced by one-third. The planting of large trees behind any retaining wall will adversely affect their performance and should be avoided. D. Seismic Coefficients The following site specific seismic parameters for the above referenced project were determined in accordance with the Uniform Building Code requirements. The following parameters are consistent with the indicated project seismic environment and may be utilized for project design work. gpk 41 4y .tsi * isnic 151v . Sc 4 0.4 B 1.0 1.0 1.0 0.40 0.58 0.580 0.116 According to Chapter 16, Division IV of the 1997 Uniform Building Code VNJE & MIDDLETON ENQ1NEERINQ INC. 2450 Vincyard Avenue, #102, Escondido, California 92029.1229 .• Phone (760) 743.1214 • Fax (760) 739-0343 QEOTECHNICAL INVESTIGATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIGATIONS Update Compaction Report Proposed Church Site June 7, 2000 Page 7 E. Setbacks Footings located on or adjacent to the top of slopes should be extended to a sufficient depth to provide a minimum horizontal distance of 8 feet or one-third of the slope height, whichever is greater (need not exceed 40 feet maximum) between the bottom edge of the footing and face of slope. The outer edge of all slopes experience "down slope creep", which may 'cause distress to structures. If any structures including buildings, patios, sidewalks, swimming pools, spas etc, are placed within the setback, FURTHER RECOMMENDATIONS WILL BE REQUIRED. Expansive soils can cause structural damage to foundations, interior and exterior slabs and walls. The economically feasible precautions that can be taken and recommended herein will only minimize the potential of volumetric changes due to changes in moisture content. **A COPY OF THIS REPORT MUST BE PROVIDED TO THE PROJECT ARCHITECT/STRUCTURAL ENGINEER TO ENSURE THE THE ABOVE FOUNDATION RECOMMENDATIONS ARE INCLUDED IN APPROPRIATE PLANS** The concrete reinforcement recommendations provided herein should not be considered to preclude the development of shrinkage related cracks, etc.; rather, these recommendations are intended to minimize this potential. If shrinkage cracks do develop, as is expected from concrete, reinforcements tend to limit the propagation of these features. These recommendations are believed to be reasonable and in keeping with the local standards of construction practice. Special attention should be given to any "re-entrant" corners (±270 degree corners) and curing practices during and after concrete pour in order to further minimize shrinkage cracks. F. Slopes All slopes should be landscaped with types of plants and planting that do not require excessive irrigation. Excess watering of slopes should be avoided. Slopes left unplanted will be subject to erosion. The irrigation system should be installed in accordance with the governing agencies. Water should not be allowed to flow over the slopes in an uncontrolled manner. Until landscaping is fullyestablished, plastic sheeting should be kept accessible to VINJE & MIDDLETON ENQINEERLNQ, INC. 2450 Vnyard Avenue, #102, Escondido, California 92029.1229 • Phone (760) 743.1214 • Fax (760) 739.0343 QEOTECHNICAL. INVESTIGATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS Update Compaction Report Proposed Church Site June 7, 2000 Page 8 protect the slopes from periods of prolonged and/or heavy rainfall. Berms should be constructed along the top edges of all fill slopes. Brow ditches should be constructed along the top of all cut slopes sufficient to guide runoff away from the building site and adjacent.fill slopes prior.to the project being completed. G. Drainage The owner/developer is responsible to insure adequate measures are taken to properly finish grade the building pad after the structures and other improvements are in place so that the drainage waters from the improved site and adjacent properties are directed away from proposed structures in accordance with the designed drainage patterns shown on the approved plans. A minimum of two percent gradient should be maintained away from all foundations. Roof gutters and downspouts should be installed on the building, all discharge from downspouts should be led away from the foundations and slab to a suitable location. Installation of area drains in the yards should also be considered. Planter areas adjacent to foundations should be provided with damp/water proofing,. using an impermeable liner against the footings, and a subdrainage system within the planter area. It should be noted that shallow groundwater conditions may still develop in areas where no such conditions existed prior to site development. This can be contributed to by substantial increases of surface water infiltration resulting from landscape irrigation which was not present before the development of the site. It is almost impossible to absolutely prevent the possibility of shallow groundwater on the entire site. Therefore, we recommend that shallow groundwater conditions be remedied if and when they develop. The property owner should be made aware that altering drainage patterns, landscaping, the addition of patios, planters, and other improvements, as well as over irrigation and variations in seasonal rainfall, all affect subsurface moisture conditions, which in turn affect structural performance. . VINJE & MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029.1229 • Phone (760) 7434214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION . PERC TESTING ENVIRONMENTAL INVESTIGATION'S Update Compaction Report Proposed Church Site June 7, 2000' Page 9 LkeI1j L4J1i1•J !L11[.iRI It should be noted that the characteristics of as-compacted fill may change due to post- construction changes from cycles of drying and wetting,, water infiltration, applied loads, environmental changes, etc. These changes can cause detrimental changes-in the fill characteristics such as in strength behavior, compressibility, behavior, volume change behavior, permeability, etc.. The owner/developer should be made aware of the possibility of shrinkage cracks in concrete and stucco materials. The American Concrete Institute indicates that most concrete shrinks about 1/8-inch in 20 feet. Separation between construction and cold joints should also be expected. The amount of shrinkage related cracks that occur in concrete slab-on-grades, flatwork and driveways depend on many factors, the most important of which is the amount of water in the concrete mix. The purpose of the slab reinforcement is to keep normal concrete shrinkage cracks closed tightly. The amount of concrete shrinkage can be minimized by reducing the amount of water in the mix. To keep shrinkage to a minimum, the following should be considered: Use the stiffest mix that can be handled and consolidated satisfactorily. Use the largest maximum size of aggregate that is practical, for example concrete made with /8 inch maximum size aggregate usually requires about 40. pounds (nearly 5 gallons) more water per cubic yard than concrete with 1 inch aggregate. Cure the concrete as long as practical. The amount of slab reinforcement provided for conventional slab-on-grade construction considers that good quality concrete materials, proportioning, craftsmanship, and control tests where appropriate and applicable are provided. This office is to be notified no later than 3 p.m. on the day before any of the following operations begin to schedule appropriate testing and/or inspections. A. Fill placed under any conditions 12 inches or more in depth, to include: Building pads. Street improvements, sidewalks, curbs and gutters. VJNJE & MIDDLETON ENGINEERING, INC.-2450 Vineyard Avenue, #102, Escondido, California 92029.1229 • Phone (760) 743.1214 • Fax (760) 739.0343 QEOTECHNICAI. INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS Update Compaction Report Proposed Church Site June 7, 2000 Page 10 Utility trench backfills. Retaining wall backfills. The spreading or placement of soil obtained from any excavation (footing or pool, etc.). Inspection and testing of subgrade and basegrade beneath driveways, patios, sidewalks, etc., prior to placement of pavement or concrete. Moisture testing. Foundation inspections. Any operation not included herein which requires our testing, observation, or inspection for certification to the appropriate agencies. V. LIMITATIONS Our description of previous grading operations have been limited to those grading operations performed during the period of September 5, 1996 through June 30, 1998. The conclusions contained herein have been based upon our observations and testing as noted. No representations are made as to the quality or extent of materials not observed and tested. This report should be considered valid for permit purposes for a period of six months and is subject to review by our firm followng that time. IF ANY CHANGES ARE MADE -PAD SIZE, BUILDING LOCATION, ELEVATIONS, ETC. - THIS REPORT WILL BECOME INVALID AND FURTHER ENGINEERING AND RECOMMENDATIONS WILL BECOME NECESSARY. If you have any questions or need clarification, please do not hesitate to contact this office. Reference to our Job #00-248-F will help to expedite our response to your inquiries. VINJE & MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, 0102, Escondido, California 92029.1229 • Phone (760) 743.1214 • Fax(760)739-0343 QEOTECHNICAI. INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATIONS Update Compaction Report Proposed. Church Site June 7, 2000 Page 11 We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC. 00, Ralph M. Vinje GE #863 RMV/MS/mpr S ( - JUJY12-31"' OF C - Mehd, Shariat RCE #46174 Si :n No. 461,4 EXP. I2-312 Distribution: Addressee (1) Mr. Rick Hill, Rick Engineering (3) Mr. David Frink, Schuss - Clark Architects (2) OF c-\' mprflhIcont-248-f.ur1 VZNJE & MIDDLETON ENQINEERThJQ. iNC. 2450 Vitwyard Avenue, #102, Escondido, California 92029.1229 • Phone (760) 743.1214 • Fax (760) 739-0343 QEOTECHNICM. INVESTIQATIONS QRADINQ SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATIONS RETAINING WALL DRAIN L PAIL Typical - no scale Waterproofing Perforated drain pipe drainage Granular, non-expansive backfill. Compacted. .. :. Filter Material. Crushed rock (wrapped in filter fabric) or Class 2 Permeable Material (see specifications below) . .. - Tfl -ci Competent, approved soils or bedrock CONSTRUCTION SPECIFICATIONS: Provide granular, non-expansive backfill soil in 1:1 gradient wedge behind wall. Compact backfill to minimum 90% of laboratory standard. Provide back drainage for wall to prevent build-up of hydrostatic pressures. Use drainage openings along base of wall or back drain system as outlined below. Backdrain should consist of 4" diameter PVC pipe (Schedule 40 or equivalent) with perforations down. Drain to suitable outlet at minimum 1%. Provide %" - 1W crushed gravel filter wrapped in filter fabric (Mirafi 140N or equivalent). Delete filter fabric wrap if Cattrans Class 2 permeable material is used. Compact Class 2 material to minimum 90% of laboratory standard. Seal back of wall with waterproofing in accordance with architects specifications. Provide positive drainage to disallow ponding of water above wall. Uned drainage ditch to minimum 2% flow away from wall is recommended. * Use 1% cubic foot per foot with granular backfill soil and 4 cubic foot per foot if expansive backfill soil is used. VINJ.E & MIDDLETON ENGINEERING, INC. PLATE 01 ISOLATION JOINTS AND RE-ENTRANT CORNER REINFORCEMENT Typical - no scale (a) (b) ISOLATION JOINTS CONTRACTION JOINTS (9) RE-ENTRANT CORNER CRACK RE-ENTRANT CORNER - REINFORCEMENT NO.4 BARS PLACED 1.5" BELOW TOP OF SLAB NOTES: . Isolation joints around the columns should be either circular as shown in (a) or diamond shaped as shown in (b). If no isolation joints are used around columns, or if the corners of the isolation joints do not meet the contraction joints, radial cracking as shown in (c)may occur (reference ACI). In order to control cracking at the re-entrant corners (±270° corners), provide reinforcement as shown in (C). Re-entrant corner reinforcement shown herein is provided as a general guideline only and is subject to verification and changes by the project architect and/or structural engineer based upon slab geometry, location, and other engineerirg and construction factors. VINJE & MIDDLETON ENGINEERING, INC. PLATE 82 T0PO map printed on 06/06/00 from "SanDiego.tpo' and Untitiec.tpg 1. 117°17'00"W WGS841171600W 7 ,PLATE 1. 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