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HomeMy WebLinkAboutDEV 2016-0043; Vaughn Residence; Results of Compaction Testing and Inspection; 2015-10-15@ B&B Engineering, Inc. CIVIL, GEOTECHNICAL, & QUALITY ENGINEERING FOUNDATION DESIGN• LAND SURVEYING• SOIL TFSrING MR & MRS. KAPLAN 2251 Paseo Saucedal Carlsbad, CA. 92009 , __ CLIENT: KAPLAN PROJECT: KAP 615-CDG DATE: 15 OCTOBER2015 Subject: Results of Compaction Testing and Inspection for the Residence located at 2605 Crest Drive, Carlsbad, CA. (APN: 156-152-29)(Grading Plan Dwg No. 485-4A) Reference (a): Limited Site Specific Soil Investigation Report-by B & B Engineering, Inc., dated 24 February 2015. Dear Mr. & Mrs. Kaplan: Pursuant to your request, we have completed our inspection and compaction testing of the rough grading operations for the subject parcel. Locations of our field density tests are shown on Enclosure (1 ), and the results of these tests are detailed on Enclosure (2). Site preparation, soil compaction and testing were accomplished between October 9 and 15 2015. Based on our observations and testing, it is our opinion that the work performed during that period was in general conformance with the requirements of Reference (a), the Approved Grading Plans and the City of Carlsbad Grading Ordinance. SITE GRADING On October 9, 2015, clearing began on the subject lot with the contractor removing some surface vegetation, trash and debris. All debris was removed from the pad grading area prior and during the grading operation. On this date, the contractor over-excavated the surface soils for the .westerly garage pad by removing the surface materials to an approximate depth of3 feet below the existing surface, where firm natural ground was encountered. The contractor continued this same over-excavation operation for the main house pad. The bottom of each ·excavation was scarified, watered, and recompacted prior to replacing the native stockpiled soils. The limits of over-excavation extended a minimum of 5 feet outside of the proposed building foundations. The over-excavation grading operation was accomplished to help mitigate the effects of differential settlement of the proposed structure. The contractor placed and compacted the native soils on the house pad until the desir~ pad grades were achieved. Density was achieved by the use of a Caterpillar 950 rubber tire loader and a D-4 bulldozer compacting the soil as fill was placed in thin lifts. Since the existing soil was low in moisture content, the contractor spent additional time and effort in his mixing operation in order to ensure near-optimum moisture and proper compaction in the fill material. As indicated by our Compaction Test Results, Enclosure (2), density tests performed in the construction of the garage and the house pad indicated over 90% relative compaction as compared to the Maximwn Dry Density per ASTM Test Procedure D 1557. 1 1611-A SO. MELROSE DRIVE #285, VISTA. CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 726-7514 __ lo_/J./l!.- D·atc . ~ B{l,B Engineering, Inc. Kap615-cdg SOIL EXPANSION The native materials exposed at surface grades for the subject pad are considered to have a very low expansion potential (EI= 2) according to Reference (a). Therefore, no additional foundation or slab requirements are considered necessary in regard to soil expansion. BUILDING SLABS AND FOUNDATIONS It is recommended that all continuous perimeter· and interior foundations and concrete slabs for a light weight, wood framed, stucco type structure founded o"n the native ve,:v low expansive soil shall be constructed and reinforced in accordance with the following minimum designs: a. For slab-on-grade floors: it is recommended that all continuous perimeter and interior foundations for single stozy structures shall extend a minimum depth of 15 inches and a minimum width of 15 inches into the firm native or compacted fill material as measured from the lowest adjacent grade. b. For slab-on-grade floors: the continuous interior and exterior foundations shall be reinforced with at least four N o.4 steel bars, two bars. shall be placed 3 inches from the top of the foundation and the other bars shall be placed 3 inches from the bottom. c. For a raised foundation system, the perimeter and interior stem wall foundations shall be designed and constructed in accordance with the structural engineer's recommendations. d. All concrete building slabs shall be a minimum of full 4-inches in thickness, and reinforced with a minimum of No. 3 steel rebars at 18-inches on center both ways and placed in the center of the slab .. The steel bars shall be wire tied to the perimeter foundation steel and bent downward into the foundations at IS-inches on center to a depth of 3-inches from the bottom. In order to minimize vapor transmission, an impermeable membrane (ie: 10 mil visqueen) shall be placed over native on-site sand or 2-inches of coarse sand, gravel or crushed rock. The visqueen shall be covered with 2-inch of sand to protect it during construction and the sand should be lightly moistened just prior to placing concrete. All concrete used on this project shall contain Type II cement with a maximum water/cement ratio of0.50 and a minimum.concrete strength of 2500 psi should be utilized for all concrete in contact with the on-site earth materials. e. Interior concrete slabs shall be provided with saw-wt joints spaced at a maximum of 10 feet on center each way within 24 hours after the pour and the saw-cuts shall be l/4 of the slab . thickness. It is imperative that the drainage system around the proposed structure shall be designed and implemented to provide positive drainage away from all buildings in order to preclude moisture intrusion into the subgrade soils beneath the building foundations and slabs. £ Exterior slabs for hardscape, pool decks; walkways, patios, etc. shall be a minimum of 4 inches in thickness and reinforced with a minimum ofNo. 3 steel rebars at 24 inches on center each way. The reinforcing steel shall be placed in the upper 1/3 of the slab and held in place with concrete chairs. 2 1611-A SO. MELROSE DRIVE #285, VISTA, CA 92081-6471 Ph: (760) 945-3150 Fax: (760) 726-7514 • ~ B&B Engineering, Inc. Kap615-cdg These foundation recommendations are minimum design requirements for the soils encountered during this investigation; however, actual foundations shall be designed by the Structural Engineer for the expected live and dead loads, and for wind and seismic loads. If imported soil materials are used during grading to bring the building pad to .the design elevations, or if variations of soils or building locations are encountered, foundation and slab designs shall be reevaluated by our firm upon the completion of the rough grading operation. 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 the cracking of slabs. Tile and other sensitive flooring can crack, reflecting the cracks in the concrete slab below. The tile installer should consider installation methods that reduce possible cracking of the tile. ·Slipsheets or a vinyl crack isolation membrane ( approved by the Council of America/Ceramic Tile Institute) are recommended between the tile and the concrete slabs on grade. If tiles are anticipated to be used as floor coverings, an expert in the field of sensitive flooring installation should be consulted. Findings of this Report are valid as of this date; however, changes in conditions ofa property can occur with passage of time, whether they be due to natural process or works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards occur whether they result from legislation or broadening of knowledge. Accordingly, fmdings of this Report may be invalidated wholly or partially by changes outside our control. Therefore, this Report is subject to review and should not be relied upon after a period of one year. In the event that any changes in the nature, design, or location of buildings are planned, the conclusions and recommendations contained in this Report shall not be considered valid unless the changes are reviewed and the conclusions of this Report are modified or verified in writing. This Report is issued with the understanding that it is the responsibility of the owner or of his representative to ensure that the information and recommendations contained herein are called to the attention of the project Architect and Engineer and are incorporated into the plans. Further, the necessary steps shall be taken to ensure that the contractor and subcontractors carry out such recommendations in the field. It is recommended that our Engineer be provided the opportunity for a get).eral review of the final design plans and specifications for this project in order that the recommendations of this report may be properly interpreted and implemented in the design. It is also recommended that the Soil Engineer be provided the opportunity to verify the foundation and slab construction in the field prior to placing concrete. (If our Engineer is not accorded the privilege of making these reviews, he can assume no responsibility for misinterpretation of his recommendations). 3 1611-ASO. MELROSE DRIVE#2B5, VISTA, CA92081-5471 Ph: (760) 945-3150 Fax: (760) 726-7514 ~ B&B Engineering, Inc. Kap 615-cdg The Engineer has prepared this Report for the exclusive use of the client and authorized agents .. This Report has been prepared in accordance with generally accepted soil and foundation engineering practices. No other warranties, either expressed or implied, are made as to the professional advice provided under the terms of this agreement, and included in the Report. B & B Engineering Inc. appreciates this opportunity to be of service. Should you have any questions regarding this project, please do not hesitateto contact us. Sincerely, ~en B. Peter RCE 38623 Expires 3-31-17 4 1611-A SO. MELROSE ORNE #285, VISTA. CA 92081-6471 Ph: (760) 945-3150 Fax: (760) 726-7514 -.. -~ }(115.I} 4QR/P RAP v;y OIS9PAT1!f ~ lo' ff!,5' M Ill f~f',f~ z. V / • \ 12 fJ) APPROXIMATE LOCATION OF FIELD DENSllY TEST PLOT PLAN Owner: TERESA KAPLAN SITE 2605 CREST DRIVE Address CARLSBAD, CA. 92008 @B&B Engineering, Inc A.P.N.: 156-152-29 Pro·ect: KAP615-CDG Date: 10/15/2015 ENCLOSURE 1 @B&B Engineering, Inc ·Client KAPLAN RESIDENCE Project KAP 615-CDG Date· 10/15/2015 -Dry Density, pcf Moisture,% Relative Relest Test Test Soil No. TestDate Test Location E1/Deoth I Tvoe Fie Id Maximum Field Opt compaction No. 1 10/9/15 GARAGE PAD 174 A 127.6 130.0 7.6 10.2 98 2 10/9/15 GARAGE PAD 174 A 127.2 "130.0 7.6 102 98 3 10/13/15 GARAGE PAD 175 A 122.5 130.0 10.9 10.2 94 4 10/13/15 GARAGE PAD 176 A 122.6 130.0 10.5 10.2 94 5 10/13/15 GARAGE PAD 177 A 122.6 130.0 12.0 10.2 94 6 10/13/15 GARAGE PAD 178 A 122.5 130.0 9.9 10.2 94 . 7 10/13/15 HOUSE PAD 177 A 120.3 130.0 9.4 10.2 93 8 10/13/15 HOUSE PAD 178 A 124.6 130.0 9.5 10.2 96 9 10/13/15 HOUSE PAD 179 A 120.7 130.0 9.3 10.2 93 10 10/13/15 HOUSE PAD 180 A 125.6 130.0 9.8 10.2 97 11 10/13/15 HOUSE PAD 181 A 123.0 130.0 10.5 10.2 95 12 10/13/15 HOUSE PAD 181 A 127.6 130.0 10.9 10.2 98 . COMPACTION CURVE DATA OPTIMUM MAXIMUM DRY SOIL TYPE AND DESCRIPTION MOISTURE% DENSITY 1~cn A. BROWN SIL TY SAND 10.2 130.0 COMPACTION TEST DATA ENCLOSURE (2) -· \ .,t." .. -·' ,- ' ([\ !~ B&B Engineering, Inc. . MAINTENANCE GUIDELINES FOR HOMEOWNERS During the wet weather season, homeowners become concerned about the stability of their building site. In general, modem design and construction practice minimizes the probability of serious slope failure. The grading codes of 1he local jurisdiction (cities and counties) in California concerning filled land, excavation, terracing and slope construction are among the most stringent in the countzy and, if followed, are adequate to meet.most natural occU1Tences. Therefore, the concern of the homeowner should be directed toward maintaining slopes, drainage provisions and facilities so that they will perform as designed. The following discussion, general recommendations and simple precautions are presented herein to help the homeowner maintain his hillside building site. The general public often regards the natural terrain as stable -"terra firma". This, of course, is an erroneous concept. Nature is always at work altering the landscape. Hills and mountains are worn down by mass wastirig (erosion, sliding, creeping), and the valleys and lowlands collect these products. Thus, the natural process is toward leveling the terrain. Periodically (over tens of millions of years) major land movements build moW1tains and erosion tends to level the terrain. In some areas, these processes are very slow, and in others, they are more rapid. Development of hillsides for residential use is carried out, in as far as possible, to enhance the natural stability of the site and to minimize the probability of instability resulting from the grading necessmy to provide home sites, streets, and yards. This has been done by the developer and designers based on geologic and soil mechanics investigations. In order to be successful, the slope and drainage provisions and facilities must be maintained by the homeowner. Homeowners are accustomed to maintaining their homes. They expect to paint their house periodically, replace wiring, clean out clogged plumbing, repair roofs, etc. Maintenance of the home site, particularly on hillsides, should be considered on an even more serious basis. In most cases, lot and site maintenance can ·be taken care of along with landscaping, and can be carried out less expensively to the homeowner than repair after neglect. Most slope and hillside lot problems are associated with water. Uncontrolled water from a broken pipe, cesspool or wet weather causes most damage. Wet weather is the largest cause of slope problems, particularly in California where rain is intermittent, but may be torrential. Therefore, drainage and erosion control are the most Important aspects of home site stability. These provisions must not be altered without competent professional advice and maintenance must be carried out to assure their continued operations. We offer these procedures as a checklist to homeowners: I. Check roof drains, gutters and downspouts to be sure they are clear. Depending on your location, if you do not have roof gutters and downspouts, you may wish to install them. Without gutters or other adequate drainage, water falls from the roof e;aves and collects against foundation and basement walls, which can be undesirable. 2. Clear surface and terrace drainage ditches and check them frequently during the rainy season, with a shovel, if necessary. Ask your neighbors to do likewise. 3. Be sure that all drainage ditches and sub-drains have outlet drains that are open, This should be tested during dry weather. Usually, this can be done sbnply with a hose. If blockage is evident, you may have to clear the drain mechanically. 4. Check all drains at the top of slopes to be sure that they are clear and that weather will not overflow the slope itself, causing erosion. S. Keep subsurface drain openings (weep-holes) clear of debris and other material, which could block them in a stonn. 6. Check for loose fill above and below your property if you live on a slope or terrace. 7. Watch hoses and sprinklers. During the rainy season, little, if any, irrigation is required .. Over-saturation of the ground is not only unnecessary and expensive, but can cause subsurface damage. 1611-A SD. MELROSE DRIVE #285, VISTA. CA 920B1-5471 Ph: (7601945-3150 Fax· 17Rlll AA"-'-'" @ B&B Engineering, Inc. ' 8. Watch for water backup of drains inside the house and toilets during a rainy season since this may indicate drain or sewage blockage. 9. Exercise ordinary precaution. Your house and building site were constructed to meet certain standards, which should protect against any natural occurrence if you do your part in maintaining them. 10. Care and maintenance of hillside homes includes being sure that terrace drains and brow ditches on slopes or at the top of cuts, or fill slopes are not blocked. They are designed to cany away runoff to a place where it can be safely distributed. Generally, a little shovel work will remove any accumulation of dirt and other debris, which may clog the drain. If several homes are located on the same terrace, it is a good idea to check with your neighbors. Water backed up on their property may eventually reach you. Water backed up in surface drains will tend to overflow and seep into the terraces, creating less stable slopes. 11. Water should ,not be permitted to collect or pond on your home site. Ponded water will tend to either seep into the ground-loosening fill or natural ground, or will overflow onto the slope and cause erosion; Once erosion is started, it is difficult to control and severe damage may result rather quickly. · 12. Roof drains and gutters or downspouts should be connected to area (surmce) drainpipes, but not to subdrain pipes. Rather, arrange them so that water either flows off'your property in a specially designed pipe or it flows out onto a paved driveway or the street. The water may then be dissipated over a wide surfuce or, preferably, be camed away in a paved gutter or storm drain. Subdrains are constructed to take care of ordinary subsurface water and cannot handle the overload from roofs during a heavy rain. 13. Water should not be allowed to spill over slopes, even where this may seem to be a good way to prevent ponding. This tends to cause erosion and, in the case of fill slopes, can cut away carefully designed and constructed sites. 14. ·Loose soil or debris should not be left on or tossed over slopes. Loose soil soaks up water more readily than compacted fill, In addition, It is not compacted to the same strength as the slope itself and will tend to slide when laden with water, and may even affect the soil beneath it. The sliding may clog terrace drains below or may cause additional damage in weakening the slope. If you live below a slope, try to be sure that loose fill is not dumped above your property. 15. Water should.not be discharged into subsurface.blanket drains close to slopes. French drains are sometimes used to get rid of excess water when other ways of disposing of water are not readily available. Overloading these drains saturates the ground and, if located close to slopes, may cause slope failure. 16. Surface water should not be discharged into septic tanks or leaching field. Not only are septic tanks constructed for a different purpose, but also they will tend, because of their construction, to accumulate additional water naturally froro the ground during a heavy rain. Overloading them artificially during the rainy season is bad for the same reason as subsurface subdrains, and is doubly dangerous since their overflow can pose a serious health hazard. In many areas, the use of septic tanks should be discontinued as soon as sewers can be made available. 17. Slopes should not be over-irpgated. In some areas ice plant and other heavy ground cover can cause surface sloughing when saturated due to the increase in weight and weakening of the near surfuce soil. Planted slopes should be located, where possible, in areas where they will be adequately irrigated by raintiill. 18. Water should not be allowed to gather against foundations, retaining walls and basement walls. These walls are built to withstand the ordinary moisture in. the ground and are, where necessary, accompanied by subdrains to carry off the excess moisture. If water is permitted to pond against them, .it may seep through the wall causing dampness and leakage inside the basement. It also may cause the soil adjacent to the foundation to swell resulting in structural damage to walls and footings. 19. Now fill placed behind walls or in trenches should not be compacted by flooding with water. Not only is flooding tho least efficient way of compacting fine-grained soil, but also could damage the wall foundation. 20. Hoses and sprinklers should not be left running on or near a slope, particularly during the rainy season. This will enhance ground saturation, which may cause damage. 21. Ditches that have been graded around your house or the lot pad should not.be blocked. These shallow ditches have been put there for the purpose of quickly removing water toward the driveway, street or other positive outlet. By all means, do not let water become ponded above slope by blocked ditches. 1611-A SO. MELROSE DRIVE #265, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 945-4221 -· ,,t I .