11731 AIRPORT RD Geotech Report 2018-01-02 MF Import

�8/18/2005 15:27 4257478561 GEOTECH PAGE 04 Lucia Development, LLC JN 05233 August 18,2005 Page 3 We antieipate that groundwater could be found in wet sand lenses above the denser silts and fracture zones fn the sllt. The stretifieation lines on the logs represent the approximate boundalies between sal types at the exploration loCations. The aetual trensNion between soil types may be gradual, and wbsurface conditions can vary between expioration loqtions. The Ioga provide specifie subsuAace i�farmation only at the locations tested. If a transition in soil type oceurred between samples in the borings, the depth of the transitian was interpreted. The relative densities and moisture deseriptions indieated on the test pit and boring logs are interpretive descriptions 6ased on the to�ditions observed during excavation and drilling, resQectively. The compaetion of backfill was not in ihe scope ot our services. Loose soil will therefore be found in tl�e area of the test pits. If this presents a problem, the bac�l! will need ro be removed and replaced with structural fitl during construction. CONCLUSIONS AND RECOMMENDATIONS GENERAt THIS SECTION CONTA/IVS A SUMMARY OF OUR STUDY AND FINDIMGS FOR THE PUAPOSES OF A GENERAL OVERVIEW ONLY. MORE SPEClFIC RECOMMENDATlONS AND CONCLUSIONS ARE CONTiUNED IN THE REMAINDER OF THIS REPORT. ANY PAR1Y ftELYING ON THIS REPORT SHOULD READ THE ENTIRE DOCUMEMT. The test pits and borings cronducted for this study encounteretl from 14 to 24 feet of loose FII an� native sals overlying dense to very dense sitty sand and silt. The loose fill and underlying organic soils are very compressible and ara not suitable to support new bullding or floor loads. Due to the depth to bearing soiis and the compressibility of the loose fill and native soils,the proposed building loads and slab loads should be transferted to the dense soils by a deep foundatian system. There are several options for deep foundations, but based on the soil cond'Rions eneountered, the proposed buil�ng loads, and the amount of debris encountered in the test pits, small-diameter pipe piles appear to be the most appropriate system. Another option for foundation and slab support would be augercast concrete piers. Pipe piles are driven with a Iarge jackhammer, but ca�� installed with reiatively minor ground vibrations. We have provided design criteria and recommEndations for pipe piles in a subsequent section of this report. Many of our test pits encauntered debris in the fill soils. Piles may be obstruGed by debris in the fill soils. It debris is encountered and prevents pile advaneement, the debris wi11 need to be removed with an excavator or the subjett pile(s) reiocated. Exterior slabs-on-grade may experience noticeable differential SetUement relative to the pile- suppoAed building. Where on-grade slabs are used, such as for walkways or patios, we recommend that they be reinforced with steel bare to reduce cracking. This will not prevent settlement, but will reduce cracking and slab breakage due to differentiai movemeM. Walkways and stairs shouid also be dowelled into perimeter grade beams�t doorways to prevent downsets at the tltreshold. This reduces the pote�tial for a fip hazard. it is likely that some settlement ot the ground surrounding pile-supported buildings will oecur over time. In order to reduce the potential problems associated with this,we recommend the following: GEOTECH CONSULTANTS,INC,