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Mr. Mark Castano, P.E. February 21, 2024 <br />Keith & Associates, Inc. . Page 4 <br />Geotechnical Study – Intra Coastal Sports Complex – 15800 Collins Avenue NV5 Project No.: 17990 <br /> <br />CONSTRUCTION QUALITY ASSURANCE - INFRASTRUCTURE - ENERGY - PROGRAM MANAGEMENT - ENVIRONMENTAL <br />found in Boring B-2 beneath the peat and extended to approximate 10 feet below grade. The <br />recorded SPT N-values in the peat layer ranges from one (1) to 6 bpf. The average SPT N- <br />values is about three (3) bpf. <br /> <br />Layer 3 – Silt: <br />This compressible layer was encountered at about 10 and 15 feet below grade and consists <br />of gray and dark gray silt. It extends to about 24 feet below grade and the thickness is eight <br />(8) to 14 feet. Boring B-1 encountered gray sand between depths of 21 and 22 feet below <br />grade. The recorded SPT N-values in the silt ranges from less than one (1) to 3 bpf and the <br />average SPT N-values is less than one (1) bpf. <br /> <br />Layer 4 – Limestone: <br />This layer consists of light brown and light gray limestone encountered at about 24 feet <br />below grade and extends to the termination depths of the borings at about 27 and 35 feet <br />below grade. This layer is at least 3 feet thick. The recorded SPT N-values vary from three (3) <br />to 50 bpf. The average SPT N-values is about 31 bpf. <br /> <br />For the layers described above, Table 1 below summarizes our estimates of engineering <br />parameters considered pertinent to the design of foundations for proposed structures. <br /> <br />TABLE 1 - SUMMARY OF ESTIMATED PERTINENT ENGINEERING PARAMETERS <br /> <br /> <br />Layer <br />ID Description <br />Thickness <br />(ft.) <br />SPT <br />N-values Modulus of <br />Elasticity <br />(ksf) <br />Unconfined <br />Compressive <br />Strength <br />(ksf) <br />Allowable <br />Side <br />Shear <br />(ksf) Range Avg. <br />1 Limestone <br />Fragments/ <br />Sand <br />8 - 9 3 – 42 16 300 - - <br />2 Peat 1 - 7 <1 – 6 3 100 - - <br />3 Silt 8 – 14 <1 – 3 <1 100 - - <br />3 Limestone 3+ 3 – 50 31 10,000 300 3 <br /> <br />We note that the values of allowable side shear estimated in Table 1 above are based on our <br />experience and laboratory data from similar rock that we have tested. <br /> <br />Groundwater <br /> <br />Groundwater was encountered at depths of about 5.3 and 5.5 feet below the existing ground <br />surface. It should be noted that groundwater readings during drilling might not represent <br />stabilized groundwater levels. Stabilized water levels would be best obtained by installing <br />groundwater monitoring devices and taking readings over an extended period. NV5 can <br />provide these services if they are of interest to the project development team. <br /> <br />Based on the assumed grade elevation, the water table is about +0.5 and +0.7 feet NGVD. <br />On average, stabilized groundwater levels in the general vicinity of the project are expected <br />to vary between approximate elevations 0 to +4 feet, NGVD, the variations being primarily <br />the result of seasonal rainfall and tidal fluctuations in the nearby water bodies. <br />Nonetheless, it should be noted that groundwater levels outside the ranges stated above <br />were encountered during the soil study and could be encountered during construction. <br />Storm, hurricane events, and construction activities can also result in the variations in the <br />groundwater levels. Notwithstanding the variations acknowledged, we anticipate that