Reso 2005-825 - Laserfiche WebLink

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" -LJ----~ n ~-. caused when the small diameter sampler encounters s mall voids, 0 r s and filled voids. When n larger excavations are perfonned the limestone will be found to be quite unifonn. u n LJ n u II u 11 LJ 11 LJ II L-J (" \~-1 II u n u II L-J II L-J n L-J " LJ " LJ / ." L-J II L-J RECREATION BUILDING The site subsurface soil conditions are not suitable for support of the proposed recreation building on shallow foundations. The proposed structure can however be safely supported on deep foundations. The most suitable deep foundation for the soil profile that exists on site is an auger cast pile foundation. Driven piles may have difficulty penetrating the limestone support layer and could induce damaging vibrations to adjacent structures. Pile lengths between 20 and 30 feet and pile di~eters between 14 and 16 inches were evaluated. During the analysis any compression capacity generated in the upper 16 feet of the soil profile was ignored due to the peat and other compressible soils that were encountered. The upper soils were considered in the calculation of tensile capacity. Piling capacity was calculated for each of the 2 deep borings. Allowable Compression Capacity and Allowable Tensile Capacity are presented graphically in Figures 1 and 2 below for 14 and 16-inch diameter auger cast piles. It should be noted that the tensile capacity is low relative to the compression capacity. This is due to the very loose soils encountered above the limestone layer and the fact that the xrl.ajority of the compression capacity is due to end bearing in the limestone layer. Vibratory rolling of the ground surface prior to piling installation can significantly increase tensile capacity. The piling analysis that was perfonned revealed an optimum piling length of 24 feet. This depth takes advantage of a hard zone encountered within t he I imestone at that depth. Longer pile lengths result in lower end bearing capacity and therefore lower compression capacity. For design purposes compression capacities of 36 tons and 44 tons are recommended for 14 and 16-inch auger cast piles installed to depths of 24 feet below the existing ground surface. This corresponds to a pile tip elevation of -20 feet We further recommend tensile capacity for design of 15 and 18 tons for 14 and 16-inch auger cast piles installed to depths of 24 feet below the existing ground surface. This value is based on the assumption that the ground surface will be rolled heavily prior to the installation of the piling. 555 Sawgrass Corporate Parkway. Sunrise, Florida 33325. (954) 835-9055. FAX (954) 835-9044 /~-'~ , I \ i ". ./