INVITATION TO BID 24-07-01 CONSTRUCTION OF INTRACOASTAL SPORTS PARK

Home Browse Search

Mr. Mark Castano, P.E. February 21, 2024 Keith & Associates, Inc. . Page 2 Geotechnical Study – Intra Coastal Sports Complex – 15800 Collins Avenue NV5 Project No.: 17990 CONSTRUCTION QUALITY ASSURANCE - INFRASTRUCTURE - ENERGY - PROGRAM MANAGEMENT - ENVIRONMENTAL Samples of the subsurface materials were recovered at roughly 2-foot intervals within the upper 10 feet of the borings and at approximately 5-foot to 15 feet below grade, and 2-foot intervals thereafter using a Standard Penetration Test split-spoon sampler (SPT) in substantial accordance with ASTM D- 1586, "Standard Test Method for Standard Penetration Test and Split-Barrel Sampling of Soils." This test procedure drives a 1.4-inch inner-diameter split-tube sampler into the subsurface profile using a 140-pound hammer falling 30 inches. The total number of blows required to drive the sampler the second and third 6-inch increments is the SPT N-value, in blows per foot, and is an indication of material strength. Upon completion of the borings, the boreholes were backfilled with soil cuttings and the upper few feet closed with cement grout. The soil/rock samples recovered from the borings were initially classified in the field. The collected samples were later re-examined in the laboratory by a geotechnical engineer to confirm field classifications. Visual soil classifications were made in accordance with ASTM D2487 and ASTM D2488. The results of the classification and consequent generalized stratification are shown in Drawing 2, the boring summary sheet, and in the records of test borings in Appendix A (sheets A-1 through A-5). Strata contacts shown on these drawings are approximate. 3.2 FIELD PERMEABILITY TEST NV5 performed also one (1) field permeability test to 15 feet deep at the location shown on Drawing 1. The test was performed in general accordance with the South Florida Water Management District’s Usual Open Hole Procedure. Test results are presented in Appendix B (sheet B-1). 4.0 LOCAL GEOLOGY AND GEOLOGIC HAZARDS 4.1 LOCAL GEOLOGY Miami-Dade County is located on the southern flank of a stable carbonate platform on which thick deposits of limestones, dolomites and evaporites have accumulated. The upper two hundred feet of the subsurface profile is composed predominantly of limestone and quartz sand. These sediments were deposited during several glacial and interglacial stages when the ocean was at elevations higher than present. In many portions of Miami-Dade County, surface sand deposits of the Pamlico Formation are encountered. The Pamlico sands overlie the Miami Limestone. In western Miami-Dade County, portions of the Everglades Region interfinger with the Pamlico sand. The Everglades soil consists of peat and calcareous silt (marl). The Miami Limestone is a soft to moderately hard, white, porous to very porous, sometimes sandy, oolitic calcareous cemented grainstone. The formation outcrops in portions of Miami-Dade County. The Miami Limestone has a maximum thickness of about 35 feet along the Atlantic Coastal Ridge and thins sharply near the coastline and more gradually in a westerly direction. The Miami Limestone was formed about 130,000 years ago at a time when the sea level was twenty-five feet higher than it is today. This environment facilitated formation of concentrically layered sand sized carbonate grains called oolites. These grains formed by repeated precipitation of calcium carbonate around the nucleus of a sand or shell grain. The Miami Limestone can be separated into two facies: the barrier bar oolitic facies and the tidal shoal limestone facies. The barrier bar facies is characterized by lenses of oolitic limestone