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

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Mr. Mark Castano, P.E. February 21, 2024 Keith & Associates, Inc. . Page 3 Geotechnical Study – Intra Coastal Sports Complex – 15800 Collins Avenue NV5 Project No.: 17990 CONSTRUCTION QUALITY ASSURANCE - INFRASTRUCTURE - ENERGY - PROGRAM MANAGEMENT - ENVIRONMENTAL separated by intermittent, 1-inch thick or less, uncemented sand layers (cross-bedded limestone). Zones of higher porosity are characteristic and parallel the bedding planes of the cross-bedded limestone. The tidal shoal limestone facies is characterized by a distinct lack of bedding planes. In addition, burrowing organisms have churned previously deposited sediments, which have resulted in high porosity channels in the rock. These ancient channels give the rock an appearance of a hardened sponge in some areas. The Fort Thompson Formation underlies the Miami Limestone, and includes sand, sandstone, and limestone. The upper zones of the Fort Thompson Formation consist of sand having a thickness ranging from 5 to 35 feet. The remainder of the formation consists of coralline limestone, quartz sandstone, sandy limestone and freshwater limestone. The type of soils within the formation and the degree of cementation vary with lateral extent and depth. The Fort Thompson Formation is underlain by the Tamiami Formation. The Tamiami Formation consists of sands, silts, clays, and sometime fossiliferous limestone. The upper portions of the Tamiami Formation are permeable and make up the lower reaches of the Biscayne Aquifer. This formation ranges in thickness from zero to 300 feet in South Florida. 4.2 GEOLOGIC HAZARDS The South Florida area is relatively free of geologic hazards. The region is not considered seismically active. Consequently, hazards such as ground shaking, liquefaction, lateral spreading, and ground rupture that are normally associated with earthquakes and other seismic activity are generally not a factor for the design of structure foundations in South Florida. Based on the 2021 International Building Code, a Site Class D classification is considered appropriate for this site. Karst topography that is associated with the formation of sinkholes and other underground discontinuities in carbonate rock formations in the central and northern portions of Florida is generally not found in South Florida. Any discontinuities in the limestone due to solutioning of the rock are typically very limited in vertical and lateral extent and are usually not considered a factor in the design of foundations in the local practice. 5.0 SUBSURFACE CONDITIONS 5.1 BORINGS In general, the subsurface conditions encountered in the borings are generally consistent with the geology described above. The detailed subsurface conditions are presented graphically in the attached boring summary sheet and in more detail on the records of test boring sheets. Layer 1 – Limestone Fragments/Sand: This surficial layer consists of light brown to gray limestone fragments and by tan sand with shells that extends to about eight (8) and 9 feet below the existing grade in the borings. This layer is covered with about two (2) inches of pavers. A thin layer of brownish yellow silt and sand was encountered in Boring B-2 between depths of six (6) and 7 feet below grade. SPT N-values recorded in Layer 1 range from three (3) to 42 blows per foot (bpf), with an average value of around 16 bpf. Layer 2 – Peat: Below the sand is a layer of dark brown peat encountered at around eight (8) and 9 feet below grade. This compressible layer extends to nine (9) and 15 feet below grade in the borings and is about one (1) and 7 feet thick. A gray sand layer about one (1) foot thick was