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13`h Street SW Bridge at 58th Avenue -2- File No. 07-5535 PROPOSED CONSTRUCTION Based on our review of a cross-section of the proposed bridge and canal, and on conversations with the project Bridge Engineer, Mr. Brian C. Rheault, P.E. with Bridge Design Associates, Inc., we understand that the proposed bridge will have an overall length of about 97 feet and will span the existing Sub -Lateral B-8 Canal. We further understand that the depth of the canal is approximately 13 feet at the location of the proposed bridge and that no significant widening or dredging of the canal is planned. Should this information differ from actual or planned site conditions, we should be notified immediately to allow for re-evaluation of the recommendations in the report. It is our understanding that the proposed bridge will consist of one 37 -foot long span with 30 -foot long approach slabs on both sides for an overall length of 97 feet. The bridge bents will be supported on conventional square, prestressed, driven concrete piles. REVIEW OF SOIL SURVEY MAPS The Soil Survey of Indian River County, Florida, which was issued by the U.S. Department of Agriculture, Soil Conservation Service in 1987, states that the predominant surficiai soil type in the area where the site is located is Manatee loamy fine sand. The Manatee loamy fine sand soil type consists of nearly level, very poorly drained soil found in depressions and poorly defined drainageways and on broad, low flats. Slopes are smooth to concave. They dominantly are Tess than 1 percent but range from 1 to 2 percent. Typically, the surface layer is black loamy fine sand about 12 inches thick. The subsoil extends to a depth of about 31 inches. The upper 10 inches of the subsoil is very dark gray fine sandy loam, the next 9 inches is dark gray sandy loam, and the lower 8 inches is dark grayish brown loamy fine sand. The substratum extends to a depth of 80 inches or more. The upper 12 inches of the substratum is light brownish gray loamy fine sand. The lower29 inches or more is Tight gray loamy fine sand and shell fragments. The water table is within a depth of 10 inches of the surface for more than 6 months during most years or above the surface for short periods after heavy rainfall. It is at a depth of 10 to 30 inches for short periods during dry seasons. Permeability is moderate. FIELD EXPLORATION PROGRAM The field exploration program included performing two Standard Penetration Test (SPT) borings to a depth of 60 feet below the existing ground surface on each side of the canal at accessible locations in the general vicinity of the proposed bridge alignment. This work was performed on March 8, 2007 in general accordance with the procedures recommended in ASTM D-1686. A description of our drilling and testing procedures is included in Appendix I. Split -spoon soil samples recovered during performance of the borings were visually classified in the field and representative portions of the samples were transported to our laboratory in sealed sample jars. Due to the possible presence of underground utilities, the upper 4 feet of each boring was conducted using a hand-held, 3 -inch diameter bucket auger.