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GRAHAM HEAVY CONSTRUCTION 2132 NW Settle Avenue Port St. Lucie, Fl. 34986 561-727-3939 June 3, 2021 Halley Engineering 13901 Northwest 118" Ave Medley, Fl. 33178 Attn John Morris RE: 66th Avenue Roadway Improvements IRC Project No. IRC -1505 FM No. 436379-1-54-01 & 436379-1-54-02 66' Avenue over North Relief Canal Design Changes Dear Mr. Morris I:FA:IIQIaM9-11 :E 5101 Cone Road P.O. Box 310167 Tampa, Fl. 310167 813-623-2856 Per our telephone conversation we will be proposing to IRC a design change in 66' Ave over the North Relief Canal. This change is being necessitated by the requirement to design the post tension bridge in phases as per the question and answers prior to bid time. The bridge as presently designed is to be constructed in a single phase. Prior to bid we looked at many options in this design and concluded that the best method would be to upgrade the bridge design and provide for the phasing of construction. Below will be the design modifications along with the benefits for the change 1. The bridge will remain the same length and width as presently designed with the same cross section for the canal. 2. All Roadway and bridge deck elevations will remain the same 3. The bridge will only be 2 spans (15'-50') versus the present design of 3 spans (15'- 35'-15'). This will eliminate one intermediate bent in the water. This will also reduce the chance debris clogging the canal by 50% due to the elimination of one intermediate bent. The drainage district would prefer no bents in the canal. On the 58th avenue bridge design we have a single span 53' bridge with beams and no bents in the canal. 4. We will change from the prestressed/post tension deck units with an asphalt topping to the prestressed Florida Slab Beam Design (FSB) with a 6" Reinforced Concrete topping a. Deleting the post tensioning will eliminate future maintenance problems caused by relaxation of the tendons and replacement of tendons if they fail. 81