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F-L Brenneman Secondary Bulkhead <br /> Construction Certification Report <br /> Page 2 <br /> The rock contact perimeter area irregularity required to <br /> develop the design compressive strength of the concrete when <br /> subject to the maximum design thrust was determined <br /> empirically to be 4% to 10% of the area. The irregularity <br /> size required was 0. 15 inch. These irregularities of the rock <br /> surface within the bulkhead were required by design to prevent <br /> the bulkhead from moving downstream upon application of the <br /> maximum design head. SGC committed to a minimum perimeter <br /> area irregularity of 10%. <br /> Quantification of perimeter area irregularity was accomplished <br /> by measuring x-sections within the bulkhead length and using <br /> the generated x-sections to quantify intrusive area verses <br /> total area between sections. This method provided an estimate <br /> of rock perimeter area irregularity of 53% which exceeds the <br /> design and committed minimums specified . Pre-pour approval <br /> was required (and received) that this design assumption was <br /> met. <br /> The bulkhead dimensions and rebar placement met or exceeded <br /> all design specifications and assumptions. <br /> Specifically, these are: <br /> 1) a depth of 8 feet (distance between forms) . <br /> 2) an air side rebar placement of #10 at 9" x 911 <br /> . <br /> 3) an air side rebar cover of 3 1/2". <br /> 4) a water side rebar placement of #6 at 12" x 12" . <br /> 5) a water side rebar cover of 3" . <br /> 6) a dimension of 10 feet for reinforced bending length (ie <br /> rib to rib dimension) . <br /> 7 ) a rebar-rib clearance of less than 611. <br /> 8) a minimum rebar lap distance for splices or continuous <br /> bars. <br /> 9) a minimum perimeter area irregularity of 10%. <br /> d) Pumping of concrete and filling of forms as well as seven and <br /> twenty-eight day compression tests for concrete strength. <br /> Testing of the design concrete dry mix prior to purchase, to <br /> insure that concrete design specifications could be met with <br /> the mix along with satisfying the practical aspect of placing <br /> the concrete, indicated that adjustments were required. To <br /> facilitate pumping, the maximum size aggregate was reduced to <br /> 3/8 inch and the sand and cement content adjusted to reflect <br /> the change in voids. The critical design parameters (ie Type <br /> V cement, fly ash of 16% of cement content and 0. 45 <br /> water/cement ratio) were not changed. This resulted in a dry <br /> mix with a target strength of 4990 psi at the 0.45 w/c ratio. <br />