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Memo to Tom Schreiner 6 February 21, 2006 <br />Bulkhead Cost Estimate Permit No. M-1983-141 <br />b =beam width (one inch) <br />h =bulkhead length (feet) <br />The forgoing analysis demonstrates that required minimum length for a plain concrete bulkhead is 10 feet, a <br />significant increase over the bulkhead length of 6.5 feet required for the hydraulic pressure gradient aspect <br />of the design. This increase in bulkhead length for plain concrete combined with the advisability of <br />including reinforcing steel on the outby end of the bulkhead to control temperature and shrinkage induced <br />stresses, leads to the conclusion that the main bulkhead must be reinforced. <br />Desi~ for Reinforced Concrete Deen Beam Bending Stress, Main Bulkhead <br />The following design calculations follow ACI 318-89, section 9.3.2.3 and Wang and Salmon (1985). <br />C=r~x f'~xbwxa=0.85x3000x12xa=30600xa <br />T = A, x fY = 60000 x A, <br />C=T <br />60000 x A <br />a= s =1.961xA, <br />30600 <br />M„ - w gQx - 53428 x 82 _ 427392 foot pounds <br />M~ - ~u - 427392 = 474880 foot pounds = 5698560 inch pounds <br />0.9 <br />M~ A, x fY(d 2) <br />d = L - m~ = 16.5 feet x 12inches 1- 3.5 = 74.5 inches <br />l foot J <br />M„ = 60000 x A, 74.5 -1.96~x As / - (4470000 x A,) - (58830 x A; ) <br />.'.5698560 = (4470000 x A,) - (58830 x Ap ) <br />58830A; -4470000Ag +5698560 = 0 <br />