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Larry Perino Page 2 November 15, 2002 <br /> <br /> <br />and temperature bars had been tied into the upstream cage at the <br />minimum 3.5-in from the face of the upstream bulkhead form and on <br />12-in centers, as specified. All the rebars had been individually <br />cut to fit, no splices used in either rebar cage. <br />Removal of loose rock from the tunnel roof, walls and floors <br />has resulted in a saw-toothed bulkhead. The blocky nature of the <br />latite porphyry results in the irregularities present on the back, <br />ribs and floor extending approximately 1-ft into the tunnel cross <br />section, considerably more than the specified 0.19-in. The shape <br />of the rock adjacent to the bulkhead is excellent for resisting <br />movement under the design hydraulic thrust. As we discussed the <br />fracture permeability in the block latite porphyry at the bulkhead <br />location will probably require low pressure grouting of the <br />concrete/rock contact to prevent leakage during water impoundment. <br />A few gallons of water was present at low spots in the floor of the <br />bulkhead section. The pump for removing the water inside the forms <br />was present inside the forms. It will be used to remove the water <br />on the floor immediately before starting the pour. <br />One thrust collar and two water stops are installed on the <br />bypass pipe. Trim bars were tied into each rebar cage where the <br />bypass pipe passes through the rebar. <br />Filling of the form should proceed as soon as possible. <br />Sincerely, <br />~~~~~~~. <br />John F. Abel, Jr. <br />Colorado P.E. 5642 <br />• <br />