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Terry Tunnel Bulkhead <br /> Construction Certification Report <br /> Page 2 <br /> The rebar cage was to be modified to provide a 3 1/2 inch <br /> clear distance around the pipe with diagonal #6 bar <br /> reinforcement around the opening . These diagonal bars were to <br /> cross at least 2 cage horizontal bars. <br /> The pipe installation met these design specifications . In <br /> addition, an additional thrust/seep collar 3/8 inch thick x 10 <br /> 5/8 inch diameter was placed at the upstream face and a non- <br /> structural 0. 035 inch thick x 10 5/8 inch diameter seep collar <br /> was placed 33 inches from the downstream face to provide <br /> additional assurance that seepage would not occur along the <br /> outside pipe wall . A design check by John Abel to conf irm <br /> that this seep collar would not adversely affect the bulkhead <br /> is attached . A 1 inch diameter , Schedule 80 Grade 316L <br /> stainless steel sampling/pressure monitoring pipe was also <br /> installed to facilitate the monitoring requirements of the TR <br /> approval . This pipe also has three seep collars 3/8 inch <br /> thick x 5 3/8 inch diameter along with couplings placed at the <br /> upstream face and within the bulkhead at approximately the <br /> same locations as the 6 inch diversion pipe. <br /> The 6 inch pipe is fitted with an ANSI B16 . 5 class 150 316L SS <br /> flange on the upstream side and an ANSI B16 . 5 class 300 316L <br /> SS flange on the downstream end . A class 300 6 inch gate <br /> valve, 316L SS construction, is installed on the pipe for <br /> eventual closure . Attached is a piping sketch, copy of the <br /> quotation sheets, purchase order and a mill test report (6 <br /> inch pipe) . <br /> 4c) Construction of concrete forms and erection of re-bar cage <br /> The forms were constructed of vertical 8 " x 8" S4S posts and <br /> horizontal 2" x 12" and 2" x 6" S4S lagging. Bracing <br /> consisted of angle iron and pipe anchored to the ribs, sill <br /> and back of the drift and was adequate to prevent movement <br /> during filling of the forms. <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 to be 40 <br /> to 10% of the area. The irregularity size required was 0. 15 <br /> inch. These irreqularities of the rock surface within the <br /> bulkhead were required by design to prevent the bulkhead from <br /> moving downstream upon application of the maximum design head . <br /> SGC committed to a minimum perimeter area irregularity of 10% . <br />