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2017WinterShotcreteEMag

Jig Support Frame Installation and Cooling Pipe and Reinforcement Placing The jig support frame is an essential support where all the reinforcement, cooling pipes, and stay-form are installed. Hence, the jig support frame installation is critical and required setting to a tolerance of 0.2 in. (±5 mm). The jig support frame was produced by laser cutting 1 in. (25 mm) thick metal plate. Cooling pipes were installed in the jig support frame with a 3.5 in. (90 mm) spacing, then No. 3 (10 mm) reinforcing bars on 4 in. (100 mm) spacing in the front and rear surfaces in an orthogonal layout. The reinforcing bars behind the longitudinal reinforcing bars were placed after the lateral reinforcing bars to facilitate the stay-form installation. Formwork and Stay-Form Installation The floor and head portions were mounted with a wooden form. A stay-form was used in the curved portion because removable wooden formwork could not be used here. The stay-form reduced the rebound during shotcrete placement and it also served to densely fill the interior. Temporary Screed Pipe Installation Temporary screed pipes were used as guides to place the shotcrete with a uniform thickness. The temporary screed pipes were mounted by taping a 1.1 in. (28 mm) plastic tube in place to get a 1.2 in. (30 mm) thickness. The screed pipes alternated in the upper and lower part of the track to allow easier shotcrete placement., The pipes were installed perpendicular to the axis of the track with 3.3 to 4.9 ft (1 to 1.5 m) spacing as shown in Fig. 4. Reinforcement Layout and Spacing Inspection Prior to shotcreting, the invited experts from both Korea and abroad inspected the reinforcement layout and spacing of the bobsleigh track after the foundation and placing of reinforcement was completed. The 6.3 in. (160 mm) thick supports satisfactorily accommodated the cooling pipe and stay-form with the 4 in. (100 mm) spacing of the reinforcement both in the front gradient and the back right-angled portion of the track. Shotcrete Placement The full-size bobsleigh track was built without forming construction joints. Shotcrete placement provided monolithic sections throughout the final cross section of the track. When shooting the floor, 50% of the arranged reinforcement was still visible after placing the first layer. During shooting, NEED A SHOTCRETE CONTRACTOR OR CONSULTANT FOR A SPECIFIC PROJECT? SUBMIT YOUR PROJECT FOR A BID REQUEST The American Shotcrete Association has created a free online tool to allow owners and specifiers the opportunity to distribute their bid request to all ASA Corporate Members in one easy form! Submit your project for a bid request from ASA’s outstanding Corporate Members today by visiting: www.Shotcrete.org/ProjectBidRequest 52 Shotcrete | Winter 2017 www.shotcrete.org


2017WinterShotcreteEMag
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