CURVED CONCRETE WALLS FOR STORAGE RESERVOIRS, 



LV. 



skewbacks to take the thrust of the arch. This also applies to 

 the joint under the base, very little artificial roughening being 

 required to make it water-tight. 



In preparing the foundation care is taken to remove all soft, 

 loose or shaken rock, and to roughen or step all smooth and inclined 

 surfaces. The rock is then well washed with a jet of water under 

 a pressure of about 20 lbs. per square inch, and all joints, fissures, 

 etc., raked out and carefully grouted, or stopped with cement 

 mortar. A half inch layer of mortar is then spread over the rock 

 surface and worked into all corners and recesses, and upon this 

 while fresh, the concrete is deposited. 



The wall is brought up in 3 feet courses, each course consisting 

 of three 12 in. layers carried along, one slightly ahead of the other. 

 The course is held between mould-boards 10 ft. long by 3 ft. 6 in. 

 high, framed of 4 in. by 2 in. hardwood, sheathed with 4 in. by 

 1^ in. tongued and grooved pine. — (See diagram). Sufficient of 

 these should be made to carry a course the full length of the dam. 

 The mould-boards overlap the preceding lower course 6 in., and 

 are held in position by 8 in. by 4 in. hardwood profiles attached 



-MOULDINC BOARDS. 



FOR 



— CONCRETE DAM — 



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Drawing 2. 



