RICHARD BRADY & ASSOCIATES, INC-A-2020-064

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1182 R. C. BENMIR Jomv.AWhVA the opportunity to satisfy public de- mand for pleasing designs of above- ground concrete reservoirs. He can also develop economical designs of un- derground reservoirs, which, by virtue of being underground, permit the space above the reservoirs to be used for parking lots, playgrounds, parks, and service yards. Figures 1 and 2 are examples of such uses. Nouprestressed circular reservoirs require a relatively thick wall and are more expensive than prestressed res- ervoirs. There has been a trend since the end of World War II toward con - Prestressed concrete reserovirs using embedded tubes or paper sheathing en- closing post -tensioning cables are built occasionally, If precautions 1-4 rec- ommended below for prestressed wire - wrapped reservoirs are followed, this type of construction should be satis- factory, provided the cables are care- fully installed in a horizontal position and, after post -tensioning the cables, the tubes, if used, are completely filled with grout. Prestressed concrete reservoirs using wire -wrapping as the post -tensioning element have been used extensively, Fig. 1. Civic Center Reservoir, Vernon, Calif, The surface above this 10-mil-gal reservoir is used for a two -level parking lot. ventional rectangular designs and cir- cular prestressed structures. Although many prestressed concrete reservoirs are still being built, they have become less popular in some areas in recent years because of difficulties experienced with corrosion of the pre- stressing elements. If careful attention is given to design and construction de- tails, a satisfactory structure should re- sult; however, some engineers feel that there exists an inherent element of un- certainty about the quality of construc- tion that may be achieved even under close supervision. but many existing reservoirs of this type have developed serious mainte- nance problems. The most common of these problems is lack of bond between the core -wall and the pneumatically ap- plied mortar used to protect the wire - wrapping, and cracking of the mortar where the wall is exposed to the weather. As the mortar is relatively thin, it tends to dry out and crack, thus permitting atmospheric corrosion of the wire -wrap. If the structure is buried, this particular problem is largely eliminated. Buried reservoirs RICHARD BRADY & ASSOCIATES, INC. F-51