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' DIVISION 03 Section 3450 - Architecturai Precast Concrete-Plant Cast <br /> ' I. Place concrebe in a continuous operation bo produce the desired bexture and color and to <br /> prevent seams or planes of weakness from developing in precast units.Comply with <br /> requirements of MNL-117 for measuring,mixing,transporting,arid placing rnncrete. <br /> ' 1. Place back-up concrete to ensure bond with face concrete. <br /> ' J. Thoroughly consolidate placed concrebe by internal and exbernal vibration without <br /> dislocating or damaging reinforcement and built-in items. Color must be uniform within <br /> concrefie panel.Use equipment and procedures complying with MNL-117. <br /> � 1. Comply with ACI 306R procedures for cold-weather concrete placement <br /> 2. Comply with AQ 305R procedures for hot weather concrebe placemen� <br /> � K. Identify pickup points of architectural precast concrete units and orientation In structure <br /> with pexmanent marlcings,complying with markings indicated on Shop Drawings.Imprint <br /> casting dafie on each architectural precast concrete unit on a surface that will not show in <br /> ' the finished structure. <br /> L. Cure concrete according to the requirements of MNL-117 by moisiure retention without <br /> heat or by accelerated heat curing,using low-pressure live steam or radiant heat and <br /> ' moisture. <br /> M. Delay detensioning architectural precast,prestressed concrete uni�s until concrete has <br /> ' reached its indicated minimum design release compressive strength as established by test <br /> cylinders cured under the same conditions as the concrete. <br /> ' N. Fabricate architectural precast concrebe units straight and true to size and shape with <br /> exposed edges and corners precise and true. <br /> 1. Edge and Corner Treatment Uniformly chamfered. <br /> ' 0. Discard architectural precast concrete units that are warped,cracked,broken,spelled, <br /> stained,or otherwise defective unless repaixs are permitted by Architect and meet <br /> ' requirements. <br /> 2.12 FABRICATION TOLERANCES <br /> ' A. Comply with the following overall height and width dimensional tolerances of <br /> Finished units measured at face adjacent to mold at time of casting: <br /> ' 1. 10 feet(3 m)or Less:Plus or minus 1/8 inch(3.2 mm). <br /> 2. 10-to 20 Feet(3 to 6 m):Plus 1/8 inch(3.2 mm),minus 3/16 inch(5 mm). <br /> 3. 20 to 40 Feet(6 to 12 m):Plus or minus 1/4 inch(6 mm.). <br /> ' 4. Each Additiona110 Feet(3m): Plus or minus 1/16 inch(1.6 mm)per 10 feet(3 m). <br /> B. Angulaz Deviation of Plane of Side Mold:Plus or minus 1/32 inch(0.8 mm)per 3 inch <br /> (76-mm)depth or plus or minus 1/16 inch(1.6 mm)total,whichever is greater. <br /> � C. Out of Square:Difference in length of two diagonal measurements oE 11/8 inch(3.2 mm)per <br /> 72 inches (1829 mm)or 1/2 inch(12 mm)total,whichever is greater. <br /> ' D. Thickness:Minus 1/8 inch(3.2 mm),plus 1/4 inch(6 mm). <br /> E. Locations of Reveals and Architectural Features.Plus or minus 1/8 inch(3.2 mm). <br /> i <br /> Q3450- 7 <br /> HENNEPIN COUNTY Orono Sah Storaee <br /> � March 22,2002 Project No.:0031569 Comract No.:0751R2 <br />