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' <br />40-27 BUILDING PRECAST CONCRETE <br />BRPH ARCHITECTS -ENGINEERS, INC. <br />1. Weld -headed studs and deformed bar anchors used for anchorage according to <br />' <br />AWS D1.1/D1.1M and AWS C5.4, "Recommended Practices for Stud Welding." <br />B. <br />Furnish loose hardware items including steel plates, clip angles, seat angles, anchors, <br />dowels, cramps, hangers, and other hardware shapes for securing architectural <br />' <br />precast concrete units to supporting and adjacent construction. <br />' <br />C. <br />Cast -in slots, holes, and other accessories in architectural precast concrete units as <br />indicated on the Contract Drawings. <br />D. <br />Cast -in openings larger than 10 inches in any dimension. Do not drill or cut openings <br />or prestressing strand without Engineer's approval. <br />E. <br />Reinforcement: Comply with recommendations in PCI MNL 117 for fabricating, <br />placing, and supporting reinforcement. <br />1. Clean reinforcement of loose rust and mill scale, earth, and other materials that <br />reduce or destroy the bond with concrete. <br />2. Accurately position, support, and secure reinforcement against displacement <br />during concrete -placement and consolidation operations. Completely conceal <br />support devices to prevent exposure on finished surfaces. <br />3. Place reinforcement to maintain at least 3/4-inch minimum coverage. Arrange, <br />space, and securely tie bars and bar supports to hold reinforcement in position <br />while placing concrete. Direct wire tie ends away from finished, exposed <br />concrete surfaces. <br />4. Install welded wire fabric in lengths as long as practicable. Lap adjoining pieces <br />at least one full mesh spacing and wire tie laps, where required by design. Offset <br />laps of adjoining widths to prevent continuous laps in either direction. <br />F. <br />Reinforce precast concrete units to resist handling, transportation, and erection <br />' <br />stresses. <br />G. <br />Comply with requirements in PCI MNL 117 and requirements in this Section for <br />' <br />measuring, mixing, transporting, and placing concrete. After concrete batching, no <br />additional water may be added. <br />H. <br />For insulating panels, place face mixture to a minimum thickness after consolidation of <br />' <br />the greater of 1 inch or 1.5 times the maximum aggregate size, but not less than the <br />minimum reinforcing cover specified. <br />I <br />I. Place concrete in a continuous operation to prevent seams or planes of weakness from <br />forming in precast concrete units. <br />1. Place backup concrete mixture to ensure bond with face -mixture concrete. <br />J. Thoroughly consolidate placed concrete by internal and external vibration without <br />dislocating or damaging reinforcement and built-in items, and minimize pour lines, <br />honeycombing, or entrapped air on surfaces. Use equipment and procedures <br />complying with PCI MNL 117. <br />1 C06922.001.00 <br />034500-7 <br />05-22-14 <br />