Coordinate paragraph below with Division 5 Section “Metal Fabrications” for furnishing and installing loose hardware items.
Furnish loose hardware items including steel plates, clip angles, seat angles, anchors, dowels, cramps, hangers, and other hardware shapes for securing architectural precast concrete units to supporting and adjacent construction.
Cast-in reglets, slots, holes, and other accessories in architectural precast concrete units as indicated on contract drawing.
Delete first paragraph below if not applicable.
Cast-in openings larger than 10 inches (250 mm) in any dimension. Do not drill or cut openings or prestressing strand without approval of Architect.
Reinforcement: Comply with recommendations in PCI MNL 117 for fabrication, placing, and supporting reinforcement.
Clean reinforcement of loose rust and mill scale, earth, and other materials that reduce or destroy the bond with concrete. When damage to epoxy coated reinforcing exceeds limits specified ASTM A775/A775M repair with patching material compatible with coating material and epoxy coat bar ends after cutting.
Accurately position, support, and secure reinforcement against displacement during concrete- placement and consolidation operations. Completely conceal support devices to prevent exposure on finished surfaces.
Place reinforcing steel and prestressing strand to maintain at least 3/4 -inch (19 mm) minimum concrete cover. Increase cover requirements for reinforcing steel to 1-1/2 inches (38 mm) when units are exposed to corrosive environment or severe exposure conditions. Arrange, space, and securely tie bars and bar supports to hold reinforcement in position while placing concrete. Direct wire tie ends away from finished, exposed concrete surfaces.
Install welded wire reinforcement in lengths as long as practicable. Lap adjoining pieces at least one full mesh spacing and wire tie laps, where required by design. Offset laps of adjoining widths to prevent continuous laps in either direction.
Reinforce architectural precast concrete units to resist handling, transportation, and erection stresses.
Delete paragraph and subparagraph below if prestressed architectural precast concrete units are not required. Option to prestress may be left to fabricator if objective is to aid handling and to control cracking of units during installation.
Prestress tendons for architectural precast concrete units by either pretensioning or post-tensioning methods. Comply with PCI MNL 117.
Revise release or post-tensioning strength in subparagraph below to an actual compressive strength if required. A release strength as low as 2500 psi (17.2 MPa) for normal-weight concrete and 3000 psi (20.7 MPa) for lightweight concrete is permitted.