Connect architectural precast concrete units in position by bolting, welding, grouting, or as otherwise indicated on approved Erection Drawings. Remove temporary shims, wedges, and spacers as soon as practical after connecting and/or grouting are completed.
1. Disruption of roof flashing continuity by connections is not permitted; concealment within roof
insulation is acceptable.
Welding: Comply with applicable AWS D1.1 and AWS D1.4 requirements for welding, welding electrodes, appearance, quality of welds, and methods used in correcting welding work.
Protect architectural precast concrete units and bearing pads from damage by field welding or cutting operations and provide noncombustible shields as required.
Welds not specified shall be continuous fillet welds, using not less than the minimum fillet as specified by AWS.
Clean weld affected metal surfaces with chipping hammer followed by brushing then apply a minimum 0.004 inch (100 μm) thick coat of galvanized repair paint to galvanized surfaces in conformance with ASTM A780.
Retain subparagraph above or below.
Clean weld affected metal surfaces with chipping hammer followed by brushing then reprime damaged painted surfaces in accordance with manufacturer’s recommendations.
Visually inspect all welds critical to precast connections. Visually check all welds for completion and remove, reweld or repair all defective welds, if services of AWS-certified welding inspector are not furnished by Owner.
At bolted connections, use lock washers, tack welding, or other acceptable means to prevent loosening of nuts after final adjustment.
Where slotted connections are used, verify bolt position and tightness. For sliding connections, properly secure bolt but allow bolt to move within connection slot. For friction connection apply specified bolt torque and check 25 percent of bolts at random by calibrated torque wrench.
Revise locations and extent of grouting in paragraph below if required.
Grouting Connections: Grout connections where required or indicated. Retain grout in place until hard enough to support itself. Pack spaces with stiff grout material, tamping until voids are completely filled. Place grout to finish smooth, level, and plumb with adjacent concrete surfaces. Promptly remove grout material from exposed surfaces before it affects finishes or hardens.
3.4 ERECTION TOLERANCES
Erect architectural precast concrete units level, plumb, square, true, and in alignment without exceeding the noncumulative erection tolerances of PCI MNL 117, Appendix I.