Rebar Tie-Wire Count and Weight
Tie wire for a rebar mat - the intersections tied and the wire consumed: bars each way = floor(span / spacing) + 1; intersections = product; ties = round(intersections x fraction); weight = ties x tie length / 12 x wire per foot. A 30 x 20 ft mat of #4 at 12 in each way has 651 intersections; tying half with 8 in ties is ~3.9 lb of wire, and a full-tie spec nearly doubles it to 7.9 lb. The spec sets the tie fraction; distinct from the bar rebar-weight-takeoff.
Formula and source
bars_each_way = floor(span_in / spacing_in) + 1; intersections = bars_x x bars_y; ties = round(intersections x tie_fraction); wire_ft = ties x tie_length_in / 12; wire_lb = wire_ft x wire_lb_per_ft.
Rebar tie-wire identity by name (grid intersections, a tied fraction, and the wire per tie); first-principles count arithmetic.
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