What is rebarin construction?

Standard nominal weights are: #3 at 0.376 lb per ft, #4 at 0.668 lb per ft, #5 at 1.043 lb per ft, #6 at 1.502 lb per ft, #7 at 2.044 lb per ft, #8 at 2.670 lb per ft, #9 at 3.400 lb per ft, #10 at 4.303 lb per ft, and #11 at 5.313 lb per ft. These come from the ASTM bar tables and hold regardless of grade. To weigh a stick, multiply by length: a 20 ft stick of #4 is 20 ft x 0.668 lb per ft = 13.4 lb.

Grade 60 bar under ASTM A615, with a 60,000 psi yield strength, is the default on most US commercial work. ASTM A706 low-alloy bar is specified where bars get welded or where seismic ductility is required, and Grade 75 or Grade 80 shows up in heavy columns and mats to relieve congestion. Epoxy-coated or galvanized bar is called out where corrosion is a concern, such as parking structures and marine work. Always price the grade and coating in the spec, not what the yard usually stocks.

Rebar is individual deformed bars that are cut, bent, placed, and tied one at a time. Welded wire reinforcement (WWR, often called mesh) arrives as prefabricated sheets or rolls with designations like 6x6 W2.9/W2.9 and is common in lighter slabs on grade and toppings. The two are estimated differently, rebar by the ton and WWR by the square foot with a lap allowance, and one cannot be swapped for the other without the engineer's approval.