How to Replace Reinforcing Steel?

In larger projects the iron-workers will place the reinforcing steel, most contractors place some reinforcement. What is important is to get it in the right place and keeping it there during concrete placement which plays a critical role to the structure’s performance. Reinforcement must be placed as planned on the placing drawings. In the placing drawings, the detailer will indicate the number of bars, bar lengths, bends, and positions.

Cover

One of the most important reason for placing the reinforcing steel in the right order is to get the right amount of concrete cover?which is the amount of concrete between the reinforcing steel and the surface of the concrete member. The other really important factor when it comes to protecting reinforcing steel from corrosion is the cover.

It is also necessary to have a cover to make sure that the steel bonds to the concrete well enough to develop its strength. The cover requirements are mostlymentioned in the project specifications or are even shown on the drawings. In case it is not specified then theACI 318 Building Code must be referred to know about the minimum cover for cast-in-place concrete.

Minimum concrete cover:

In case of concrete cast against and permanently exposed to earth (such as footings): 3 inches

In case of concrete exposed to weather or earth (such as basement walls):

6 bars and larger: 2 inches

5 bars or smaller: 1? inches

For concrete not exposed to weather or in contact with ground:

Slabs, walls, and joists: 14 and 18 bars: ? inch

Slabs, walls, and joists: 11 bars and smaller: ? inch

Beams and columns: 1? inches

Positioning

The design of the structure depends on having the steel in the right place, that is something one must remember. Incorrect reinforcing steel placement must never take place as it can and has led to serious concrete structural failures.

Such as, by lowering the top bars or raising the bottom bars by ? inch more than that specified in a 6-inch-deep slab could lead to a reduction in its load-carrying capacity by 20%.

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