Concrete Rebar Installation

Prior to set reinforcing steel in forms, finish the work of oiling to all forms. One should refrain from providing oil on reinforcing bars since the bond among the bars and the concrete becomes weak.

By applying a piece of burlap, the rust, mill scale, grease, mud, or other foreign matter can be eliminated from the bars. A light film of rust or mill scale can be retained.

Marking of bars ensures the exact locations for fitting. In order to mark bars, the following most recognized systems should be used according to the marking system demonstrated on the engineering or assembly drawings.

1. All bars in one type of member provide the mark of that member. This system is suitable for column bars, beam bars, footing bars, and so on.

2. The bars are marked in higher detail. These marks indicate the perfect position of the bar. Aside from the fact that the type member (that is, beam (B), wall (W), column (C), and so on), the marks demonstrate the floor on which the bars should be arranged as well as the size and individual number of every specific bar.

The mark presents the bar size in code by eighths rather than providing the bar size with its diameter measurement. Given below the instance of the second type of marking system.

213805 2 = second floor B = beam member 8 = 8/8- or 1 -inch (2.5 cm)-square bar 05 = part of the second floor plan selected with the number 5.

Also Read: Steel reinforcement bars for concrete

2130605 2 = second floor B = beam member 06 = 6/8- or 3/4-inch (1.9 cm)-round bar 05 = part of second floor plan selected with the number 5.

The rebar is retained in proper position by the tie wire to make sure that while arranging the bars, they do not move out of position. The reinforcing bars are fastened with sixteen gauge wire. Approximately 12 pounds (5.4 kg) of wire is necessary to bind an average ton (0.9 tome) of bars.

Several types of ties are utilized with reinforcing bars which range from snap or simple tie, wall tie, double-strand single tie, saddle tie, saddle tie with twist, cross tie or figure-eight tie.

The exact location for the reinforcing bars is normally provided on drawings. The structure can resist the loads enforced on it when the steel is placed properly as per drawing. The bars should be tied in position in a manner so that the bars are not moved with concrete-placing operations. It is performed with the reinforcing bar supports.

The correct coverage of bars should be maintained to safeguard the bars against fire hazards, chance of corrosion, and revelation to weather.

FOOTINGS-3 inches at the sides where concrete is cast against the earth and on the bottoms of footings or other major structural members where concrete is provided on the ground.

WALLS-2 inches for bars greater than No. 5, where concrete surfaces, after detaching the forms, would be uncovered to the weather or get in touch with the ground; 1 1/2 inches for No. 5 bars and smaller; 3/4 inch from the faces of all walls not uncovered directly to the ground or the weather.

COLUMNS-1 1/2 inches over spirals and ties.

BEAMS AND GIRDERS-1 1/2 inches to the adjacent bars on the top, bottom, and sides.

JOISTS AND SLABS-3/4 inch on the top, bottom, and sides of joists and on the top and the bottom of slabs where concrete surfaces are not uncovered directly to the ground or the weather.

NOTE: All measurements should be provided from the exterior of the bar to the face of the concrete, not from the main steel, unless otherwise indicated.

Footings and other major structural members which are against the ground should contain minimum 3.