after it has been laid out upon the forms. For the larger sized bars, however, such as are often used in girderless-floor construction, it may be more satisfactory to do the bending upon the bench. Bars or rods of structural grade steel should not, in any case, be bent to a RADIUS OF LESS THAN FOUR TIMES THE LEAST DIMENSION OF THE ROD or bar, and this should be increased to EIGHT TIMES THE LEAST DIMENSION in the case of intermediate or hard grade steel. 3. Assembling and Placing Reinforcement. Under some conditions the

Courtesy Universal Form Clamp Company

Fig. 5. Beam Bar-Supporters and Separators

reinforcement of beams and girders can be advantageously made up into FRAMES, the longitudinal bars being held in place by the stirrups and the whole laid in the forms as a unit. Owing, however, to the interference of the steel bars over the supports of continuous beams, it is often necessary, for at least a portion of the members, to ASSEMBLE the reinforcement in the forms. Under these conditions the stirrups are first placed in the beam troughs, the straight bars are then laid on the bottom, and these are followed by the double-bend bars. Fig. 4

illustrates a typical beam-and-slab installation. The stirrups are securely wired to the horizontal bars which they encircle, and the steel-frame held up from the bottom of the troughs by means of CHAIRS, or small BLOCKS OF MORTAR, previously cast of the required thickness. Quite recently a CONTINUOUS STIRRUP has been placed upon the market. The units are shop-fabricated with the designed spacing, and the bottom member is provided with a chair to hold the stirrup frame at the required distance above the bottom of the beam-trough. When more than one layer of bars lies in the bottoms of beams or girders, through the central portion of the span, the layers are SEPARATED by spacers, and clear

distances between bars must be provided as given on page 64. Figs. 5 and 6 illustrate several types of bar supporters and separators.

SMALL BAR REINFORCEMENT, such as used for slabs and walls, is conveyed in bundles from the ground, or place of storage, to the part of the structure in which it is to be used. These bundles, as well as the assembled reinforcement for columns, or beams and girders, are usually raised by an easily movable JENNY WINCH as illustrated in Fig. 7. Particular care should be exercised to

locate correctly and hold in place all LOOSE BARS such as those sometimes used to furnish additional negative reinforcement over supports. Likewise, the short bars of small diameter, usually required across the tops of girders in beam-andslab construction, should be securely wired to the slab-reinforcement. It is occasionally necessary to use TEMPLETS for the correct locating of reinforcement such as the dowels connecting a footing pedestal with the superimposed column.

When the bending is done upon the floor, the desired spacings of the slab

steel and the lines along which the bars are bent adjacent to the quarter-points of the spans are laid out upon the flooring. There are a number of patented BAR-TIES which are used to advantage for wiring the intersections of reinforce

ment, or short lengths of annealed wire, not less than No. 18 gauge and preferably 14 or 16 gauge, may be employed for the purpose, the tie being made with ordinary pliers, or a patented tying device. In any case, a SUFFICIENT NUMBER

of intersections are wired to insure the fact of the reinforcement remaining in its DESIGNED POSITION during the depositing and compacting of the concrete.

SLAB-REINFORCEMENT should not only be adequately secured against lateral displacement, but also held at the CORRECT HEIGHT above the forms by means of suitable supports, such as cement-mortar blocks, or one of the many patented chairs as illustrated in Fig. 8. These latter are designed to hold the bars at the correct height and at any desired spacing. In GIRDERLESS-FLOOR CONSTRUCTION it is of particular importance to keep the bars comprising the reinforcement of the various bands at the designed height. Satisfactory methods as applied to various systems are illustrated in Figs. 9 to 11. In the two-way system 5% or

3/4-in supporting bars are shown placed upon concrete blocks cast to the required thickness. The illustration of the three-way system shows the use of metalchair supports. Any effective means of holding the reinforcement in the desired position may of course be adapted to any system of design.

The entire reinforcement for each column is made up as a FRAME by wiring the hoops to the vertical rods, and placed in the forms as a unit. Spiral hooping is usually bent at the mill and shipped collapsed, being assembled with the vertical spacers upon the job as illustrated in Fig. 12.

4. Splicing Reinforcement. Where it is necessary to splice tensile reinforcement LAP SPLICES are generally used and are made of sufficient length to