Safe load in pounds including the weight of the beam, for rectangular beams 1 in thick Allowable fiber-stress 700 lb per sq in. Safety factor six. Modulus of rupture 4 200 lb per sq in. To obtain the safe load for a beam of any thickness, multiply the value given in the table by the thickness of the beam in inches.

The black line crossing the table indicates the limits of spans for which the safe load produces a deflection that is within 1560 of the span length. Values above this line give deflections less than this, and those below give greater deflections.

Reprinted from Cambria Handbook by permission of the Bethlehem Steel Co.

8q in.

Table III. Short-leaf Yellow Pine Beams Uniformly Loaded

Safe load in pounds including the weight of the beam, for rectangular beams 1 in thick

Allowable fiber-stress 1 000 lb per sq in. Safety factor six. Modulus of rupture 6 000 lb per To obtain the safe load for a beam of any thickness, multiply the value given in the table by the thickness of the beam in inches.

The black line crossing the table indicates the limits of spans for which the safe load produces a deflection that is within 360 of the span length. Values above this line give deflections less than this, and those below give greater deflections.

Reprinted from Cambria Handbook by permission of the Bethlehem Steel Co.

CHAPTER XIX

REINFORCEMENT

1. Care of Reinforcement. By a proper SORTING and STACKING of the reinforcement much confusion and resulting labor-cost can be saved. As deliveries are made the various lengths and sizes should immediately be checked,

segregated, and stored so that the bars for the several portions of the work can, when needed, be easily identified and quickly removed.

Steel coated with RUST-SCALE, GREASE, PAINT, or other foreign substances,

should be CLEANED before placing, as such matter reduces the BOND between the steel and the concrete. When OIL is applied to the forms, this should be done before the steel is placed. A superficial bright, red rust, such as forms in a few days upon reinforcement exposed to rain, or dew, is not in any way detrimental. DEEP RUSTING, however, as evidenced by actual rust-scales upon the surface, may well indicate a reduction in the effective cross-section of the bar. If such

reduction has occurred the reinforcement should not be used, or at least not counted upon to develop the same strength as an unrusted bar of like nominal size. In all cases the rust should be removed by the use of wire brushes and a dilute solution of muriatic acid, after the application of which the bar is washed in running water. When steel is stored for an extended period it should be protected from RAIN or SNOW. This can be easily accomplished by covering the racks with tar paper nailed upon wooden frames, or if the expense is warranted, by the construction of low sheds.

2. Bending Reinforcement. The BENDING of steel used in concrete building-construction, except for the hooping of spiral columns, is usually accomplished upon the job unless a proprietory system of fabricated units is employed. The steel lists described under Purchasing Materials give the length and type of the bends. Sizes up to 1 or 1% in are ordinarily bent cold by HAND, upon a wooden bench constructed as shown in Fig. 1, or by some type of PATENTED BENDER similar to that illustrated in Fig. 2. The bench consists of a heavy table with the legs preferably sunk into the ground to secure rigidity. The two plates A are adjusted to the proper position by means of bolts, and the two plates B are spiked to the table in the proper position. The necessary leverage is obtained by means of a heavy pipe slipped over one end of the rod.

If it is necessary to heat the bars before bending the temperature should not be higher than that indicated by a DULL, CHERRY RED. Cutting of sizes up to 1⁄2 in can be done with a light-weight cutter; above that size a large shear is required, or a hack-saw used for special work. Fig. 3 illustrates two types of bar-cutters. As reinforcement above 1/2-in sizes is usually cut to length at the mill, there should be practically no cutting of larger sizes upon the job. The designs employed in concrete-construction should be made with a view to reducing, as far as practicable, both the NUMBER and TYPES of bends required, and in arranging the work to be done upon the bench similar sizes and shapes are grouped together in order to avoid constantly RESETTING THE TEMPLETS. Steelbar reinforcement for floor-slabs is usually bent in place, by means of a HICKEY,