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#Aci class b lap splice plus
#Aci class b lap splice crack

As floor systems become shallower (which also leads to overall economy), beams generally need to become wider. To avoid potential congestion issues at beam-column joints, it is good practice to specify beams that are at least 4 inches wider than the columns into which they frame. Even though this arrangement increases the amount of reinforcing steel that is required, the cost of the additional material may be more than offset by the savings in labor and other costs it may be the most cost-effective arrangement in certain situations. This arrangement works very well with preassembled beam cages because no bottom bars pass through the column during installation. One way to circumvent this issue is to use the detail in Figure 2b: splice bars are provided in the joint, which are spliced to the bottom bars on both sides of the joint. However, it can result in congestion in the beam-column joints. This arrangement is the simplest to detail and is most suitable where the beams are wider than the columns. For example, it is common to splice all the bottom bars over the columns away from the section of maximum positive reinforcement, as shown in Figure 2a.

Lapping of continuous bottom bars at supports often presents congestion and installation problems. Splice arrangement for bottom bars in a reinforced concrete beam: a) All bottom bars spliced over the column b) Separate splice bars provided in the beam-column joints.

Where the requirements in Note 2 are not satisfied for beams other than perimeter beams, closed stirrups in accordance with ACI Section 25.7.1.6 or hoops along the clear span must be provided.įor simpler detailing, all the bottom bars are often extended the entire span instead of cutting off a portion of them, as shown in Figure 1.įigure 2.

Closed stirrups in accordance with ACI 318-14, Section 25.7.1.6, or hoops must be provided along the clear span.

At least the larger of ( A ‒ s1/6) or ( A ‒ s2/6) but not less than 2 bars must be continuous or spliced with Class B tension splices or mechanical or welded splices.

At least the larger of (A + s1/4) or ( A + s2/4) but not less than 2 bars must be continuous or spliced with Class B tension splices or mechanical or welded splices.

(Standard hooks are depicted in Figure 1.)

Reinforcement to be anchored to develop fy at the face of the support.

These recommended details include the requirements for structural integrity reinforcement in ACI 318-14, Section 9.7.7, and can be used for beams that have been designed using the approximate bending moment coefficients in ACI Table 6.5.2. For beams subjected to uniformly distributed gravity loads where the shape of the moment diagram is known, the development lengths in Figure 1 can be used. Recommended bar extensions for flexural reinforcement in beams subjected to uniformly distributed gravity loads.ĪCI 318-14, Section 9.7.3, contains the requirements for the development of reinforcing bars in beams.

#Aci class b lap splice plus

Table 1 contains values of the minimum number of bars required in a single layer for various beam widths based on Grade 60 reinforcement ( f s = 40,000 psi), c c = 2 inches (1.5-inch cover plus the diameter of a #4 stirrup), and the overall longitudinal reinforcing bar diameter (approximate diameter to the outside deformations of the bar), which is given in Table 2.įigure 1. It is permitted to assume that f s = 2 f y/3 where f y is the specified yield strength of the reinforcement. Where f s is the calculated stress in the flexural reinforcement closest to the tension face of the section due to service loads and cc is the least distance from the surface of the reinforcement to the tension face of the member.

#Aci class b lap splice crack

Thus, the maximum center-to-center spacing, s, of the deformed longitudinal bars to limit crack widths is given by the following equation (see ACI Table 24.3.2):

Reinforcing bars that are spaced too far apart could result in relatively large flexural crack widths. Minimum number of reinforcing bars required in a single layer.