Frequently, the basic gravity load combination will govern the design of the column itself, but a load combination including wind or seismic loads may induce greater tension in some column bars, and the column splice should be designed for this tension. Note that the column splice should satisfy requirements for all load combinations for the column. The 1989 code clarifies this section on the basis that a com-pressive lap splice has a tension capacity of at least one-quarter fy, which simplifies the calculation requirements in previous codes. Furthermore, a minimum tension capacity is required in each face of all columns even where analysis indicates compression only. When such tensions occur, 12.17 requires tension splices to be used or an adequate tensile resistance to be provided. In columns subject to flexure and axial loads, tension stresses may occur on one face of the column for moderate and large eccentricities as shown in Fig. R12.17 - Special splice requirements for columns R12.16.4.3 - This limitation was added in the 1971 code to ensure a minimum shear resistance in sections containing end-bearing splices. R12.16.4.2 - These tolerances were added in the 1971 code, representing practice based on tests of full-size members containing No. If bars are significantly inclined from the vertical, special attention is required to ensure that adequate end-bearing contact can be achieved and maintained. R12.16.4.1 - Experience with end-bearing splices has been almost exclusively with vertical bars in columns. A splice shall satisfy requirements for all load combinations for the column.ġ2.17.2.1 - Where the bar stress due to factored loads is compressive, lap splices shall conform to 12.16.1, 12.16.2, and, where applicable, to 12.17.2.4 or 12.17.2.5.ġ2.17.2.2 - Where the bar stress due to factored loads is tensile and does not exceed 0.5fy in tension, lap splices shall be Class B tension lap splices if more than one-half of the bars are spliced at any section, or Class A tension lap splices if half or fewer of the bars are spliced at any section and alternate lap splices are staggered by ld. Where bars of different sizes are lap spliced in compression, l sc is the longer l dc of the larger bar calculated in accordance with 25.4.9.1, and l sc of the smaller bar is calculated in accordance with 25.5.5.1 as appropriate.12.17.1 - Lap splices, mechanical splices, butt-welded splices, and end-bearing splices shall be used with the limitations of 12.17.2 through 12.17.4. 80000 psi, l sc is the longer of (0.0009f y – 24)d b and l stcalculated in accordance with 25.5.2.1.įor f ' c < 3000 psi, the length of the lap is automatically increased by one-third.Ĭompression lap splices are not used for bars larger than No. Maximum percent of A s spliced within required lap length Tension lap splice length l st for deformed bars and deformed wires in tension is controlled with Table 25.5.2.1.Ī s,provided/A s,required over length of splice Lap splice lengths of deformed bars and deformed wires in tension Transverse reinforcement is provided such that K tr is not smaller than 0.5d b, for bars with fy≥80000 psi, according to 25.5.1.5. for noncontact splices, according to 25.5.1.3. The transverse center-to-center spacing of spliced bars does not exceed the lesser of 1/5 the required lap splice length and 6 in. Minimum Spacing of Reinforcement per ACI 318-19 with ideCAD ![]() Minimum clear spacing between the contact lap splice and adjacent splices or bars is controlled according to 25.2.1. ![]() Lap splices couldn’t be done for rebars larger than No. K tr = transverse reinforcement index, in.ĭ b = nominal diameter of bar, wire, or prestressing strand, inį' c = specified comprehensive strength of concrete, psiį y = specified yield strength of nonprestressed reinforcement, psi L sc = compression lap splice length, in. L dc = development length in compression of deformed bars and deformed wire, in. L d = development length in tension of deformed bar, deformed wire, plain and deformed welded wire reinforcement, or pretensioned strand, in. Compression lap splice length l sc is controlled automatically according to 25.5.5.Ī s = area of nonprestressed longitudinal tension reinforcement, in.2
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