R12.17.The evaluation report, ESR-4057, was recently updated to allow the design of SET-3G adhesive for post-installed reinforcing bars using the ACI 318 development length provision. Spirals should meet requirements of 7.10.4 and 10.9.3. R12.17.2.5 - Compression lap lengths may be reduced when the lap splice is enclosed throughout its length by spirals because of increased splitting resistance. This calculation is critical in one direction, which normally can be determined by inspection. R12.17.2, where four legs are effective in one direction and two legs in the other direction. The tie legs perpendicular to each direction are computed separately and the requirement must be satisfied in each direction. R12.17.2.4 - Reduced lap lengths are allowed when the splice is enclosed throughout its length by minimum ties. In the case shown, four legs are effective R.12.17.2-Tie legs which cross the axis of bending are used to compute effective area. Mechanical or welded splices in columns shall meet the requirements of 12.14.3.2 or 12.14.3.4.įig. Tie legs perpendicular to dimension h shall be used in determining effective area.ġ2.17.2.5 - In spirally reinforced compression members, lap splice length of bars within a spiral shall be permitted to be multiplied by 0.75, but lap length shall not be less than 12 in.ġ2.17.3 - Mechanical or welded splices in columns R12.17-Special splice requirements for columnsġ2.17.2.4 - In tied reinforced compression members, where ties throughout the lap splice length have an effective area not less than 0.0015hs, lap splice length shall be permitted to be multiplied by 0.83, but lap length shall not be less than 12 in. R12.17.2.1 - The 1989 code was simplified for column bars always in compression on the basis that a compressive lap splice is adequate for sufficient tension to preclude special requirements.ġ2.17.2.3 - Where the bar stress due to factored loads is greater than 0.5fy in tension, lap splices shall be Class B tension lap splices. 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. 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.
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