Depending on the shear strength requirements, the required tie spacing may be less than that in the figure. The clear spacing between ties must be at least (4/3) d agg. Tie spacing requirements for reinforced concrete columns in buildings assigned to SDC A and B are given in Figure 3. Requirements for columns with tie reinforcement are given in ACI 318 Sections 10.7.6 and 25.7.2, and standard hook dimensions for ties are given in ACI Section 25.3.2. These lap splices also must be located away from the ends of the column where spalling of the concrete shell surrounding the transverse reinforcement is likely to occur due to a seismic event (ACI 318 Section 18.7.4.3). By Authority of the Code of Federal Regulations: 30 CFR 250. The type of lap splice that must be used depends on the stress in the longitudinal bars due to the factored load combinations (see ACI 318 Section 10.7.5.2).įor columns that are part of special moment frames in buildings assigned to SDC D, E, or F, lap splices must be tension lap splices and located within the center half of the column length. BY ORDER OF THE EXECUTIVE DIRECTOR Office of the Federal Register Washington, D.C. Similar tables can be created for other tie bar sizes and circular longitudinal bar arrangements.įor columns in ordinary moment frames in buildings assigned to Seismic Design Category (SDC) A or B, or in intermediate moment frames in buildings assigned to SDC C, lap splices of the longitudinal bars are permitted to occur immediately above the top of the slab, which is the preferred location for ease of construction ( Figure 2).
The column face dimensions have been rounded to the nearest inch. To facilitate the selection of the longitudinal bars, Table 2 contains the minimum face dimension of rectangular tied columns with normal lap splices based on the minimum spacing requirements assuming 1.5-inch clear cover to #4 ties. Minimum face dimension (inches) of rectangular tied columns with normal lap splices.
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