2107.2 TMS 402/ACI 530/ASCE 5, Section 126.96.36.199.1.1, Lap Splices
The minimum length of lap splices for reinforcing bars in tension or compression, ld, shall be:
For SI: ld = 0.29dbfs
but not less than 12 inches (305 mm). The length of the lapped splice shall be not less than 40 bar diameters.
db = Diameter of reinforcement, inches (mm).
fs = Computed stress in reinforcement due to design loads, psi (MPa).
In regions of moment where the design tensile stresses in the reinforcement are greater than 80 percent of the allowable steel tension stress, Fs, the lap length of splices shall be increased not less than 50 percent of the minimum required length, but need not be greater than 72 db. Other equivalent means of stress transfer to accomplish the same 50 percent increase shall be permitted. Where epoxy coated bars are used, lap length shall be increased by 50 percent.