An experimental study was performed to evaluate the applicability of ACI 318 to the Class B splice of 600 MPa (87 ksi) reinforcing bars. Twelve simply supported beams and slabs with reinforcing bar splices were tested under monotonic loading. The test parameters were the reinforcing bar diameter, concrete cover thickness, concrete strength, and stirrup spacing. Concrete strengths ranged from 24.7 to 55.3 MPa (3582 to 8021 psi). Most of the specimens were designed to satisfy the Class B splice length specified by ACI 318. The average bar stresses resulting from this test were compared with the predictions by the ACI 318 provisions. The results showed that the reinforcing bar splices gave a satisfactory performance for all D13 (diameter = 13 mm [0.51 in.]) bar splices. For D22 and D32 bars, the use of either transverse reinforcement or thick concrete cover was recommended to develop the specified yield strength of 600 MPa (87 ksi). The test results were also compared with the predictions by the ACI 408R-03 and Eurocode 2 provisions.