Effects of Type of Bar Lap Splice on Reinforced Concrete Columns Subjected to Cyclic Loading

In this study, tension lap splices of longitudinal bars on columns subjected to cyclic lateral loading and low axial load (N = 0.15 to 0.185A(g)f(c)(')) were investigated. Cyclic lateral loading tests were performed for eight columns with different lengths and methods of lap splices. The test results showed that the flexural strength and ductility of columns were significantly affected by the lap splice offset methods, as well as by the lap splice length and the moment gradient. When the lower bars were offset inside the column for the lap splice, the ductility of the column was the greatest but the flexural strength was less than the nominal flexural strength without bar offsets. On the other hand, when the upper bars were offset or when the upper and lower bars were lap-spliced side by side without offset bends, the flexural strength of the columns satisfied the nominal strength but the ductility decreased. Based on the test results, design considerations for the lap splices are recommended.