Bond behaviour with tension lap splice for deformed steel bars in normal-strength concrete

Abstract

The unconfined bond strength of deformed steel bars was experimentally investigated using splice beam specimens under four-point loading. The splicing was provided in the constant moment region with the parameters in the investigation being the grade of concrete (normal- strength), rebar diameter (12 mm), splice length (15 db and 25db), and the ratio of concrete cover to rebar diameter (c/db = 1.25 and 2). It was experimentally observed that in all the splice beam specimens bond failure pre-empt yielding of rebar with bond degradation localized at the end of splice length and within the constant moment region. Failure pattern and crack propagation of the numerically investigated splice beam specimens correlated well with the experimental results however the numerically computed bond stress underestimates the bond strength due to the immobilization of bearing action in the adopted embedded truss model.