Pile‐type debris‐flow and driftwood protection facilities, which can be applied in no‐flow streams, use high‐strength posts, known as Lotus root Steel Tube (LST) posts. LST posts can be long and difficult to transport depending on ground conditions, so it is desirable to develop a method to split the posts and make joints. In this study, static bending tests were conducted on LST posts connected by lap joints between reinforcing bars, and a method for evaluating the load‐bearing capacity of the joints was investigated. The experimental results show that the bending moment that can be estimated to be within the elastic range of the joint is larger than the yield moment of the upper post, which was determined by the section partition method using the nominal strength values.