Rotational stiffness of a connection made using a single prestressed bolt

The often overlooked rotational stiffness of connections utilizing a single prestressed bolt leads to the common assumption of treating such connections as pinned or even modeling them as rigid. Nevertheless, considering the friction between interconnected elements, it is evident that the actual rotational stiffness lies between these simplified assumptions. This study is dedicated to quantifying this stiffness and addressing the question of whether simplifying such connections to pinned or rigid is justifiable. Experimental, theoretical, and numerical analyses were conducted. The results reveal a substantial variability in this phenomenon, which can be effectively described by a normal distribution. Illustrated through a case study involving built-up battened columns, it was demonstrated that the maximum normal force in the column, when considering rotational stiffness of connections, significantly surpasses that obtained for a model assuming pinned connections. This underscores the necessity of employing a model with nonlinear rotational stiffness for an accurate analysis of such constructions. • Rotational stiffness of a connection made using a single prestressed bolt. • The moment resistance for connection with one slip surface. • The rotational stiffness in the considered ranges was calculated.