Despite all the efforts made to investigate the dynamics of jointed structures, they still remain as one of the uncertain dynamical systems in structural dynamics. Modelling the dynamic behaviour of bolted joint contact interfaces is one of the most challenging tasks in structural dynamics. The multi-frequency response of nonlinear systems, particularly bolted joint structures, is an important characteristic for the model identification of such structures. The alternating frequency-time approach using a harmonic balance (AFTHB) is used in this study to identify the nonlinear model of the bolted joint of the Brake-Reuß beam. Vibration tests with harmonic excitation were performed over a range of frequencies to measure the dynamic response of the structure. The two beams of the structure are modelled using Timoshenko beam theory. A model selection procedure using the measured data is applied to a range of candidate models to model the dynamics of the joint contact interface. The AFTHB approach is then applied to estimate the unknown parameters of the assumed nonlinear model of the structure utilizing the experimentally measured data. The estimated parameters are used to reconstruct the measured dynamic response of the structure.