PSI - Issue 78

Giacomo Iovane et al. / Procedia Structural Integrity 78 (2026) 521–527

525

configuration joint (Beltran, 2016). An exception is a 1.1 configuration joint, where the internal plate is connected to the beam by screws and to the column by bolts (Beltran, 2016), which is classified as semi-rigid. Among Type 2, on 12 joints, 7 joints are classified as semi-rigid and 5 joints as pinned, with a dimensionless rotational stiffness ranging between k̅ =0.1203, provided by the 2.2 configuration joint (Wang et al., 2021) and k̅ =8.2898, provided by a 2.1 configuration joint, where dowels are in a double circular arrangement (Polastri, 2010). Among Type 3, all 5 joints are classified as semi-rigid joints, with a dimensionless rotational stiffness ranging between k̅ =0.8927, provided by a 3.1 configuration joint, where steel L-shaped plates are connected to the beam and column through bolts (Kang et al., 2022) and k̅ =8.0000, provided by the 3.2 configuration joint (Kasal et al., 2014). Among Type 4, on 24 joints, 22 joints are classified as semi-rigid and 2 joints as pinned, with a dimensionless rotational stiffness ranging between k̅ =0.1745, provided by a specimen where IPE100 steel link is used (Iovane et al., 2023b) and k̅ =5.0340, provided by a specimen where HE120B steel link is used (Andreolli, 2011). Among Type 5, all 6 joints are classified as semi rigid joints, with a dimensionless rotational stiffness ranging between k̅ =0.9161 and k̅ =2.0668 (Rahmzadeh and Iqbal, 2021), the latter one is provided by a specimen characterized by a double pre-tension value of the cable as respect to the specimen with the lowest dimensionless rotational stiffness. Table 1. Minimum and maximum values of the dimensionless rotational stiffness k̅ . ̅ Reference ̅ Reference Type 1 0.0009 Masaeli et al., 2020 0.5780 Beltran, 2016 Type 2 0.1203 Wang et al,, 2021 8.2898 Polastri, 2010 Type 3 0.8927 Kang et al., 2022 8.0000 Kasal et al., 2014 Type 4 0.1745 Iovane et al., 2023b 5.0340 Andreolli, 2011 Type 5 0.9161 Rahmzadeh and Iqbal, 2021 2.0668 Rahmzadeh and Iqbal, 2021 4. Conclusion The paper focuses on the classification in terms of stiffness of 106 timber beam-to-column joints studied through experimental tests comprehensively presented in scientific literature. Specifically, 5 types of common joints have been identified based on the connection devices and the configurations. By applying the mechanical classification method in terms of stiffness to the study joints, the following overall results can be highlighted: In particular, among the semi-rigid joints, the highest dimensionless rotational stiffness is provided by the Polastri et al. joint (2010; Type 2, k̅ =8.2898), the lowest one by the Yang et al. joint (2021; Type 4, k̅ =0.5203), while among the pinned joints, the highest dimensionless rotational stiffness is provided by the Liu and Xiong joint (2018, Type 1, k̅ =0.3842), the lowest one by the Masaeli et al. joint (2023; Type 1, k̅ =0.0009. The order of joint dimensionless rotational stiffness from the highest to the lowest one is given hereafter: Type 2, Type 5, Type 4, Type 3, Type 1. Research is in progress toward, on one side, the application of the classification method to other types and configurations of beam-to-column joint analyzed through experimental tests or numerical investigations from scientific literature, on the other side, the optimization of the joint design for achieving the required stiffness according to the degree of restraint to be offered. Acknowledgements The research projects DPC–ReLUIS 2024-2026–WP12 and RETURN, as well as the student Giovanni De Luca are acknowledged. Type 1 - 2% of joints are semi-rigid, 98% are pinned; Type 2 - 58% of joints are semi-rigid, 42% are pinned; Type 3 - 100% of joints are semi-rigid; Type 4 - 92% of joints are semi-rigid, 8% are pinned; Type 5 - 100% of joints are semi-rigid.