Research on Lateral Resistance Capacity of Single-Span Column Frames in Traditional Timber Structures Considering E-Fang Effects

E-fang, a critical horizontal timber beam, has undergone morphological evolution across successive dynasties and is essential to the structural mechanical analysis of traditional timber frames. To investigate the influence of E-fang on the lateral resistance performance of timber frames, two single-span column frames were constructed: one with E-fang and one without. Quasi-static tests under different constant vertical loads were applied to the two frames. The deformation patterns, hysteresis curves, skeleton curves, stiffness degradation laws, and energy dissipation characteristics of the two frames were compared. The results revealed that both frames exhibited rocking behavior under cyclic loading, with lateral resistance, stiffness, and energy dissipation capacity increasing with vertical load. Under varying vertical loads, the uplift and compression of column feet in the single-span column frame with E-fang were lower than those of the frame without E-fang. Under vertical loads of 10, 15, and 20 kN, the maximum positive lateral resisting forces of the single-span column frame with E-fang increased by 56.28%, 69.64%, and 45.23%, respectively, compared with that of the frame without E-fang under the corresponding vertical loads. On average, E-fang contributed 54.55%, 50.54%, and 43.19% to the positive load-bearing capacity of the frame with E-fang under these three vertical load levels.