Experimental Investigation of Bracket sets of 1st Eave of Taihe Palace in the Forbidden City under Vertical Loads

To effectively protect Chinese ancient timber buildings, bracket sets (tou-kung) of 1st eave of Taihe Palace in the Forbidden City were taken as an example to investigate the bearing performances of Chinese ancient liujin type of bracket sets under vertical loads. Based on constitution characteristics of intermediate set, column set and corner set, models with a geometrical scaled ratio of 1 to 2 were built, and experiments under vertical loading were carried out. By the experiments, damage modes, internal forces and deformation of the bracket sets were discussed. In addition, a calculation model for vertical stiffness of the bracket sets was deduced. The experimental results show that under vertical loads, the top 2-layer parts of the bracket sets are easy to damage. Compared with the underparts, the upper parts of the bracket sets bear more loads. In three types of the bracket sets, i.e., column set, corner set and intermediate set, column set and intermediate set have respectively the largest and smallest ultimate bearing capacities; intermediate set has the greatest deformation and residual deformation, and corner set comes second; compared with column set, intermediate set has a great ductility performance, while the ductility performance of corner set is small. The internal force of back part of the balance arm is small. Under vertical loads, the calculation model for vertical stiffness of the bracket sets can be simplified as a 3-line model.