THEORETICAL AND EXPERIMENTAL ANALYSIS ON MECHANICAL BEHAVIOR OF COLUMN IN TRADITIONAL TLMBER STRUCTURE DURING ROCKING

Columns were often set on the stone base directly in traditional timber structure. ‘Rocking’ might occur to the column under repeated loads, such as seismic or wind loads. The column was the main load bearing part of the whole structure. The mechanical behavior of the column during rocking in traditional timber structure had great effect on the stability and integrity of the whole structure. To study the mechanical behavior of the column during rocking, the motion principle of column rocking is obtained and the lifting judgement condition of the column foot is proposed by theoretical analysis firstly. Then, the 7 ts'ai full-scale column model based on <Ying-tsao-fa-shih> is produced to verify the lifting judgement condition and study deformation characteristic, hysteretic curve of load and displacement, skeleton curve, lateral resistant ability and stiffness degradation law of column by quasi static test. The results show that ‘rocking’ occurs to the column and compression deformation happens to the column foot under repeated loads. Lifting at one side and compression at other side occurs at the column foot after the horizontal displacement at the column head up to 10 mm. During loading, there is no slipping at the column foot; Hysteresis curve of load and displacement with an S-shaped has a pinch effect; the original lateral stiffness of the column is largest and the lateral resistant ability decreases with the increase of lateral displacement. The degradation phenomenon of stiffness is obvious before the displacement reaches 60mm, after which it is weaken.