Nonlinear mechanical behavior and seismic response analysis of a multi-story traditional timber structure based on a planar model considering column rocking

Abstract

Muti-story timber structures exhibited prominent rocking behavior under earthquakes, this paper investigated the nonlinear mechanical behavior and seismic response analysis of a multi-story traditional structure based a planar model considering column rocking. First, a modelling and characterization method of the column rocking behavior was proposed. Second, a planar model of a typical multi-story traditional timber structure was developed, based on which the lateral performance of each frame layer was obtained, the layers’ stiffness and load-resisting capacities along the structural height was analyzed. Third, time history analyses were performed to reveal the seismic displacement response and damage characteristics of such a multi-story traditional timber structure. The research indicated that the lateral load-resisting capability of the frame layers mainly derived from the column rocking mechanism, the lateral stiffness and load-resisting capacity contribution of timber columns to a frame layer was more than 87 % and 79 %, respectively. Owing to the increasing of vertical compression load, the lateral performance of lower frame layers was superior than upper frame layers. Due to the maximum shear force at the bottom frame layer and the minimum stiffness of the top frame layer, these two layers had larger inter-story drifts than other layers. Under frequently-met earthquakes, the column joint damage was uneven distributed along structural height, with the column head damaged most. Under fortification and rarely-met earthquakes, the damage index of the column head and foot joints exceeded 0.6. The research could provide reference to the protection of multi-story traditional timber structures.