Spatial rotational behavior of intact and damaged column foot joints: experiment-based numerical modelling

Abstract

Columns in traditional Chinese timber structures barely rested on stone bases, and the column foot joints were capable to resist moment around any direction. This study numerically investigated the spatial rotational behavior of intact and damaged column based on experiments. Unidirectional cyclic loading tests were carried out on two intact and three damaged column foot joint specimens. A fiber element-based numerical model for the column foot joints was developed and validated by use of the unidirectional loading test results. Numerical analyses were performed based on the fiber element-based model to obtain the rotational behavior of the intact and damaged column foot joints under spatial loading. The analyses indicated that the moment-rotation curve of an intact column foot joint under spatial loading was on an umbrella-shaped surface. The damage at the column foot not only unidirectionally decreased the moment-resisting capacity of a column foot joint, but also resulted to a rotational performance degradation valley on the joint’s moment-rotation surface. The rotational behavior of both the intact and damaged column foot joints under spatial loading was highly nonlinear. This developed fiber element-based model can be further utilized to analyze the structural performance of traditional timber structures under three-dimensional excitations.