Analysis on the mechanical performance of Dougong bracket sets under eccentric vertical load

Abstract

This paper investigates the mechanical performance of Dougong bracket sets under eccentric vertical loads. Three full-scale Dougongs under different eccentricities of loads are tested. The failure patterns, load–displacement curves, stiffness analyses, load distribution, displacement analyses, and the load distribution in the tail of the Taojian-Beam are discussed. Test results indicate that the failure pattern of the Dougongs under the eccentric load is brittle failure, and bearing capacities significantly decrease. Elastic stiffness of Dougongs under eccentric loads is greater than that of Dougong under axial load, while plastic stiffness of all Dougong specimens is similar. The load eccentricities significantly change the load transferring path in the Dougongs and aggravate the rotation of timber members in the width direction. On this basis, stress and strain analyses are conducted by finite element calculation. Parametric analyses considering eccentricities of vertical load, compressive strength, elastic moduli, and friction coefficients on the mechanical performance of Dougongs are also discussed. Parametric studies show that as the eccentricities of the load increase, the elastic and plastic stiffness decrease. However, as the compressive strength, elastic moduli, and friction coefficients increase, ultimate displacement decreases, and stiffness of the Dougongs obviously increases.