Damping model of a reinforced concrete frame structure

In tradition, the damping for structural dynamic analysis was simply considered as Rayleigh damping or its different development forms without obvious physical meaning. Here, concrete materials were considered as a viscoelastic material described by Kelvin model, the relationship between viscous coefficient of concrete materials and damping matrix of a shear-type reinforced concrete (RC) frame within elastic stage was derived with dynamic analysis, and a judgment criterion of the proportional damping matrix was obtained. Then, the expression of the damping matrix and the 1^st modal damping ratio of a 10-floor RC frame structure with fibers were given on the basis of the damping experimental results of fiber-reinforced concrete materials. It was found that the damping matrix can be represented quantitatively, similar to the structural mass and stiffness, possessing an obvious physical meaning; compared with an ordinary reinforced concrete frame, the fiber-reinforced concrete frame structure has a larger 1^st modal damping ratio; the damping reinforcement of RC frames with latex powder or fibers lies in the polymer molecules' dissipating energy ability and interfaces' friction of fibers and cement hydration products.