Sumio G. Nomachi

Estimation of Viscoelastic Properties by Loading Test of Soil Materials Confined in Cylinder.

The present paper firstly deals with the analysis of the displacement of viscoelastic material confined in a cylindrical mold under repeated load whose frequency is far less than the natural frequency of the test body, with an assumption of no friction between the test body and the mold, by means of finite Fourier-Hankel transform. Distortional deformation is modeled by a Voigt model and volumetric deformation is modeled by an elastic or Voigt model. In so doing, two viscoelastic models are formulated. As for the test, the surface displacement was measured for dried standard sand, sandy soil, cohesive soil and undisturbed Kanto loam. Then viscoelastic properties of the test materials confined in the mold are evaluated by means of nonlinear least squares method. In the case of applying Voigt model to both distortional and volumetric deformations, the analytical results agree well with the experimental ones.

EXPERIMENTAL STUDY ON FATIGUE CHARACTERISTICS OF CONCRETE BEAMS REINFORCED BY BRAIDED AFRP RODS

There are many studies on application of fiber reinforced plastic rods (FRP rods) to the reinforcement of concrete members. Those fibers have high tensile strength, light weight and excellent corrosion resistance. But, they have also some defects such as low modulus of elasticity and low bond strength.The authors have conducted the researches to utilize braided AFRP rods made from aramid fiber as PC tendons under static loading. It would be effective to improve the composite action between rod and concrete by means of braiding the fibers and using them as PC tendons. In addition, application of spirally formed shear reinforcement keeping the continuity of fibers have also investigated. On the otherhand, there are few past researches on the fatigue characteristics of members reinforced by FRP rods, subjected to shear force under cyclic loading.In this paper, fatigue characteristics of concrete beams reinforced by braided AFRP rods are discussed from the experiments.