Naoshi Ueda

Rapid Jacketing Technique by Using UHP- SHCC for Damaged RC Column under Seismic Loading

This paper introduces a rapid jacketing technique for RC column, which involves spraying UHP-SHCC. Any formwork and/or additional reinforcement are not needed. The technique may be helpful in reducing construction time and cost. Cyclic loading tests were conducted for the column specimens repaired by UHP-SHCC and ordinary polymer cement mortar. It was confirmed experimentally that the developed technique using UHP-SHCC improve not only ultimate load but also ductility of recovered specimen. It seems that the prevention of buckling of longitudinal reinforcement, which was constrained by UHP-SHCC, imparts the mechanical improvement to the column specimens.

Influence of Coarse Aggregate on the Mechanical Behavior of Strain Hardening Cementitious Composites

Influences of coarse aggregate on the mechanical properties of Strain Hardening Cementitious Composite (SHCC) were experimentally investigated at the material and structural level. In the experiments, maximum size and volume fraction of coarse aggregate were varied as parameters. Direct uniaxial tensile tests and bending tests were carried out in order to evaluate the mechanical performance such as tensile strength and elongation capacity of SHCC itself. And also, bending-shear loading tests of steel reinforced SHCC (R/SHCC) beams were conducted. As the results, decreasing of tensile performances of SHCC in material level were observed by an increasing of the volume fraction of coarse aggregate. However, shear capacity of R/SHCC beam did not decrease. Both the tensile performance and the aggregate interlocking has effect on the mechanical behavior of R/SHCC beam failed in diagonal shear. It was suggested that these two mechanisms are the trade-off relation and the aggregate interlocking had significant effect on the shear capacity in this study.

Post-peak Behavior of Shear Failing Beams Governed by Snapback Instability

This paper describes how snapback load-deflection relations of shear failing beams are numerically obtained using Arc Length Method with Selected Displacement Control Points. Identifying stress loading area while load decreases, failure process of snapback shear failure of a beam is clarified in the paper. The fundamental understanding of the phenomena is extended to failure concept of a structure through energy balance calculation.