In-Plane Shear Behavior of Reinforced Concrete Elements with High-Strength Materials

Abstract

This thesis presents the results of twelve reinforced concrete elements subjected to shear and biaxial stresses. These elements were constructed by one-third scale of real nuclear power plant wall elements. And the load conditions were determined by considering earthquake and accidental inner pressure when the nuclear power plant is overheated. Elements were loaded until failure using University of Torontos Shell Element Tester. The concrete compressive strength, steel yield strength and reinforcement ratio of APR 1400 that is current model of nuclear power plant in Korea were used for reference element. And the high strength concrete, high yield strength steel and decreased reinforcement ratio were used for other elements to compare with the shear behavior of reference elements. On the other hand, in recent years, design codes have incorporated compression field theory for the design of reinforced concrete structures subjected to shear. Especially the Modified Compression Field Theory has become the basis of the shear provisions in CSA Standards, AASHTO LRFD, fib Model code and Eurocode 2. It is expected that ASME, ACI 318 and ACI 349 design codes that commonly used in the design of nuclear power plant structures will implement Modified Compression Field Theory based provisions in the near future. The ultimate load was accurately predicted with a mean test to predicted ratio of 1.03 and a coefficient of variation of 6.4 %. The shear strains at peak shear stress were also accurately predicted with a mean test to predicted ratio of 1.04 and a coefficient of variation of 13.5 %. The Modified Compression Field Theory also well predicted the cracked shear stiffness of elements. These results show the applicability of the Modified Compression Field Theory to shear design of nuclear power plant wall. And the new tension stiffening equation for large reinforced concrete elements is proposed based on the test results.