Prediction of Corner Columns’ Load Capacity Using Composite Material Analogy

Abstract

There are numerous reasons for which concrete has become the most widely used construction material in buildings, one of them being its availability in different types, such as fiber-reinforced, lightweight, high strength, conventional and self-compacting concrete. This advantage is specially realized in high-rise building construction, where common construction practice is to use concretes of different types or strength classes in slabs and columns. Columns in such structures are generally made from concrete which is higher in compressive strength than the one used in floors or slabs. This raises issue of selection of concrete strength that should be used for estimating column capacity. Current paper tries to address this issue by testing nine (09) sandwich column specimens under axial loading. The floor concrete portion of the sandwich column was made of normal strength concrete, whereas column portions from comparatively higher strength concrete. Test results show that aspect ratio (h/b) influences the effective concrete strength of such columns. A previously adopted methodology of composite material analogy with some modifications has been found to predict well the capacity of columns where variation in floor and concrete strength is significant.

The Proposition of an EI Equation of Square and L–Shaped Slender Reinforced Concrete Columns under Combined Loading

“…Each simulated column had a different combination of cross section, geometric, and material proprieties. The effect of ƒ c has an increasing influence on the flexural stiffness of the slender column .This was already predicted and proven in [19] which presented the effect and impact of this strength on the general behavior of corner columns. In addition to the axial load level, it has an increasing effect on the EI of the column.…”

Behavior and Strength of Composite Columns under the Impact of Uniaxial Compression Loading

“…They concluded that concrete strength, level of axial load, and column slender ratio were the most important factors affecting the reduction coefficients and the effective bending stiffness. Authors in [14] estimated the column capacity by testing 9 sandwich column specimens under axial compression load. The columns were made of normal strength concrete, whereas column portions were made from comparatively higher strength concrete.…”