DEVELOPMENT OF METHODS OF SOLUTION FOR BIAXIALLY LOADED SECTIONS IN ACCORDANCE WITH THE EGYPTIAN CODE OF PRACTICE

Abstract

Many building codes have developed different approaches for design of sections subjected to axial loads and biaxial bending moments. The Egyptian code of practice ECP 203 has two different approaches; a detailed investigation for those two approaches was carried out in this study. It was concluded that the two approaches have drawbacks preventing them from being used for designing general sections subjected to axial loads and biaxial bending moments. There are some restraints for both approaches. The first method can only be used for sections having equal reinforcement in all sides and can give unconservative results when dealing with sections having general reinforcement distribution conservatively. The second approach forces the designer to use reinforcements in each direction relative to the applied moments. This presented a need to develop a new approach in the Egyptian code of practice, applicable for designing any general section without restraints on reinforcement distribution. A study was carried out on different design codes such as the British Standards BS-8110, American Concrete institute ACI 318, Euro Code EC-2 and Indian code. It was recognized from this study that the most common approaches are the load contour method and the equivalent eccentricity method. In this research a parametric study was carried out on those two approaches to evaluate an improved function for the alpha factor used in the load contour method. The beta factor that is used in equivalent eccentricity method was derived from the alpha factor. The results of those two approaches were compared to the strain compatibility method, which is the most accurate approach that can be used to design any general section subjected to axial load and biaxial bending moments. The strain compatibility method is complicated for practical use as it requires many trials that can be time consuming. The new approaches are proposed to the Egyptian code committee for discussion in order to be addressed in the upcoming editions of the Egyptian