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|Title:||COMPUTER AIDED DESIGN OF REINFORCED CONCRETE COLUMNS UNDER BIAXIAL BENDING|
|Authors:||Pande, Chandra Pal|
|Keywords:||CIVIL ENGINEERING;COMPUTER AIDED DESIGN;REINFORCED CONCRETE COLUMNS;BIAXIAL BENDING|
|Abstract:||Computer Aided Design of Reinforced Concrete Columns, under biaxial bending especially on mini and micro computers is a challenging but difficult task. Non-linearity of parameters involved in the ultimate load and moment carrying capacities of column sections render the design algorithms extremely unwieldy. Hence a lot of approaches have been proposed but only few such as the Bresler's Load Contour Approach or PCA load contour approach have been adopted by the designer's. As a simplification step, the researchers have introduced straight line approximations to biaxial load profile curve. Additionally, the authors have been using membrane analogy or the uniform distribution of reinforcing bars on the adjacent faces' of the column sections. In this dissertation work, a design algorithm has been developed which performs all capacity calculations on the basis of actual positions of bars in the section with equal or unequal reinforcement placed on respective faces of the column section. The method of design is to reduce the design biaxial moments at the giyen design axial load into an equivalent uniaxial moment and providing longitudinal reinforcement in the section. For this purpose, a parametric form of Load Contour Equation has been developed which determines the uniaxial moment capacities of the columh section required for design purposes in an easier and precise manner. Use of such an equation results in more realistic estimation of design uniaxial moment capacities which provide better control over the economical estimation of the cross-sectional properties and area of reinforcement. This improves the (iv)' economy of the designs by 5% to 15% depending on the axial load and biaxial bending moments. For the computation of reinforcement to be provided in a section with known geometrical and materialproperties a modified linear numerical computation method has been adopted. Based on the algorithm so developed, a computer program has been developed in FORTRAN for the design of short, biaxially loaded rectangular column sections, which presents 'an easy to use production oriented user interface to control the functioning of the computational algorithm.* Also an analysis algorithm has been developed for computations of axial load capacity and biaxial moment carrying capacities of the non-rectangular sections, such as T, L, Channel and I-sections under axial load and biaxial moments on the basis of basic assumptions of combined axial load and flexure propounded by I.S.-456 1978. Due to the lack of expressions relating design parameters such as the exponent of the Bresler's Load Contour Equation, reinforcement index and the ratio of the uniaxial moment capacities etc. in case of such sections, it is not possible to extend the existing approaches to their design. Hence an analysis based interactive computer program has been developed for the design of non-rectangular sections with known sectional dimensions and material properties. This approach is highly convergent and produces the most optimal—, design in a few iterations. Many reinforced concrete column designS have been successfully completed using these programs.|
|Research Supervisor/ Guide:||Jain, V. C.|
Nayak, G. C.
|Appears in Collections:||MASTERS' DISSERTATIONS (Civil Engg)|
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