Optimum Design of Reinforced Concrete Flat Slab using Simplified Method

Abstract

Reinforced Concrete flat slabs are commonly chosen for its architectural convenience in construction of reinforced concrete frame Buildings. More over this slab type is economical compared with other types of conventional reinforced concrete slabs. The code requirement is generally concerned on safety and alternative designs, apart from the code requirement; the design should be economically chosen. For a given design, there are alternatives that satisfy the requirement imposed by the codes. The designer must be in a position to choose an optimal design against constrain measure of optimality. The main objective function is to minimize the total cost in the design process of the reinforced concrete flat slab. The structure is modeled and analyzed by using Ethiopian Building Code Standard for concrete structures. The optimization processes is done for different grades of concrete, different grades of steel, different number of panels in a given total span length and different total span length. Design constraints for the optimization are hence considered according to Ethiopian Building Code Standard 2, 1995, structural use of concrete. The analysis and design for an optimization is done by using MATLAB software. Optimization is formulated in nonlinear programming problem (NLPP) by using sequential unconstrained minimization technique (SUMT).Minimum depth constraints and punching shear stress constraints are very active constraints in the optimization procedures. The total cost of reinforced concrete flat slab decreases as the number of panels increases in a given slab size of flat slab and the total cost increases as the grade of concrete and the grade of steel increases for a given slab size of reinforced concrete flat slab. The reduction of weight for reinforced concrete flat slab is directly proportional to the number of panel increment in a given slab size