Cost Optimization of R.C.C. T-Beam Girder

In this present study, cost optimization approach of R.C.C. T-beam girder is presented. The main objective function is to minimize the total cost in the design process of the bridge system considering the cost of materials. The cost of each structural element covers that of material and labor cost for reinforcement, concrete and formwork. For a particular girder span and bridge width, the design variables considered for the cost minimization of the bridge system, are deck slab depth, width of web of girder and, girder depth, (i.e. X1, X2, X3 resp.) Design constraints for the optimization are considered according to IRC-21:2000 (Indian road congress) Standard Specifications. The optimization process is done for different grade of concrete and steel. The comparative results for different grade of concrete and steel is presented in tabulated form. The optimization problem is characterized by having a combination of continuous, discrete and integer sets of design variables. The structure is modeled and analyzed using the direct design method. Optimization problem is formulated is in nonlinear programming problem (NLPP) by SUMT. The model is analyzed and designed for an optimization purpose by using Matlab Software with SUMT (Sequential Unconstrained Minimization Technique), and it is capable of locating directly with high probability the minimum design variables. Optimization for reinforced concrete R.C.C. T-beam girder system is illustrated and the results of the optimum and conventional design procedures are compared. The evolution of bridges from the ancient times to present age is a continues process and is a result of human desire to use more and more improved methods and materials in order to build cheaper, finer and stronger bridges of any spans and of lasting quality. The search for further improvement is not over and experimentations for building cheaper, stronger and aesthetically better bridges for all times to come. Iqbal motiwala in 1969 described, Design of simple span R.C.C. T-beam Bridge by working stress design method and by ultimate strength design method - and economical comparison of both methods. The aim of the project was to simply know which method requires more material when all other factors such as length, width of bridge, other cross-sectional properties, and the site of the bridge as well as difficulties arising during erection are assumed to be constant. Also various factors affecting life of a bridge such as continued application of moving loads, control of cracking and deflection, stresses distributed in steel and concrete etc. were studied and advised how to control it.