Optimization of reinforced concrete cantilever retaining walls considering environmental impact and investment cost

Abstract: Today's civil engineering structures are most often designed through a trial anderror approach, which means that the designer tests a design solution andevaluates whether all requirements are met. If any of the requirements are notmet, changes are made to the design until a feasible solution is obtained. It is atime-consuming process where the  nal design is not always optimal concerningmaterial consumption. In this study, a program has been developed in MATLAB®for the design of reinforced concrete retaining walls and by using optimizationalgorithms, the design process has been made automated and time-ecient. Theuse of optimization algorithms also allows for  nding a solution that is not onlyfeasible but also optimal. The developed program utilizes two objective functions,minimizing environmental impact or investment cost based on materialconsumption. In addition, the design calculations are developed according toEurocode and additional national requirements of Swedish standards.This thesis presents the background to the study, fundamental optimization theoryand how the developed program is designed. A case study is also presented whereexisting retaining walls have been examined to evaluate what savings could havebeen made using optimization algorithms in the design process. Lastly, guidelinesare also presented for designers to facilitate the choice of cross-sectional dimensionsand reinforcement bar dimensions when designing retaining walls.The results obtained in the case study show that using optimization algorithms inthe design process can make signi cant savings (10-20%) on investment cost andenvironmental impact. Moreover, the results show that an optimized retaining wallconcerning environmental impact also leads to a substantial reduction ininvestment costs and vice versa.