Optimization of Material Cost and Carbon Footprint of Flat Reinforced Concrete Slabs with Simple Steel Piles : Designed according to Eurocode and Swedish appendix EKS

Abstract: When designing reinforced concrete (RC) slabs with steel piles various variables must be considered, from the internal force to the distance of piles. An endless number of designs are possible, leaving space for optimizing designs. The purpose of this thesis is to analyze how different variables may affect the design and how to design for different situations. With the rising interest of the environmental impact of constructions the thesis will analyze both optimal cost and carbon footprint. The analysis is limited to the materials cost and carbon footprint excluding transportation and construction work. To analyze optimized design a method was created to calculate RC slabs using minimum amount of material. Limitations were made analyzing a range of pile distances, acting live loads, pile length, and slab thicknesses. The method used a finite element analysis software to analyze internal forces after creep and crack. A code was programmed to execute the method and extracted results presented as graphs. The results indicated that the smallest slab thickness is the optimal design up to a certain pile distancing. The curve of cost and carbon footprint dependent on the slab thickness flattens out with an increased pile distance. When pile distance is the variable of cost and carbon footprint, an exponential curve is found. The pile length impact on the result is found more prominent for lower live loads. When the slab is exposed to the highest live load (20 MPa) the optimal design is found at the lowest pile distance (2 meters). In general cost and carbon footprint is affected equally. However, there are differences in the results as materials have different ratios between cost and carbon footprint. When designing according to pile distance a shorter distance is more optimal for cost than the carbon footprint.