Experimental Analysis of Stresses in Subsoil below a Rectangular Fiber Concrete Slab

This paper is focused on sensitivity analysis of the behavior of subsoil foundation systems by considering the variant properties of a fiber concrete slab that result in different relative stiffness of the whole cooperating system. The character of the slab and its properties are very important for the character of external load transfer. However, the character of the subsoil also cannot be neglected because it determines the stress–strain behavior of the entire system and, consequently, the bearing capacity of the structure. The sensitivity analysis was carried out based on experimental results, which included both the stress values in the soil below the foundation structure and settlements of the structure that are characterized by different quantities of fibers in it. Flat GEOKON dynamometers were used for the stress measurements below the observed slab, the strains inside the slab were registered by tensometers, and the settlements were monitored geodetically. This paper is focused on the comparison of soil stresses below the slab for different quantities of fibers in the structure. Results obtained from the experimental stand can contribute to more objective knowledge of the soil-slab interaction, the evaluation of real carrying capacity of the slab, the calibration of corresponding numerical models, the optimization of quantity of fibers in the slab and finally, contribute to higher safety and more economical designs of slabs.