PROBABILISTIC ANALYSIS FOR DESIGN ASSESSMENT OF COMPOSITE STEEL-AND-CONCRETE COMPRESSION MEMBERS

Steel-concrete composite columns are extensively used in modern buildings. Steel being of high tensile strength presents a high quality building material, concrete on the other hand carries the compressive stresses and protects the steel from high temperatures and corrosion. The theoretical analysis of the actual behaviour of modern concrete-steel structures is more frequently performed during design, realization and utilization of such structures. The main goal of the presented paper is the non-linear analysis of the load-carrying capacity of concrete encased steel columns. Ample information, obtained from experimental research, on the material characteristics of steel was available and was considered during analysis as random input variables. Statistical information on the input variables has an influence on the reliability of results obtained from statistical analysis of the ultimate limit state. Stresses in both concrete ad steel sections were evaluated using principles of elasticity and plasticity. Numerical LHS simulation methods were applied. These methods take into account the variability influences of input imperfections. Obtained output is the random load-carrying capacity, which quantifies the uncertainty due to the random character of material and geometrical characteristics. The important output of the statistical analysis is the design load-carrying capacity, which was evaluated according to EN1990 as 0.1 percentile.