Compression Failure of Beams Made of Different Concrete Types and Sizes

To investigate whether the current numerical models and procedures are capable of realistically predicting compression failure of concrete structures, RILEM TC 148SSC recently proposed a so-called round-robin analysis for over-reinforced concrete beams. Beams of two different sizes made of three different concrete types (normal-strength, high-strength, and fiber-reinforced concrete) were proposed to be studied numerically. In the present paper the results of a 3D finite-element analysis are shown, discussed, and compared with the test results. The analysis was performed before the test data were available. After the experimental results were known, additional parameter study was carried out. The microplane model for concrete was employed within the framework of the crack band theory. The comparison between measured and calculated data exhibits good agreement. It is confirmed that the finite-element code based on the smeared fracture analysis is able to realistically predict compression failure of concrete beams. The results show that the relative resistance of beams made of different concrete types is not proportional to the uniaxial compressive strength. The efficiency of high-strength concrete is much lower than the efficiency of normal-strength concrete. It is shown that the size effect on the strength of normal-strength concrete beams that fail in compression is relatively small. However, the size effect on the postpeak response is stronger.