Marta Słowik

Experimental study of shear failure mechanism in concrete beams

In this paper, recent results of the experimental investigation, which was aimed at disclosing some aspects of shear failure mechanism in concrete beams reinforced longitudinally, are presented. The aim of the test was to investigate the influence of a shear span-to-depth ratio and a beam size on failure mode and shear capacity in the tested beams. It has been found that the shear span-to-depth ratio a/d is an important parameter, which significantly affects the shear failure mechanism in the investigated members. This fact was presented in several scientific papers. However, the second important parameter, which must be taken into account when analysing reinforced concrete beams without stirrups, is the size of the member. The “size effect”, which is described in professional literature as a decrease of shear strength with an increase of the members depth, is not evaluated sufficiently enough. The effective length-to-depth ratio leff/d, which has been identified in this paper, also has a considerable influence on the contributions of the shear resistance mechanism and thus the ultimate shear capacity. In this paper it has been shown that members characterized by the same a/d but different leff/d can fail in a different way.

The Analysis of Crack Formation in Concrete and Slightly Reinforced Concrete Member in Bending

Abstract In the paper the authors own experimental investigation and numerical calculations concerning cracking moment in flexural concrete members are presented. Two kinds of members were examined: non-reinforced concrete beam and slightly reinforced concrete one. The analysis of crack formation in such members was made by Finite Element Method and the influence of reinforcement on the process of crack formation was discussed.

The Influence of Aggregate Size on the Width of Fracture Process Zone In Concrete Members

In this paper the problem of the influence of aggregate size on concrete parameters is considered. The discussed parameters include fracture energy and width of the fracture process zone. The results of the numerical simulations concerning bent concrete members with different width of the fracture process zone are analyzed.