Deformability and Crack Resistance of Reinforced Concrete and Fiber-Reinforced Concrete Cross-Beam Systems

The paper presents the results of experimental studies and computer modeling of reinforced concrete and fiber-reinforced concrete cross-beam systems. The authors have made a special stand, the design of which allows for experimental studies of the load-bearing capacity, deformability and crack resistance of cross-beam systems under concentrated and distributed static loads. Samples of reinforced concrete and steel fiber concrete were tested, which are systems consisting of four mutually perpendicular beams of rectangular cross-section. The samples are reinforced in the lower zone with longitudinal reinforcement of class A400C with a diameter of 8 mm. Steel fiber concrete samples have additional dispersed reinforcement with steel fiber with curved ends in an amount of 1% by volume of concrete. A methodology for finite element modeling and calculation of cross-beam systems in ANSYS 17.1 has been developed, and the results obtained experimentally and based on computer modeling have been compared. Tests have shown that dispersed reinforcement leads to an increase in the load-bearing capacity of the system by 1.23 times. In finite element analysis, this increase was 1.18 times. The load-bearing capacity of the reinforced concrete cross-beam system obtained by the finite element method is 13% less than in the experiment, and that of the fiber-reinforced concrete system is 15% less. The number of cracks in a fiber-reinforced concrete system increases significantly (2 times), but the length of the cracks decreases by 2.1 times, and the width of their opening is significantly reduced - from 3 mm to 0,5 mm.