TWISTING RIGIDITY OF REINFORCED CONCRETE ELEMENTS OF I–BEAM SECTION WITH INCLINED CRACKS

Abstract

The article shows that to determine the torsional stiffness of an element, one should first dissect the reinforcement in the place of an inclined crack. After cutting the reinforcement, the mutual displacement of the crack edges should be determined. This problem is the main and most difficult one in the general problem of determining the torsional stiffness of elements with both normal and inclined cracks. The article is devoted to solving just this most difficult part of the problem – determining the mutual displacement of the sides of an inclined crack of an I-beam element. According to the proposed technique, a real element with an oblique crack is replaced by an element with different stiffness in sections. Within the inclined crack, the element has a real slope equal to the slope of the inclined crack. In the area behind the tip of the inclined crack, it is assumed that the height of the element section changes from a height equal to the height of the zone above the crack to the full section height. Moreover, the change in height occurs according to the law of a straight line. This line is inclined at some angle to the horizontal.