BEHAVIOR OF REINFORCED CONCRETE BEAMS WITH OPENINGS IN THE SHEAR ZONE

This paper presents results of nonlinear finite element analyses of reinforced concrete beams, with and without openings using ANSYS. The results are used to study the effect of the presence of rectangular openings in the shear span of reinforced concrete beams. Effects of both opening size and its distance from support are investigated. It isshown that opening presence reduces beam strength and increases its deflection and crack intensity. It is also shown that these opening effects become more pronounced as the opening size increases or as the opening becomes closer to the support. Four alternative methods to enhance the beam strength and stiffness were studied: using extra stirrups; adding diagonal bars around opening; increasing section breadth in opening zone; and using intense (closely-spaced) stirrups at opening ends. The suggested enhancement solutions improved the beam behavior and partially regained the strength and stiffness of the original beams (i.e. beams without openings).

Keywords:

reinforced concrete , beams , web openings , finite elements)