Title: Boundary between Plane Stress and Plane Strain of Compression Concrete
Author(s): Vitalii Mitrofanov, Pavel Voskoboynik, and Nataliia Pinchuk
Publication: Structural Journal
Appears on pages(s): 43-52
Keywords: increased concrete compressive strength; plane strain; plane stress; strain constraint
It is noted that the concrete compression zone of reinforced concrete (RC) slabs in the failure section under pure bending is unlike that of beams. The ratio b/x—section width b to the concrete compression zone height x—is great enough, leading to strain constraint in the direction of size b, and to the appearance of the plane strain instead of the plane stress taking place in the beams. The due increase of concrete compressive strength under the plane strain conditions is shown. The method of experimental determination of the concrete compressive ultimate stress fcu in the RC bending slabs is stated, and the experimental results are given, showing the considerable stress fcu increment with an increase of the b/x. The decrease of crack openings and deflections of the slabs with an enhanced b/x is noted. A relationship is offered for taking into account the b/x influence on the concrete compressive strength of the RC elements under bending.