EXPERIMENTAL RESEARCH ON IMPROVEMENT OF THE DUCTILITY OF R/C SEISMIC WALLS THROUGH SLIP PREVENTION WITH THE USE OF STEEL RHS

Abstract

Several researchers propose placing diagonal reinforcing bars at the base of the wall to treat the shear slip, while others have suggested various ways to address this problem associated with halting the effects incurred by the through-crack in the base of the wall during cyclic loading. An indicative proposal of the bibliography is the use of large diameter reinforcement bars in the web of the wall as vertical reinforcements, so as to be able to better control the shear action through the dowel action of these bars. The two aforementioned proposals, while adequately addressing the phenomenon of shear slip, present significant disadvantages. The use of diagonal reinforcement is very difficult to construct, because of the density of the existing reinforcement in the base of the walls, which involves compromising good concrete condensation. Also, the use of large diameter vertical reinforcement along the length of the whole wall section, including its web, is a strongly uneconomical solution. This work examines a solution without the aforementioned side-effects. The innovation of the present work is the fact that it positions stoppers in combination with the use of conventional reinforcing bars at positions in the critical zones of the walls, in order to prevent the expected slip along the through-crack in the base of the rigidly supported wall. The work is experimental and includes two stages. The first stage was carried out with the construction of six test specimens, which can be considered as preliminary base specimens used for a first examination of the mechanical behavior of the walls with integrated steel hollow beams at their ends. These test results are a prelude to the second stage of the present study, including the experimental investigation of the seismic mechanical properties of a wall specimen, detailed either with conventional reinforcement according to EC8 or with the same conventional reinforcement but including also steel hollow beams at its confined edges. © 2022. Ingegneria Sismica. All Rights Reserved.