Non-linear finite element analysis of reinforced concrete flat plates with opening adjacent to column under eccentric punching loads

Abstract

Nonlinear finite element analyses were performed on interior slab-column connections to investigate the effects on the punching strength of flat slabs. A total of twenty-seven threedimensional finite element models were constructed to represent large-scale flat plate slabs (2000 Â 2000 Â 155 mm) subjected to concentric and eccentric punching loads. The main parameters in this study were the eccentricity of the load, the opening size, the location of the opening relative to the direction of the transfer moment, and the configuration of the reinforcement adjacent to the opening that is used to compensate the cutting bars. The dimensions and reinforcement of the slab and column were kept constant. Predictions of the numerical models were in good agreement with experimental results published in the literature for slab column connections subjected to concentric loading. The numerical investigation showed that the presence of an opening adjacent to a column in a specimen subject to concentric loads could cause a significant reduction in the ultimate shear capacity which increases with the increase in the size of the opening. Specimens with 250 Â 250-mm size openings indicated a reduction of 35% in their ultimate shear strength capacity while specimens with 250 Â 450-mm size openings indicated a reduction of 45%. Specimens without openings subjected to load eccentricities of 112.5 and 225 mm resulted in a reduction in the load capacity of 18 and 28%, respectively. It was found that providing continuous bars adjacent to the opening to compensate the cutting areas of reinforcement could result in a considerable improvement in the serviceability of the slab represented by an increase the stiffness of the slab-column connection and no significant effect on the punching capacity for the case of concentric loads. Finite element analyses performed are in good agreement with provisions in the building code (e.g., ACI-318) for the case when the opening is located parallel to the direction of the principal moment and provide conservative values when the opening is in the upward side of the bending moment.

Finite element analysis on composite steel-concrete shear walls with centered and staggered openings

“…All the reinforcement bars were modelled with an assumption of perfect bond to concrete macroelements. The SBETA (StahlBETonAnalyse) CC3DNonLinCementitious2 material model was used to calibrate the nonlinear behavior of concrete in tension and compression, based on the recommendations from other researches [5]- [8]. All the nonlinear concrete parameters were automatically calculated by the software using the mean cubic strength of concrete determined experimentally.…”

Efficiency of (GFRP- Steel) Stirrups in Reinforcing the Punching of Slab-Column Connections subjected to Eccentric Load

“…Khalil et al tested four halfscale reinforced concrete S-S-C for verifying the effectiveness of applying FRPS techniques to strengthen S-S-C subjected to punching shear [13]. Reinforced concrete F-S subjected to eccentric punching loads was studied by more few researchers [14][15][16]. The slabs were subjected to failure under association of axial load and unbalanced moment in order to determine the effectiveness of GFRPS for punching reinforcement in edge S-S-C strengthened with GFRP bars [17].…”