Investigation of the effects of openings on the behavior of one-way RC slab with varied openings size,position,and number and strengthened with CFRP strips

Abstract

This study investigated load-displacement behavior under the effect of flexural loading of the one-way reinforced concrete (RC) slab with openings in more than one location and size. In addition, the strengthened RC slab with openings with carbon fiber-reinforced polymer (CFRP) strips was also investigated in the study to reduce the negative effects of the openings on the behavior of one-way RC slabs. The first part of the study investigates the load-displacement behavior under the influence of the flexural loading of one-way RC slabs with the openings in different sizes, locations and numbers more than one. A comprehensive literature review revealed that studies on one-way RC slabs generally focus on examining the effects of a single opening of varying size and location on the slab’s behavior under flexural loading. However, no comprehensive study was found in the literature that investigated the load-displacement behavior of slabs with multiple openings under flexural loading, supported by a parametric numerical analysis study with experimental data that could be generalized to the original findings. The variables examined within the first experimental part of the study are the opening sizes, the number of openings, and the openings’ position on the one-way RC slab. In the second part of the experimental study, two series of specimens with the same features were produced. The first series was produced to examine the effects of openings on the overall behavior of the one-way RC slabs. In contrast, the second series was produced to examine how much the openings’ negative effects can be enhanced and strengthened by using CFRP strips. The one-way RC slab specimens were static monotonic loaded until a four-point flexural test until failed, and load-midpoint displacement graphs were obtained. The specimens’ ultimate load capacity, stiffness at yield load, displacement ductility ratios, and energy dissipation capacities were calculated and interpreted, and the effects of the experimental study variables were examined. In this study, finite element models of the one-way RC slabs tested were created using ABAQUS software, and the numerical analysis model was validated by comparing them with the experimental results. In the third and final part of the study, an ultimate load capacity multiplier was determined to determine how the ultimate load capacity values change compared to the reference slab without openings by performing simulations in the finite element analysis (FEA) of one-way RC slabs with different concrete compressive strengths, different opening sizes and locations using the finite element model verified by using the experimental results. When the experimental results were examined, it was seen that the openings left in RC slabs caused the yield load capacities, ultimate load capacities, and stiffness values at yield loading of the slabs to decrease by an average of 36%, 34%, and 28%, respectively.

Keywords

one way RC slab strengthening CFRP multiple opening FEA

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