Experimental and analytical investigations on two-way flexural capacity of biaxial voided slab

Abstract: Biaxial voided slab is an emerging slab system which reduces its self-weight up to 50% in comparison with the conventional reinforced concrete solid slab. The reduction in the concrete volume does not affect its flexural capacity significantly, however, it reduces both one-way and two-way (punching) shear capacity about 40%. Therefore, an effective way of predicting the punching shear capacity is investigated as the presence of voids alters the critical failure section. The applicability of conventional methods for solid slabs in the design standards, such as ACI 318 (2014), EN 1992-1-1 (2004) and IS 456 (2000) to predict the punching shear capacity of the voided slab is examined. In addition, eight full-scale specimens were tested with the sphere and cuboid shape of voids. Finally, experimental results of present study and test data collected from literature (33 specimens) were compared with predictions by the relevant code provisions. The estimation of punching shear capacity of biaxial voided slab by existing provisions for solid slabs in standards does not lead to satisfactory results. Hence, the presence of voids is considered by modifying the critical section depending on the void location. Further, only the effective concrete area is considered to predict the punching shear capacity. After the modifications, the predictions by all three building standards lead to satisfactory results.

Abstract: The slab is a fundamental component of any building that are used as floors and roofs. It is, most commonly, made up of reinforced concrete. Slabs are the structural elements whose thickness is significantly less than their other dimensions. Slabs can have different shapes and conditions of support. It may be a solid, waffle-type or a ribbed slab. They are categorized as one way and two-way slab according to their load-carrying nature. In this paper, a comprehensive statistical analysis of factors that influence the design parameters of slab is presented. It is found that there is low correlation between that there is high but negative correlation found between Effective Depth Required and spacing_x and Inputs variable is able to explain well only two variables Effective_depth require and Spacing_x. The effect of magnitude of different input variables on output variables and interaction of combination of different input variables on output variables for design of Two-Way Slab is also performed.

Abstract: It is known from experiments that the actual load-carrying capacities of plates are larger than those predicted by the limit analysis theory. The behavior of plastic structures beyond the bending collapse load is influenced by the changes in geometry of a structure during the process of plastic deformation. In the present paper, an investigation of the load-deflection relationship for simply supported rectangular reinforced concrete plates is presented. The tensile membrane action is found to be localized in zones of bending yield hinges. The zones of pure membrane response consequently develop as the load increases. The paper presents a kinematical method of analysis of plastic plates beyond the bending collapse load. Kinematically admissible collapse modes are studied and the associated dissipation functions are derived. Load-deflection relationships are obtained for various yield patterns. The theoretical results are compared with experimental data following from model tests.

Abstract: Summary Tests on 10 two-way spanning, simply supported, reinforced concrete slabs are reported. The slabs were designed to have similar ultimate loads, but different arrangements of the reinforceme...

Abstract: Summary Because of tensile membrane action, reinforced concrete slabs can sustain loads far in excess of the ultimate load calculated by the yield-line theory. To take advantage of this, it is necessary to establish de flexion criteria for ultimate load conditions and to develop a method of calculating the corresponding load-carrying capacity. Such a method is proposed, and the possible advantages are indicated.