A limit state design approach for hybrid reinforced concrete column‐supported flat slabs

Abstract

Hybrid reinforced technology (combination of steel reinforcing bars and fibers) can be considered as a competitive alternative to the already existing solutions for the construction of column-supported flat slabs. Constructed hybridreinforced buildings prove that hybrid solutions have sufficient bearing capacity to maintain structural integrity despite being exposed to high stress levels, thereby providing a beneficial solution in terms of toughness, ductility, and sustainability performance. However, the lack of design-oriented recommendations based on the accepted limit state format for dealing with both serviceability and ultimate limit states slows down the wider implementation of this technology. Considering the above-mentioned, this article presents a simplified design-oriented method that covers the evaluation of the structural response of hybrid reinforced concrete column-supported flat slabs in terms of flexural strength, cracking, and instantaneous deformations. Two hybrid reinforced alternatives for a given flat slab are studied by means of the proposed approach. Furthermore, a nonlinear finite element analysis is carried out in order to evaluate the effectiveness of the developed simplified method. Based on the achieved results, its suitable accuracy and precision can be pointed out. This outcome may motivate current practitioners to consider hybrid reinforced concrete solutions as a possible alternative during the design of residential and office buildings.

Proposal for estimating the punching shear load-carrying capacity of steel fibers reinforced concrete flat slabs

“…Silva [26] presented that the residual tensile strength of the steel fiber does not present a constant behavior in relation with the crack opening. This is also observed by other authors ( [3], [4], [7], [8], [13]- [15], [22], and [23]). In additions, the use of safety factor for the steel fibers (𝛾𝛾 𝐹𝐹 = 1,5) still gives estimative higher than experimental tests.…”

Design of Steel Fibre Reinforced Concrete Structures According to the Annex L of the Eurocode-2 2023

“…Alternatively, and specifically oriented to non-linear structural analysis, the method proposed in [26] to calibrate the global resistance safety factor -and reported in the Annex F of the EC-2-was satisfactorily used and implemented in SFRC flat slabs [27][28][29]. The test up to failure of the SFRC flat slab (200 mm thickness, and four bays of 5 × 6 m) presented in [29] (see Figure 2) proved that the design carried out combining FE-based non-linear models and the safety factor calibration approach [26] lead to safe-side results for the ultimate load [30].…”

“…The combination of SFRC and longitudinal ordinary reinforcement -both with the suitable SC and quantity, respectively-has proven to provide sufficient rotation capacity of the bending-controlling cross-sections to allow for bending moment redistribution in statically indeterminate structures [14,27,30,32,66].…”

Macrosynthetic fibers as replacement of conventional steel reinforcement for concrete of partition walls

“…The adequacy of the CDP approach for FRC structures was already confirmed in other researches. [37][38][39][40][41] To simulate the mechanical response of the materials, constitutive models proposed in the fib Model Code 2010 33 for both steel and FRC were used. The behavior of steel was set through the uniaxial stress-strain curves (σ-ε) constitutive model.…”