Analytical Bond Model for GFRP Bars to Steel Fiber Reinforced Self-Compacting Concrete

Valente

et al. 2013

Composite Structures

a b s t r a c tIn this paper, an innovative and thermally efficient sandwich panel is proposed for the structural walls of a pre-fabricated modular housing system. Traditionally, sandwich concrete panels consist of reinforced concrete wythes as outer layers, polystyrene foam as core material and steel connectors. However, steel connectors are known to cause thermal bridges on the building envelope, with possible consequent occurrence of condensation and mould problems. Furthermore, the reduction/optimization of the thickness of conventionally reinforced concrete layers is frequently limited by minimum concrete cover requirements for the protection of the reinforcement from corrosion. To overcome these issues, the proposed sandwich panel comprises Glass Fibre Reinforced Polymer (GFRP) connectors and two thin layers of Steel Fibre Reinforced Self-Compacting Concrete (SFRSCC). This paper presents the material and structural concept of the proposed building system. Moreover, the feasibility of using the proposed connectors and SFRSCC on the outer wythes is experimentally investigated through a series of pull-out tests where failure modes and load capacity of the connections are analysed.

Section: Pull-out Tests: Results and Discussionmentioning

confidence: 88%

Development of sandwich panels combining fibre reinforced concrete layers and fibre reinforced polymer connectors. Part I: Conception and pull-out tests

Lameiras

Valente

et al. 2013

Composite Structures

“…When the load is applied to the member, it is transmitted to the FRC throughout a part of embedded length of reinforcing bar in which the total bond shear force over this distance is in static balance with the applied load. This part of embedded length can be named as transferred bond length ( tr L ), which depends on the bond mechanism between the reinforcing bars and surrounding FRC [27]. The part of the member beyond the tr L behaves as a real composite element ("tie region" in Figure 1), where the slip (  ) between the bars and surrounding FRC is null and the total applied force is shared between them in accordance with their axial stiffness.…”

Section: Crack Formation Stagementioning

confidence: 99%

Tension-stiffening model for FRC reinforced by hybrid FRP and steel bars

Mazaheripour

Composites Part B: Engineering

Sena-Cruz

2016

This paper presents a tension stiffening model for Fiber Reinforced Concrete (FRC) tensile member reinforced by hybrid glass fiber reinforced polymer (GFRP) and steel bars. The model is developed through an explicit analytical bond formulation by considering a four-linear bond shear stress-slip relationship to simulate the bond behavior between reinforcing bars and surrounding FRC. The model is also capable of simulating both the fiber reinforcement contribution and the yielding stage of steel bar at cracked section. Additionally, a FE Model is carried out using a multi-directional smeared crack approach for modeling cracking process in FRC, and adopting interface finite elements to simulate the bond behavior between reinforcements and FRC, whose constitutive model was defined from the aforementioned bond law. Both the analytical and numerical approaches showed a good agreement with some recent experimental results on tension-stiffening in the literature. Finally, an extensive parametric study is performed by using the analytical model, and the influence of the involved parameters on the tension-stiffening and cracking behavior of hybrid GFRP/steel FRC tensile member is investigated.

“…The effectiveness of the developed SFRSCC on the shear resistance of the fabricated beams was compared with that of the reference high strength self compacting concrete, SCC, beams with and without conventional stirrups. The beams were flexurally reinforced by employing a hybrid system of a steel strand and glass fiber reinforced polymer, GFRP, bars, being the steel strand positioned with a relatively thick concrete cover for providing proper protection against corrosion, while the GFRP bars are placed near the outer surface of the tensile zone with the highest possible internal arm considering the limitations imposed by the bond performance of these bars (Mazaheripour et al [17], Mazaheripour et al [21], Soltanzadeh et al [22]). The effect of prestressing the GFRP bars on increasing the shear resistance of the SFRSCC elements developed according to the introduced strategy was assessed in previous studies (Soltanzadeh et al [23], Soltanzadeh et al [24]).…”

Section: Introductionmentioning

confidence: 99%

Effect of fiber dosage and prestress level on shear behavior of hybrid GFRP-steel reinforced concrete I-shape beams without stirrups

Soltanzadeh

Edalat-Behbahani

Composites Part B: Engineering

et al. 2016

Corrosion of steel reinforcements embedded in concrete elements is generally known as one of the most common reasons that shorten the service life of the structures. The present study aims to contribute in overcoming this problem by replacing steel stirrups as shear reinforcement of concrete beams using a steel fiber reinforced self-compacting concrete (SFRSCC). In the present research the potential of SFRSCC for improving the shear resistance of the beams without stirrups is explored. In order to further reduce the risk of corrosion in this type of beams, a hybrid system of flexural reinforcement composed of a steel strand and GFRP rebars is applied and properly arranged in order to assure a relatively thick concrete cover for the steel reinforcement. The GFRP bars are placed with the minimum cover thickness for providing the maximum internal arm and, consequently, mobilizing efficiently their relatively high tensile strength. The effectiveness of applying different dosages of steel fibers and varying the prestress force to improve the shear behavior of the designed beam are evaluated. By considering the obtained experimental results, the predictive performance of a constitutive model (plastic-damage multidirectional fixed smeared crack model) implemented in a FEM-based computer program, as well as the one from three analytical formulations for estimating shear resistance of the developed beams were assessed. The FEM-based simulations have provided a good prediction of the deformational response and cracking behavior of the tested beams. All the analytical formulations demonstrated acceptable accuracy for design purposes, but the one proposed by CEB-FIP Modal Code 2010 predicts more conservative shear resistance.