Albert de la Fuente Antequera

Influence of the Type of Fiber on the Structural Response and Design of FRC Slabs

Most codes for the design of fiber reinforced concrete (FRC) structures are based on the experience achieved throughout the years with steel fibers. Recent codes include the possibility of applying the same considerations for FRC structures with plastic fiber. However, the consequences of assuming identical design considerations regardless of the type of fiber is scarcely known in terms of the structural behavior of full-scale elements. The main goal of this paper is to assess the influence of the type of fiber on the performance of full-scale concrete slabs, emphasizing on the consequences of using a common design approach. For that, a comparative experimental study was conducted in order to expose differences regarding the crack pattern and load-deflection behavior. Then, finite element simulations were performed using the constitutive equations from the Model Code 2010. The results indicate distinct levels of overestimation of the structural behavior measured experimentally, confirming that specific design considerations are required depending on the type of fiber used. Based on the findings, correction factors are proposed for the design of FRC slabs with each fiber.

Bi-layer diaphragm walls: structural and sectional analysis

AbstractThe bi-layer diaphragm wall, a new slurry wall type designed to cope with the problem of watertightness is studied in this paper. These walls consist of two bonded concrete layers, the first, a conventional Reinforced Concrete (RC) diaphragm wall, and the second, a Sprayed Steel Fibre Reinforced Concrete (SFRC). The main objective of this paper is to analyze the structural and sectional behaviour of these walls. A study in the form of an uncoupled structural-section analysis based on various hypothetical cases of bi-layer diaphragm walls was performed to fulfil the objective. It is concluded that there exists a potential of reduction in the reinforcement of the RC layer through the structural use of the SFRC layer. However, when the reduction is quantified, even though a reduction of between 3.2% and 1.7% in the RC reinforcement is confirmed, it appears insufficient to offer a cost-effective solution. Nonetheless, the system becomes a promising solution when particular conditions are taken into ac...