In most countries, for the production and execution of concrete structures with textile reinforcement, building owners must have a general approval (e.g., “abZ” in Germany) or an individual license (e.g., “ZiE” in Germany). Therefore, it is quite common for building authorities to request experimental tests that evaluate the ultimate limit state (ULS) and the serviceability limit state (SLS). However, these experimental tests are detailed, time-consuming and expensive. A practical and simple design model would help to reduce the number of tests needed and would offer structural planners a useful tool. An important aspect is that such design model must fulfil a set of reliability requirements in order to guarantee an adequate safety standard. To this end, probabilistic calculations are required. For the setup of such model, different parameters must be considered, namely the effective depth d and the tensile failure stress of the textile ft for the concrete compressive strength fc. This article presents the probabilistic calculations needed to attain a general safety factor γT that satisfies all the safety requirements for the textile reinforcement of concrete structures with bending load.
Textile-reinforced concrete has emerged in recent years as a new and valuable construction material. The design of textile-reinforced concrete requires knowledge on the mechanical properties of different textile types as well as their reinforcing behaviour under different loading conditions. Conventional load-bearing tests tend to be complex, time-consuming, costly and can even lack consistent specifications. To mitigate such drawbacks, a standardised tensile test for fibre strands was used to characterise the material properties needed for the design of a textile-reinforced concrete member. The standardised tensile test uses a fibre strand with 160 mm length, which is cut out of a textile grid. For the sake of this study, an epoxy resin-soaked AR-glass reinforcement was considered. The results show that the textile reinforcement has a linear-elastic behaviour, and the ultimate tensile strength can be statistically modelled by a Gumbel distribution. Furthermore, the results indicate that the modulus of elasticity is not influenced by the length or the number of fibre strands. Therefore, the mean value attained from the standardised test can be used for design purposes. These findings are essential to derive an appropriate partial safety factor for the calculation of the design values of the tensile strength and can be used to determine the failure probability of textile-reinforced concrete members.
Textile-reinforced concrete has emerged in recent years as a new and valuable construction material. The design of textile-reinforced concrete requires knowledge on the mechanical properties of different textile types as well as their reinforcing behaviour under different loading conditions. Conventional load-bearing tests tend to be complex, time-consuming, costly and can even lack consistent specifications. To mitigate such drawbacks, a standardised tensile test for fibre strands was developed aiming at characterising the material properties needed for the design of a textile-reinforced concrete component. For the sake of this study, an epoxy resin-soaked AR-glass reinforcement was considered. The standardised tensile test uses a fibre strand with 160 mm length, which shall be cut out of a textile grid. The results show that the textile reinforcement has a linear-elastic behaviour, and the ultimate tensile strength can be statistically modelled by a Gumbel distribution. Furthermore, the results indicate that the modulus of elasticity is not influenced by the length or the number of fibre strands. Therefore, the mean value from the standardised test can be used for the design purpose. These findings are essential to derive an appropriate partial safety factor for the calculation of the design values of the tensile strength and can be used to determine the failure probability of textile-reinforced concrete components.