Today, the need for structural strengthening is more important than ever. Flexural strengthening with textile reinforced concrete (TRC) is a recommendable addition to already proven methods. In order to use this strengthening method in construction practice, a design model is required. This article gives a brief overview of the basic behavior of reinforced concrete slabs strengthened with TRC in bending tests as already observed by various researchers. Based on this, a design model was developed, which is presented in the main part of the paper. In addition to the model, its assumptions and limits are discussed. The paper is supplemented by selected application examples to show the possibilities of the described strengthening method. Finally, the article will give an outlook on open questions and current research.

Featured Application: The present paper contributes to the discussion on modeling methods appropriate for the structural analysis of thin-walled concrete shells, a rapidly developing field of material and structural design utilizing the high-performance cementitious composites reinforced with non-metallic reinforcement. An effective modeling support is paramount for the derivation of reliable and economic design and assessment principles in a wide range of applications.Abstract: The paper focuses on the specifics of macro-scale modeling of thin-walled textile-reinforced concrete shells. Application of layered shell finite elements requires systematic procedures for identification of material characteristics associated with the individual layers within the cross section. The identification of the material parameters describing the tensile behavior of a composite cross section is done using data obtained from the tensile test. Such test is usually performed only for a reference configurations with a simple layup of fabrics and a chosen thickness. The question is how to derive the strain-hardening response from the tensile test that is relevant for a changed cross-sectional configuration. We describe and discuss scaling and mixture rules that can be used to modify the material parameters for modified cross-sectional layups. The rules are examined in the context of the test results obtained on a shell that was reinforced non-uniformly, with varying types of textile fabrics and varying thickness within the shell surface.

Carbonbeton ermöglicht dünne Querschnitte und leichte, hochfeste Tragwerke. Dies wird im vorliegenden Beitrag am Beispiel eines leichten, vorgefertigten Deckenträgers demonstriert, der einfach montierbar z. B. als Ersatz von sanierungsbedürftigen Trägern in Bestandsbauten einsetzbar wäre. Hierbei kommt ein neuartiges zementgebundenes Verbundmaterial, bestehend aus Schichten von betongetränkten Nadelvliesstoffen sowie carbonbewehrtem Feinbeton, zur Anwendung, mit feiner Rissbildung und hoher Duktilität. Der Träger ist als dünne zylindrische Schale mit seitlichen Stegen konzipiert. Neben Material, Entwurf und Herstellung beschreibt der Beitrag experimentelle und numerische Untersuchungen zum Spannungs‐Dehnungsverhalten des Verbundmaterials sowie zum Tragverhalten des Deckenträgers. Bei geringem Gewicht wird eine sehr hohe Tragfähigkeit nachgewiesen, welche die Gebrauchslasten um ein Vielfaches überschreitet. Entwurf sowie experimentelle und rechnerische Analysen sind exemplarisch und sollten ein größeres Anwendungsspektrum ermöglichen.