Experimental investigation on existing precast prc elements strengthened with cementitious composites

Existen varias investigaciones experimentales sobre el polímero reforzado con fibra (PRF), con el objetivo de comprender su comportamiento cuando se aplican como refuerzo de elementos de hormigón armado, pero hay muy pocos datos disponibles sobre el reforzamiento de elementos a escala real con materiales compuestos cementicios. En particular, las formulaciones de código de diseño son escasas o inexistentes. En este estudio se investigó el comportamiento de cuatro vigas TT pretensadas tomados de un edificio industrial existente. Uno de ellos se consideró como viga TT no reforzada de control, mientras que los otros se reforzaron con diferentes técnicas, concretamente con laminados FRP (pegados con resina epóxica), fibras de carbono con matriz cementicia y fibras de acero con matriz cementicia. Cada material involucrado en este estudio también se caracterizó mecánicamente para obtener las principales propiedades físicas. Se obtuvieron especímenes adecuados de la viga TT existente para caracterizar el hormigón y las barras de acero de refuerzo.A number of experimental investigations on fibre reinforced polymer (FRP), with the aim of understanding their behaviour when applied as strengthening of reinforced concrete elements, are available in the literature but very few information is available on strengthening real-scale elements with cementitious composites. In particular design code formulations are scanty or non-existent.In this study the behaviour of four precast pre-stressed TT beams taken from an existing industrial building was investigated. One of them was considered as control unstrengthened TT beam, whereas the others were strengthened with different techniques, namely with FRP laminates (glued with epoxy resin), carbon fibres with cementitious matrix and steel fibres with cementitious matrix. Each material involved in this study was also mechanically characterized to obtain the main physical properties. Adequate specimens were obtained from the existing TT beam to characterize the concrete and the reinforcing steel bars

Experimental investigation on existing precast PRC elements strengthened with cementitious composites

A number of experimental investigations on fibre reinforced polymer (FRP), with the aim of understanding their behaviour when applied as strengthening of reinforced concrete elements, are available in the literature but very few information is available on strengthening real-scale elements with cementitious composites. In particular design code formulations are scanty or non-existent. In this study the behaviour of four precast pre-stressed TT beams taken from an existing industrial building was investigated. One of them was considered as control unstrengthened TT beam, whereas the others were strengthened with different techniques, namely with FRP laminates (glued with epoxy resin), carbon fibres with cementitious matrix and steel fibres with cementitious matrix. Each material involved in this study was also mechanically characterized to obtain the main physical properties. Adequate specimens were obtained from the existing TT beam to characterize the concrete and the reinforcing steel bars

Experimental investigation on existing precast PRC elements strengthened with cementitious composites

none5nonePellegrino C; D’Antino T; Giacomin G; Franchetti P; da Porto FPellegrino, Carlo; D'Antino, Tommaso; Giacomin, G; Franchetti, P; DA PORTO, Francesc

Experimental Analysis of the Bond Behavior of Glass, Carbon, and Steel FRCM Composites

In recent decades, the construction industry has witnessed a rapid growth of interest in strengthening and retrofitting of existing reinforced concrete (RC) and masonry structures. Fiber reinforced polymer (FRP) composites have gained great popularity, and several studies are now available in the literature on their use in strengthening and retrofit applications. Promising newly-developed composite materials are represented by the so-called fiber reinforced cementitious matrix (FRCM) composites. FRCM composites are comprised of high strength fibers embedded within a cementitious matrix that is responsible for the stress transfer between the existing structure and the strengthening material. FRCM composites are still in their infancy, and very limited results are available in the literature on RC and masonry strengthening applications. This study presents an experimental campaign conducted on different FRCM composites comprised of glass, carbon, or steel fibers embedded within two different cementitious matrices and applied to concrete prisms. The single-lap direct-shear test was used to study the stress-transfer mechanism between the FRCM composite and the concrete substrate. Two different composite bonded lengths were investigated. Debonding occurred at the matrix-fiber interface for some of the composites tested and at the concrete-matrix interface for others. This work contributes to the study of the bond behavior of FRCM composites, which represents a key issue for the effectiveness of FRCM composite strengthening

Internal and external transversal reinforcement interaction in RC beams strengthened in shear with externally bonded composites

The overall shear strength of Reinforced Concrete (RC) beams strengthened in shear with Fiber Reinforced Polymer (FRP) and Fiber Reinforced Cementitious Matrix (FRCM) composites is generally computed as the simple summation of the individual contributions of concrete and transversal internal (i.e. steel stirrups) and external (i.e. FRP or FRCM composites) reinforcement. However, the interaction between transversal internal and external shear reinforcement might cause an overestimation of the strength of the strengthened beams when this simplified approach is used for FRP strengthened elements. Although the experimental evidence is still limited, a similar interaction has been reported for beams strengthened in shear with FRCM composites. This paper presents the results of an experimental campaign carried out to investigate the aforementioned interaction. RC beams were strengthened in shear using FRP and FRCM composites and then tested using a traditional four point bending scheme. Interaction between the internal and external transversal reinforcement was observed, as strains measured in the stirrups of the strengthened beams were lower than those measured in the unstrengthened beams at peak load. Although this reduction was more evident for FRP strengthened beams, the presence of the external reinforcement precluded stirrups from yielding for either FRP or FRCM strengthened beams in this study

Recupero di rilevazioni ufficiali correnti per lo studio delle epatopatie: epatopatie croniche non malformative

epatopatie, rilevazion

Prestressed FRP systems

This chapter provides an overview on the state-of-the-art in prestressing systems for the structural retrofitting of reinforced concrete (RC) structures using Externally Bonded (EB) Fibre Reinforced Polymers (FRP). Focus is put on flexural strengthening, which currently is the most common application field for composite materials in structural engineering. The manuscript provides information regarding commercially available prestressing systems and their anchorage procedures. In addition to conventional mechanical anchorages, the innovative ‘gradient anchorage’ that lacks any remaining plates or bolts is also presented. Additionally, the authors mention various current prototypes at the laboratory-scale level. Performed experimental investigations, results, and conclusions represent the core content of this chapter. Several studies from various universities and research institutes worldwide are presented and explained. In these research projects, the previously mentioned systems are applied to specific reinforced or prestressed reinforced concrete members for strengthening purposes. Static and/or dynamic loading indicate the efficiency of the retrofitting concept compared to the reference structure. Generally, prestressed FRP will be demonstrated to follow the principle of conventional prestressed concrete by resulting in higher cracking, yielding, and bearing loads. Especially under service loads, the structural behaviour is improved.(undefined