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This paper investigates the behavior of glass fiber reinforced polymer (GFRP)-reinforced concrete (RC) continuous beams subjected to unsymmetrical loading conditions. A total of six large-scale RC continuous beams were constructed and tested to failure. Three different loading cases were considered, (I) loading both spans equally, (II) loading both spans maintaining a load ratio of 1.5 and (III) loading one span only. The effects of reinforcing material type, assumed percentage of moment redistribution and serviceability requirements on the performance of the test beams were investigated. Also, a comparison between the experimental deflection and that predicted by available models, using effective moment of inertia approach, is presented. Test results revealed that, beams tested under unsymmetrical loading case II showed less crack widths, strains and deflections in the higher load span compared to those in the less load span or those symmetrically loaded. Moreover, the unsymmetrical loading conditions adversely affected the moment redistribution. [ABSTRACT FROM AUTHOR]

Adobe constructions were widespread in the ancient world, and earth was one of the most used construction materials in ancient times. Therefore, the preservation of adobe structures, especially against seismic events, is nowadays an important structural issue. Previous experimental tests have shown that the ratio between mortar and brick mechanical properties (i.e., strength, stiffness and elastic modulus) influences the global response of the walls in terms of strength and ductility. Accurate analyses are presented in both the case of unreinforced and reinforced with fiberglass mesh when varying the mechanical properties of the materials composing the adobe masonry structure. The main issues and variability in the behavior of seismic resisting walls when varying the mechanical properties are herein highlighted. The aim of the overall research activity is to improve the knowledge about the structural behavior of adobe structural members unreinforced and reinforced with fiberglass mesh inside horizontal mortar joints. [ABSTRACT FROM AUTHOR]

Highlights: [•] We suggested a section of a new module that would apply a large section. [•] We developed a new FRP composite girder that is filled with concrete. [•] It was confirmed the composite effect from confining concrete. [ABSTRACT FROM AUTHOR]

• A SHM method is presented and discussed on the example of an aircraft spoiler. • An in-depth numerical study with varying damage sizes is performed. • The validation of the numerical results is done by a DIC system and SG measurements. This paper investigates a strain-based structural health monitoring (SHM) method for damage detection and localization in composite sandwich structures. As case example, an idealized aircraft spoiler of a large civil aircraft is considered. Critical failure modes of such sandwich structures composed of fiber reinforced polymer (FRP) face layers and a honeycomb core are, e.g., face layer delamination and debonding from the core. The latter challenges today's non-destructive testing methods, and thus, shall be addressed in the present work. The presented research compromises an idealized spoiler model of the real spoiler structure in the scale 1:2. The model is composed of glass fiber reinforce polymer (GFRP) face layers and a honeycomb core. The damage identification is investigated based on static strain measurements along so-called zero-strain trajectories (ZST) at the loaded structure. A zero-strain direction exists for every plane strain state with major strain directions with opposite signs (tensile and compression). Connecting zero-strain direction vectors at various points of a structure yields a ZST. Strains along ZST are most sensitive to changes of the load path due to, e.g., damage. This work investigates the use of strain measurements along ZST for damage detection at the edge of the considered sandwich structure by means of numerical and experimental analysis. A real wind-load condition of a large civil aircraft spoiler is considered as load case. An in-depth numerical and experimental investigation is performed to calculate the ZST for the pristine structure. The experimental validation of the Finite element (FE) model is realized by deformation measurements via a digital image correlation system (DIC). Moreover, strain measurements via strain gauge (SG) rosettes were performed to evaluate the correct calculation of the zero-strain directions. Finally, the application of strain measurements along a ZST for debonding detection and localization is demonstrated and its potential and issues for real online monitoring is discussed. [ABSTRACT FROM AUTHOR]

In this study, stiff stab-resistant materials for riot shields were developed by using fiber reinforced polymer composites (FRPs) made of three different types of fibers: carbon, glass and p-aramid. The stab resistance of the FRPs were investigated with respect to the thickness and types of reinforced fibers according to the U.S.A. National Institute of Justice (NIJ) standard. Hybrid composites were then developed to compensate for the weaknesses of each FRP, and the stacking sequences were optimized. The mechanisms of the stab resistance and the blade penetration for each FRP were investigated via static stab compressive tests. Additionally, the failure mode and fracture topography after the stab resistance tests were obtained using a micro-CT scanner. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the performance of pultruded glass fiber reinforced polymer (pGFRP) I-section columns subject to short-term concentric compression, bringing up a discussion on the relevant parameters affecting their local buckling behavior and the interpretation of tests results. An experimental program was carried out, including a detailed material characterization and twenty-nine compression tests on short I-columns made of either polyester or vinyl ester matrices, with variable flange width-to-section depth ratios (b f / d), column lengths and local end conditions. The theoretical critical loads predicted using generalized beam theory (GBT) and finite element method (FEM) were compared to experimental results obtained by Southwell and Koiter techniques, with better agreements obtained for the latter. It is shown that, besides the length and local end conditions for loaded edges, post-buckling with associated non-linear elastic strains distribution throughout the cross-section and damage prior to buckling have relevant influence on the measured critical loads. On the other hand, the influence of the rotational stiffness of web-flange junctions were considered small for the material and cross-sections studied. Finally, results have shown that the usual boundary condition adopted in literature approaches a clamped condition instead of simply-supported one. [ABSTRACT FROM AUTHOR]

In this paper, a comprehensive study of CFRP and GFRP strengthened circular concrete columns is presented. Previous experimetal work is reviewed including the effect of different parameters affecting the strenght and behaviour of circular concrete columns confined with FRP and new equations are propsed which has more accurate prediction of the enhanced circular concrete column strength and behvaviour than previously proposed ones. [ABSTRACT FROM AUTHOR]