@article {13364, title = {Ductilidade e resist{\^e}ncia no refor{\c c}o de pilares de bet{\~a}o armado sem aumento de sec{\c c}{\~a}o}, journal = {Constru{\c c}{\~a}o Magazine}, volume = {84}, number = {Mar{\c c}o/Abril}, year = {2018}, note = {

REFER{\^E}NCIAS
1. Chastre, C. and M.A.G. Silva, Monotonic axial behavior and modelling of RC circular columns confined with CFRP. Engineering Structures, 2010. 32(8): p. 2268-2277.
2. Faustino, P., C. Chastre, and R. Paula, Design model for square RC columns under compression confined with CFRP. Composites Part B: Engineering, 2014. 57: p. 187-198.
3. Chastre, C., CREatE, um sistema inovador de refor{\c c}o estrutural utilizando comp{\'o}sitos de CFRP, in Constru{\c c}{\~a}o Magazine. 2017. p. 46-47.
4. Chastre, C., H. Biscaia, and N. Franco, Refor{\c c}o de Vigas de Bet{\~a}o Armado com Armaduras P{\'o}s-Instaladas de A{\c c}o Inox ou de Comp{\'o}sitos de FRP. Mec{\^a}nica Experimental, 2017. 28: p. 39-46.
5. Chastre, C., et al., Experimental Analysis of Reinforced Concrete Beams Strengthened with Innovative Techniques, in 41th IAHS Word Congress of Housing. Sustainability and Innovation for the Future. 2016: Albufeira, Portugal. p. 10.6. Biscaia, H.C., et al., Flexural Strengthening of Old Timber Floors with Laminated Carbon Fiber-Reinforced Polymers. Journal of Composites for Construction, 2017. 21(1): p. 04016073.
7. Faustino, P. and C. Chastre, Flexural Strengthening of Columns with CFRP Composites and Stainless Steel: Cyclic Behavior. Journal of Structural Engineering, 2016. 142(2): p. 04015136.8. Faustino, P. and C. Chastre, Damage Effect on Concrete Columns Confined with Carbon Composites. ACI Structural Journal, 2016. 113(5): p. 951-692.
9. Faustino Marques, P., Strengthening to seismic action of reinforced columns with rectangular cross-section. Tese de Doutoramento, Universidade NOVA de Lisboa, Caparica, 2015.

}, month = {Mar{\c c}o/Abril de 2}, pages = {48-49}, abstract = {

O aumento da resist{\^e}ncia e/ou da ductilidade {\'e} um objetivo primordial quando se procede ao refor{\c c}o de pilares. Um m{\'e}todo bastante eficaz de aumentar a ductilidade, particularmente em regi{\~o}es s{\'\i}smicas, {\'e} atrav{\'e}s do encamisamento com coletes de FRP, uma vez que esta t{\'e}cnica permite uma diminui{\c c}{\~a}o da deforma{\c c}{\~a}o transversal do pilar e a limita{\c c}{\~a}o da encurvadura das armaduras longitudinais, aumentando consequentemente a ductilidade do mesmo. Diversos ensaios experimentais permitiram detetar que os incrementos s{\~a}o maiores em sec{\c c}{\~o}es circulares do que em sec{\c c}{\~o}es quadradas ou retangulares [1, 2]. A atenua{\c c}{\~a}o deste efeito {\'e} obtida atrav{\'e}s do arredondamento dos cantos nos pilares de sec{\c c}{\~a}o retangular. Contudo, o encamisamento com coletes de FRP, por si s{\'o}, n{\~a}o aumenta significativamente a resist{\^e}ncia do pilar {\`a} flex{\~a}o composta. Para que isso aconte{\c c}a e se mantenha um n{\'\i}vel elevado de ductilidade, {\'e} necess{\'a}rio adicionar armaduras longitudinais {\`a} armadura do pilar e posteriormente proceder ao encamisamento com colete de FRP. Uma forma muito eficiente de o conseguir, mantendo a se{\c c}{\~a}o transversal do pilar, {\'e} utilizando o sistema CREatE (Continuous Reinforcement Embedded at Ends) desenvolvido na Universidade NOVA e j{\'a} anteriormente apresentado nesta coluna, na edi{\c c}{\~a}o de Junho/Agosto de 2017 [3], para o caso do refor{\c c}o de vigas. O sistema CREatE foi idealizado para ser utilizado com diversos materiais e diferentes elementos estruturais [4-7], em que {\'e} necess{\'a}rio aumentar a sua capacidade resistente atrav{\'e}s de armaduras p{\'o}s-instaladas, caracterizando-se pela utiliza{\c c}{\~a}o de armaduras cont{\'\i}nuas embutidas nas extremidades do elemento estrutural sem o uso de dispositivos mec{\^a}nicos para as fixar. Antes da ancoragem da armadura de refor{\c c}o no interior do elemento, {\'e} necess{\'a}rio utilizar uma curva de transi{\c c}{\~a}o suave para alterar a forma da armadura de refor{\c c}o e evitar a ocorr{\^e}ncia de concentra{\c c}{\~o}es de tens{\~o}es na armadura ou na interface [4, 7, 8]. Este conceito foi aplicado no refor{\c c}o de pilares realizado no {\^a}mbito da tese de doutoramento de Faustino Marques [9].Na Figura 1 {\'e} poss{\'\i}vel observar dois pilares de se{\c c}{\~a}o retangular (20x40cm2) encamisados com coletes de 3 camadas de CFRP (200gr/m2) em que foi utilizado o sistema CREatE com armaduras p{\'o}s-instaladas de a{\c c}o inox (2x20x5mm2) ou de laminados de CFRP (2x(10+20){\texttimes}1.4 mm2/face) para refor{\c c}o longitudinal [7, 8]. Na Figura 2 pode observar-se os resultados dos ensaios experimentais de um conjunto de pilares de se{\c c}{\~a}o retangulares sujeitos a esfor{\c c}o axial e a a{\c c}{\~o}es horizontais c{\'\i}clicas. O pilar P11 {\'e} o de refer{\^e}ncia pois, n{\~a}o foi refor{\c c}ado, enquanto os pilares P12, P15 e P16 foram encamisados com coletes de 3 camadas de CFRP e nos pilares P15 e P16 foi utilizado adicionalmente o sistema CREatE com armaduras p{\'o}s-instaladas de a{\c c}o inox (P15) ou de laminados de CFRP (P16) para refor{\c c}o longitudinal [7]. Na Figura 3 mostra-se a envolvente dos diagramas For{\c c}a-Deslocamento dos ensaios dos diferentes pilares de se{\c c}{\~a}o retangular (P11; P12; P15 e P16), sendo poss{\'\i}vel de constatar um excelente desempenho n{\~a}o s{\'o} em termos de ductilidade (incremento de 67\%) como de resist{\^e}ncia (incrementos entre 29\% e 43\%, para drifts entre 2 e 4\%) dos pilares refor{\c c}ados com o sistema CREatE relativamente ao pilar de refer{\^e}ncia n{\~a}o refor{\c c}ado.

}, keywords = {Bet{\~a}o armado, Comp{\'o}sitos de FRP, Pilares, Refor{\c c}o, T{\'e}cnica CREatE}, url = {http://www.construcaomagazine.pt/noticias/revista-n84-marco-abril-2018/}, author = {Chastre, Carlos} } @article {12336, title = {Design method and verification of steel plate anchorages for FRP-to-concrete bonded interfaces}, journal = {Composite Structures}, volume = {192}, year = {2018}, note = {

n/a

}, month = {5/15/}, pages = {52-66}, abstract = {

Concrete structures Externally Bonded Reinforced (EBR) with Fibre Reinforced Polymers (FRP) have been studied and used since the end of the last century. However, several issues need to be better studied in order to improve performance. The influence of size of anchorage plates used on Reinforced Concrete (RC) structures strengthened with EBR FRP composites, the external compressive stress to be applied on the anchorage plate and the numerical simulation of this region are some of the topics that need to be more carefully studied in order to clarify the performance of the FRP-to-concrete interface within the anchorage plate region. This study proposes a design methodology to estimate the amount of external compressive stress necessary to be applied on the anchorage plate of EBR systems with FRP composites, in order to avoid premature debonding. The external compressive stress imposed on the FRP composite is intended to simulate the effect produced by a mechanical anchorage system tightened to the EBR system. The results from the design proposal, when compared with the numerical ones, were efficient enough on the prediction of the bond strength improvement of FRP-to-concrete interfaces.

}, keywords = {Bond, Concrete, Design methodology, FRP, interfaces, Mechanical anchorage}, isbn = {0263-8223}, url = {https://www.sciencedirect.com/science/article/pii/S0263822317341703}, author = {Biscaia, Hugo C. and Chastre, Carlos} } @conference {13389, title = {Degradation of EB-GFRP systems due to artificial aging conditions}, booktitle = {XVI Portuguese Conference on Fracture (PCF2018)}, year = {2018}, note = {

REFERENCES[1] Silva, MAG, Biscaia, HC. Effects of exposure to saline humidity on bond between GFRP and concrete. Comp Struct, 2010; 93(1): 216-224.[2] Micelli, F, Nanni, A. Durability of FRP rods for concrete structures." Construction and Building Materials, 2004; 18: 491-503.[3] Biscaia, HC. Behaviour and modeling of GFRP-to-concrete interfaces of reinforced concrete elements exposed to aggressive environments. PhD thesis, FCT/UNL, 2012.

}, month = {23-24th April 20}, address = {Universidade da Beira Interior, Covilh{\~a}, Portugal}, abstract = {

The use of adhesively bonded joints between Fiber Reinforced Polymers (FRP) and concrete elements have been spread out in the past decades. However, due to their recent applications, the durability aspects related with these bonded joints requires the use of high safety factors which strongly restricts the mechanical capacity of the FRP composites. The experimental assessment of the degradation of FRP-to-concrete interfaces is an important task because it provides useful data that can be used to calibrate analytical or numerical models with the aim of helping on the correct understanding of the interfacial degradation. In this work, a new and simple interfacial bond-slip model that needs only one parameter to be experimentally defined is proposed. Compared to unaged Glass (G) FRP-to-concrete interfaces, the relative degradation of these bonded interfaces is studied after being subjected to: (i) salt fog cycles; (ii) wet-dry cycles; (iii) temperature cycles between -10{\textordmasculine}C and +30{\textordmasculine}C; and (iv) between +7.5{\textordmasculine}C and +47.5{\textordmasculine}C. The subsequent full debonding processes are predicted through an analytical model that takes into account the degradations experimentally determined from the tests.

}, keywords = {Analytical model., Bonded joints, Durability, GFRP-to-concrete interface}, url = {http://193.136.66.99/fractura/}, author = {Biscaia, Hugo and Chastre, Carlos} } @article {12342, title = {Determination of weathering degree of the Persepolis stone under laboratory and natural conditions using fuzzy inference system}, journal = {Construction and Building Materials}, volume = {145}, year = {2017}, note = {n/a}, pages = {28-41}, chapter = {28}, abstract = {

Weathering imposes vital effects on stony monuments. Mostly, the degree of weathering is determined by simple test results, ignoring simultaneous effects of various weathering factors. Hence, the main purpose of this study is to develop prediction models with fuzzy inference systems to determine the weathering degree of the Persepolis stone, using various accelerated ageing tests in laboratory condition and to extrapolate the results to the natural condition, considering climatic information. The results suggest reliable conformity between the prediction of the weathering degree of the stone and the weathering degree observed in the Persepolis complex in natural condition.

}, keywords = {Fuzzy inference system, Persepolis stone, Weathering degree}, isbn = {09500618}, author = {Heidari, Mojtaba and Torabi-Kaveh, Mehdi and Chastre, Carlos and Ludovico-Marques, Marco and Mohseni, Hassan and Akefi, Hossein} } @conference {10025, title = {Durability Assessment of Consolidation Effect on Sandstone Monuments}, booktitle = {41th IAHS Word Congress of Housing. Sustainability and Innovation for the Future}, year = {2016}, note = {

REFERENCES[1] ICOMOS - International Scientific Committee for Stone, {\textquotedblleft}Illustrated Glossary on Stone Deterioration Patterns{\textquotedblright}, 2008.[2] M. Ludovico-Marques, {\textquotedblleft}Contribution to the Knowledge of the Effect of Crystallization of Salts in the Weathering of Sandstones. Application to the Built Heritage of Atouguia da Baleia{\textquotedblright}, PhD Thesis in Geotechnical Engineering, Specializing in Rock Mechanics,Universidade NOVA de Lisboa, Lisbon, 2008, (in Portuguese).[3] M. Ludovico-Marques, C. Chastre, {\textquotedblleft}Effect of Salt Crystallization Ageing on the Compressive Behavior of Sandstone Blocks in Historical Buildings{\textquotedblright} Engineering Failure Analysis, vol. 26, pp. 247-257, 2012.[4] M. Ludovico-Marques; C. Chastre, 2014. "Conservation of sandstone monuments: a new approach in consolidation treatments", 40th IAHS World Congress on Housing-Sustainable Housing Construction. Proceedings 2014, Funchal.[5] R. Folk (1974): Petrology of Sedimentary Rocks, Hemphill Publishing, Austin.[6] RILEM, {\textquotedblleft}Recommended Tests to Measure the Deterioration of Stone and to Assess the Effectiveness of Treatment Methods{\textquotedblright} Mat{\'e}rieux et Constructions, Bourdais-Dunoud, vol. 13 (75), pp. 175-253, 1980.[7] EN 1936, {\textquotedblleft}Natural Stone Test Method-Determination of Real Density and Apparent Density, and of Total and Open Porosity{\textquotedblright}, European Standard, 1999.[8] F. Pellerin, {\textquotedblleft}La Porosimetrie au Mercure Appliquee a l{\textasciiacute} Etude Geotechnique des Sols et des Roches{\textquotedblright} Bulletin de Liaison des Laboratoires des Ponts et Chauss{\'e}s, vol. 106, pp. 105-116, 1980.[9] NORMAL-29/88, {\textquotedblleft}Misura dell{\textquoteright} Indice di Asciugamento (Drying Index). Alterazioni dei Material Lapidei e Trattamenti Conservativi - Proposte per l{\textquoteleft}Unificazione dei Metodi Sperimentali di Studio e di Controllo{\textquotedblright}, CNR{\textendash}ICR, Roma, 1991.[10] NP EN12370. M{\'e}todos de ensaio para pedra natural.Determina{\c c}{\~a}o da resist{\^e}ncia {\`a} cristaliza{\c c}{\~a}o de sais. Instituto Portugu{\^e}s da Qualidade 2002, 10 p.

}, month = {13-16 September }, pages = {10p}, address = {Albufeira, Portugal}, abstract = {

The fa{\c c}ades of St. Leonard{\textquoteright}s church and the castle in Atouguia da Baleia village in western region of Portugal are monuments built in Middle Ages. Significant stone degradation patterns are visible, being the alveolization an outstanding case study.The more porous type of sandstones similar to the variety found in the vernacular architecture of Atouguia da Baleia was treated with ethyl silicates. In order to allow the study of the durability of these conservation treatments, accelerated artificial ageing salt crystallization tests were carried out and an automatic ageing chamber was developed.Physical and mechanical behaviour was assessed on consolidated specimens before and after accelerated artificial ageing salt crystallization tests. The authors propose a prediction of the durability of these consolidation treatments by means of the salt crystallization ageing results.

}, keywords = {Durability, Ethyl silicates, Sandstone Monuments, sustainability}, attachments = {https://docentes.fct.unl.pt/sites/default/files/cmcr/files/41_iahs_2016_-_marco_marques_-_ext-abstract_durability_assessment_of_consolidation_effect_on_sandstone_monuments_ludovico_marques__chastre.pdf}, author = {Ludovico-Marques, Marco and Chastre, Carlos} } @article {10009, title = {Damage Effect on Concrete Columns Confined with Carbon Composites}, journal = {ACI Structural Journal}, volume = {113}, number = {4}, year = {2016}, note = {

http://dx.doi.org/10.14359/51687916

}, abstract = {

Five experimental cyclic tests were carried out on reinforced concrete rectangular columns with rounded corners, different condition (new and damaged) and different strengthening systems: that included confinement through carbon fiber (CFRP) jackets, anchor dowels, high strength repair mortar and external longitudinal stainless steel bars. Lateral load - displacement relationship, energy dissipation, ductility and curvature results were analyzed together with two different damage assessment classifications. The overall evaluation concludes that the use of external confinement with CFRP on RC columns is viable and of effective performance enhancement alone and combined with other techniques. Damaged columns that were retrofitted showed an increased load capacity up to 20\% along with good ductile behavior within the limits of the US, European, Canadian and Japanese codes, with minor/moderate degree of damage at 1\% drift ratio and moderate degree of damage at 2\% drift ratio.

}, keywords = {CFRP, confinement, cyclic behavior, reinforced concrete columns, seismic behavior, stainless steel strengthening}, url = {https://www.concrete.org/publications/internationalconcreteabstractsportal.aspx?m=details\&ID=51687916}, author = {Faustino, Pedro and Chastre, Carlos} } @article {5879, title = {Delamination process analysis of FRP-to-parent material bonded joints with and without anchorage systems using the Distinct Element Method}, journal = {Composite Structures}, volume = {116}, year = {2014}, pages = {104{\textendash}119}, abstract = {

This study looks at the analysis of the interface between Fiber Reinforced Polymer (FRP)-to-parent material bonded interfaces. The performance of FRP-to-parent material bonded joints for the Externally Bonded Reinforcement (EBR) technique is numerically modelled with the PFC2D software which is based on the Distinct Element Method (DEM). It is believed that this represents the first time the DEM has been used to simulate the delamination process of FRP-to-parent material bonded joints. In order to validate the analysis performed with the DEM, a Pull-out test with no slip constrains was modelled and different linear bond-slip laws were assumed. The numerical results revealed that the DEM is capable of estimating with good accuracy the exact solutions of bond stresses, strains or slippages along the bonded length for linear bond-slip laws. The bi-linear law available in PFC2D was then compared to the numerical results obtained from other another code developed by the author. The delamination process of Pull-out tests with slip constrain at one of the free ends of the FRP plate is also described and analyzed. The results obtained from the DEM revealed that the delamination process ends with stiffness equal to the axial stiffness of the FRP plate. This evidence highlights the need to design mechanical anchor devices capable of preventing premature debonding which is known to occur on EBR systems.

}, url = {http://dx.doi.org/10.1016/j.compstruct.2014.04.021}, author = {Biscaia, Hugo C. and Rui Micaelo and Teixeira, Jo{\~a}o and Chastre, Carlos} } @article {4992, title = {Design model for square RC columns under compression confined with CFRP}, journal = {Composites Part B: Engineering}, volume = {57}, year = {2014}, note = {

n/a

}, pages = {187-198}, abstract = {

The enhancement of the mechanical behaviour of reinforced concrete (RC) columns with regard to axial compression is an up-to-date concern, namely if the strengthening of existing structures is to be considered. In view of this, external confinement with FRP systems has been tested in order to become a feasible technique, since it seems to have important advantages over other systems such as its high strength and stiffness in relation to weight and its improvement of strength and ductility while confining RC columns. Square columns confined with FRP show a more complex interpretation of their behaviour, when compared to circular columns. Accordingly, the present work includes the analysis of two experimental programs regarding axial compression on CFRP confined RC columns: one on circular and square specimens with different corner radii; the other on square specimens with side lengths ranging from medium to large. Based on this, modelling equations are proposed to predict maximum axial load, axial strain and lateral strain, as well as the entire behaviour until failure with curves of axial load-axial strain and axial load-lateral strain. The modelling results show that the analytical curves are in general agreement with the presented experimental curves for a wide range of dimensions.

}, keywords = {A. Carbon fibreB. Mechanical propertiesB. StrengthB. ConfinementC. Analytical modelling}, isbn = {1359-8368}, url = {http://www.sciencedirect.com/science/article/pii/S1359836813005659}, attachments = {https://docentes.fct.unl.pt/sites/default/files/cmcr/files/faustino_chastre_et_al._2014.pdf}, author = {Faustino, Pedro and Chastre, Carlos and Paula, Raquel} } @article {3020, title = {Development of an injectable grout for concrete repair and strengthening}, journal = {Cement and Concrete Composites}, year = {2013}, note = {

n/a

}, abstract = {

This paper deals with the coupled effect of temperature and silica fume addition on rheological, mechanical behaviour and porosity of grouts based on CEMI 42.5R, proportioned with a polycarboxylate-based high range water reducer. Preliminary tests were conducted to focus on the grout best able to fill a fibrous network since the goal of this study was to develop an optimized grout able to be injected in a mat of steel fibers for concrete strengthening. The grout composition was developed based on criteria for fresh state and hardened state properties. For a CEMI 42.5R based grout different high range water reducer dosages (0, 0.2\%, 0.4\%, 0.5\%, 0.7\%) and silica fume (SF) dosages (0, 2\%, 4\%) were tested (as replacement of cement by mass). Rheological measurements were used to investigate the effect of polycarboxylates (PCE) and SF dosage on grout properties, particularly its workability loss, as the mix was to be injected in a matrix of steel fibers for concrete jacketing. The workability behaviour was characterized by the rheological parameters yield stress and plastic viscosity (for different grout temperatures and resting times), as well as the procedures of mini slump cone and funnel flow time. Then, further development focused only on the best grout compositions. The cement substitution by 2\% of SF exhibited the best overall behaviour and was considered as the most promising compared to the others compositions tested. Concerning the fresh state analysis, a significant workability loss was detected if grout temperature increased above 35{\textdegree}C. Below this temperature the grout presented a self-levelling behaviour and a life time equal to 45 minutes. In the hardened state, silica fumes increased not only the grout{\textquoteright}s porosity but also the grout{\textquoteright}s compressive strength at later ages, since the pozzolanic contribution to the compressive strength does not occur until 28 days and beyond.

}, keywords = {Cement grout, Mix optimization, Rheology, Self leveling, Temperature, Thixotropy, Unidirectional steel fiber}, isbn = {09589465}, url = {http://www.sciencedirect.com/science/article/pii/S0958946512002144?v=s5}, author = {Bras, Ana and Gi{\~a}o, Rita and V{\'a}lter L{\'u}cio and Chastre, Carlos} } @proceedings {3023, title = {Degrada{\c c}{\~a}o da ader{\^e}ncia entre comp{\'o}sitos de GFRP e bet{\~a}o devido a condi{\c c}{\~o}es ambientais severas}, journal = {Bet{\~a}o Estrutural 2012}, year = {2012}, note = {

n/a

}, publisher = {FEUP}, address = {Porto}, abstract = {

A degrada{\c c}{\~a}o da liga{\c c}{\~a}o entre comp{\'o}sitos de matriz polim{\'e}rica refor{\c c}ada por fibras (FRP) e o bet{\~a}o {\'e} uma das principais causas de poss{\'\i}vel rotura das vigas e lajes de bet{\~a}o armado refor{\c c}adas
externamente por comp{\'o}sitos de FRP. Desde h{\'a} mais de 10 anos que se estuda, por isso, na UNL o
comportamento dessa liga{\c c}{\~a}o, integrado em programa mais alargado de estudo da durabilidade deste tipo de refor{\c c}o, especialmente quando sujeito a condi{\c c}{\~o}es ambientais severas que se simulam por processos artificialmente acelerados no laborat{\'o}rio. Em particular a degrada{\c c}{\~a}o da ader{\^e}ncia e o poss{\'\i}vel descolamento precoce do refor{\c c}o t{\^e}m sido modelados f{\'\i}sica e computacionalmente com principal incid{\^e}ncia no uso de fibras de vidro (GFRP) e resina epox{\'\i}dica. Nesta comunica{\c c}{\~a}o mostram-se resultados obtidos em termos de capacidade de carga, for{\c c}a transmitida ao refor{\c c}o e tens{\~o}es de ader{\^e}ncia ap{\'o}s envelhecimentos de pequenas vigas de bet{\~a}o armado (BA) por ciclos de nevoeiro salino, ciclos seco/molhado em solu{\c c}{\~a}o salina, ciclos de temperatura entre +7,5{\textordmasculine}C e +47,5{\textordmasculine}C e gelo-degelo de -10{\textordmasculine}C a +30{\textordmasculine}C. Faz-se recomenda{\c c}{\~a}o quanto {\`a} extens{\~a}o m{\'a}xima para diferentes envelhecimentos. Apresenta-se compara{\c c}{\~a}o entre resultados de modela{\c c}{\~a}o num{\'e}rica e experimental.

}, attachments = {https://docentes.fct.unl.pt/sites/default/files/cmcr/files/silva2012bich_-_be2012_-_feup.pdf}, author = {Silva, M. A. G., and Biscaia, H. C. and Chastre, C.} } @article {3039, title = {Double shear tests to evaluate the bond strength between GFRP/concrete elements}, journal = {Composite Structures}, volume = {94}, number = {2}, year = {2012}, note = {

n/a

}, pages = {681-694}, abstract = {

Externally bonded reinforced systems have been widely used in civil engineering. However, the problems associated with bond between structural elements are not yet fully solved. As a consequence, many researchers have been proposing tests and techniques to standardize procedures and reach better agreement for design purposes. In the present paper, an experimental program is described that was developed to characterize the glass FRP/concrete interface by double shear tests made on 15\&$\#$xa0;cm side cubes with GFRP bonded on two opposite faces. The GFRP wrap had two layers applied by the wet lay-up technique and three classes of concrete were considered. With the support of the experimental program, cohesion and friction angle for GFRP{\textendash}concrete interfaces were found leading to different envelope failure laws, based on the Mohr{\textendash}Coulomb failure criterion for each concrete class, capable of predicting GFRP debonding. Results are discussed.

}, keywords = {Bond, Concrete, GFRP, Interface, Mohr{\textendash}Coulomb criterion}, isbn = {0263-8223}, url = {http://www.sciencedirect.com/science/article/pii/S0263822311003370}, author = {Biscaia, Hugo C. and Chastre, Carlos and Silva, Manuel A. G.} } @booklet {3042, title = {Displacement measurements with ARPS in T-beams load tests}, volume = {349 AICT}, year = {2011}, note = {

Export Date: 7 November 2011Source: ScopusReferences: Chu, T.C., Ranson, W.F., Sutton, M.A., Peters, W.H., Applications of Digital.Image-Correlation Techniques to Experimental Mechanics (1985) Experimental Mechanic, 25 (3), pp. 232-244; Sutton, M.A., Wolters, W.J., Peters, W.H., Ranson, W.H., McNeill, S.R., Determination of displacements using an improved digital correlation method (1983) Image and Vision Computing, pp. 133-139; Peters, W.H., Ranson, W., Digital Imaging Techniques in Experimental Stress Analysis (1982) Optical Engineering, 21 (3), p. 5; Almeida, G., Biscaia, H., Melicio, F., Chastre, C., Fonseca, J., Displacement Estimation of a RC Beam Test based on TSS algorithm 5th Iberian Conference on Information Systems and Technologies (CISTI 2010), Santiago de Compostela (2010); Barjatya, A., (2004) Block Matching Algorithms for Motion Estimation, , DIP 6620 Spring, Final Project Paper; Carvalho, T., Paula, R., Biscaia, C.C., Flexural Behaviour of Rc T-Beams Strengthened with Different Frp Materials 3rd Fib International Congress, Washington, D.C (2010); Carolin, A., Olofsson, T., Taljsten, B., Photographic strain monitoring for civil engineering (2004) FRP Composites in Civil Engineering - CICE 2004, , Seracino; Yao Nie, K.-K.M., Adaptive Rood Pattern Search for Fast Block-Matching Motion Estimation (2002) IEEE Transactions on Image Processing, 11 (12), p. 8

}, pages = {286-293}, abstract = {

The measurement of deformations, displacements, strain fields and surface defects in many material tests in Civil Engineering is a very important issue. However, these measurements require complex and expensive equipment and the calibration process is difficult and time consuming. Image processing could be a major improvement, because a simple camera makes the data acquisition and the analysis of the entire area of the material under study without requiring any other equipment like in the traditional method. Digital image correlation (DIC) is a method that examines consecutive images, taken during the deformation period, and detects the movements based on a mathematical correlation algorithm. In this paper, block-matching algorithms are used in order to compare the results from image processing and the data obtained with linear voltage displacement transducer (LVDT) sensors during laboratorial load tests of T-beams. {\textcopyright} 2011 IFIP International Federation for Information Processing.

}, keywords = {Block Motion Estimation, Digital Image Correlation, image processing}, url = {http://link.springer.com/book/10.1007/978-3-642-19170-1/page/2}, author = {Almeida, G and Melicio, F. and Chastre, C. and Fonseca, J.} } @proceedings {3048, title = {Displacement Estimation of a RC beam test based on TSS algorithm}, journal = {CISTI{\textquoteright}2010 - 5{\textordfeminine} Conferencia Ib{\'e}rica de Sistemas y Tecnolog{\'\i}as de Informaci{\'o}n}, year = {2010}, note = {

n/a

}, address = {Santiago de Compostela}, abstract = {

The traditional methodology used in civil engineering measurements requires a lot of equipment and a very complex procedure especially if the number of target points increase. Since the beginning of the current century, several studies have been conducted in the area of photogrametry using digital image
correlation associated with block motion algorithms to estimate displacements in reinforced concrete (RC) beams during a load test. Using image processing techniques it is possible to measure the whole area of interest and not only a few points of the tests materials. In this paper, block-matching algorithms are used in order to compare the results from photogrametry techniques and the data obtained with linear voltage displacement transducer (LVDT) sensors during the load tests of RC beams, which are very common to find in civil engineering laboratories.

}, author = {Almeida, G and Biscaia, H. and Chastre, C. and Fonseca, J. and Mel{\'\i}cio, F.} }