Strand bond performance in prestressed concrete accounting for bondslip

This paper presents the results of an experimental research program addressing the bond behavior of prestressing strands in pretensioned prestressed concrete members after anchorage failure has occurred. A test methodology based on measuring the prestressing strand force and strand end slip at the specimens free end was employed. Transmission- and anchorage-length tests were performed on several series of prestressed specimens with different embedment lengths using twelve concrete mixes. Average bond stresses along the transmission length and the anchorage length were obtained for specimens with release strengths ranging from 24 MPa to 55 MPa. For the anchorage analysis, a parameter was developed that includes strand slip to be used in determining anchorage length. Based on the test results, an analysis to experimentally substantiate the Stress Waves Theory of Janney has been proposed. Additionally, the potential bond performance of prestressing strands after anchorage failure at the end regions has been suggested.The content of the present paper is based on tests which were conducted in the Institute of Concrete Science and Technology (ICITECH), at Universitat Politecnica of Valencia (Spain), in collaboration with the companies PREVALESA and ISOCRON. Funding for this experimental research work was provided by the Spanish Ministry of Education and Science/Science and Innovation and ERDF (Project BIA2006-05521 and Project BIA2009-12722). The authors wish to thank the above companies as well as the concrete structures laboratory technicians at the Universitat Politecnica of Valencia for their cooperation. Finally, the authors also wish to pay their respects to C.A. Arbelaez.Martí Vargas, JR.; Serna Ros, P.; Hale, WM. (2013). Strand bond performance in prestressed concrete accounting for bondslip. Engineering Structures. 51:236-244. doi:10.1016/j.engstruct.2013.01.023S2362445

Unitats funcionals aproximades per a processadors de baix consum

Actualment els multiplicadors són una de les unitats funcionals que requereixen més consum d'energia degut al gran nombre de portes lògiques que contenen. Aprofitant el fet que diverses aplicacions poden tolerar un cert error en el resultat del càlcul de les multiplicacions, principalment aplicacions relacionades amb els sentits de l'ésser humà ja que els nostres sentits no són perfectes, podem implementar multiplicadors aproximats que realitzen el càlcul de la multiplicació de manera aproximada i permeten reduir el consum d'energia, mantenint un error relatiu petit en el resultat de l'operació. En aquest projecte s'estudien diverses implementacions de multiplicadors aproximats de 8, 16 i 32 bits i també s'ha estudiat l'efecte de combinar multiplicadors aproximats en una mateixa implementació.Currently multipliers are one of the functional units that consume more energy due to the large number of logic gates used. Taking advantage of the fact that some applications tolerate a small error on the result of the multiplications, mainly applications related to the human senses since our senses are not perfect, we can implement approximate multipliers that calculate the result of the multiplications approximately and, hence, reduce the energy needed while maintaining a small relative error in the result of the operation. In this project, we study different approximate multiplier implementations of 8, 16 and 32 bits and we also study the effect of combining different implementations of approximate multipliers in one implementation

Time-dependent evolution of strand transfer length in pretensioned prestressed concrete members

For design purposes, it is generally considered that prestressing strand transfer length does not change with time. However, some experimental studies on the effect of time on transfer lengths show contradictory results. In this paper, an experimental research to study transfer length changes over time is presented. A test procedure based on the ECADA testing technique to measure prestressing strand force variation over time in pretensioned prestressed concrete specimens has been set up. With this test method, an experimental program that varies concrete strength, specimen cross section, age of release, prestress transfer method, and embedment length has been carried out. Both the initial and long-term transfer lengths of 13-mm prestressing steel strands have been measured. The test results show that transfer length variation exists for some prestressing load conditions, resulting in increased transfer length over time. The applied test method based on prestressing strand force measurements has shown more reliable results than procedures based on measuring free end slips and longitudinal strains of concrete. An additional factor for transfer length models is proposed in order to include the time-dependent evolution of strand transfer length in pretensioned prestressed concrete members. © 2012 Springer Science+Business Media Dordrecht.Funding for this experimental research work has been provided by the Spanish Ministry of Education and Science and ERDF (Projects BIA2006-05521 and BIA2009-12722). Tests have been conducted at the Institute of Concrete Science and Technology (ICITECH), at the Universitat Politecnica de Valencia (Spain).Caro Forero, LA.; Martí Vargas, JR.; Serna Ros, P. (2013). Time-dependent evolution of strand transfer length in pretensioned prestressed concrete members. Mechanics of Time-Dependent Materials. 17(4):501-527. doi:10.1007/s11043-012-9200-2S501527174ACI: ACI 318-11 Building code requirements for reinforced concrete. ACI Committee 318. American Concrete Institute, Farmington Hills, MI (2011)AENOR: UNE 36094:1997 Alambres y cordones de acero para armaduras de hormigón pretensado. Asociación Española de Normalización: Madrid (1997)Balevicius, R.: An average stress strain approach to creep analysis of RC uncracked elements. Mech. Time-Depend. Mater. 14, 69–89 (2010)Barnes, R.W., Grove, J.W., Burns, N.H.: Experimental assessment of factors affecting transfer length. ACI Struct. J. 100(6), 740–748 (2003)Base, G.D.: Some tests on the effect of time on transmission length in pretensioned concrete. Mag. Concr. Res. 4, 73–82 (1957)Base, G.D.: An investigation of transmission length in pretensioned concrete. Cement and Concrete Association, Research Report n∘ 5 (1958)Bruce, R.N., Russell, H.G., Roller, J.J., Martin, B.T.: Feasibility evaluation of utilizing high-strength concrete in design and construction of highway bridge structures. Louisiana Transportation Research Center. Report n $^{\rm{o}}$ FHWA/LA-94-282. Baton Rouge, LA (1994)Buckner, C.D.: A review of strand development length for pretensioned concrete members. PCI J. 40(2), 84–105 (1995)CEN: European standard EN 197-1:2000: Cement. Part 1: Compositions, specifications and conformity criteria for common cements. Comité Européen de Normalisation, Brussels (2000)Cousins, Th.E., Johnston, D.W., Zia, P.: Transfer length of epoxy-coated prestressing strand. ACI Mater. J. 87(3), 193–203 (1990)Deatherage, J.H., Burdette, E., Chew, Ch.K.: Development length and lateral spacing requirements of prestressing strand for prestressed concrete bridge girders. PCI J. 39(1), 70–83 (1994)den Uijl, J.A.: Bond modelling of prestressing strand. In: Bond and Development of Reinforcement (SP 180-7), pp. 145–169. ACI International, Farmington Hills (1998)Dorsten, V., Hunt, F.F., Preston, H.K.: Epoxy coated seven-wire strand for prestressed concrete. PCI J. 29(4), 100–109 (1984)Evans, R.H.: Research and developments in pre-stressing. Proc., Inst. Civ. Eng. 35, 231–261 (1951)Evans, R.H., Robinson, W.R.: Bond stresses in prestressed concrete from X-ray photographs. Proc., Inst. Civ. Eng. 6(14), 212–235 (1955)FIB: Model Code 2010 (First complete draft). FIB Bulletin n∘55. International federation for structural concrete. Lausanne (2010)Floyd, R.W., Howland, M.B., Hale, W.M.: Evaluation of strand bond equations for prestressed members cast with self-consolidating concrete. Eng. Struct. 33, 2879–2887 (2011)Girgis, A.F., Tuan, Ch.Y.: Bond strength and transfer length of pretensioned bridge girders cast with self-consolidating concrete. PCI J. 50(6), 72–87 (2005)Grace, N.F.: Transfer length of CFRP/CFCC strands for double-T girders. PCI J. 45(5), 110–126 (2000)Guyon, Y.: Béton Précontrainte. Étude Théorique et Experiméntale. Eyrolles, Paris (1953)Holmberg, A., Lindgren, S.: Anchorage and prestress transmission. National Swedish Building Research, Document D1/1970 (1970)Issa, M.A., Sen, R., Amer, A.: Comparative study of transfer length in fiberglass and steel pretensioned concrete members. PCI J. 38(6), 52–63 (1993)Kaar, P.H., LaFraugh, R.W., Mass, M.A.: Influence of concrete strength on strand transfer length. PCI J. 8(5), 47–67 (1963)Kahn, L.F., Dill, J.C., Reutlinger, C.G.: Transfer and development length of 15-mm strand in high performance concrete girders. J. Struct. Eng. 128(7), 913–921 (2002)Kose, M.M., Burkett, W.R.: Formulation of new development length equation for 0.6 in prestressing strand. PCI J. 50(5), 96–105 (2005)Krishnamurthy, D.: Influencia del procedimiento de destesado sobre las tensiones en las zonas de anclaje y sobre la longitud de transmisión, en elementos de hormigón pretensado con armaduras pretesas. Traslation of paper published in The Indian Concrete Journal 44(3). Hormigón y Acero June, 49–65 (1970)Lane, S.N.: A new development length equation for pretensioned strands in bridge beams and piles. Federal Highway Administration. Research FHWA-RD-98-116, Mclean, VA (1998)Larson, K.H., Peterman, R.J., Esmaeily, A.: Bond characteristics of self-consolidating concrete for prestressed bridge girders. PCI J. 52(4), 44–57 (2007)Logan, D.R.: Acceptance criteria for bond quality of strand for pretensioned prestressed concrete applications. PCI J. 42(2), 52–90 (1997)Lu, Z., Boothby, Th.E., Bakis, Ch.E., Nanni, A.: Transfer and development lengths of FRP prestressing tendons. PCI J. 45(2), 84–95 (2000)Mahmoud, Z.I., Rizkalla, S.H., Zaghloul, E.R.: Transfer and development lengths of carbon fiber reinforcement polymers prestressing reinforcing. ACI Struct. J. 96(4), 594–602 (1999)Martí-Vargas, J.R., Serna-Ros, P., Fernández-Prada, M.A., Miguel-Sosa, P.F., Arbeláez, C.A.: Test method for determination of the transmission and anchorage lengths in prestressed reinforcement. Mag. Concr. Res. 58(1), 21–29 (2006a)Martí-Vargas, J.R., Arbeláez, C.A., Serna-Ros, P., Fernández-Prada, M.A., Miguel-Sosa, P.F.: Transfer and development lengths of concentrically prestressed concrete. PCI J. 51(5), 74–85 (2006b)Martí-Vargas, J.R., Serna-Ros, P., Arbeláez, C.A., Rigueira-Victor, J.W.: Bond behaviour of self-compacting concrete in transmission and anchorage. Mater. Constr. 56(284), 27–42 (2006c)Martí-Vargas, J.R., Arbeláez, C.A., Serna-Ros, P., Navarro-Gregori, J., Pallarés-Rubio, L.: Analytical model for transfer length prediction of 13 mm prestressing strand. Struct. Eng. Mech. 26(2), 211–229 (2007a)Martí-Vargas, J.R., Arbeláez, C.A., Serna-Ros, P., Castro-Bugallo, C.: Reliability of transfer length estimation from strand end slip. ACI Struct. J. 104(4), 487–494 (2007b)Martí-Vargas, J.R., Serna, P., Navarro-Gregori, J., Bonet, J.L.: Effects of concrete composition on transmission length of prestressing strands. Constr. Build. Mater. 27, 350–356 (2012a)Martí-Vargas, J.R., Serna, P., Navarro-Gregori, J., Pallarés, L.: Bond of 13 mm prestressing steel strands in pretensioned concrete members. Eng. Struct. 41, 403–412 (2012b)Martí-Vargas, J.R., Caro, L.A., Serna, P.: Experimental technique for measuring the long-term transfer length in prestressed concrete. Strain. doi: 10.1111/str.12019 (2012c)Marshall, G.: End anchorage and bond stress in prestressed concrete. Mag. Concr. Res. 1, 123–127 (1949)Mayfield, B., Davies, G., Kong, F.K.: Some tests on the transmission length and ultimate strength of pretensioned concrete beams incorporating Dyform strand. Mag. Concr. Res. 22(73), 219–226 (1970)Mitchell, D., Cook, W.D., Khan, A.A., Tham, Th.: Influence of high strength concrete on transfer and development length of pretensioning strand. PCI J. 38(3), 52–66 (1993)Nanni, A., Utsunomiya, T., Yonekura, H., Tanigaki, M.: Transmission of prestressing force to concrete by bonded fiber reinforced plastic tendons. ACI Struct. J. 89(3), 335–344 (1992)Oh, B.H., Kim, E.S.: Realistic evaluation of transfer lengths in pretensioned, prestressed concrete members. ACI Struct. J. 97(6), 821–830 (2000)Peterman, R.J.: The effects of as-cast depth and concrete fluidity on strand bond. PCI J. 52(3), 72–101 (2007)Pozolo, A.M., Andrawes, B.: Transfer length in prestressed self-consolidating concrete box and I-girders. ACI Struct. J. 108(3), 341–349 (2011)Ramirez, J.A., Russell, B.W.: Transfer, development, and splice length for strand/reinforcement in High-Strength Concrete. NCHRP Report 603. National Cooperative Highway Research Program (2008)Russell, B.W., Burns, N.H.: Measured transfer lengths of 0.5 and 0.6 in strands in pretensioned concrete. PCI J. 41(5), 44–65 (1996)RILEM: RPC6 Specification for the test to determine the bond properties of prestressing tendons. Réunion Internationale des Laboratoires et Experts des Matériaux, Systèmes de Constructions et Ouvrages, Bagneux., France (1979)Roller, J.J., Martin, B.T., Russell, H.G., Bruce, R.N.: Performance of prestressed high strength concrete bridge girders. PCI J. 38(3), 34–45 (1993)Shahawy, M., Issa, M., Batchelor, B.: Strand transfer lengths in full scale AASHTO prestressed concrete girders. PCI J. 37(3), 84–96 (1992)Shing, P.B., Frangopol, D.M., McMullen, M.L., Hutter, W., Cooke, D.E., Leonard, M.A.: Strand development and transfer length tests on high performance concrete box girders. PCI J. 45(5), 96–109 (2000)Soudki, K., Green, M., Clapp, F.: Transfer length of carbon fiber rods in precast pretensioned concrete beams. PCI J. 42(5), 78–87 (1997)Staton, B.W., Do, N.H., Ruiz, E.D., Hale, W.M.: Transfer lengths of prestressed beams cast with self-consolidating concrete. PCI J. 54(2), 64–83 (2009)Swamy, R.N., Anand, K.L.: Losses in transmission length and prestress in high alumina cement concrete. Proc., Inst. Civ. Eng. 59, 293–307 (1975)Tabatabai, H., Dickson, Th.: The history of the prestressing strand development length equation. PCI J. 38(5), 64–75 (1993)Tadros, M.K., Baishya, M.C.: Discussion of a review of strand development length for pretensioned concrete members. PCI J. 41(2), 112–127 (1996)Trent, J.: Transfer length, development length, flexural strength, and prestress loss evaluation in pretensioned self-consolidating concrete members. MS Thesis, Virginia Polytechnic Institute and State University, Blacksburg, VA (2007)Weerasekera, I.: Transfer and Flexural Bond in Pretensioned Prestressed Concrete. UMI Dissertation Services, University of Calgary (1991). Dissertation, ISBN 0-315-71095-5William, G.W., Shoukry, S.N., Riad, M.Y.: Development of early age shrinkage stresses in reinforced concrete bridge decks. Mech. Time-Depend. Mater. 12, 343–356 (2008)Zia, P., Mostafa, T.: Development length of prestressing strands. PCI J. 22(5), 54–65 (1977)Zou, P.X.V.: Long-term properties and transfer length of fiber-reinforced polymers. J. Compos. Constr. 7(1), 10–19 (2003

Prestress losses evaluation in prestressed concrete prismatic specimens

This paper presents an experimental research work to evaluate prestress losses in pretensioned prestressed concrete. An experimental program including variables such as concrete mix design, specimen cross-section size and concrete age at the prestress transfer was carried out. Several pretensioned prestressed concrete prismatic specimens were made and tested using the ECADA+ test method, based on measuring prestressing reinforcement force. In addition, specimens were instrumented to obtain the longitudinal concrete strains profiles at any time. Measurements from both techniques were taken over 1 year. Measured prestress losses included elastic shortening losses and time-dependent losses due to concrete shrinkage and creep. A coefficient to account for the relationship between the prestress losses from the measured prestressing forces and the actual prestress losses from concrete compressive strains is proposed. The experimental results were compared with the predicted prestress losses using methods from several codes.Funding for this experimental research work has been provided by the Spanish Ministry of Education and Science and ERDF (Project BIA2006-05521 and Project BIA2009-12722). Tests have been conducted at the Institute of Concrete Science and Technology (ICI-TECH), at the Universitat Politecnica de Valencia (Spain).Caro Forero, LA.; Martí Vargas, JR.; Serna Ros, P. (2013). Prestress losses evaluation in prestressed concrete prismatic specimens. Engineering Structures. 48:704-715. doi:10.1016/j.engstruct.2012.11.038S7047154

Experiências de mulheres migrantes cuidadoras em cuidados formais no final da vida

Objective: To describe and understand the experience of Latin American migrant women as caregivers of elderly people in situations of advanced illness and end of life. Method: Qualitative study using Gadamer’s hermeneutic phenomenology. Data were collected in 2019 through 9 semi-structured interviews with Latin American women caregivers, who had cared for people at the end of life, in the Province of Granada (Spain). Results: Two themes emerged: “Migrant caregiver at the end of life” and “And now, what should I do?”: the impact of the loss at the economic, emotional and labor level Conclusion: Care during the end of life of the cared person generates an additional overload to the situation of migrant women. The experience of this stage is related to the bond with the persons cared and their families, which may affect the development of complicated grief and personal problems related to the loss of employment and the absence of economic support.Objetivo: Describir y comprender la experiencia de las mujeres migrantes latinoamericanas como cuidadoras de personas mayores en situación de enfermedad avanzada y final de la vida. Método: Estudio cualitativo desde la fenomenología hermenéutica de Gadamer. Los datos fueron recogidos en 2019 mediante 9 entrevistas semiestructuradas a cuidadoras latinoamericanas, que hubieran atendido a personas al final de la vida en Granada (España). Resultados: Surgieron 2 temas: “Cuidadora migrante al final de la vida” e “Y ahora ¿qué hago?”: El impacto de la pérdida a nivel económico, emocional y laboral Conclusión: La atención durante el final de la vida de la persona cuidada genera una sobrecarga adicional a la situación de las mujeres migrantes. La vivencia de esta etapa se relaciona con el vínculo con la persona cuidada y su familia, que puede incidir en la elaboración de un duelo complicado y problemas personales relacionados con la pérdida de empleo y la ausencia de apoyo económico.Objetivo: Descrever e compreender a experiência de mulheres migrantes latino-americanas, cuidadoras de idosos em situações de doença avançada e de fim da vida. Método: Estudo qualitativo baseado na fenomenologia hermenêutica de Gadamer. Os dados foram coletados em 2019 por meio de 9 entrevistas semiestruturadas com mulheres cuidadoras latino-americanas que cuidaram de pessoas no final da vida em Granada (Espanha). Resultados: Surgiram dois temas: “Cuidador migrante no fim da vida” e “E agora, o que eu faço?”: o impacto da perda nos níveis econômico, emocional e de trabalho. Conclusão: O cuidado durante o fim da vida da pessoa cuidada gera uma sobrecarga adicional à situação das mulheres migrantes. A experiência dessa fase está relacionada ao vínculo com a pessoa cuidada e sua família, o que pode ter um impacto na elaboração de luto complicado e problemas pessoais relacionados à perda do emprego e à ausência de apoio econômico

Experimental Technique for Measuring the Long-term Transfer Length in Prestressed Concrete

This article presents a proposal of a test set-up and methodology for testing the transfer length evolution through time of prestressing reinforcement in pretensioned prestressed concrete members, aimed at providing a basis for standardization. The proposed test method is based on the instantaneous and time-related analysis of the prestressing reinforcement force profile at only one end of a pretensioned prestressed concrete member. The basis of the test method and the requirements of the prestressing frame and its components are presented, as well as the test procedure stages and the measurement devices. The interpretation of the test results and the criteria to determine both the initial and the long-term transfer lengths are explained. A test method application and the equipment for testing seven-wire prestressing strands have been designed. Some experimental results are provided to validate the test. A comparative analysis of test reliability with other existing experimental methods is also included. © 2012 Wiley Publishing Ltd.Funding for this experimental research work was provided by the Spanish Ministry of Education and Science and ERDF (Projects BIA2006-05521 and BIA2009-12722). Tests were conducted in the Institute of Concrete Science and Technology (ICITECH), Universitat Politecnica de Valencia (Spain).Martí Vargas, JR.; Caro Forero, LA.; Serna Ros, P. (2013). Experimental Technique for Measuring the Long-term Transfer Length in Prestressed Concrete. Strain. 49(2):125-134. doi:10.1111/str.12019S125134492Balaji Rao, K., Anoop, M. B., Sreeshylam, P., Sridhar, S., Kesavan, K., & Ravisankar, K. (2009). Assessment of Pre-Stress Losses in Instrumented Pre-Stressed Concrete Beams Using Stochastic Analysis. Strain, 47, e175-e188. doi:10.1111/j.1475-1305.2008.00551.xBase, G. D. (1957). Some tests on the effect of time on transmission length in pre-tensioned concrete. Magazine of Concrete Research, 9(26), 73-82. doi:10.1680/macr.1957.9.26.73Grace, N. F. (2000). Transfer Length of CFRP/CFCC Strands for Double-T Girders. PCI Journal, 45(5), 110-126. doi:10.15554/pcij.09012000.110.126Russell, B. W., & Burns, N. H. (1996). Measured Transfer Lengths of 0.5 and 0.6 in. Strands in Pretensioned Concrete. PCI Journal, 41(5), 44-65. doi:10.15554/pcij.09011996.44.65Marti-Vargas, J. R., Arbelaez, C. A., Serna-Ros, P., Navarro-Gregori, J., & Pallares-Rubio, L. (2007). Analytical model for transfer length prediction of 13 mm prestressing strand. Structural Engineering and Mechanics, 26(2), 211-229. doi:10.12989/sem.2007.26.2.211Floyd, R. W., Howland, M. B., & Micah Hale, W. (2011). Evaluation of strand bond equations for prestressed members cast with self-consolidating concrete. Engineering Structures, 33(10), 2879-2887. doi:10.1016/j.engstruct.2011.06.012Weerasekera , I. 1991 Transfer and flexural bond in pretensioned prestressed concrete University of Calgary, UMI Dissertation ServicesArango, S. E., Serna, P., Martí-Vargas, J. R., & García-Taengua, E. (2011). A Test Method to Characterize Flexural Creep Behaviour of Pre-cracked FRC Specimens. Experimental Mechanics, 52(8), 1067-1078. doi:10.1007/s11340-011-9556-2Wu, C.-H., Zhao, W., Beck, T., & Peterman, R. (2009). Optical Sensor Developments for Measuring the Surface Strains in Prestressed Concrete Members. Strain, 47, e376-e386. doi:10.1111/j.1475-1305.2009.00621.xDeatherage, J. H., & Burdette, E. G. (1994). Development Length and Lateral Spacing Requirements of Prestressing Strand for Prestressed Concrete Bridge Girders. PCI Journal, 39(1), 70-83. doi:10.15554/pcij.01011994.70.83Lu, Z., Boothby, T. E., Bakis, C. E., & Nanni, A. (2000). Transfer and Development Lengths of FRP Prestressing Tendons. PCI Journal, 45(2), 84-95. doi:10.15554/pcij.03012000.84.95Kahn, L. F., Dill, J. C., & Reutlinger, C. G. (2002). Transfer and Development Length of 15-mm Strand in High Performance Concrete Girders. Journal of Structural Engineering, 128(7), 913-921. doi:10.1061/(asce)0733-9445(2002)128:7(913)Martí-Vargas, J. R., Fernández-Prada, M. A., Arbeláez, C. A., Serna-Ros, P., & Miguel-Sosa, P. F. (2006). Transfer and Development Lengths of Concentrically Prestressed Concrete. PCI Journal, 51(5), 74-85. doi:10.15554/pcij.09012006.74.85Martí-Vargas, J. R., Serna, P., Navarro-Gregori, J., & Bonet, J. L. (2012). Effects of concrete composition on transmission length of prestressing strands. Construction and Building Materials, 27(1), 350-356. doi:10.1016/j.conbuildmat.2011.07.038Martí-Vargas, J. R., Serna, P., Navarro-Gregori, J., & Pallarés, L. (2012). Bond of 13mm prestressing steel strands in pretensioned concrete members. Engineering Structures, 41, 403-412. doi:10.1016/j.engstruct.2012.03.056EVANS, R. H., & ROBINSON, G. W. (1955). BOUND STRESSES IN PRESTRESSED CONCRETE FROM X-RAY PHOTOGRAPHS. Proceedings of the Institution of Civil Engineers, 4(2), 212-235. doi:10.1680/iicep.1955.11375Linger, D. A., & Bhonsle, S. R. (1963). An Investigation of Transfer Length In Pretensioned Concrete Using Photoelasticity. PCI Journal, 8(4), 13-30. doi:10.15554/pcij.08011963.13.30Chen, H.-L. (Roger), & Wissawapaisal, K. (2001). Measurement of Tensile Forces in a Seven-Wire Prestressing Strand Using Stress Waves. Journal of Engineering Mechanics, 127(6), 599-606. doi:10.1061/(asce)0733-9399(2001)127:6(599)Caro, L. A., Martí-Vargas, J. R., & Serna, P. (2012). Time-dependent evolution of strand transfer length in pretensioned prestressed concrete members. Mechanics of Time-Dependent Materials, 17(4), 501-527. doi:10.1007/s11043-012-9200-

Modificación de la estrategia educativa y diseño de material didáctico para fortalecer el Programa de Educación Ambiental Campamentos Educativos en Faro de Bucerías, Michoacán, México

El fomento de laeducación ambiental en comunidades indígenas de la costa oeste de México en el marco del desarrollo sustentable ha sido el elemento motivador de este proyecto. El objetivo fundamental es el diseño y la aplicación de un material didáctico y de una propuesta de estrategia educativa orientados al conocimiento, gestión y conservación del entorno natural y social de la localidad de Faro de Bucerías, Michoacán, México. En primer lugar se ha realizado una investigación y estudio teórico-práctico para contextualizar el área de estudio. Se ha analizado la propuesta educativa preexistente y se han realizado estudios de carácter socio-ambiental con el fin de seleccionar las líneas temáticas que serán la base de la nueva propuesta, vinculada con el material de trabajo. Posteriormente, se elabora el cuaderno de trabajo en conjunción con la estrategia educativa y se aplican a la sesión de Campamentos Educativos, para evaluar su eficiencia. Se hace un análisis cualitativo y cuantitativo de los resultados obtenidos para poder modificar el material didáctico en los puntos débiles detectados, y se propone la versión definitiva del material.El foment de l'educació ambiental en comunitats indígenes de la costa oest de Mèxic en el marc del desenvolupament sostenible ha estat l'element motivador d'aquest projecte. L'objectiu fonamental és el disseny i l'aplicació d'un material didàctic i d'una proposta d'estratègia educativa orientats al coneixement, gestió i conservació de l'entorn natural i social de la localitat de Faro de Bucerías, Michoacán, Mèxic. En primer lloc s'ha realitzat una investigació i estudi teòric-pràctic per contextualitzar l'àrea d'estudi. S'ha analitzat la proposta educativa preexistent i s'han realitzatestudis de caràcter sòcio-ambiental per tal de seleccionar les línies temàtiques que seran la base per la nova proposta, vinculada amb el material de treball. Posteriorment, s'elabora el quadern de treball en conjunció amb l'estratègia educativa i s'apliquen a la sessió de Campaments Educatius, per tal d'avaluarne l'eficiència. Es fa una anàlisi qualitativa i quantitativa dels resultats obtinguts per poder modificar el material didàctic en els punts febles detectats, i es proposa la versió definitiva del material

Content analysis of the effects of palliative care learning on the perception by nursing students of dying and dignified death

Background: Providing care for dying people and the death of patients are stressing situations faced by nursing students during their clinical practice. Learning about palliative care improves the management of emotions and the ability to cope when caring for patients in end-of-life processes. However, there is little knowledge on the effect of this learning on the students' perceptions of their own death. Objectives: To determine the effect of a palliative care course on the thoughts of nursing students about their own death. Design: A qualitative, descriptive, and comparative study was conducted based on content analysis, administering an open-ended questionnaire on dying and death at the start and end of a palliative care course. Participants: The study included 85 volunteers studying Palliative Care in the second year of their Nursing Degree at the University of Granada (Spain). Results: Students described their perceptions in more detail after the course, with more numerous code citations, and their post-course responses evidenced a reduction in anxiety about their own death and an increased recognition of the need to respect the decisions of patients for a dignified death. Conclusions: Palliative care learning modifies the perception by nursing students of their own death and their understanding of a dignified death, which may enhance the care they deliver to patients at the end of life

Cultural Adaptation, Validation, and Analysis of the Self-Efficacy in Palliative Care Scale for Use with Spanish Nurses

The aim of the present study is to validate the Self-Efficacy in Palliative Care Scale (SEPC) in Spanish nursing professionals and students, to describe their levels of self-e cacy, and to determine the influencing factors. A validation study and a cross-sectional descriptive study were carried out, with the data analysed using contrast tests and multiple linear regression; 552 nurses and 440 nursing students participated. The Spanish version consists of 23 items and has a high degree of reliability (alpha = 0.944). Confirmatory factor analysis revealed one additional factor (i.e., management of psychosocial and spiritual aspects) in comparison to the original scale. Contrast tests revealed that the mean SEPC score was higher in professionals than in students (p < 0.001) and that the professionals who had higher levels of self-efficacy were older (p < 0.001), had more previous training (p < 0.001), and had more experience in end-of-life care (p = 0.001). The linear analysis results confirm a significant association between age and previous training in end-of-life care. The Spanish version of the SEPC is a reliable tool for both nursing professionals and students. The level of self-efficacy of both groups is moderate and is influenced by age, experience, and training in end-of-life care.The present study has been supported by the Spanish Ministry of Education through a University Faculty Training contract granted to RHH (FPU15/02487)

The concept of death in children aged from 9 to 11 years: Evidences through inductive and deductive analysis of drawings

The objective of the research was to analyze children’s conceptualization of death through drawings, using a mixed approach, which combines deductive and inductive qualitative analysis. The sample consisted of 99 children aged 9–11 years, who were asked to elaborate a drawing about their idea of death and to explain it to the researchers. Drawings were coded basing on Tamm and Granqvist’s model (deductive analysis) and codes and categories were created and modified (inductive analysis). Three main categories were identified in the analysis and four sub-categories were modified and/or created: causes of death, good death, anxiety-fear and symbolization