Assessment of RC hollow-piers for seismic limit state of damage - Direct repair costs

Due to the vulnerability of reinforced concrete hollow piers subjected to seismic actions, it becomes urgent to assess the expected shear damage and its evolution with the increase of the intensity level. Additionally, the focus of the scientific research dedicated to seismic behaviour of these elements is still reduced, in particular with regard to the limit states of damage and to the economic consequences of repairing and retrofitting the physical damages existing in RC hollow piers subjected to the seismic action. This information is deemed crucial when cost-benefit analysis is concerned for the definition of measures for repair and retrofit of seismic damage. This paper focus on the issue of damage to hollow piers due to the seismic action, proposing a methodology to characterize the limit states of damage under the perspective of the physical behaviour. It also intends to discuss adequate strengthening strategies and their direct costs, associated with each seismic physical limit state of damage. An extensive review of numerous cyclic experimental works on RC hollow piers will be performed, and in liaise with specialized construction companies, the direct repair costs will be estimated.6612-034D-AE05 | PEDRO DA SILVA DELGADON/

Seismic analysis of a Mexican viaduct with nonlinear modeling of soil-structure interaction

Every day the need to understand earthquakes and how that phenomenon affects construction grows, to make it possible to prevent and minimize inherent risks to their relation. That need increases when projects are located in regions with large seismicity. Therefore, the present paper, which was developed in partnership with GEG ? Gabinete de Estruturas e Geotecnia, has, as a final goal, to study and compare the variety of calculation methods available on Eurocode 8 to design and evaluate earthquake resistant structures, using a real case study. The methods approached are linear dynamic analysis, also known as spectral analysis, nonlinear static analysis, also recognized as pushover analysis, and non-linear dynamic analysis, well-known as time-history analysis. Simultaneously to the seismic analyses, it is developed a detailed study of the parameters that affect the damping of soil-structure interaction.6612-034D-AE05 | PEDRO DA SILVA DELGADON/

Earthquake source effect and impact of the applied methodology to assess the overstrength factors of RC bridges

Seismic hazard assessment in several sites worldwide depends on two or more seismic sources. Many countries affected by subduction zones have strong motions earthquakes originated in at least two important seismic sources. In Mexico, interplate earthquakes (subduction process) have epicenters located in the Pacific coast with hypocenter depths less than 45 km and intraplate earthquakes (intermediate-depth earthquakes) normally have epicenters inside the continent with depth hypocenters greater than 45 km. Both seismic sources can potentially produce events with magnitudes Mw greater than 8.0 and, therefore, generate severe damage to the country's infrastructure. The design process of the bridges in Mexico is based on the chapter of Seismic Design of the Manual of Civil Structures of the Federal Electricity Commission. The standard allows to reduce the spectral ordinates of the design spectra by ductility and overstrength. It establishes an overstrength factor of 1.5 to reduce the design spectra, value not well supported by the Manual. This study evaluates the effect of the seismic source and methodology used to compute overstrength factors of common typologies of reinforced concrete bridges. The seismic capacity of the bridges was calculated with nonlinear static analysis and nonlinear time history analysis. The results showed that the importance of the seismic source on the overstrength factors depends on the seismic location of the bridges and, in general terms, nonlinear static analysis overestimates the bridges overstrength.6612-034D-AE05 | PEDRO DA SILVA DELGADON/

Conception and justification of a new test setup for assessment of the fatigue strength of connections between precast railway bridge girders

Important investments have been made worldwide in the modernization and construction of railway lines. Plans for new constructions, have also been laid out. Recently, precast concrete has been widely employed in the construction of railway bridges and viaducts. Several precast solutions have been applied, namely: I-shaped or U-shaped precast girders and uni-cellular or bi-cellular precast box girders. Regarding the structural scheme in the longitudinal direction, either simple span or continuous decks have been used. In this context, this work aims to contribute to the knowledge about the real performance of these structures through the development of a laboratory tests setup, for the study of this type of structure, focusing on the connection between the precast beams. The setup will be implemented at the Laboratory of Earthquake and Structural Engineering (LESE), several experimental campaigns on the cyclic behaviour of reinforced concrete elements have been carried out.6612-034D-AE05 | PEDRO DA SILVA DELGADON/

Overstrength factors of RC bridges supported on single and multi-column RC piers in Mexico

Mexico highway network has more than 14,000 bridges. Most of them are reinforced concrete (RC) structures. The bridges design process incorporates the use of an overstrength factor that is not justified and has received little attention in published works. Mexican regulations allow using an overstrength factor for buildings in the range of 2?3, to reduce the design spectra as a function of the selected seismic behavior factor. However, for bridges, a single factor of 1.5 is proposed independent of any design parameter. The bridges in Mexico are mostly simply supported structures with maximum span lengths of 50 m. A relevant and distinctive aspect of the bridges designed in Mexico is the large load amplitudes of the trucks used to define the live load and the high seismic activity in the country. This study determines overstrength factors of a family of medium-length RC bridges composed of simply supported superstructures and substructure made up of single and multi-column RC piers. Non-linear dynamic analyzes using a set of 80 accelerograms were carried out. The results show that the height of the bridges and their seismic location are relevant parameters in the overstrength of the structures. Finally, analytical expressions are proposed to assess the overstrength factors of a very common bridge typology in Mexico and the world.6612-034D-AE05 | PEDRO DA SILVA DELGADON/

Acompa?amiento familiar en el rendimiento escolar en el grado tercero de la Instituci?n Educativa Mar?a Inmaculada del municipio de Flandes

55 p. Recurso Electr?nicoEn el presente trabajo de investigaci?n se pretende identificar la influencia del acompa?amiento familiar en el rendimiento escolar de los ni?os y ni?as del grado tercero de la instituci?n educativa Mar?a Inmaculada del municipio de Flandes del departamento del Tolima. Con el prop?sito de determinar el bajo resultado de las pruebas saber 2015 y fortalecer los v?nculos entre padres e hijos. En cuanto al dise?o metodol?gico se utiliz? el enfoque cualitativo, apoyado en el enfoque etnogr?fico, realizando un tipo de investigaci?n por medio del estudio de casos porque hace una descripci?n en particular del entorno familiar, la comunicaci?n en la familia y vivencia personal del ni?o. La muestra del estudio son 10 familias, con ni?os entre 8-10 a?os. Los instrumentos que se utilizaron fueron entrevistas con los estudiantes, entrevista con el director del curso, encuestas a padres de familia y talleres grupales con una estrategia participativa y reflexiva donde se crearon espacios propicios para el di?logo y la comunicaci?n. Los resultados de esta investigaci?n, revelaron que el acompa?amiento escolar en este contexto es escaso, ya que las pr?cticas educativas para el aprendizaje son limitadas, por la falta de tiempo, escolaridad, estrategias, h?bitos de estudio, motivaci?n por parte de los padres o figuras representativas, le atribuyen importancia desde sus visiones, expectativas y significados.his research aims to identify the influence of family support on the school performance of children in the third grade of the educational institution Mar?a Inmaculada in the municipality of Flandes in the department of Tolima. In order to determine the low-test results to know 2015 and strengthen the links between parents and children As for the methodological design, the qualitative approach was used, based on the ethnographic approach, carrying out a type of investigation through the study of cases because it makes a particular description of the family environment, communication in the family and personal experience of the child. The sample of the study are 10 families, with children between 8-10 years. The instruments used were interviews with the students, interview with the course director, parent surveys and group workshops with a participatory and reflective strategy where spaces were created conducive to dialogue and communication. The results of this research revealed that school attendance in this context is scarce, since the educational practices for learning are limited, due to lack of time, schooling, strategies, study habits, motivation by parents or figures Represent it from their visions, expectations and meanings. Keywords: learning practices, accompaniment, performanc

Seismic analysis of a viaduct in Mexico considering soil-structure interaction

De modo a prevenir e minimizar os riscos s?smicos das estruturas, existe a necessidade crescente de compreender os sismos e a forma como estes afetam as constru??es. Essa necessidade aumenta quando se estudam projetos em zonas de grande sismicidade, como ? o caso do M?xico. Assim, o presente estudo, elaborado em parceria com o GEG ? Gabinete de Estruturas e Geotecnia, pretende analisar as v?rias abordagens de c?lculo inerentes ao dimensionamento e avalia??o de estruturas sismo-resistentes, sendo o principal objetivo compar?-las e avaliar a adequabilidade de cada uma delas ao caso de estudo. S?o essas abordagens a an?lise din?mica linear ou espetral, a an?lise est?tica n?o-linear, tamb?m designada an?lise pushover, e a an?lise din?mica n?o linear ou time-history. Simultaneamente ser? levado a cabo um estudo detalhado ao n?vel dos par?metros que afetam o amortecimento proveniente da intera??o solo-estrutura.6612-034D-AE05 | PEDRO DA SILVA DELGADOinfo:eu-repo/semantics/publishedVersio

Maharam-type kernel representation for operators with a trigonometric domination

[EN] Consider a linear and continuous operator T between Banach function spaces. We prove that under certain requirements an integral inequality for T is equivalent to a factorization of T through a specific kernel operator: in other words, the operator T has what we call a Maharam-type kernel representation. In the case that the inequality provides a domination involving trigonometric functions, a special factorization through the Fourier operator is given. We apply this result to study the problem that motivates the paper: the approximation of functions in L2[0, 1] by means of trigonometric series whose Fourier coefficients are given by weighted trigonometric integrals.This research has been supported by MTM2016-77054-C2-1-P (Ministerio de Economia, Industria y Competitividad, Spain).Sánchez Pérez, EA. (2017). Maharam-type kernel representation for operators with a trigonometric domination. Aequationes Mathematicae. 91(6):1073-1091. https://doi.org/10.1007/s00010-017-0507-6S10731091916Calabuig, J.M., Delgado, O., Sánchez Pérez, E.A.: Generalized perfect spaces. Indag. Math. 19(3), 359–378 (2008)Calabuig, J.M., Delgado, O., Sánchez Pérez, E.A.: Factorizing operators on Banach function spaces through spaces of multiplication operators. J. Math. Anal. Appl. 364, 88–103 (2010)Delgado, O., Sánchez Pérez, E.A.: Strong factorizations between couples of operators on Banach function spaces. J. Convex Anal. 20(3), 599–616 (2013)Dodds, P.G., Huijsmans, C.B., de Pagter, B.: Characterizations of conditional expectation type operators. Pacific J. Math. 141(1), 55–77 (1990)Flores, J., Hernández, F.L., Tradacete, P.: Domination problems for strictly singular operators and other related classes. Positivity 15(4), 595–616 (2011). 2011Fremlin, D.H.: Tensor products of Banach lattices. Math. Ann. 211, 87–106 (1974)Hu, G.: Weighted norm inequalities for bilinear Fourier multiplier operators. Math. Ineq. Appl. 18(4), 1409–1425 (2015)Halmos, P., Sunder, V.: Bounded Integral Operators on $$L^2$$ L 2 Spaces. Springer, Berlin (1978)Kantorovitch, L., Vulich, B.: Sur la représentation des opérations linéaires. Compositio Math. 5, 119–165 (1938)Kolwicz, P., Leśnik, K., Maligranda, L.: Pointwise multipliers of Calderón- Lozanovskii spaces. Math. Nachr. 286, 876–907 (2013)Kolwicz, P., Leśnik, K., Maligranda, L.: Pointwise products of some Banach function spaces and factorization. J. Funct. Anal. 266(2), 616–659 (2014)Kuo, W.-C., Labuschagne, C.C.A., Watson, B.A.: Conditional expectations on Riesz spaces. J. Math. Anal. Appl. 303, 509–521 (2005)Lindenstrauss, J., Tzafriri, L.: Classical Banach Spaces II. Springer, Berlin (1979)Maharam, D.: The representation of abstract integrals. Trans. Am. Math. Soc. 75, 154–184 (1953)Maharam, D.: On kernel representation of linear operators. Trans. Am. Math. Soc. 79, 229–255 (1955)Maligranda, L., Persson, L.E.: Generalized duality of some Banach function spaces. Indag. Math. 51, 323–338 (1989)Neugebauer, C.J.: Weighted norm inequalities for averaging operators of monotone functions. Publ. Mat. 35, 429–447 (1991)Okada, S., Ricker, W.J., Sánchez Pérez, E.A.: Optimal Domain and Integral Extension of Operators Acting in Function Spaces. Operator Theory: Adv. Appl., vol. 180. Birkhäuser, Basel (2008)Rota, G.C.: On the representation of averaging operators. Rend. Sem. Mat. Univ. Padova. 30, 52–64 (1960)Sánchez Pérez, E.A.: Factorization theorems for multiplication operators on Banach function spaces. Integr. Equ. Oper. Theory 80(1), 117–135 (2014)Schep, A.R.: Factorization of positive multilinear maps. Ill. J. Math. 28(4), 579–591 (1984)Schep, A.R.: Products and factors of Banach function spaces. Positivity 14(2), 301–319 (2010

A new ex vivo method to evaluate the performance of candidate MRI contrast agents: a proof-of-concept study

BACKGROUND: Magnetic resonance imaging (MRI) plays an important role in tumor detection/diagnosis. The use of exogenous contrast agents (CAs) helps to improve the discrimination between lesion and neighbouring tissue, but most of the currently available CAs are non-specific. Assessing the performance of new, selective CAs requires exhaustive assays and large amounts of material. Accordingly, in a preliminary screening of new CAs, it is important to choose candidate compounds with good potential for in vivo efficiency. This screening method should reproduce as close as possible the in vivo environment. In this sense, a fast and reliable method to select the best candidate CAs for in vivo studies would minimize time and investment cost, and would benefit the development of better CAs. RESULTS: The post-mortem ex vivo relative contrast enhancement (RCE) was evaluated as a method to screen different types of CAs, including paramagnetic and superparamagnetic agents. In detail, sugar/gadolinium-loaded gold nanoparticles (Gd-GNPs) and iron nanoparticles (SPIONs) were tested. Our results indicate that the post-mortem ex vivo RCE of evaluated CAs, did not correlate well with their respective in vitro relaxivities. The results obtained with different Gd-GNPs suggest that the linker length of the sugar conjugate could modulate the interactions with cellular receptors and therefore the relaxivity value. A paramagnetic CA (GNP (E_2)), which performed best among a series of Gd-GNPs, was evaluated both ex vivo and in vivo. The ex vivo RCE was slightly worst than gadoterate meglumine (201.9 ± 9.3% versus 237 ± 14%, respectively), while the in vivo RCE, measured at the time-to-maximum enhancement for both compounds, pointed to GNP E_2 being a better CA in vivo than gadoterate meglumine. This is suggested to be related to the nanoparticule characteristics of the evaluated GNP. CONCLUSION: We have developed a simple, cost-effective relatively high-throughput method for selecting CAs for in vivo experiments. This method requires approximately 800 times less quantity of material than the amount used for in vivo administrations

Generation and characterization of two immortalized human osteoblastic cell lines useful for epigenetic studies

Different model systems using osteoblastic cell lines have been developed to help understand the process of bone formation. Here, we report the establishment of two human osteoblastic cell lines obtained from primary cultures upon transduction of immortalizing genes. The resulting cell lines had no major differences to their parental lines in their gene expression profiles. Similar to primary osteoblastic cells, osteocalcin transcription increased following 1,25-dihydroxyvitamin D3 treatment and the immortalized cells formed a mineralized matrix, as detected by Alizarin Red staining. Moreover, these human cell lines responded by upregulating ALPL gene expression after treatment with the demethylating agent 5-aza-2 Œ-deoxycytidine (AzadC), as shown before for primary osteoblasts. We further demonstrate that these cell lines can differentiate in vivo, using a hydroxyapatite/tricalcium phosphate composite as a scaffold, to produce bone matrix. More importantly, we show that these cells respond to demethylating treatment, as shown by the increase in SOST mRNA levels, the gene encoding sclerostin, upon treatment of the recipient mice with AzadC. This also confirms, in vivo, the role of DNA methylation in the regulation of SOST expression previously shown in vitro. Altogether our results show that these immortalized cell lines constitute a particularly useful model system to obtain further insight into bone homeostasis, and particularly into the epigenetic mechanisms regulating sclerostin production