Influence of Different European Code Provisions for Capacity Design on the Seismic Performance of Reinforced Concrete Frames

Performance-based seismic codes ensure proper inelastic behaviour of reinforced concrete frames through capacity design, among others. This strategy relies not only on avoiding brittle failures and providing ductility to plastic hinges but also in their distribution within the frame aimed at a greater number of storeys involved in the eventual collapse mechanism. Although codes are generally in agreement to some basic principles in order to ensure capacity design, they show some discrepancies regarding the specific strategies. In this paper, capacity design provisions proposed by some European current codes—Eurocode 8, Italian NTC, and Spanish NCSE-02—are compared, and their effectiveness is discussed. The alternative formulation proposed by Italian code for “strong column–weak beam” turns out to be not suitable under specific circumstances, such as with large gravity loads or significant cantilever deformation in lower storeys. Regarding the value of axial load in columns to be considered for the calculation of shear and moment capacities, provisions in the three codes could eventually cause unconservative design for perimeter columns. The Spanish whole set of provisions is proved to not be effective due to their different fundamentals—they are based on overstrength instead of capacity. For all the three cases, some alternative procedures are suggested in this work

Natural structures: strategies for geometric and morphological optimization

p. 893-906For centuries, architects and engineers have been searching the most efficient structural arrangements for their projects. Some of them have founded their proposals on the principle of biomimesis. The aim of their approach was to check how useful were 'for structural purposes' some geometrical patterns displayed by Nature on organic or inorganic bodies. Nature develops its structures in order to reach always optimal energetic solutions on a long term basis. The most usual arrangements are: pneus, shells, trees, webs and skeletons. All of them are controlled by four main factors: nature of forces, global form, local design and quality of material. Additional parameters, like pattern or material lightening, sometimes changes substantially the resulting geometry, and also some other general features as flexibility, integration, continuity, or self-straining are surrounding in most examples. This paper presents the achieved results on this topic by relevant authors of diverse fields: from the drawings of micro-organisms by the naturalist Häckel and the descriptive studies of the biologist Thompson, through the topological analysis of the patterns by the engineer Wester, the studies of natural lightweight structures by the architect F. Otto, to the final applications to light mega-structures by the engineers R. Le Ricolais or Buckminster Fuller.Pérez García, AJ.; Gómez Martínez, F. (2010). Natural structures: strategies for geometric and morphological optimization. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/695

Effect of width and boundary conditions on meeting maneuvers on two-way separated cycle tracks

Cycle track design guidelines are rarely based on scientific studies. In the case of off-road two-way cycle tracks, a minimum width must facilitate both passing and meeting maneuvers, being meeting maneuvers the most frequent. This study developed a methodology to observe meeting maneuvers using an instrumented bicycle, equipped with video cameras, a GPS tracker, laser rangefinders and speed sensors. This bicycle collected data on six two-way cycle tracks ranging 13-2.15 m width delimitated by different boundary conditions. The meeting maneuvers between the instrumented bicycle and every oncoming bicycle were characterized by the meeting clearance between the two bicycles, the speed of opposing bicycle and the reaction of the opposing rider: change in trajectory, stop pedaling or braking. The results showed that meeting clearance increased with the cycle track width and decreased if the cycle track had lateral obstacles, especially if they were higher than the bicycle handlebar. The speed of opposing bicycle shown the same tendency, although were more disperse. Opposing cyclists performed more reaction maneuvers on narrower cycle tracks and on cycle tracks with lateral obstacles to the handlebar height. Conclusions suggested avoiding cycle tracks narrower than 1.6 m, as they present lower meeting clearances, lower bicycle speeds and frequent reaction maneuvers. (C) 2015 Elsevier Ltd. All rights reserved.García García, A.; Agustin Gomez, F.; Llorca Garcia, C.; Angel-Domenech, A. (2015). Effect of width and boundary conditions on meeting maneuvers on two-way separated cycle tracks. Accident Analysis and Prevention. 78:127-137. doi:10.1016/j.aap.2015.02.019S1271377

Motor vehicles overtaking cyclists on two-lane rural roads: Analysis on speed and lateral clearance

Two-lane rural roads in Spain accommodate significant bicycle traffic volumes, mainly associated to sport and leisure activities. Motor vehicles' higher speed, weight and volume, compared to cyclists, represent a serious safety concern when overtaking a bicycle. Spanish traffic rules determine a minimum 1.5. m lateral distance.This research characterised 2928 overtaking manoeuvres in the overtaking lateral clearance between motor vehicle and bicycle, as well as in the motor vehicle speed, in contrast with previous research. Two instrumented bicycles were equipped with laser rangefinders, a GPS tracker and three video cameras. They rode along seven rural road segments at a speed between 15 and 25. km/h, centred on the paved shoulder, or as close as possible to the outer edge. Besides, this methodology allowed the characterisation of the overtaken vehicle type, its left lane occupation as well as its interaction with opposing traffic flow. For each session, rider's general risk perception was also registered.The analysis suggested that lateral clearance is not the only factor that influenced rider's risk perception, although current standards are only related to it. On the contrary, a combined factor of lateral clearance, vehicle type and vehicle speed had a more significant correlation with the perceived risk. This agreed with literature models of transient aerodynamic forces between overtaking and overtaken vehicles. Results showed that effect of heavy vehicles on bicyclists was also strong. In addition to this, the combined factor of clearance and speed was higher on tangent sections where overtaking was permitted.Llorca Garcia, C.; Ángel-Domènech, A.; Agustin Gomez, F.; García García, A. (2017). Motor vehicles overtaking cyclists on two-lane rural roads: Analysis on speed and lateral clearance. Safety Science. 92:302-310. doi:10.1016/j.ssci.2015.11.005S3023109

The structural role played by masonry infills on RC building performances after the 2011 Lorca, Spain, earthquake

The final publication is available at Spriger via http://dx.doi.org/10.1007/s10518-013-9500-1On May 11, 2011 an earthquake of magnitude 5.1 (Mw) struck Murcia region causing nine casualties and damage to buildings and infrastructures. Even if the main characteristics of the event would classify it as a moderate earthquake, the maximum Peak Ground Acceleration (PGA) registered (equal to 0.37 g) exceeded significantly local code provisions in terms of hazard at the site. This high PGA was a result of directivity effects in the near source region. An overview of earthquake characteristics and damage observed is provided. Notwithstanding the lack of proper structural design characterizing building stock in the area, most of the losses were caused by non-structural damage. According to in field observations, it emerges that masonry infills provided additional, not designed , strength to reinforced concrete (RC) buildings. Observed damage data, collected after the earthquake, are shown and compared to the results of a simplified approach for nonstructural damage assessment of RC infilled structures (FAST vulnerability approach). The latter comparison provided a fair accordance between observed data and analytical results.The work presented has been developed in cooperation with Rete dei Laboratori Universitari di Ingegneria Sismica-ReLUIS-Linea 1.1.2. for the research program funded by the Dipartimento della Protezione Civile (2010-2013).De Luca, F.; Verderame, GM.; Gómez Martínez, F.; Pérez García, AJ. (2014). The structural role played by masonry infills on RC building performances after the 2011 Lorca, Spain, earthquake. 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IGN, UCM, UPM, IGME, AEIS. http://www.ign.es/ign/resources/sismologia/Lorca.pdfCalconsa XXI (2011) Photographic report of the building “Menorca”, Avda. de las Fuerzas Armadas, 28–30-32, 30800 Lorca (Murcia), Spain. www.calconsa.comCEN (2004) Eurocode 8: design of structures for earthquake resistance-part 1: general rules, seismic actions and rules for buildings. European Standard EN 1998–1:2003- Comité Européen de Normaliation, BrusselsCEN (2005) Eurocode 8: design of structures for earthquake resistance-part 3: assessment and retrofitting of buildings, European Standard EN 1998–1:2005- Comité Européen de Normaliation, BrusselsChioccarelli E, De Luca F, Iervolino I (2009) Preliminary study on L’Aquila earthquake ground motion records, V5.20. http://www.reluis.it/Chopra AK (2007) Dynamics of the structures, 3rd edn. Prentice Hall, Upper Saddle River New YerseyCS.LL.PP (2009) Istruzioni per l’applicazione delle norme tecniche delle costruzioni. Gazzetta Ufficiale della Repubblica Italiana, 47. (in Italian)Colangelo F (2012) A simple model to include fuzziness in the seismic fragility curve and relevant effect compared with randomness. Earthq Eng Struct Dyn 41:969–986Cornell CA, Krawinkler H (2000) Progress and challenges in seismic performance assessment. PEER News, AprilCrowley H, Pinho R (2010) Revisiting Eurocode 8 formulae for periods of vibration and their employment in linear seismic analysis. Earthq Eng Struct Dyn 39(2):223–235De Luca F (2012) Records, capacity curve fits and reinforced concrete damage states within a performance based earthquake engineering framework. Ph.D. Thesis. University of Naples Federico II, Naples, Italy. Available at http://wpage.unina.it/flavia.deluca/outreach.htmDe Luca F, Verderame GM (2013) A practice-oriented approach for the assessment of brittle failures in existing RC elements. Eng Struct 48:373–388De Luca F, Vamvatsikos D, Iervolino I (2013) Near-optimal piecewise linear fits of static pushover capacity curves for equivalent SDOF analysis. Earthq Eng Struct Dyn 42(4):523–543Dolce M, Cardone D, Ponzo FC, Valente C (2005) Shaking table tests on reinforced concrete frames without and with passive control systems. Earthq Eng Struct Dyn 34:1687–1717Dolšek M, Fajfar P (2001) Soft storey effects in uniformly infilled reinforced concrete frames. J Earthq Eng 5(1):1–12Dolšek M, Fajfar P (2004) Inelastic spectra for infilled reinforced concrete frames. Earthq Eng Struct Dyn 33:1395–1416Dolšek M, Fajfar P (2005) Simplified non-linear seismic analysis of infilled reinforced concrete frames. Earthq Eng Struct Dyn 34:49–66Dolšek M, Fajfar P (2008) The effect of masonry infills on the seismic response of a four storey reinforced concrete frame-a probabilistic assessment. Eng Struct 30(11):3186–3192EHE (1999) Instrucción de hormigón estructural. Comisión permanente del hormigón estructural, Ministerio de Fomento, MadridEHE-08 (2008) Instrucción de hormigón estructural. Comisión permanente del hormigón estructural, Ministerio de Fomento, MadridEnomoto T, Schmitz M, Abeki N, Masaki K, Navarro M, Rocavado V, Sanchez A (2000) Seismic risk assessment using soil dynamics in Caracas, Venezuela. In: Proceedings of the 12th World Conference on earthquake engineering, Auckland, New ZelandErdik M, Durukal E, Siyahi B, Fahjan Y, Sesetyan K, Demircioglu M, Akman H (2004) Earthquake risk mitigation in Istanbul, Chap 7. In: Mulargia F, Geller RJ (eds) Earthquake science and seismic risk reduction. Kluwer, DordrechtFajfar P (1999) Capacity spectrum method based on inelastic demand spectra. Earthq Eng Struct Dyn 28:979–993Fardis MN (1997) Experimental and numerical investigations on the seismic response of RC infilled frames and recommendations for code provisions. Report ECOEST-PREC8 No 6. Prenormative research in support of Eurocode 8Fardis MN (2009) Seismic design, assessment and retrofitting of concrete buildings based on EN-Eurocode 8. Springer, BerlinFEMA (1994) NEHRP recommended provisions for seismic regulations for new buildings. FEMA 273, Federal Emergency Management Agency, Washington, DCFeriche M, Vidal F, Alguacil G, Navarro M, Aranda C, Vulnerabilidad y daño en el terremoto de Lorca de 2011 (2012) $$7^{\rm a}$$ 7 a Asamblea hispano-portuguesa de Geodesia y Geofísica. San Sebastián, 25–29 de junio de 2012Feriche M, y Equipo de Trabajo del IAGPDS (2011) Efectos del Terremoto de Lorca en las edificaciones. Available at http://www.ugr.es/~iag/lorca/Efecto_edificaciones.pdf . Last accessed 03–2013Galasso C, Cosenza E, Maddaloni G (2010) Statistical analysis of reinforcing steel properties for seismic design of RC structures. 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Eng Struct 33(2):308–319Rossetto T, Peiris N (2009) Observations of damage due to the Kashmir earthquake of October 8, 2005 and study of current seismic provisions for buildings in Pakistan. Bull Earthq Eng 7(3):681–699Sezen H, Moehle JP (2004) Shear strength model for lightly reinforced concrete columns. ASCE J Struct Eng 130(11):1692–1703Uang C, Bertero VV (1990) Evaluation of seismic energy in structures. Earthq Eng Struct Dyn 19:77–90Verderame GM, De Luca F, De Risi MT, Del Gaudio C, Ricci P (2012) A three level vulnerability approach for the damage assessment of infilled RC buildings: the Emilia 2012 case, V1.0. Available at http://www.reluis.it/Verderame GM, Ricci P, De Luca F, Del Gaudio C, De Risi MT (2013) Damage scenarios for RC buildings during the 2012 Emilia (Italy) earthquake. Soil Dyn Earthq Eng (under review)Verderame GM, De Luca F, Ricci P, Manfredi G (2011) Preliminary analysis of a soft-storey mechanism after the 2009 L’Aquila earthquake. Earthq Eng Struct Dyn 40(8):925–944Vidal F, Alguacil G, Feriche M, Aranda C, Morales J, Stich D, Pérez Muelas J, Benito J, López JM (2011) El terremoto de Lorca: Mayo 2011. Causas del impacto y primeras medidas. Análisis preliminar. Informe IAGPDS, Universidad de Granada. http://www.ugr.es/~iag/lorca/Impacto_Lorca.pdfVidic T, Fajfar P, Fischinger M (1994) Consistent inelastic design spectra: strength and displacement. Earthq Eng Struct Dyn 23:502–521Vielma JC, Barbat AH, Oller S (2010) Seismic safety of low ductility structures used in Spain. Bull Earthq Eng 8:135–155VV.AA (2006) Riesgo Sísmico de la Comunidad Autónoma de la Región de Murcia (RISMUR). 6 Vols. Instituto Geográfico Nacional y Dirección General de Protección Civil CAR

FAST simplified approach for seismic assessment of infilled RC MRF buildings: application to the 2011 Lorca earthquake

Comunicación oral presentada en el Congreso ERES 2013: 9th World Conference on Earthquake Resistant Engineering Structures: Resultados de la investigación realizada en el campo de la ingeniería estructural sísmica que consiste en la elaboración de un método propio que permite evaluar la vulnerabilidad sísmica a gran escala y que es capaz de predecir los daños esperados cuando los edificios con estructura de hormigón armado y con tabiquería de fábrica se ven sometidos a un evento sísmico. El método ha sido validado contrastando sus predicciones con los daños producidos por el terremoto del año 2011 en los edificios construidos con dicha tipología estructural en la ciudad de Lorca.A generalized formulation of the FAST vulnerability method for Reinforced Concrete Moment Resisting Frame (RC-MRF) buildings with irregular distribution of infills in elevation is presented. This method, which belongs to the wider family of spectral-based methodologies for the simplified assessment of infilled RC MRF buildings, has been already proposed for uniformly infilled frames and applied in the case of post-earthquake damage survey results for benchmarking purposes. The generalized approach allows to consider a reduction of the amount of infills at the ground floor. Thus, this new form of FAST is capable of computing all intermediate situations between the uniformly infilled and pilotis (no infills at ground storey) cases. Finally, the approach provided is applied to the case of Lorca (Spain) 2011 earthquake damage survey data.Gómez Martínez, F.; Perez Garcia, A.; Verderame, G.; De Luca, F. (2013). FAST simplified approach for seismic assessment of infilled RC MRF buildings: application to the 2011 Lorca earthquake. http://hdl.handle.net/10251/3270

Estudio del modelamiento de la calidad del agua del Río Sinú, Colombia.

En este estudio se presenta la modelación de la calidad del agua en el río Sinú, Colombia, en el tramo central entre la central hidroeléctrica de Urrá y la desembocadura al mar Caribe, usando el modelo QUAL2KW que incorpora el algoritmo genético PIKAIA, que permite la calibración de las constantes cinéticas. Específicamente, se presenta la metodología usada para la caracterización hidráulica, la segmentación de la corriente y el uso del método de muestreo Monte-Carlo para determinar los parámetros de calidad de agua de mayor sensibilidad, y demostrar que el modelo QUAL2KW no pudo ser calibrado para el río Sinú con la información de campo disponible, debido a que varias combinaciones de los parámetros producen soluciones igualmente óptimas

Infilled RC buildings performances during the 2011 Lorca, Spain, earthquake: application of FAST approach

[EN] A back analysis aimed at the evaluation of reinforced concrete frame buildings performance during the 2011 Lorca, Spain, earthquake is provided by applying FAST method. This is a simplified approach for the estimation of largescale vulnerability of RC moment resisting frame buildings. It accounts for the structural contribution of non-structural masonry infills. Lorca earthquake showed a Peak Ground Acceleration (PGA) three times higher with respect to that recommended by local design code. However, damage observed seldom included building collapses. Characteristics of the seismic event and features of the local building stock are studied aimed at showing, through the application of FAST, whether the low amount of collapses could be a consequence of the additional contribution provided by infills, despite their non-structural role in local code design framework. FAST damage scenario showed a fair agreement with observed damage, providing a confirmation on the structural role played by masonry infills.[ES] Se ofrece una hipótesis de comportamiento de los edificios porticados de hormigón armado de Lorca ante el terremoto de 2011, mediante la aplicación del método FAST, procedimiento de estimación simplificada de la vulnerabilidad a gran escala de dichos edificios contando con la contribución estructural de la tabiquería de fábrica. Este terremoto tuvo una aceleración de pico (PGA) tres veces superior a la básica de proyecto; sin embargo, se caracterizó por la práctica ausencia de colapsos. Se estudian las propiedades del evento sísmico y las particularidades de la edificación para, a través de la aplicación de FAST, tratar de confirmar que dicha ausencia de colapsos pudiera deberse a la contribución estructural de la tabiquería, a pesar de no ser proyectada con ese fin ni regulada por las sucesivas regulaciones normativas. Los resultados obtenidos confirman en buena medida dicha hipótesis, siendo el nivel medio de daño previsto consistente con el escenario real.Gómez-Martínez, F.; Pérez-García, A.; De Luca, F.; Verderame, GM. (2015). Comportamiento de los edificios de HA con tabiquería durante el sismo de Lorca de 2011: aplicación del método FAST. Informes de la Construcción. 67(537):1-14. doi:10.3989/ic.12.110S11467537(4) De Miguel, J.L. (2011). Lorca. Madrid: Departamento de Estructuras - ETSAM.De Luca, F., Verderame, G. M., Gómez-Martínez, F., & Pérez-García, A. (2013). The structural role played by masonry infills on RC building performances after the 2011 Lorca, Spain, earthquake. Bulletin of Earthquake Engineering, 12(5), 1999-2026. doi:10.1007/s10518-013-9500-1Ricci, P., De Luca, F., & Verderame, G. M. (2010). 6th April 2009 L’Aquila earthquake, Italy: reinforced concrete building performance. Bulletin of Earthquake Engineering, 9(1), 285-305. doi:10.1007/s10518-010-9204-8(8) Ricci, P. (2010). Seismic vulnerability of existing RC buildings (Tesis). Nápoles, Italia: Università degli Studi di Napoli Federico II.Verderame, G. M., De Luca, F., Ricci, P., & Manfredi, G. (2010). Preliminary analysis of a soft-storey mechanism after the 2009 L’Aquila earthquake. Earthquake Engineering & Structural Dynamics, 40(8), 925-944. doi:10.1002/eqe.1069Hermanns, L., Fraile, A., Alarcón, E., & Álvarez, R. (2013). Performance of buildings with masonry infill walls during the 2011 Lorca earthquake. Bulletin of Earthquake Engineering, 12(5), 1977-1997. doi:10.1007/s10518-013-9499-3Benavent-Climent, A., Escobedo, A., Donaire-Avila, J., Oliver-Saiz, E., & Ramírez-Márquez, A. L. (2013). Assessment of expected damage on buildings subjected to Lorca earthquake through an energy-based seismic index method and nonlinear dynamic response analyses. Bulletin of Earthquake Engineering, 12(5), 2049-2073. doi:10.1007/s10518-013-9513-9Manfredi, G., Prota, A., Verderame, G. M., De Luca, F., & Ricci, P. 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Effect of the thermal characteristics of dielectric fluids on the loading capacity of a power transformer

The use of biodegradable dielectric liquids in power transformers has several advantages, such as increased fire safety or their biodegradability in the event of a leak in the tank. However, they also have a higher viscosity that does not benefit their cooling function within these machines. Although there are many references that analyze the transformers hotspot temperature for dynamic loading, there are hardly any references that focus on the dynamic evaluation of the hotspot when the viscosity of the dielectric and cooling fluid changes, with respect to that of the oil of mineral origin. In this work, the algorithms proposed in the bibliography will be combined with the use of computational fluid dynamics software ANSYSFLUENT, which uses the finite volumes method to solve the equations that govern fluid flow. The software tool will be used to calculate the temperatures of a 100MVA transformer winding. Once these temperatures have been calculated, they can be entered into the hotspot temperature estimation algorithm when the machine's load regime is varied. This analysis will be repeated using dielectric liquids with different thermal characteristics. Transformer fleet managers may use the results of this study in order to adapt their procedures when the machines they manage do not have conventional mineral oil insidePart of the work was performed during secondments between University of Valle and the Universidad de Cantabria executed in the framework of the BIOTRAFO project “Raising knowledge and developing technology for the design and deployment of high performance power transformers immersed in biodegradable fluids”, H2020-MSCARISE-2018-823969, 2019–21. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 823969. Also, we acknowledge the support of the Spanish Ministry of Science and Innovation by means of the National Research Project Asset management of biodegradable-fluid-based transformers (PID2019-107126RB-C22/AEI/10.13039/501100011033). The authors also want to thank the grant received from the Call for the Development of the 2020 Industrial Doctorate Program of the Universidad de Cantabria

Spatial distribution of the soil carbon pool in a Holm oak dehesa in Spain

Aims Dehesas are agroforestry systems characterized by scattered trees among pastures, crops and/or fallows. A study at a Spanish dehesa has been carried out to estimate the spatial distribution of the soil organic carbon stock and to assess the influence of the tree cover. Methods The soil organic carbon stock was estimated from the five uppermost cm of themineral soil with high spatial resolution at two plots with different grazing intensities. The Universal Kriging technique was used to assess the spatial distribution of the soil organic carbon stocks, using tree coverage within a buffering area as an auxiliary variable. Results A significant positive correlation between tree presence and soil organic carbon stocks up to distances of around 8 m from the trees was found. The tree crown cover within a buffer up to a distance similar to the crown radius around the point absorbed 30 % of the variance in the model for both grazing intensities, but residual variance showed stronger spatial autocorrelation under regular grazing conditions. Conclusions Tree cover increases soil organic carbon stocks, and can be satisfactorily estimated by means of crown parameters. However, other factors are involved in the spatial pattern of the soil organic carbon distribution. Livestock plays an interactive role together with tree presence in soil organic carbon distribution