Review of Research in the Field Study of the Stress-Strain State of Concrete-Filled Structures

The paper presents an analytical review of the literature, which reflects the results of national and foreign scientific researches aimed to studying the features of the composition and dosage of components of self compacting concrete as one of the most promising aggregate for modern composite structures. In addition, the results of numerical and experimental researches of stress-strain state of composite structures (concrete-filled tubes) under the influence of various power factors, have been considered. The description and features of existing analytical methods for the determination of the bearing capacity of the considered structures under compression and bendings, have been given. The analysis of deformation model of confined concrete in a composition of the composite structure, as well as non-linear models of steel works with their distinctive features, has been carried out. The main approaches to the finite element modeling of composite structures have been determined

Experimental Damage Identification in Masonry Structures by OMA

This paper presents a study carried out in different types of masonry structures to identify existing damage through dynamic identification techniques using operational modal analysis. A cross vault, a masonry wall and a simple clay brick construction have been analyzed. The three cases have been tested on a full scale in the laboratory. The cross vault has been subjected to a settlement of one of its supports, the damage has occurred and then it has been repaired by using Textile Reinforced Mortars (TRM). In the case of the wall and the simple construction, the damage has been generalized by means of horizontal loads simulating a seismic action by a cyclic incremental load, after the generation of the damage, it has been repaired using TRM. In all cases, a dynamic identification has been carried out prior to the generation of the damage, after the generation of the damage and later after its repair, finally after a new process of damage the structural health changes have been monitored. In the four phases, an identification of the dynamic characteristics of the structures has been carried out, both main frequencies and damping factor associated with each mode shape. Regarding operational modal analysis, the first vibration modes have been identified. Singular Value Plot have been obtained through the EFDD technique. In general terms, the results of the investigation showed that the effect of cracking generated by both horizontal cyclic loads and vertical displacements located in one of the supports generated a decrease in the vibration frequencies and an increase in the structural damping factors for the different vibration modes. On the other hand, in relation to the effect of the reinforcement techniques employed, the results showed the feasibility of recovering or even slightly increasing the stiffness of the original damaged structure. However, the results for the strengthened structures also showed that the intervention on the damaged structure tended to reduce the structural damping factors with respect to the unreinforced structure. In addition, it was also observed that after the tests the reinforced and newly damaged structures showed dynamic characteristics very similar to the unreinforced damaged structures.The authors want to acknowledge Spanish Ministry of Universities for the funding provided through Projects RTI2018-101148-B-100 and BIA2015-69952-R, and also the Grupo Mapei and the Grupo Puma for their invaluable assistance

Monumental tree protection by an unique pedestrian bridge

Congreso celebrado en la Escuela de Arquitectura de la Universidad de Sevilla desde el 24 hasta el 26 de junio de 2015.This paper describes the conceptual design, the structural analysis and the results of a viewpoint pedestrian bridge, situated in Daya Vieja (Alicante-Spain). This structure is designed to protect a land-mark palm-tree from wind loads. This six – trunk palm tree was declared monument by the Valencian government in 2012. The structure that now protect it appears to fly around de palm tree creating a helicoidally skywalk made of steel, while retrofitting the lateral trunks of the tree to protect them from collapse. An 18 m long straight beam starts on the top of this helix, and stretches towards a lookout point that offers a view of the whole village and its surroundings. The reduction of the visual impact of the structure on the tree was a major aim for the project design. The structural elements are as slender as possible to avoid the visual obstruction of tree. This structure has been a finalist in the Architecture Awards for the 2010-2014 best construction projects, held by the Diputación of Alicante

La participación ciudadana en el desarrollo sostenible. El caso de las agendas 21 locales de la provincia de Valencia (España)

La importancia de la contribución del mundo local, al desarrollo sostenible se recoge en el capítulo 28 del Programa 21, estableciendo las Agendas 21 como un instrumento básico para encaminarse hacia el desarrollo sostenible. Las administraciones locales desempeñan una función importantísima en la movilización y educación de la ciudadanía, en pro del desarrollo sostenible. La participación es necesario planificarla. Los planes de participación ciudadana y las herramientas participativas a emplear deben ser anteriores a la puesta en marcha de los procesos de agenda 21. La formación, información, sensibilización y la educación en materia de medio ambiente, constituyen pasos previos imprescindibles para alcanzar un desarrollo sostenible, considerándose la educación ambiental como una herramienta fundamental para el impulso de las democracias participativas, e imprescindible para tener una población mejor informada y con un mayor sentido de la corresponsabilidad. El presente artículo se centra en el estudio de los procesos participativos en el seno de las agendas 21 locales en la provincia de Valencia (España), así como de la importancia de la educación ambiental en dichos procesos

Violin Ceramic Joist Slabs: Evaluation and Proposal for Intervention with Duplex-Type Stainless Steel

Due to the present significant need to repair and maintain our buildings and the building repair sector’s minimal experience in special structural elements, we here describe a study on the repair of ceramic violin joist slabs in an actual intervention on a building erected in the 1950s that had been unsuccessfully repaired several times. Due to damp and being close to the sea, the main reinforcement elements had undergone considerable corrosion causing a significant risk to the building’s safety. The intervention necessarily involved replacing the affected steel rebars with appropriate elements with mechanical and corrosion resistance properties, as required by the latest building codes. An appropriate strengthening and repair system was developed with a stainless steel prosthesis fitted to the lower third of the joists that almost tripled their resistance, gave them 120 min of fire resistance, and increased their durability against corrosion at a cost of less than 50% of the current repair systems with minimum generation of construction waste. One of the most appealing characteristics of this new repair system is its avoidance of the full replacement of the joists, which can be considered as a relevant contribution to the sustainability of the construction industry

Dynamic behavior of masonry chimney with different reinforcement schemes

Congreso celebrado en la Escuela de Arquitectura de la Universidad de Sevilla desde el 24 hasta el 26 de junio de 2015.This paper presents a structural analysis of a masonry chimney built in the 1950’s, which is currently being catalogued as local interest heritage. These structures exhibit insufficient tensile strength to resist the seismic action because the masonry is not reinforced. For this reason, the aim of this work is to analyze different structural reinforcement schemes so the chimney is capable of withstanding seismic actions. Ten numerical models, for nine reinforcement configurations, have been defined using Ansys software. A glass fiber reinforced cement composite was always used as reinforcement. For each model, a modal analysis and time history analyses were made. Five different synthetic accelerograms were used for the structural analysis, according to NCSE02 Spanish standard. The final reinforcement, capable of resisting the seismic action, consisted of a helicoid wrap and eight longitudinal stripes along the shaft, and the inner and outer reinforcement of all masonry walls of the base

Steel Pedestrian Bridge to Protect a Unique Tree

This paper describes the “Variation Guggenheim 3: Mirador de la palmera” project, situated in Daya Vieja (Alicante-Spain). This structure is inspired by the Guggenheim museum of New York and is designed to protect a land-mark palm-tree from wind loads. This six – trunk palm tree was declared monument by the Valencian government in 2012. The structure that now protect it appears to fly around de palm tree creating a helicoidally skywalk made of steel, while retrofitting the lateral trunks of the tree to protect them from collapse. An 18 m. long straight beam starts on the top of this helix, and stretches towards a lookout point that offers a view of the whole village and its surroundings. The reduction of the visual impact of the structure on the tree was a major aim for the project design. The structural elements are as slender as possible to avoid the visual obstruction of tree. They are painted white, while the walkway steel corrugated plate is painted green in order to highlight its neat shape among the blur created by the apparent mess of bars of the supporting structure. The two main piles of this pedestrian bridge were designed in steel and geometrically resemble trees. A Ground Penetrating Radar analysis was performed to detect the palm root location and to decide the best foundation system. Slender cast in-situ steel-concrete micropiles along with a concrete pile-cap, raised some centimeters above the ground level, were used to reduce the damage to the roots. The projected pile-cap is a slender, continuous, circular ring; which geometry resembles a concrete bench. This structure has been a finalist in the Architecture Awards for the 2010-2014 best construction projects, held by the Diputación de Alicante

ランドマークのヤシの木を保護する歩道橋（スペイン）

Pedestrian Unique Bridge in prestesed white concrete. Pilar de la Horadada. Alicante

Las Agendas 21 Locales en la Provincia de Valencia: Análisis de los municipios firmantes de la Carta de Xàtiva

Los problemas medioambientales se han ido incrementando hasta adquirir dimensiones planetarias. Por lo que se hace necesario buscar la compatibilidad entre el crecimiento y la protección del medio ambiente. En este sentido, en la Conferencia de Naciones Unidas sobre el Medio Ambiente y el Desarrollo, celebrada en Río de Janeiro en 1992, se adquirió el compromiso de establecer políticas acordes con el desarrollo sostenible, a través de la implantación de las Agendas 21 Locales. Este documento reconoció el papel fundamental de las ciudades y pueblos, al considerar que es la unidad más pequeña donde se pueden dar solución a los problemas. El capítulo 28 del Programa 21 recogió la obligación de las administraciones locales de poner en marcha sus Agendas 21, como herramientas de gestión a largo plazo para alcanzar la sostenibilidad del planeta, facilitando la participación entre los poderes públicos y la sociedad. Las Agendas 21 se consideran desde el punto de vista técnico como instrumentos de planificación estratégica de rango superior a cualquier otro tipo de plan estratégico o plan sectorial. Para la consecución de la sostenibilidad, se elabora una Ecoauditoría y un Plan de Acción basado en un diagnóstico ecosistémico participado. El proceso de Agenda 21 Local en un municipio supone la adopción de una serie de principios que en muchas ocasiones son difíciles de asumir y cumplir. Es por ello por lo que se viene observando una falta de coherencia entre los compromisos públicos adoptados por las corporaciones locales y las acciones que realmente se están llevando a término para la aplicación de la Agenda 21 Local. En este sentido, se podría concluir que la adhesión a la Carta de Aalborg, a los Compromisos de Aalborg+10, o a la firma de la Carta de Xàtiva, no presupone la realización por parte de los signatarios de acciones integradas y participadas hacia la sostenibilidad local, ya que no obliga legalmente. Por otro lado, la obligación y el compromiso asumido con las generaciones futuras con la firma de estos documentos públicos conlleva la obligación moral de una continuidad en el tiempo de este tipo de procesos, que deberán revisarse y retroalimentarse de forma continuada en el tiempo. Por todo ello, para saber el alcance logrado por los diferentes municipios firmantes se hace necesario un estudio como el realizado en esta investigación. Teniendo presente que los procesos de Agenda 21 en las primeras fases (1999-2003) en la Comunidad Valenciana y en la provincia de Valencia eran muy escasos, consideramos necesario estudiar qué ha ocurrido desde 2003 hasta 2015, así como conocer cuál es el estado actual de los procesos de Agenda 21. Es por esto por lo que se ha visto interés en la realización de esta investigación con la finalidad de conocer el grado de implementación de estas herramientas de gestión municipal estratégicas, su estado y evolución. Para el análisis de los datos obtenidos se han establecido 14 categorías o temáticas: Descripción de los municipios que han participado en el estudio (muestra). El compromiso municipal con el desarrollo sostenible (firma de documentos oficiales y desarrollo de políticas ambientales). Actuaciones para la sostenibilidad local distintas o complementarias a la Agenda 21 Local. El inicio del proceso de Agenda 21. Principales obstáculos a la hora de implantar las Agendas 21 Locales (los aspectos económicos, técnicos y políticos, la falta de apoyos, o la débil influencia de los participantes en la toma de decisiones). Los aspectos motivadores que han permitido iniciar procesos de Agenda 21. La organización interna para afrontar dicho proceso. Las características de los procesos de Agenda 21 desarrollados. La financiación de los procesos de Agenda 21. Estado actual de las Agendas 21 (procesos activos, procesos paralizados y sus causas, medios empleados). Las fases de la Auditoría Ambiental (Diagnóstico, Plan de Acción y Sistema de Indicadores: Estado en el que se encuentra, medios empleados y aspectos metodológicos). La participación. La comunicación e información a la comunidad. y la importancia de la Educación Ambiental en los procesos de Agenda 21

Failure analysis of the collapse of a raised steel wine tank

As structural damage or even catastrophic collapses are sometimes due to improper design, underestimated design loads or unexpectedly extreme loads, progressive collapse and structural robustness has recently received a great deal of attention, while the number of scientific papers published on the topic has grown considerably. This paper describes an analysis of the failure of a 106 m3 steel raised wine tank belonging to a local wine producer that suddenly collapsed, fortunately without personal injury, but causing significant damage to the company's facilities. The collapse generated the progressive failure of other tanks next to the first one that failed. After several visits to inspect the accident on site, a diagnosis was made to determine the causes. Possible reasons were examined by visual inspections and experimental tests on steel specimens recovered from the collapsed structures, which allowed to determine the mechanical properties and study the fracture surfaces by scanning electron microscopy and micrographs. On the other hand, the load-carrying capacities of the structure were studied by a linear-static finite-element and a nonlinear-static push-over analysis. The collapse mechanism of the system was found to be due to cyclic horizontal loads generated by a pressurized air injection system. The results allowed to conclude that this type of structure is highly vulnerable to horizontal loads and has very little capacity to activate alternative loas paths. The paper also describes a possible solution that could be used to improve the mechanical performance of this structural typology against horizontal loading, based on the lessons learned from the experience