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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Diseño de puente segmental de 385 metros de longitud por la metodología constructiva de dovelas sucesivas como propuesta de solución a los efectos del Fenómeno del Niño sobre la quebrada venados en el distrito de Lancones, Sullana-Piura / Design of segmental bridge of 385 meters in length by the constructive methodology of free cantilever as a proposed solution to the effects of the phenomenon of “El Niño” over Venados gully in Lancones district, Sulla-Piura

Guerra Anaya, Diego Eduardo, Valle Alburqueque, Jose Alejandro 13 July 2020 (has links)
A inicios del año 2017 se registró una anomalía sen los efectos climatológicos generados por el Fenómeno del Niño, siendo superior a otros años y generando lluvias extraordinarias a lo largo de la costa peruana con mayor incidencia en la zoma norte. Ello conllevo al aumento de caudal y reactivación de quebradas por donde antes transcurrió un rio, el resultado fue de más de 280 mil damnificados que carecían de ayuda debido a que los caminos y puentes habían sufrido daños que impedían su operatividad al punto de estar colapsados. Posterior al sucedido se detectaron las causas que llevaron al fallo de las estructuras y se llegó a la conclusión de que no se consideraron los eventos extraordinarios del Fenómeno del Niño, la definición del tipo de estructura no fue el adecuado y los estudios de ingeniería básica no dieron la información adecuada a fin de prever este tipo de problemas. Para el caso de estudio se eligió el puente ubicado en la quebrada Venados en el distrito de Lancones (Sullana-Piura), donde la estructura de 60 metros de longitud fue excedida hidráulicamente debido a que el caudal cubrió un área mucho mayor a la cubierta por el puente. Se aborda el caso proponiendo un puente construido por la metodología de dovelas sucesivas, con dos pilares oblongos huecos y dos estribos; además de efectuarse el calculo hidrológico para diseñar enrocados como protección de riberas. / At the beginning of the year 2017, an anomaly was registered without the climatological effects generated by the “El Niño” Phenomenon, being higher than in other years and generating extraordinary rains along the Peruvian coast with the highest incidence in the northern area. This led to the increase in flow and reactivation of streams where a river previously passed, the result was more than 280 thousand victims who lacked help because the roads and bridges had suffered damages that prevented their operation to the point of being collapsed. After the event, the causes that led to the failure of the structures were detected and it was concluded that the extraordinary events of the El Niño phenomenon were not considered, the definition of the type of structure was not adequate and the basic engineering studies were not they gave the appropriate information in order to foresee these kinds of problems. For the case study, the bridge located in the Venados gully in the Lancones district (Sullana-Piura) was chosen, where the 60-meter-long structure was hydraulically exceeded because the flow covered a much larger area than the one covered by the bridge. The case is approached proposing a bridge built by the methodology of successive segments, with two oblong hollow pillars and two abutments; in addition to carrying out the hydrological calculation to design rocky as protection of banks. / Tesis
2

Use of Fiber Reinforced Polymer Composite Cable for Post-tensioning Application

Yang, Xiong 13 November 2015 (has links)
Corrosion of steel tendons is a major problem for post-tensioned concrete, especially because corrosion of the steel strands is often hard to detect inside grouted ducts. Non-metallic tendons can serve as an alternative material to steel for post-tensioning applications. Carbon fiber reinforced polymer (CFRP), given its higher strength and elastic modulus, as well as excellent durability and fatigue strength, is the most practical option for post-tensioning applications. The primary objective of this research project was to assess the feasibility of the use of innovative carbon fiber reinforced polymer (CFRP) tendons and to develop guidelines for CFRP in post-tensioned bridge applications, including segmental bridges and pier caps. An experimental investigation and a numerical simulation were conducted to compare the performance of a scaled segmental bridge model, post-tensioned with two types of carbon fiber strands and steel strands. The model was tested at different prestress levels and at different loading configurations. While the study confirms feasibility of both types of carbon fiber strands for segmental bridge applications, and their similar serviceability behavior, strands with higher elastic modulus could improve structural performance and minimize displacements beyond service loads. As the second component of the project, a side-by-side comparison of two types of carbon fiber strands against steel strands was conducted in a scaled pier cap model. Two different strand arrangements were used for post-tensioning, with eight and six strands, respectively representing an over-design and a slight under-design relative to the factored demand. The model was tested under service and factored loads. The investigation confirmed the feasibility of using carbon fiber strands in unbonded post-tensioning of pier caps. Considering both serviceability and overload conditions, the general performance of the pier cap model was deemed acceptable using either type of carbon fiber strands and quite comparable to that of steel strands. In another component of this research, creep stress tests were conducted with carbon fiber composite cable (CFCC). The anchorages for all the specimens were prepared using a commercially available expansive grout. Specimens withstood 95% of the guaranteed capacity provided by the manufacturer for a period of five months, without any sign of rupture.

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