Análisis de Reforzamiento Sísmico del Edificio de Docentes Nº1 de la Universidad Técnica de Manabí

Este estudio nació debido a lo observado en el edificio de docentes post terremoto del 16 de abril del 2016, observándose falencias en su estructura. El propósito de desarrollar esta investigación tiene que ver con optar por un reforzamiento idóneo para el edificio con el propósito de que sea capaz de disipar la energía de los sismos, previo a esta investigación se contó con un análisis, el que demostró que el edificio no cumplía con los requerimientos de diseño sismorresistente que exigen los códigos modernos. Para esto, el principal objetivo de esta investigación es proponer dos alternativas de reforzamientos sísmico del edificio de docentes Nº1 de la Universidad Técnica de Manabí. Para cumplir el objetivo de esta investigación se plantearon dos sistemas de reforzamiento: uno es el de muros de cortes y el segundo es de pórticos arriostrados concéntricamente en V invertida, ambas estructuras fueron modeladas en el software Etabs, se analizaron las propiedades dinámicas de las estructuras con el fin de evaluar las variaciones de esfuerzos globales y desplazamientos de piso. Se efectuaron dos tipos de análisis sísmicos, estático y dinámico (modal espectral) se empleó el espectro de diseño que plantea la norma correspondiente a un suelo tipo “D” y además el espectro del sismo del 16 de abril con el fin de identificar el tipo de reforzamiento más eficiente que puede implementarse y ejecutarlo por medio de las especificaciones técnicas suscritas en las normas vigentes. De esta investigación se puede concluir principalmente que: i) Los máximos valores de desplazamiento de piso se los encontró al usar el espectro de diseño del sismo del 16 de abril, este se dio en la estructura reforzada con muros de corte. ii) Los esfuerzos globales fueron relativamente mayores al emplear el espectro de diseño del sismo del 16 de abril, esto se dio al analizar las estructuras con su reforzamiento. iii). La estructura presentó un periodo natural de 0.36 s, al usar los muros de corte a comparación de los pórticos arriostrados concéntricamente en V invertida que se obtuvo un valor de. 0.23 s. Se recomienda el uso de los muros de corte como reforzamiento ya que aportan mayor rigidez lateral además de que son más económicos, de esta manera se prolongará la vida útil de esta estructura. Palabras clave: Espectros de Diseño, Microzonificación Sísmica, Análisis Sísmico, Análisis Modal Espectral, Periodo Natural, Rigidez Lateral. Abstract— This study was born due to observations made in the building of teachers after the earthquake of April 16, 2016, observing flaws in its structure, the purpose of developing this research has to do with opting for an ideal reinforcement for the building in order to be ableto dissipate the energy of earthquakes, prior to this research was an analysis , which demonstrated that the building did not meet the sism-resistant design requirements required by modern codes. For this, the main objective of this research is to propose two alternatives of seismic reinforcements of the teaching building No.1 of the Technical University of Manabí. To meet the objective of this research, two reinforcement systems were developed: one is that of shear wall and the second is of concentrically inverted V-portico, both structures were modeled in the Etabs software, the dynamic properties of the structures were analyzed in order to evaluate variations in global efforts and floor displacements. Two types of seismic analysis were carried out, static and dynamic (spectral modal), the spectrum design proposed by the norm for a type “D” soil was used, in addition to the spectrum of the April 16 earthquake in order to identify the more efficient type of reinforcement that can be implemented and executed by means of the technical specifications subscribed in the current regulations. From this research it can be mainly concluded that: (i) The maximum floor displacement values were found when using the spectrum design of the April 16 is, this was given in the structure reinforced with shear wall. (ii) Global efforts were relatively greater in using the sism spectrum design of April 16, this was given by analyzing the structures with their strengthening. iii). The structure had a natural period of 0.36 s, using the shear wall compared to the concentrically inverted V-portico that a value of. 0.23 s. It is recommended to use the shear wall as reinforcement as they provide greater lateral stiffness in addition to being more economical, in this way the life of this structure will be extended. Keywords: Spectrum design, Seismic Microzoning, Seismic Analysis, Spectral Modal Analysis, Natural Period, Lateral Stiffness

Candidate Core Designs for the Transformational Challenge Reactor

Early cycle activities under the Transformational Challenge Reactor (TCR) program focused on analyzing and maturing four reactor core design concepts: two fast-spectrum systems and two thermal-spectrum systems. A rapid, iterative approach has been implemented through which designs can be modified and analyzed and subcomponents can be manufactured in parallel over time frames of weeks rather than months or years. To meet key program initiatives (e.g., timeline, material use), several constraints—including fissile material availability (less than 250 kg of HALEU), component availabilities, materials compatibility, and additive manufacturing capabilities—were factored into the design effort, yielding small (less than one cubic meter in volume) cores with near-term viability. The fast-spectrum designs did not meet the fissile material constraint, so the thermal-spectrum systems became the primary design focus. Since significant progress has been made on advanced moderator materials (YHx) under the TCR program, gas-cooled thermal-spectrum systems using less than 250 kg of HALEU that occupy less than 1 m3 are now feasible. The designs for two of these systems have been evolved and matured. In both thermal-spectrum design concepts, bidirectional coolant flow is used. Coolant flows down through YHx moderator elements and is reversed in a bottom manifold and core support structure, and then flows up though or around the fuel elements. The main difference between the two thermal-spectrum design concepts is the fuel elements—one uses traditional UO2 ceramic fuel, and the other uses UN-bearing TRISO fuel particles embedded inside a SiC matrix. Core neutronics and thermal performance for these systems are assessed and summarized herein.