The main objective of this investigation is to examine how various material properties, governed by code specification, affect the seismic response of a twelve- story reinforced concrete building. This study incorporates the pushover and response history analysis to examine how varying steel yield strength (Fy), 28 day nominal compressive concrete strength (f’c), modes, and ground motions may affect the base shear capacity and displacements of a reinforced concrete structure. Different steel and concrete strengths were found to have minimal impact on the initial stiffness of the structure. However, during the post-yielding phase, higher steel and concrete compressive strengths resulted in larger base shear capacities of up to 22%. The base shear capacity geometric median increased as f’c or Fy increased, and the base shear capacity dispersion measure decreased as f’c or Fy increased. Higher mode results were neglected in this study due to non-convergent pushover analyses results. According to the response history analysis, larger yield and concrete compressive strengths result in lower roof displacement. The difference in roof displacement was less than 12% throughout. This displays the robustness of both analysis methods because material properties have insignificant impact on seismic response. Therefore, acceptable yield and compressive strengths governed by seismic code will result in acceptable building performance.

No description available.

Master of Science / Department of Architectural Engineering and Construction Science / Kimberly W. Kramer / The basic tenets of performance based seismic design (PBSD) are introduced. This includes a description of the underlying philosophy of PBSD, the concept of performance objectives, and a description of hazard levels and performance indicators. After establishing the basis of PBSD, analysis procedures that fit well within the PBSD framework are introduced. These procedures are divided into four basic categories: linear static, linear dynamic, nonlinear static, and nonlinear static. Baseline FEMA requirements are introduced for each category. Each analysis category is then expanded to include a detailed description of and variations on the basic procedure. Finally, optimization procedures that mesh well with a PBSD framework are introduced and described. The optimization discussion focuses first on the solution tools needed to effectively execute a PBSD multi-objective optimization procedure, namely genetic and evolutionary strategies algorithms. Next, multiple options for defining objective functions and constraints are presented to illustrate the versatility of structural optimization. Taken together, this report illustrates the unique aspects of PBSD. As PBSD moves to the forefront of design methodology, the subjects discussed serve to familiarize engineers with the advantages, possibilities, and finer workings of this powerful new design methodology.

In Turkey, most of the existing buildings have been designed according to Turkish Earthquake codes of 1975 and 1997. It is a well known fact that, poor material quality, poor design, poor control on site and inadequate workmanship makes existing buildings vulnerable to earthquake. In addition, change in function of buildings becomes another problem. These problems increase the importance of assessment of existing buildings. For this purpose, a new chapter has been added to the new code and assessment methods of existing buildings is regulated. 2007 Turkish Earthquake Code offered two analysis methods, linear and nonlinear analysis methods. Due to comprehensive computational, modeling and assessment challenges involved in applying the code procedures that are generally not well understood by practicing engineers, the use of commercial package computer programs is preferred. There are widely used three software&rsquo / s in Turkey / Idestatik, Sta4 and Probina. These programs currently handle linear assessment method only. This study aims to compare the assessment results of the most widely used three structural analysis and design softwares in Turkey. For this purpose, four v different structures having different property and plan were employed. These buildings were selected to be representative of the mostly common building types. Each building has been modeled and identified with the same material properties, the same reinforcement details and the same geometric properties in each software. The results of the assessment are compared in order to determine the inconsistencies among the software&rsquo / s and their reliability.

En la presente tesis se determina la influencia de las irregularidades de piso blando y torsión mediante el desempeño sísmico de ocho edificios de diez pisos - Sistema Dual, ubicados en la ciudad de Lima (Zona 4). Se plantea cuatro modelos por cada irregularidad de estudio, donde el primer modelo es una estructura regular y los tres modelos restantes presentan irregularidades, esto con la finalidad de determinar la influencia de las irregularidades en el desempeño sísmico frente a diferentes niveles de amenaza sísmica (Sismo frecuente, Ocasional, Raro y Muy raro). Todos los modelos se definieron en función de los parámetros y criterios de la Norma de Diseño Sismo Resistente E.030 (2018). Luego se realiza el Análisis Sísmico Estático y Dinámico, para verificar que los modelos cumplen con el diseño sísmico. Efectuado el Análisis Sísmico se prosigue a diseñar los elementos estructurales, tales como: vigas, columnas y muros de concreto armado, cuyo resultado del diseño se refleja en los planos estructurales. Cabe recalcar que los planos tienen el mismo diseño estructural de acuerdo a la norma E.060. Seguidamente se realiza el Análisis Estático No Lineal (AENL) – Pushover, haciendo uso de las recomendaciones del ASCE/SEI 41-13 con la finalidad de determinar la curva de capacidad de los ocho modelos de estudio y obtener los mecanismos de formación de rótulas plásticas en los elementos estructurales. El punto de desempeño de los ocho modelos de estudio se obtiene mediante el Método del Espectro de Capacidad (ATC-40 y FEMA 440), donde la demanda sísmica se define a través del espectro de diseño de la norma E.030 (2018). Finalmente, se realiza la evaluación de las irregularidades de piso blando y torsión en el desempeño sísmico de acuerdo con los objetivos de desempeño según Comité Visión 2000 y el ATC-40, para el caso de estudio de irregularidad de piso blando, la curva de capacidad tiene una disminución en la cortante basal y un aumento en el desplazamiento a medida que la irregularidad aumenta en ambas direcciones. Mientras que, en el caso de la irregularidad de torsión, la curva de capacidad tiene una reducción de la cortante basal y desplazamiento a medida que la irregularidad aumenta en ambas direcciones. En todos los casos de estudio de los modelos regulares e irregulares, cumple con la evaluación del desempeño sísmico para los distintos niveles de amenaza sísmica. / In this thesis, the influence of soft floor and torsional irregularities is determined through the seismic performance of eight ten-story buildings - Dual System, located in the city of Lima (Zone 4). Four models are proposed for each irregularity under study, where the first model is a regular structure and the remaining three models present irregularities, with the purpose of determining the influence of irregularities on the seismic performance against different levels of seismic hazard (Frequent, Occasional, Rare and Very Rare earthquakes). All models were defined based on the parameters and criteria of the Earthquake Resistant Design Standard E.030 (2018). Then, the Static and Dynamic Seismic Analysis is performed to verify that the models comply with the seismic design. Once the Seismic Analysis is performed, the structural elements are designed, such as: beams, columns and reinforced concrete walls, whose design result is reflected in the structural drawings. It should be noted that the plans have the same structural design according to the E.060 standard. Next, the Non-Linear Static Analysis (NLSA) - Pushover is performed, making use of the recommendations of ASCE/SEI 41-13 in order to determine the capacity curve of the eight study models and to obtain the mechanisms of formation of plastic hinges in the structural elements. The performance point of the eight study models is obtained through the Capacity Spectrum Method (ATC-40 and FEMA 440), where the seismic demand is defined through the design spectrum of the E.030 (2018) standard. Finally, the evaluation of soft-story and torsional irregularities on seismic performance is performed according to the performance objectives according to Vision 2000 Committee and ATC-40, for the soft-story irregularity study case, the capacity curve has a decrease in basal shear and an increase in displacement as the irregularity increases in both directions. While, in the case of torsional irregularity, the capacity curve has a decrease in basal shear and displacement as the irregularity increases in both directions. In all the case studies of the regular and irregular models, it complies with the seismic performance evaluation for the different seismic hazard levels. / Tesis

El trabajo de investigación se ha denominado “Evaluación del desempeño sísmico de una nave industrial de acero para el sector minero utilizando el ATC-40”, tiene como propósito determinar el comportamiento sísmico de la nave industrial de acero para el sector minero mediante el código ATC-40. La aplicación de análisis estático no lineal como Pushover y Pushover Modal al modelo de cálculo de estructuras existentes ayuda a determinar el grado de daño y el desempeño sísmico. De esta manera, se aplicó satisfactoriamente el análisis estático no lineal al modelo de una estructura existente mediante el uso del software SAP2000, y a través de datos y gráficos proporcionados por el programa, se conoció el nivel de daño para la nave industrial de acero sometida a grandes solicitaciones sísmicas. El desarrollo de esta tesis se divide en siete capítulos: El primer capítulo es de introducción e importancia. La segunda comprende de las generalidades, objetivos generales y específicos del proyecto de tesis; en el tercero se desarrolla el marco teórico para el análisis Pushover; en el cuarto se muestra el análisis estático lineal y no lineal; el quinto comprende el diseño por el método LRFD y su validación; el sexto presenta el criterio de desempeño sísmico usando el código ATC-40; en el séptimo se muestra el análisis de resultados; el octavo muestra las conclusiones y recomendaciones. Del análisis presentado, se concluye que mediante el análisis Pushover se pudo determinar el nivel de desempeño deseado asegurando continuidad para la producción del mineral, de lo cual se puede garantizar que la estructura va tener un comportamiento aceptable ante los 3 niveles de peligro sísmico y no se verá afectada su producción de mineral. / The present research project is entitled "Evaluation of the seismic performance of a mining steel building according to ATC-40" and has the purpose of determining the seismic performance of a mining building defined in the technical report ATC-40. The application of a static nonlinear analysis to the computational model of an existing structure can determine the level of damage and the expected seismic performance. Accordingly, the nonlinear static analysis was successfully applied to the model of an existing structure using SAP2000 software, and through data and graphics provided by the program, the level of damage in the industrial building subjected to great seismic actions was determined. This thesis is divided into seven chapters: the first chapter cover the introduction and the importance of the thesis. The second chapter include the generalities, general objectives and specific objectives of the thesis project; the third reviews the Pushover analysis theoretical framework; the fourth shows the linear and nonlinear static analyses; the fifth includes the design by the LRFD method and its validation; the sixth presents the criteria of seismic performance using the ATC-40 method; the seventh shows the analysis of results; the eighth shows the conclusions and recommendations. From the presented analysis, it is concluded that it was possible to achieve the level of performance desired ensuring continuous ore production, and with this, it can be guaranteed that the structure will have an acceptable behavior for the 3 levels of seismic hazard and that the ore production will not be affected. / Tesis

En esta investigación, se evalúa el comportamiento elasto- plástico y el desempeño sísmico de estructuras aporticadas aplicando el método Pushover. Esta evaluación se hace sobre diversos casos de edificios reforzados con acero de alta ductilidad (Grado 40), acero convencional (Grado 60) y acero de alta resistencia (Grado 75). Para lo anterior, se realiza la evaluación de la capacidad de deformación de los elementos estructurales a partir de las gráficas de momento-rotación de los elementos estructurales más críticos que causa el colapso de la estructura. También, se utilizó la gráfica de curva de capacidad obtenida a partir del método de coeficientes de desplazamiento para medir la capacidad de la estructura. Teniendo en cuenta los valores resultantes de ductilidad y rigidez de cada caso, se evalúa el desempeño de la estructura para diferentes niveles de diseño sísmico. Los resultados mostraron que reforzar una estructura con un acero de Grado 40 aumenta la capacidad de disipación de energía, y si se refuerza con acero de grado 75 aumenta la capacidad de resistencia en la estructura. Finalmente, se presenta el resultado comparativo de los diversos casos para demostrar la influencia del acero de refuerzo en el comportamiento plástico de las estructuras de concreto armado. / In this investigation, the elasto-plastic behavior and the seismic performance of concrete reinforced frame structures are evaluated by applying the Pushover method. This evaluation is done on several cases: with high ductility steel (Grade 40), conventional steel (Grade 60) and high strength steel (Grade 75). For the above, the capacity curve graph obtained from the displacement coefficient method was used to measure the capacity of the structure. In addition, the performance of the structure for different levels of seismic design are evaluated with the resulting values of ductility and rigidity in each case. The results showed that reinforcing a structure with a Grade 40 reinforcing steel increases the energy dissipation capacity, and if reinforced with a Grade 75 reinforcing steel it increases the strength capacity in the structure. Finally, the comparative result of the various cases is presented to demonstrate the influence of reinforcing steel on the plastic behavior of concrete reinforced frame structures. / Tesis