Thesis METODOLOGÍA DE DISEÑO PARA LAS CONEXIONES ENTRE PANELES DE MURO PARALELOS EN EDIFICIOS DE MEDIANA ALTURA ESTRUCTURADOS CON MUROS Y LOSAS DE CLT, EN ZONAS DE ALTA SISMICIDAD
Date
2021-10-14
Authors
FERCOVIC DE LA PRESA, JÉCAR ROBERTO
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Abstract
La madera contralaminada o CLT (por sus siglas en inglés), es un producto de madera de ingeniería que ha ganado popularidad en aplicaciones residenciales y no residenciales en Europa y Norteamérica. Los paneles CLT tienen una rigidez muy alta en el plano y, como tales, permanecen elásticos cuando están en servicio, de modo que las deformaciones plásticas se concentran en las conexiones de anclaje de muros a fundación y las conexiones verticales entre paneles de muros paralelos. En Chile, el diseño de estructuras de madera está regulado por la NCh 1198 Of. 2014, la cual no contempla la madera contralaminada entre sus disposiciones. Por ello, determinar una metodología para el diseño de conexiones verticales entre muros paralelos de CLT en edificios de mediana altura permitirá avanzar en la incorporación del CLT en la normativa nacional. Mediante una revisión bibliográfica de las metodologías de diseño utilizadas en los códigos de diseño de Europa (EC5), Canadá (CSA O86) y Estados Unidos (NDS), así como las principales investigaciones sobre conexiones en CLT, como las realizadas por Uibel & BlaB (2006, 2007), se establen tres metodologías de diseño compatibles con el modelo de fluencia utilizado en la normativa chilena: determinación de una longitud de aplastamiento equivalente (NDS), cálculo de la resistencia al aplastamiento con la ecuación de Hankinson extendida o con la relación derivada por Uibel & BlaB. Para esta última ecuación, se necesita la aplicación de un factor de ajuste, debido a que está desarrollada para la metodología de estados límites de diseño. Realizando una comparación numérica de la capacidad de carga lateral estimada utilizando el modelo de fluencia de la normativa nacional en conjunto con los diferentes modelos estudiados, se determinó que la ecuación de resistencia al aplastamiento para medios de unión de tipo cilíndrico derivada por Uibel & BlaB dividida por un factor de ajuste igual a 2,0, es idónea para ser usada en conjunto con el modelo de fluencia de la NCh 1198 Of. 2014. Adicionalmente debe ser aplicado un factor de corrección de 1,05 sobre la capacidad de carga en extracción lateral de los modos de falla frágil. Con este modelo, se pueden diseñar de forma sencilla y satisfactoria las conexiones entre muros paralelos de CLT.
Junto con los factores de ajuste y corrección para el uso de la ecuación de Uibel & BlaB, se recomiendan espaciamientos y distancias mínimas para CLT, así como factores de sobrerresistencia y degradación de resistencia utilizados en el diseño por desempeño de edificios de mediana altura fabricados con paneles de madera contralaminada. La idoneidad del uso de la ecuación de Uibel & BlaB en conjunto con el modelo de fluencia nacional, así como los resultados obtenidos en esta Memoria, deben ser validados experimentalmente.
Cross-laminated Timber or CLT, is an engineered wood product that has gained popularity in residential and non-residential applications in Europe and North America. CLT panels have very high in-plane stiffness and as such remain elastic when in service, so plastic deformations are concentrated in the anchor connections of walls to foundation and the vertical connections between parallel wall panels. In Chile, the design of wooden structures is regulated by NCh 1198 Of. 2014, which does not include cross-laminated timber among its provisions. Therefore, determining a methodology for the design of vertical connections between parallel CLT walls in medium-rise buildings will allow to make progress in incorporating CLT into national regulations. After carrying out a bibliographic review of the design methodologies used in the design codes of Europe (EC5), Canada (CSA O86) and the United States (NDS), as well as the main research on connections in CLT, such as those conducted by Uibel & BlaB (2006, 2007), three design methodologies compatible with the yield model used in Chilean regulations are established: determination of an equivalent bearing length (NDS), calculation of bearing resistance with the extended Hankinson equation or with the equation derived by Uibel & BlaB. For this latter equation, the application of an adjustment factor is needed, since it is developed for the limit state design method. Carrying out a numerical comparison of the estimated lateral load capacity using the national regulations’ yield model in conjunction with the different models studied, it was determined that the bearing resistance equation for dowel-type fasteners derived by Uibel & BlaB divided by an adjustment factor equal to 2.0, is suitable to be used in conjunction with the yield model of the NCh 1198 Of. 2014. Additionally, a correction factor of 1.05 must be applied on the load capacity in lateral extraction of brittle failure modes. With this model, the connections between parallel CLT walls can be easily and satisfactorily designed. Along with the adjustment and correction factors for the use of the Uibel & BlaB equation, minimum spacings and distances are recommended for CLT, as well as over-strength and strength degradation factors used in the performance design of mid-rise buildings manufactured with cross-laminated wood panels. The suitability of using the Uibel & BlaB equation in conjunction with the national yield model, as well as the results obtained in this Thesis, must be experimentally validated.
Cross-laminated Timber or CLT, is an engineered wood product that has gained popularity in residential and non-residential applications in Europe and North America. CLT panels have very high in-plane stiffness and as such remain elastic when in service, so plastic deformations are concentrated in the anchor connections of walls to foundation and the vertical connections between parallel wall panels. In Chile, the design of wooden structures is regulated by NCh 1198 Of. 2014, which does not include cross-laminated timber among its provisions. Therefore, determining a methodology for the design of vertical connections between parallel CLT walls in medium-rise buildings will allow to make progress in incorporating CLT into national regulations. After carrying out a bibliographic review of the design methodologies used in the design codes of Europe (EC5), Canada (CSA O86) and the United States (NDS), as well as the main research on connections in CLT, such as those conducted by Uibel & BlaB (2006, 2007), three design methodologies compatible with the yield model used in Chilean regulations are established: determination of an equivalent bearing length (NDS), calculation of bearing resistance with the extended Hankinson equation or with the equation derived by Uibel & BlaB. For this latter equation, the application of an adjustment factor is needed, since it is developed for the limit state design method. Carrying out a numerical comparison of the estimated lateral load capacity using the national regulations’ yield model in conjunction with the different models studied, it was determined that the bearing resistance equation for dowel-type fasteners derived by Uibel & BlaB divided by an adjustment factor equal to 2.0, is suitable to be used in conjunction with the yield model of the NCh 1198 Of. 2014. Additionally, a correction factor of 1.05 must be applied on the load capacity in lateral extraction of brittle failure modes. With this model, the connections between parallel CLT walls can be easily and satisfactorily designed. Along with the adjustment and correction factors for the use of the Uibel & BlaB equation, minimum spacings and distances are recommended for CLT, as well as over-strength and strength degradation factors used in the performance design of mid-rise buildings manufactured with cross-laminated wood panels. The suitability of using the Uibel & BlaB equation in conjunction with the national yield model, as well as the results obtained in this Thesis, must be experimentally validated.
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Keywords
ESTRUCTURAS DE MADERA , CONSTRUCCION DE MADERA , RESISTENCIA DE MATERIALES