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This paper presents results of an ongoing study on the seismic performance of a retrofitted concrete building located in the soft soil area of Mexico City. The original structure consisted of reinforced concrete frames in two directions. The building was repaired and retrofitted after having been damaged during a moderate earthquake in 1979. The retrofit strategy consisted mainly of installing external steel braces in one direction of the building, and reinforced concrete infill walls in the other direction. The retrofitted structure showed minor damage after the 1985 and 2017 earthquakes. The goal of this investigation is to assess the structural response of the building and the effectiveness of the retrofit strategy by combining post-earthquake damage inspections, analytical modeling and ambient vibration testing. This paper focuses on the development and calibration of a three-dimensional analytical model of the building, and on the analysis of the vibration properties of the retrofitted structure. The analytical model has been calibrated using data from ambient vibration tests conducted after the 2017 event. The study of the vibration properties of the building has shown the strong influence of soil-structure interaction in the response of this building., Postprint (published version)

Recognising that in situ conditions for URM walls rarely reflect the idealised conditions assumed in analytical predictive models, nineteen unreinforced masonry (URM) walls in six different buildings were physically tested in situ to establish their out-of-plane (OOP) force-displacement behaviour, and the measured results were compared to the forecasted results obtained from established predictive methods. The considered wall configurations represented a variety of geometries, boundary conditions, pre-test damage states, and material properties. The average ratio and associated coefficient of variation (CV) of predicted strengths to measured strengths were determined to be 0.84 (CV 0.56) and 0.93 (CV 0.25) for the “unbounded” and “bounded” wall conditions, respectively, where the latter group represents walls used to infill frames. Use of the existing predictive methods resulted in over-prediction of the measured displacement parameters, which was likely due to most of the predictive methods being based on historical walls tests in one-way spanning conditions and without rigid bounding restraints capable of effectuating arching action in the wall, in contrast to many of the wall test conditions employed in the current study.

AUCTORITAS Projektstyrning AB arbetar med att få fram förfrågningsunderlag för två nya flerbostadshus i en miljö som är bullerutsatt. Ett problem som uppstått är att hitta en utfackningsvägg som klarar kraven för buller samt U-värde som samtidigt är ekonomisk försvarbar. Författarna har på uppdrag av AUCTORITAS Projektstyrning AB undersökt 10 olika utfackningsväggar med hänsyn till ljudreduktion, U-värde samt pris. Syftet med arbetet var att utreda de tekniska egenskaperna för utfackningsväggarna. Frågeställningen som behandlades var följande: Hur påverkar olika materialval ljuddämpningen? Vilka utfackningsväggar klarar bullerkraven vid en nybyggnation på Albyberget? Kan problematiken lösas enbart med väggarna eller krävs det ytterligare åtgärder? Är det ekonomiskt försvarbart att välja en tjockare vägg med hänsyn till u-värde istället för att maximera BOA? För att besvara dessa frågor har författarna genomfört laborationer, litteraturstudier samt tagit del av ett referensobjekt, akustikrapporter, energiberäkningsrapporter och kalkylböcker/offerter. Intervju med en person som besitter kunskap inom området buller/akustik har utförts och använts som kompletterande underlag. Resultatet ledde till att en standard träregelvägg på 395 mm som uppfyllde samtliga projektkrav som samtidigt var ekonomisk försvarbar med en kostnad på 1 391 kr/m2 rekommenderades till flerbostadshusen på Albyberget, AUCTORITAS Projektstyrning AB is working on obtaining contract documents for two new apartment buildings in an environment that is exposed to noise. One problem that has arisen is to find an infill wall that meets the requirements for noise and U-value, which at the same time is economically justifiable. The authors, on behalf of AUCTORITAS Projektstyrning AB, have examined 10 different infill walls with regard to noise reduction, U-value and price. The purpose of the work was to investigate the technical properties of the infill walls. The question that was addressed was the following: How does different materials affect the sound attenuation? Which infill walls can handle the noise requirements of a new construction on Albyberget? Can the problem be solved solely with the walls or does it require further action? Is it economically justifiable to choose a thicker wall with regard to u value instead of maximizing the living space? In order to answer these questions, the authors have carried out laboratory work, literature studies and also taken part in a reference object, acoustics reports, energy calculation reports and costing books/offers. An interview with a person with knowledge in the area of noise/acoustics have been completed and used as a complementary basis. The results led to a recommendation of a standard timber frame wall with a thickness of 395 mm, that met all of the project requirements and with a cost of 1 391 kr/m2 to be used in the buildings at Albyberget.

AUCTORITAS Projektstyrning AB arbetar med att få fram förfrågningsunderlag för två nya flerbostadshus i en miljö som är bullerutsatt. Ett problem som uppstått är att hitta en utfackningsvägg som klarar kraven för buller samt U-värde som samtidigt är ekonomisk försvarbar. Författarna har på uppdrag av AUCTORITAS Projektstyrning AB undersökt 10 olika utfackningsväggar med hänsyn till ljudreduktion, U-värde samt pris. Syftet med arbetet var att utreda de tekniska egenskaperna för utfackningsväggarna. Frågeställningen som behandlades var följande: Hur påverkar olika materialval ljuddämpningen? Vilka utfackningsväggar klarar bullerkraven vid en nybyggnation på Albyberget? Kan problematiken lösas enbart med väggarna eller krävs det ytterligare åtgärder? Är det ekonomiskt försvarbart att välja en tjockare vägg med hänsyn till u-värde istället för att maximera BOA? För att besvara dessa frågor har författarna genomfört laborationer, litteraturstudier samt tagit del av ett referensobjekt, akustikrapporter, energiberäkningsrapporter och kalkylböcker/offerter. Intervju med en person som besitter kunskap inom området buller/akustik har utförts och använts som kompletterande underlag. Resultatet ledde till att en standard träregelvägg på 395 mm som uppfyllde samtliga projektkrav som samtidigt var ekonomisk försvarbar med en kostnad på 1 391 kr/m2 rekommenderades till flerbostadshusen på Albyberget, AUCTORITAS Projektstyrning AB is working on obtaining contract documents for two new apartment buildings in an environment that is exposed to noise. One problem that has arisen is to find an infill wall that meets the requirements for noise and U-value, which at the same time is economically justifiable. The authors, on behalf of AUCTORITAS Projektstyrning AB, have examined 10 different infill walls with regard to noise reduction, U-value and price. The purpose of the work was to investigate the technical properties of the infill walls. The question that was addressed was the following: How does different materials affect the sound attenuation? Which infill walls can handle the noise requirements of a new construction on Albyberget? Can the problem be solved solely with the walls or does it require further action? Is it economically justifiable to choose a thicker wall with regard to u value instead of maximizing the living space? In order to answer these questions, the authors have carried out laboratory work, literature studies and also taken part in a reference object, acoustics reports, energy calculation reports and costing books/offers. An interview with a person with knowledge in the area of noise/acoustics have been completed and used as a complementary basis. The results led to a recommendation of a standard timber frame wall with a thickness of 395 mm, that met all of the project requirements and with a cost of 1 391 kr/m2 to be used in the buildings at Albyberget.

In the current state of structural engineering, physical experimentation still offers the most reliable means for the determination of parameters for accurate modeling of complex systems. However, engineers usually face time and financial constraints that prevent them from performing such experiments. On the other hand, engineers are in increased need of a reliable predicting computational power so that resources are optimized in the design of new structures and the retrofit of existing ones. Moreover, society expects us to be able to guarantee that structures will have adequate performance during their life. In the present work, a computational framework for the analysis of masonry structures is presented. The framework relies on the well-established theory of micromechanical homogenization. The dissertation consists of two distinct parts: I. Constitutive modeling on the component level and II. Applications at the structural level. First, homogenization is conducted for the elastic parameters. Those parameters are used in a linear elastic analysis of masonry at a macro-scale. Then, with proper engineering judgments, a representative state of strain is determined where the unit cell is subjected to a monotonically increasing state of strain. A stress versus strain relationship is obtained accounting for material regularization so that dimensional effects and proper softening behavior are considered. Effective material parameters are tested against experiments as well as against micro-modeling leading to acceptable results at an affordable computational cost. The framework is applied to the modeling of reinforced concrete frames with masonry infills subjected to in-plane and out-of-plane loading. A three-dimensional model is needed for explicitly accounting for the out-of-plane arching action, which makes the homogenization procedure the only feasible approach for such problem.

In the current state of structural engineering, physical experimentation still offers the most reliable means for the determination of parameters for accurate modeling of complex systems. However, engineers usually face time and financial constraints that prevent them from performing such experiments. On the other hand, engineers are in increased need of a reliable predicting computational power so that resources are optimized in the design of new structures and the retrofit of existing ones. Moreover, society expects us to be able to guarantee that structures will have adequate performance during their life. In the present work, a computational framework for the analysis of masonry structures is presented. The framework relies on the well-established theory of micromechanical homogenization. The dissertation consists of two distinct parts: I. Constitutive modeling on the component level and II. Applications at the structural level. First, homogenization is conducted for the elastic parameters. Those parameters are used in a linear elastic analysis of masonry at a macro-scale. Then, with proper engineering judgments, a representative state of strain is determined where the unit cell is subjected to a monotonically increasing state of strain. A stress versus strain relationship is obtained accounting for material regularization so that dimensional effects and proper softening behavior are considered. Effective material parameters are tested against experiments as well as against micro-modeling leading to acceptable results at an affordable computational cost. The framework is applied to the modeling of reinforced concrete frames with masonry infills subjected to in-plane and out-of-plane loading. A three-dimensional model is needed for explicitly accounting for the out-of-plane arching action, which makes the homogenization procedure the only feasible approach for such problem.

En España, la mayoría de los edificios de hormigón armado son de forjados reticulares y los cerramientos en estos edificios se suelen materializar con paredes de fábrica que rellenan los marcos entre pilares y forjados. Estas paredes no son portantes y, generalmente, no se considera su contribución resistente ante cargas gravita- torias. No obstante, ante acciones laterales (sismo o viento) la existencia o no de estas paredes puede influir en la respuesta de la estructura. El objetivo de este trabajo es conocer la influencia de la tabiquería en la respuesta sísmica. A partir de planos estructurales reales se define un edificio tipo de 8 plantas, se evalúa su capacidad y respuesta sísmica con y sin tabiquería mediante un análisis estático no lineal. Los resultados muestran la influencia de las paredes en el comportamiento de la estructura frente a cargas laterales, tanto en su rigidez como en su capacidad resistente. The seismic behaviour of a very common building typology in Spain, reinforced concrete (RC) frame buildings, is inves- tigated. Usually, divisions in these buildings are made by means of non-bearing masonry infill walls. It is the traditional practice not to consider the contribution of these in the resisting mechanism, especially for gravitational loads. However, under lateral loading, such as wind or earthquake, the existence or not of these infill walls may significantly influence the structural response. The objective of this paper is to know the influence of masonry infill walls in the seismic response of RC buildings. Based on structural details of a series of real drawings, an 8 stories reference building was defined and by means of non-linear static analysis, structural response and capacity with and without infill walls are evaluated. The results shown that infill walls are determinant in the structural behaviour against lateral loads, both in terms of stiffness and resistance., Postprint (published version)