Dr. Oyarzo-Vera, Claudio

Vibrations on timber floors are among the most common serviceability problems in social housing projects. The presence of low damping levels on these floors could cause excessive vibrations in a range of frequency and amplitude that generate discomfort in users. This study focuses on the influence of the damping ratio in the dynamic serviceability of social housing timber floors due to walking excitations. More than 60 human-walking vibration tests were conducted on both laboratory and in-situ timber floors. The floors were instrumented with accelerometers, and fundamental modal damping ratios were estimated by applying Enhanced Frequency Decomposition Domain (EFDD) and Subspace Stochastic Identification (SSI) methods. The vibration dose value (VDV) was used to estimate the dynamic serviceability of floors. The results indicated that timber floors had an impulsive-type vibration response, with fundamental damping ratios between 1.9% and 14.8%, depending on their constructive characteristics. The in-situ floors had damping ratios between two to three times greater than the laboratory floors due to the presence of non-structural elements. Finally, it was possible to demonstrate that the floors with the highest damping ratios reached lower vibration dose values and, therefore, a better dynamic serviceability performance.

Several damage indicators based on changes in modal properties validated for homogeneous materials were applied to detect damage in an unreinforced masonry cantilever panel. Damage was created by a “clean diagonal cut” at the center of the specimen which length was progressively extended towards the specimen’s corners. Numerical simulations were employed to determine the modal response at several damage states and this data was used to calculate the damage indicators. Those indicators presenting a good performance were then applied to identify damage on a physical specimen tested in the laboratory. The outcomes of this study demonstrated that vibration-based damage detection in unreinforced masonry structures can be satisfactorily performed.However, the identification of the damage spatial distribution using vibration-based methods in unreinforced masonry structures is still difficult. To improve the prediction of damage distribution, a large number of measurement points need to be considered to obtain an acceptable level of resolution.

Este trabajo presenta una experiencia de educación en ingeniería orientada a la prevención de desastres, a través de la revisión y adecuación de los planes integrales de seguridad escolar en tres establecimientos educacionales de la comuna de Talcahuano, Chile, a solicitud del Departamento de Educación Municipal. La experiencia se desarrolló en el contexto del curso Desastres naturales y cultura de la prevención de las carreras de Ingeniería Civil e Ingeniería Civil Geológica de la Universidad Católica de la Santísima Concepción, mediante la aplicación de la metodología aprendizaje servicio. El objetivo de la experiencia es que los estudiantes del curso y la comunidad escolar estudiada reconozcan de manera eficaz los riesgos generados por el entorno natural, describan las etapas asociadas a gestión de desastres y colaboren en la generación de una cultura de prevención y preparación frente a ellos. Los resultados obtenidos corresponden a la entrega de planes integrales de seguridad escolar adecuados a los establecimientos estudiados con un diagnóstico de vulnerabilidades y mapa s de riesgo. La experiencia de aprendizaje servicio desarrollada muestra el fomento del compromiso social en los estudiantes y la importancia del aprendizaje orientado a resolver necesidades reales, con una visión integral en su formación profesional.