Thermal effects in the Long-Term Monitoring of Bridges

Daily and seasonal temperature variations induce deflections of bridges. The amplitude of these moments is significant in comparison with the yearly increment caused by irreversible long-term deflections. To improve the quality of the interpretation of monitoring measurements, thermal movements thus need to be taken into account in the long-term monitoring of bridge deflections. The paper presents the results of the long-term monitoring of deflections of several bridges in Switzerland over the past 20 years, with a particular attention given to thermal effects. The daily and seasonal movements of bridges under thermal effects are shown. The correlation between the measured temperatures and gradients and the position of bridge is shown, and methods to compensate for thermal effects are outlined. This allows to filter out the largest part of the thermal effects and to make more accurate assessments of the actual irreversible deformations. The significant influence of temperature on the measurement results is illustrated on the basis of a large number of manual measurements by hydrostatic leveling and automatic measurements by electronic inclinometers. The simultaneous measurement of the ambient temperature and of the temperature of the concrete of the bridge itself gives useful information to take thermal effects into account

Analysis and Design of Anchorage Zones in Post-Tensioned Concrete Bridges

Recherche sur le comportement et la modélisation de zones d'ancrages de câbles de précontrainte. Analyse élastique et modèle de treillis. Etudes paramétriques. Proposition de codification

Experience in the Long-Term Monitoring of Bridges

At the end of the 1980’s, a series of existing bridges in Switzerland were equipped with a network of hydrostatic leveling devices, with the aim of following their longterm behavior. Some of the bridges were known to exhibit a steady increase in their deformations, while others were considered in stable condition. The paper describes the measurement system, and the choices that were initially made to ensure that it would be durable. After more than twenty years of operation, the long-term experience related to the operation of this system is presented. The mode of operation of the system is discussed. The results of the monitoring are shown for several bridges. In the mean time, several bridges have been strengthened by additional post-tensioning, one bridge was even strengthened twice. The effect of the additional prestressing and the subsequent changes on the long-term behavior are shown

Gebrauchstauglichkeit

Aptitude au service. Cours d'introduction de la norme SIA 262, version allemande

Transposing multimedia into a virtual course

The present paper describes the challenges posed by transposing a successful conventional course into an – hopefully – equally successful web-based course, with the name i-Structures. This work is under way as part of the Swiss Virtual Campus project. The i-Structures project team is composed of members from the Swiss Federal Institute of Technology in Lausanne, the Swiss Italian University in Mendrisio and Lugano, the Swiss Federal Institute of Technology in Zürich and the University of Applied Sciences in Manno. In addition to the use of text and illustrations, technical courses, in the present case engineering courses, often make use of some multimedia components, in the form of in-class demonstrations, videos and models. The idea behind the project proposed to the Swiss Virtual Campus in its second call for projects was to transpose this course into a web-based course that would offer both the teacher and the students more possibility for interaction with the phenomena and more freedom to consider complex problems. At the same time, the idea was to also extend this course to civil engineering students, who, in the process of being trained to use analytical method, often lose sight of the way structures work, and are often less creative in their approach to structural problems

Dynamic load testing of Swiss bridges

Ponència presentada al Congrés Internacional Docència Universitària i Innovació (7è : 2012 : Barcelona, Catalunya)Dins del període de canvis que es produeixen en l’ensenyament universitari arrel de la implementació del Pla Bologna, hem dedicat una especial atenció a la internacionalització de l’ensenyament artístic com a motor de canvi i progrés en la nostra activitat pedagògica, investigadora i artística. Compartir coneixements i experiències amb altres docents, investigadors, alumnes i artistes, ens permet avançar i ens ofereix unes eines imprescindibles per a un futur que evoluciona i canvia a un ritme vertiginós, dins del qual la capacitat d’adaptació serà la intel·ligència que tots haurem de desenvolupar per a sobreviure amb una certa garantia d’èxit.PMI

Aptitude au service

Vérification de l'aptitude au service des structures en béton. Cours d'introduction de la norme SIA 262