Comparative Durability Analysis of CFRP Strengthened RC Highway Bridges

The paper presents parametric analysis of durability factors of RC highway bridges strengthened with CFRP laminates during their service life. Durability factors considered are concrete cover and CFRP laminate thickness. Three deterioration factors were considered. First, growth of live load with time. Second, resistance reduction due to chloride-attack corrosion which causes reduction in steel properties. Corrosion losses are evaluated through a time–temperature dependent corrosion current. Two types of corrosion are considered; uniform and pitting corrosion. Third, deterioration due to aging of CFRP. The reliability analysis is controlled by three failure modes; concrete crushing, CFRP mid span debonding and CFRP rupture. Monte-Carlo simulation is used to develop time dependent statistical models for rebar steel area and live load extreme effect. Reliability is estimated in term of reliability index using FORM algorithm. For illustrative purpose, a RC bridge is assumed as an example. The reliability of interior beam of the bridge is evaluated under various traffic volumes and different corrosion environments. The bridge design options follow AASHTO-LRFD specifications. The present work also extends to calibrate CFRP resistance safety factor corresponds to three target reliability levels, β = 3.5, 3.85, and 4.2. The results of the analysis have shown that corrosion has the most significant effect on bridge life time followed by live load growth. Pitting corrosion type is more hazardous than uniform. Also, initial safety index is proved to be traffic dependent. AASHTO design equation (that corresponds βtarget = 3.5) seems to be overestimated for strengthening purpose. Strengthening with (βtarget = 4.2) provide better reliability than βtarget proposed by AASHTO provision with no significant differences in CFRP amounts required

Projet UNIT GIMIROB : Gestion Immobilière, Maintenance, Inspection pouR les Ouvrages et les Bâtiments

Méthodes et approchesInternational audienceLe projet GIMIROB constitue un produit de formation portant sur divers aspects liés à la gestion des ouvrages de génie civil et des bâtiments. Il se situe à l'interface des besoins de connaissance des ingénieurs en construction civile qui souhaitent mieux appréhender des problématiques de gestion de patrimoine(s), et des gestionnaires de patrimoine(s) qui souhaitent mieux comprendre comment le vieillissement des matériaux et des ouvrages affectent le patrimoine. Les modules de formation de base sont pour l'instant disponibles. Ils ont été produits par un collectif de 8 établissements et une équipe de 12 personnes sur des supports multiples (pages web, fichiers pdf, présentations ou document OpenOffice) à l'aide de la chaîne éditoriale Opale-Scenari. Les supports de formation seront prochainement accessibles que le portail d'UNIT. La suite du projet consistera à étendre les modules de formation et à les rendre plus interactifs les uns avec les autres pour qu'ils participent à un support effectif de web-formation

Denis Peschanski, Brigitte Sion, dirs, La Vérité du témoin. Mémoire et mémorialisation, vol. 2

L’ouvrage collectif La Vérité du Témoin, dirigé par Denis Peschanski et Brigitte Sion est le second tome de Mémoire et mémorialisation. Le tome 1, De l’absence à la représentation, s’attachait à comprendre les dynamiques mémorielles en associant aux sciences sociales les neurosciences et la neuropsychiatrie pour intégrer les processus cérébraux et cognitifs aux études autour de la mémorialisation. Denis Peschanski définit ce concept de mémorialisation comme étant la mise en récit publique d‘u..

Molecular implications of prohibitin-1 deficiency in liver homeostasis

Comunicaciones a congreso

Seismic retrofitting of reinforced concrete structures using composites

International audienc

Detection of Faults and Drifts in the Energy Performance of a Building Using Bayesian Networks

Despite improved commissioning practices, malfunctions or degradation of building systems still contribute to increase up to 20% the energy consumption. During operation and maintenance stage, project and building technical managers need appropriate methods for the detection and diagnosis of faults and drifts of energy performances in order to establish effective preventive maintenance strategies. This paper proposes a hybrid and multilevel fault detections and diagnosis (FDD) tool dedicated to the identification and prioritization of corrective maintenance actions helping to ensure the energy performance of buildings. For this purpose, we use dynamic Bayesian networks (DBN) to monitor the energy consumption and detect malfunctions of building equipment and systems by considering both measured occupancy and the weather conditions (number of persons on site, temperature, relative humidity (RH), etc.). The hybrid FDD approach developed makes possible the use of both measured and simulated data. The training of the Bayesian network for functional operating mode relies on on-site measurements. As far as dysfunctional operating modes are concerned, they rely mainly on knowledge extracted from dynamic thermal analysis simulating various operational faults and drifts. The methodology is applied to a real building and demonstrates the way in which the prioritization of most probable causes can be set for a fault affecting energy performance. The results have been obtained for a variety of simulated situations with faults deliberately injected, such as increase in heating preset temperature and deterioration of the transmission coefficient of the building\u27s glazing. The limitations of the methodology are discussed and are translated in terms of the ability to optimize the experiment design, control period, or threshold adjustment on the control charts used

Time-variant flexural reliability of RC beams with externally bonded CFRP under combined fatigue-corrosion actions

Time-variant reliability analysis of RC highway bridges strengthened with carbon fibre reinforced polymer CFRP laminates under four possible competing damage modes (concrete crushing, steel rupture after yielding, CFRP rupture and FRP plate debonding) and three degradation factors is analyzed in terms of reliability index β using FORM. The first degradation factor is chloride-attack corrosion which induces reduction in steel area and concrete cover cracking at characteristic key times (corrosion initiation, severe surface cover cracking). The second degradation factor considered is fatigue which leads to damage in concrete and steel rebar. Interaction between corrosion and fatigue crack growth in steel reinforcing bars is implemented. The third degradation phenomenon is the CFRP properties deterioration due to aging. Considering these three degradation factors, the time-dependent flexural reliability profile of a typical simple 15 m-span intermediate girder of a RC highway bridge is constructed under various traffic volumes and under different corrosion environments. The bridge design options follow AASHTO-LRFD specifications. Results of the study have shown that the reliability is very sensitive to factors governing the corrosion. Concrete damage due to fatigue slightly affects reliability profile of non-strengthened section, while service life after strengthening is strongly related to fatigue damage in concrete