An experimental study was performed to evaluate the bond strength between two concrete layers, for different techniques for increasing the roughness of the substrate surface. In a total of 25 slant shear specimens and 25 pull-off specimens the substrate surface was prepared by wire-brushing; sand-blasting; chipping with a light jackhammer; or were left as-cast against steel formwork. Three months later, the new concrete was added. Pull-off tests were performed to evaluate the bond strength in tension. Slant shear tests were conducted to quantify the bond strength in shear. Analysis of results indicated that: the highest value of bond strength was achieved with sand-blasting; pull-off tests are adequate to estimate the bond strength in situ; and pre-wetting the substrate surface does not seem to influence the bond strength.

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SummaryStrengthening and rehabilitation by reinforced concrete jacketing of columns is assessed, considering different practical aspects: anchoring and slab crossing of the added longitudinal reinforcement, interface surface preparation, spacing of added stirrups, temporary shoring of the structure and addition of new concrete. Recent research on these topics and the main recommendations to achieve good RC jacketing are presented.

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Models and frameworks used for managing construction projects are typically inspired in business 'cultures' that prevail within industrial contexts. The conceptual backgrounds of quality, performance, and risk environments are explored to ascertain whether these 'cultures' can complement each other. A new general approach towards Risk-Managed Performance-Based Building (RM-PBB) is presented, including the principles and inputs used for designing and implementing an RM-PBB framework. Such a framework envisages the fulfilment of end-users' (society and individuals) and other interested parties' requirements relating to the building product, as well as the agile interaction between and within the building, manufacturing, property, and capital and insurance markets, at both national and international levels.Les modèles et les cadres utilisés pour gérer les projets de construction trouvent habituellement leur inspiration dans les « cultures » d'entreprise qui prévalent dans les contextes industriels. Les arrière-plans conceptuels en matière de qualité, de performance et de milieux à risques sont examinés afin d'établir si ces « cultures » peuvent être complémentaires les unes des autres. Il est présenté une nouvelle approche générale visant à une Construction Performancielle à Risques Maîtrisés, incluant les principes et les apports utilisés pour l'élaboration et la mise en oeuvre d'un cadre de référence performanciel dans le bâ timent. Un tel cadre permet d'envisager la satisfaction des exigences des utilisateurs finaux (société et individus) comme des autres parties intéressées par rapport à ce produit qu'est le bâ timent, ainsi qu'une souplesse d'interaction entre et au sein des marchés du bâ timent, de la production, de l'immobilier, des capitaux et des assurances, aussi bien au niveau national qu'au niveau international.

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