Renaud Favre

BASIC MODEL AND SIMPLIFIED CALCULATIONS OF DEFORMATIONS ACCORDING TO THE CEB-FIP MODEL CODE 1990

The principle objective of this article is to present the CEB-FIP moment-curvature relationship. This basic model is valid in the case of simple-bending or combined bending and takes into account the effect of reinforcement, the effect of cracking, and the time-dependent effects (creep and shrinkage). This relationship and the derived simplified methods were essentially developed for the CEB Permanent Commison V, and were definitively adopted by the CEB general assembly in Paris, September, 1990, for the new Model Code CEB-FIP 1990. A parametric study is presented that shows the influence of different factors on the curvature in State I-noncracked, the curvature in State 2-naked, and the mean curvature. Also, different simplifed calculation methods are presented and discussed.

Ultrasonic measurements and static load tests in bridge evaluation

Abstract The cross-sectional stiffness of a bridge depends on one hand on its geometry and on the other hand on its material properties. The inclusion in the stiffness of ‘nonstructural’ elements such as parapets or asphalt layers leads to better estimates of deflections under the load test. The most important unknown variable remains however the concretes modulus of elasticity. Ultrasonic measurements offer a cost-effective and nondestructive alternative for the determination of the modulus of elasticity of concrete in an existing structure. A computerized database was established to investigate the actual behaviour of bridges subjected to a load test. The database currently contains the results of over 200 load tests carried out by our institute, along with the geometry of the bridges. Ultrasonic measurements are currently being used to determine the actual modulus of elasticity of these bridges, with the purpose of better understanding the behaviour of structures subjected to short term loads. Drilled cores were taken from a limited number of bridges and the modulus of elasticity of cores is compared with the modulus predicted by the ultrasonic measurements. A case study showing the evolution of the modulus of elasticity of the Aubonne bridge determined by these various methods is presented.

DESIGN OF A CURVED INCREMENTALLY LAUNCHED BRIDGE

Using the example of the Ile Falcon Bridge, it is shown that, given proper attention during design and rigorous quality control during construction, incremental launching can be used successfully f...

Calcul non linéaire du béton armé et précontraint

ABSTRACT This article purpose is to describe theoretical basis of a algorithm for analysis of cracking and creep effect on reinforced and prestressed concrete structures. The algorithm allows essentially to anticipate work cracking degree and long term displacement. Purely academical examples as well a examples corresponding to real structures, the behavior of which has been analysed by mean of the proposed algorithm, are given as illustrations.

Experimental Research of Reinforced Concrete Columns Behavior under the Long-Term Eccentric Normal Force

The research described in this paper makes a part of a voluminous research project the experimental part of which has been carried out in the laboratories of the Swiss Federal Institute of Technology (EPFL) in Lausanne, under the direction of Professor Renaud Favre, the Director of the Institute for Reinforced and Prestressed Concrete at EPFL. It is primarily oriented towards time-dependent behavior of reinforced concrete structures under the service loads. The purpose of the investigation of the reinforced concrete columns behavior under the long-term action of eccentric compressive normal force was to experimentally establish the moment-normal force-curvature relationship as well as to follow the appearance and time-dependent development of cracks.