The improvement in mechanical and adhesion properties of polymer resins have allowed to progressively substitute cast-in place rebars by polymer-based anchors in some applications, by providing equivalent or even higher mechanical properties at ambient temperature. However, a temperature increase has the effect of weakening the bond and leads to a significant decay in the bearing capacity of the adhesive anchors. This paper presents a study of the phenomena that occur at high temperature in an adhesive anchor when exposed to high temperatures by means of two pull-out test procedures and by thermomechanical characterization of the polymer resin. Results showed that the resin glass transition is the responsible for the decay in the fire resistance of adhesive anchors. The paper highlights the non-conservative aspect of the current design method used to calculate the fire resistance of chemical anchors and proposes to consider the pull-out curves as input data.

This study describes an experimental and numerical investigation of the use of CFRP material for strengthening finger-jointed Spruce timber beams. The corresponding experimental work was based on a four-point bending test configuration in order to characterise stiffness, ductility and strength. The results show that the external bonding of CFRP increased the ultimate load-bearing capacity of finger-jointed Spruce timber beams under flexure. FE simulations were also carried out, based on the cohesive zone model (CZM) available in Abaqus software to allow an accurate description of the damage evolution of the bond lines within the finger joint until failure. The FE models incorporated the different materials' nonlinear constitutive laws including bond-slip action between finger joints and CFRP-timber interface. The results indicated increases of 33.84% and 16.7% for flexural capacity and initial stiffness, respectively, in comparison with unreinforced finger-jointed Spruce specimens. Besides, comparisons of computed and experimental ultimate loads for all tested specimens showed that the absolute error was around 5%. It is concluded that the developed FE models are able to predict accurately ultimate load and failure mode of finger-jointed Spruce timber beams strengthened with CFRP materials.

Fire design of post-installed bonded rebars: Full-scale validation test on a 2.94 x 2 x 0.15 m 3 concrete slab subjected to ISO 834-1 fire. Engineering Structures, Elsevier, 2018, 174, pp. AbstractThanks to the improvement in mechanical and adhesion properties of polymer resins, Post-Installed Rebars (PIRs) succeeded progressively in replacing cast-in place rebars in some applications by offering equivalent or even higher mechanical properties at ambient temperature. However, the mechanical behavior of PIRs is essentially governed by the mechanical behavior of polymer resins, which is highly sensitive to temperature. Consequently, fire safety presents a potential hazard that should be taken into account when designing. This paper presents an experimental full-scale fire test carried out on the Vulcain furnace of CSTB Champs-sur-Marne on its 7m x 4 m horizontal configuration, in order to test a new fire design method proposed for PIRs. The 2.94 x 2 x 0.15 m 3 tested slab was mechanically loaded by 325 kg and heated following the ISO 834-1 time-temperature curve until its collapse. The experimental time of collapse is compared to that predicted by the new design method.