Anchoring the CFRP strengthening of concrete bridge decks: A comparison of methods

Debonding failures are a common problem in concrete bridge decks strengthened with adhesively attached carbon-fibre reinforced polymer (CFRP) strips. Accordingly, in this study, rectangular concrete slabs strengthened with CFRP have been experimentally evaluated to simulate the strengthening of T-beam and box girder slabs. The resulting static load data have been used to compare the effects of four different anchoring methods in terms of crack distribution, deflection, reinforcing steel strain curve, and CFRP strain distribution. The most suitable bridge deck strengthening anchoring method has been then identified and analysed using extant strengthening design methods. The results show that the most practical anchoring method is the use of open CFRP strips attached with concentrated adhesive. The findings of this study indicate that when strengthening T-girder bridges, more than two CFRP anchorage strips should be evenly spaced within the extension of the anchorage length, while for box girder bridges, even more evenly spaced strips should be used. This research and its conclusions can be used as a reference for the improved design of bridge deck strengthening

Anchoring the CFRP strengthening of concrete bridge decks: A comparison of methods

288-299Debonding failures are a common problem in concrete bridge decks strengthened with adhesively attached carbon-fibre reinforced polymer (CFRP) strips. Accordingly, in this study, rectangular concrete slabs strengthened with CFRP have been experimentally evaluated to simulate the strengthening of T-beam and box girder slabs. The resulting static load data have been used to compare the effects of four different anchoring methods in terms of crack distribution, deflection, reinforcing steel strain curve, and CFRP strain distribution. The most suitable bridge deck strengthening anchoring method has been then identified and analysed using extant strengthening design methods. The results show that the most practical anchoring method is the use of open CFRP strips attached with concentrated adhesive. The findings of this study indicate that when strengthening T-girder bridges, more than two CFRP anchorage strips should be evenly spaced within the extension of the anchorage length, while for box girder bridges, even more evenly spaced strips should be used. This research and its conclusions can be used as a reference for the improved design of bridge deck strengthening

Fabrication Of Si3N4/Sic Nanocomposites By Spark Plasma Sintering Of Amorphous Sicn Powders Derived From A Polymeric Precursor

Si3N4/SiC nanocomposites were fabricated by spark plasma sintering (SPS) of amorphous SiCN ceramic powders derived from a polymeric precursor with 3 wt% yttria as an additive. It was found that the SPS parameters, such as sintering temperature, dwell time, pressure and heating rate, remarkably affected the density and grain size of the nanocomposites obtained. This provided a new method to fabricate Si3N 4/SiC nanocomposites without applying the high pressure and high sintering temperature used by the conventional process

Direct observation of multiple rotational stacking faults coexisting in freestanding bilayer MoS2.

Electronic properties of two-dimensional (2D) MoS2 semiconductors can be modulated by introducing specific defects. One important type of defect in 2D layered materials is known as rotational stacking fault (RSF), but the coexistence of multiple RSFs with different rotational angles was not directly observed in freestanding 2D MoS2 before. In this report, we demonstrate the coexistence of three RSFs with three different rotational angles in a freestanding bilayer MoS2 sheet as directly observed using an aberration-corrected transmission electron microscope (TEM). Our analyses show that these RSFs originate from cracks and dislocations within the bilayer MoS2. First-principles calculations indicate that RSFs with different rotational angles change the electronic structures of bilayer MoS2 and produce two new symmetries in their bandgaps and offset crystal momentums. Therefore, employing RSFs and their coexistence is a promising route in defect engineering of MoS2 to fabricate suitable devices for electronics, optoelectronics, and energy conversion