Numerical simulation of the shear behaviour of reinforced concrete rectangular beam specimens with or without FRP-strip shear reinforcement
The successful validation of a numerical model is presented that can realistically approximate the shear behaviour of reinforced concrete (R/C) rectangular beams strengthened against shear with externally applied open hoop fibre reinforcing polymer (FRP) strips. For this purpose, the measured load-deformation response of ten (10) full-scale R/C beam specimens is utilised. These specimens were loaded monotonically in a four-point bending arrangement up to failure. Open hoop FRP strip shear reinforcement was applied externally to upgrade the shear capacity of eight (8) R/C beam specimens. Four of these specimens had these FRP strips without anchorage, whereas for the other four the FRP strips were attached together with novel anchoring devices. This successful numerical simulation predicts with a very good degree of approximation the observed load-deformation behaviour and the ultimate shear capacity of all these specimens as well as the observed modes of failure including diagonal concrete cracking, debonding of the FRP strips in the case of no anchoring, or the plastification of parts of the anchoring devices plus the adjacent crushing of the concrete.
Shear Capacity of Fiber-Reinforced Polymer-Strengthened Reinforced Concrete Beams: Fiber Reinforced Polymer Rupture
A recent innovation in shear strengthening of reinforced concrete beams is to externally bond fiber-reinforced polymer (FRP) composites. Many studies have been undertaken on this strengthening technique. These studies have established clearly that such strengthened beams fail in shear mainly in one of the two modes: FRP rupture and FRP debonding, and have led to preliminary design proposals. This paper is concerned with the development of a simple, accurate, and rational design proposal for the shear capacity of FRP-strengthened beams which fail by FRP rupture. To this end, existing design proposals are reviewed, and their efficiencies highlighted. A new strength model is then developed, which recognizes the fundamental characteristics of FRP. The model is validated against experimental data collected from the existing literature. Finally, a new design proposal is presented.
Substation automation based on IEC 61850 with new process-close technologies
New technologies in primary equipment like nonconventional instrument transformers require new interfaces to the substation automation system. The future standard IEC 61850 perfectly supports this requirement. With the introduction of the new technologies and the use of IEC 61850, a more decentralized architecture of the substation automation system will be possible. This provides several benefits but a careful system design is required to maintain the overall reliability of the system.