Experimental research and numerical simulation of RC beams strengthened with bonded steel plates

It is a common method to strengthen the damaged RC structures with bonded steel plates. At present the ultimate bearing ca- pacity of RC structures strengthened with bonded steel plates is calculated mostly using the theory based on the test. Four beams, including one reference beam, two strengthened concrete beams in primary force and secondary force respectively, and one strengthened concrete beam which was not anchored enough, were tested under four-point bending (4PB) in order to get the data of strain of longitudinal bars, bonded bottom steel plate in tension and deflection of beams in the middle span. The experimental program was supported by a three-dimensioned finite analysis using ABAQUS. At the end of experiments and finite analysis, it is concluded that the investing strengthening technique can significantly improve the load-carrying capacity and the phenomenon of stress concentration at the end of interface, as well as the damage at interface, can be well simulated with cohesive element provided by ABAQUS.

Semi-solid Processing of Steel-Al-7 Graphite Binding Plate

The bonding of steel plate to Al 7graphite slurry was studied for the first time. The relationship model about preheat temperature of steel plate,solid fraction of Al 7graphite slurry, rolling speed and interfacial shear strength of bonding plate could be established by artificial neural networks perfectly.This model could be optimized with a genetic algorithm.The optimum bonding parameters are:516℃ for preheat temperature of steel plate,32.5% for solid fraction of Al 7graphite slurry and 12mm/s for rolling speed,and the largest interfacial shear strength of bonding plate is 70.6MPa.

The Bonding Properties of Solid Steel to Liquid Aluminum

The bonding of solid steel plate to liquid al uminum was studied using rapid solidification. The relationship models of interf acial shear strength and thickness of interfacial layer of bonding plate vs bond ing parameters (such as preheat temperature of steel plate, temperature of alumi num liquid and bonding time) were respectively established by artificial neural networks perfectly.The bonding parameters for the largest interfacial shear stre ngth were optimized with genetic algorithm successfully. They are 226℃ for preh eating temperature of steel plate, 723℃ for temperature of aluminum liquid and 15.8s for bonding time, and the largest interfacial shear strength of bonding pl ate is 71.6 MPa . Under these conditions, the corresponding reasonable thickne ss of interfacial layer (10.8μm) is gotten using the relationship model establi shed by artificial neural networks.

Thickness of compound layer in steel-aluminum solid to liquid bonding

The bonding of solid steel plate to liquid aluminum was studied using rapidsolidification. The surface of solid steel plate was defatted, descaled, immersed (in K_2ZrF_6 fluxaqueous solution) and stoved. In order to determine the thickness of Fe-Al compound layer at theinterface of steel-aluminum solid to liquid bonding under rapid solidification, the interface ofbonding plate was investigated by SEM (Scanning Electron Microscope) experiment. The relationshipbetween bonding parameters (such as preheat temperature of steel plate, temperature of aluminumliquid and bonding time) and thickness of Fe-Al compound layer at the interface was established byartificial neural networks (ANN) perfectly. The maximum of relative error between the output and thedesired output of the ANN is only 5.4%. From the bonding parameters for the largest interfacialshear strength of bonding plate (226℃ for preheat temperature of steel plate, 723℃ for temperatureof aluminum liquid and 15.8 s for bonding time), the reasonable thickness of Fe-Al compound layer10.8 μm was got.

Reinforcement and numerical analysis on the corbel of a halfthrough arch bridge

Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we bonded steel plates onto bridge corbels to strengthen them. We carried out a numerical analysis on the effectiveness of the reinforcement by using the commercial sof^are ANSYS. The numerical analysis shows that the stresses near the section break increased slightly, but the variation amplitude was small and all the stresses were within an allowable range. The loading test indicates that it is feasible to strengthen the corbel with vertical bonded steel plates. Therefore, the reinforcement is effective and economical. This reinforcement method is suitable for this type of corbel and can be applied in similar cases.