الفهرس 
Concept of moment redistribution
EXPERIMENTAL PROGRAMOnly 14 pages are availabe for public view
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Abstract
It is common practice to retrofit continuous reinforced concrete (RC) beams by fiber reinforced polymer (FRP) or steel plates. This can cause a significant amount of Moment redistribution (MR) which results in an efficient and economic design when taken into consideration. There is lack in research regarding MR in continuous RC beams when strengthening plates are applied only at the top side at the hogging regions. The main purpose of this research is to assess MR in continuous RC beams top strengthened with steel and carbon fiber reinforced polymer (CFRP) plates. In this respect, an experimental study was conducted on eight T-section continuous reinforced concrete beams top strengthened with CFRP and steel plates. The beams had a constant cross section and flexural steel reinforcement which was designed to prevent brittle failure due to crushing of concrete before steel yielding. The plates were installed on both sides of the slab above the beam web as near surface mounted or externally bonded to investigate the effect of different plating techniques on the moment redistribution in reinforced concrete beams. The number of plates in each specimen was changed. Steel stirrups were used and designed so that no premature shear failure occurs. A nonlinear finite element (FE) model was developed using ABAQUS 6.14 and validated using the experimental results. The model was found accurately capable of stimulating the behavior of such beams and hence assessing the percentage of MR which can be achieved using steel and CFRP strengthening. A parametric study is conducted to investigate the effect of various parameters, different from those investigated in the experimental program, on the MR in continuous RC beams. Parameters related to the concrete compressive strength, reinforcement ratio, beam thickness and thickness of strengthening plates were considered in this study. The results show that the steel plating can cause up to 50 % redistribution of moments from the sagging to the hogging regions compared to the control specimen as well as a significant increase in the loading capacity of the beams. The results also revealed that the application of CFRP plates can lead to substantial amounts of moment redistribution when they are installed as near surface mounted plates, but without significantly affecting the load carrying capacity. Moreover, MR is enhanced with the change in concrete compressive strength. While it was found out that the change in steel bars reinforcement ratio or in thickness of the strengthening plates has different effect on the beams strengthened with steel plates than those strengthened with CFRP plates. Furthermore, Debonding of the EB steel plates form the surface of concrete beams tend to occur at upper flexural stress levels higher than 470 MPa. These stress levels were close to the stresses at failure, hence allowing for significant values for MR to take place until collapse.