تقوية الكمرات الخراسانية المسلحة باستعمال قمصان من الخرسانة ذاتية الدمك مع شبكة اسلاك

This research presents the experimental investigations of the structural behavior of reinforced concrete (RC) beams. The strengthening technique that was used section enlargement using Self-Compacting Concrete (SCC) reinforced with welded wire mesh (WWM). Different mechanical bonding between old and new concrete techniques were also investigated. These included dowels, expansion bolts and surface roughening. Strengthening of beams was achieved by casting a SCC U-formed jacket that reinforced with small diameter of WWM to increase their shear resistance and increasing the flexural strength of concrete beams. Four-point bending flexural tests were conducted on small-scale RC beams in the testing program up to failure. The test specimens were 1200 mm long with a cross section of 100 mm x 150 mm and after section enlargement the cross section was increased to 160 mm x 200 mm. The test program included eighteen beams; three out of them were used as control beams; four out of these beams were used as monolithic control casted beams. While the other eleven beams were tested as strengthened beams and classified into two groups based on bonding technique and WWM properties. The obtained results from the investigation indicated that the enlarged section using SCC jacketing with WWM improved significantly structural performance of beam measured in terms of ultimate load carrying capacity, stiffness, crack width and deflection. The strengthened beams were able to reach their full flexural capacities comparable to their monolithic counterpart’s beams. The interlaminar shear failure was prevented in all strengthened beams. To understand the structure behavior of the strengthened beams, theoretical analysis was carried out and a simplified design procedure was presented in this thesis to predict the flexural strength and deflection at yielding and at ultimate stages. This analysis is done based on the basics of flexural theory and its assumptions and a good agreement at ultimate stage between experiment test results and prediction values was achieved