This work is a development of constitutive model for concrete by the theory of plasticity. In this model, non-uniform work hardening plasticity model adopts the most sophisticated failure model of Hsieh-Chen as a bounding surface by assuming an initial yield surface with a shape that is different from the failure surface; proposing a non-uniform hardening rule for the subsequent loading surfaces with a hydro static pressure and lode-angle dependent and utilizing a non-associated flow rule for a general formulation.

Limit analysis of an infinity long shell stiffened by rectangular ring stiffeners subjected to internal radial uniform pressure and axial load is treated. Shell stiffener interaction is studied, tacking into account the stiffener effect in a discretized way as ring 1oad. Octagon yield condition and rigid perfect material are adopted. The results are given in form of charts easy to be used for the design of such shells.

Limit analysis of an infinity long shell stiffened by rectangular ring stiffeners subjected to internal radial uniform pressure and axial load is treated. Shell stiffener interaction is studied, tacking into account the stiffener effect in a discretized way as ring 1oad. Octagon yield condition and rigid perfect material are adopted. The results are given in form of charts easy to be used for the design of such shells.

Limit analysis of an infinity long shell stiffened by rectangular ring stiffeners subjected to internal radial uniform pressure and axial load is treated. Shell stiffener interaction is studied, tacking into account the stiffener effect in a discretized way as ring 1oad. Octagon yield condition and rigid perfect material are adopted. The results are given in form of charts easy to be used for the design of such shells.

Corrosion of reinforcing bars for most of concrete structures is considered to be the main reason of deterioration of concrete cover. The deterioration of concrete cover increases the corrosion of steel bars which causing a reduction of bars cross-section. which is considerably the main reason of failure of the concrete structures. So, the coating of bars with epoxy coating is very important specially for elements of structures subjected to a humidity ambient conditions. The coating of reinforcing bars by epoxy coating is to protect the bars from corrosion and consequently affecting the behavior of R.C. beams practically the bond strength between steel bars and adjacent concrete. Most of the previous works are dealing with the field of behavior of R.C. beams reinforced with epoxy- coated bars under static loading. This paper is concerning with the behavior of R.C. beams reinforced with coated bars under repeated loading. The main parameters. which are taken into consideration. are the thickness of the coating film and the percentage area of main steel. Some beams are tested under static loading are taken as reference beams. The results are given in the form of tables and curves. Conclusions and important recommendations are presented.

Corrosion of reinforcing bars for most of concrete structures is considered to be the main reason of deterioration of concrete cover. The deterioration of concrete cover increases the corrosion of steel bars which causing a reduction of bars cross-section. which is considerably the main reason of failure of the concrete structures. So, the coating of bars with epoxy coating is very important specially for elements of structures subjected to a humidity ambient conditions. The coating of reinforcing bars by epoxy coating is to protect the bars from corrosion and consequently affecting the behavior of R.C. beams practically the bond strength between steel bars and adjacent concrete. Most of the previous works are dealing with the field of behavior of R.C. beams reinforced with epoxy- coated bars under static loading. This paper is concerning with the behavior of R.C. beams reinforced with coated bars under repeated loading. The main parameters. which are taken into consideration. are the thickness of the coating film and the percentage area of main steel. Some beams are tested under static loading are taken as reference beams. The results are given in the form of tables and curves. Conclusions and important recommendations are presented.

Corrosion of reinforcing bars for most of concrete structures is considered to be the main reason of deterioration of concrete cover. The deterioration of concrete cover increases the corrosion of steel bars which causing a reduction of bars cross-section. which is considerably the main reason of failure of the concrete structures. So, the coating of bars with epoxy coating is very important specially for elements of structures subjected to a humidity ambient conditions. The coating of reinforcing bars by epoxy coating is to protect the bars from corrosion and consequently affecting the behavior of R.C. beams practically the bond strength between steel bars and adjacent concrete. Most of the previous works are dealing with the field of behavior of R.C. beams reinforced with epoxy- coated bars under static loading. This paper is concerning with the behavior of R.C. beams reinforced with coated bars under repeated loading. The main parameters. which are taken into consideration. are the thickness of the coating film and the percentage area of main steel. Some beams are tested under static loading are taken as reference beams. The results are given in the form of tables and curves. Conclusions and important recommendations are presented.

Five reinforced concrete beams with rectangular cross section 120 x 300 mm and flexural reinforcement ratio of 0.0124 were cast and tested under three-point static loading. One beam was tested up to failure as control beam. The rest of the beams were loaded up to the inclined cracking load. Then the load was removed and the beams were repaired using steel fiber-reinforced self-consolidating concrete (SFRSCC) jacket with varied thicknesses and fiber contents. Then the repaired were retested up to failure. The fiber contents of 0.5, 0.75 and 0.75% by the volume of concrete as well as jacket thicknesses of 30 and 50 mm were considered for this study. The experimental results showed that the proposed technique enhanced the load capacity of the repaired beams by up to 121% with respect to the original specimen, and reduced the induced deflections and strains at the different stages of loading. Moreover, increasing fiber content with a fixed jacket thickness was found to be more effective than increasing the jacket thickness with the same fiber content.

Five reinforced concrete beams with rectangular cross section 120 x 300 mm and flexural reinforcement ratio of 0.0124 were cast and tested under three-point static loading. One beam was tested up to failure as control beam. The rest of the beams were loaded up to the inclined cracking load. Then the load was removed and the beams were repaired using steel fiber-reinforced self-consolidating concrete (SFRSCC) jacket with varied thicknesses and fiber contents. Then the repaired were retested up to failure. The fiber contents of 0.5, 0.75 and 0.75% by the volume of concrete as well as jacket thicknesses of 30 and 50 mm were considered for this study. The experimental results showed that the proposed technique enhanced the load capacity of the repaired beams by up to 121% with respect to the original specimen, and reduced the induced deflections and strains at the different stages of loading. Moreover, increasing fiber content with a fixed jacket thickness was found to be more effective than increasing the jacket thickness with the same fiber content.

Five reinforced concrete beams with rectangular cross section 120 x 300 mm and flexural reinforcement ratio of 0.0124 were cast and tested under three-point static loading. One beam was tested up to failure as control beam. The rest of the beams were loaded up to the inclined cracking load. Then the load was removed and the beams were repaired using steel fiber-reinforced self-consolidating concrete (SFRSCC) jacket with varied thicknesses and fiber contents. Then the repaired were retested up to failure. The fiber contents of 0.5, 0.75 and 0.75% by the volume of concrete as well as jacket thicknesses of 30 and 50 mm were considered for this study. The experimental results showed that the proposed technique enhanced the load capacity of the repaired beams by up to 121% with respect to the original specimen, and reduced the induced deflections and strains at the different stages of loading. Moreover, increasing fiber content with a fixed jacket thickness was found to be more effective than increasing the jacket thickness with the same fiber content.