In this paper, a new methodology is presented to study the corrosion of RC STRUCTURES in chloride laden environments under concerned uncertainties. To deal with the involved uncertainties, fuzzy random variables are exploited. An effective computational procedure named as a-level optimization is also introduced and utilized to analysis the FR fundamental equations of corrosion process. The proposed system is applied to predict the various life cycles of corrosion affected RC STRUCTURES. Moreover, an illustrative example is presented to demonstrate the applicability of proposed method in service life assessment of the RC beams.

The Boumerdes 2003 earthquake which has devastated a large part of the north of Algeria has raised questions about the adequacy of framed STRUCTURES to resist strong motions, since many buildings suffered great damage or collapsed. To evaluate the performance of framed buildings under future expected earthquakes, a non linear static pushover analysis has been conducted. To achieve this objective, three framed buildings with 5, 8 and 12 stories respectively were analyzed. The results obtained from this study show that properly designed frames will perform well under seismic loads.

In statically indeterminate prestressed CONCRETE STRUCTURES, prestressing force produces secondary moment in addition to primary moment due to eccentricity. This condition is different from statically determinate STRUCTURES where there is no secondary moment effect and the moment due to prestressing is due to primary moment only, i.e., prestressing force times eccentricity. With the presence of secondary moment, prestressing force design becomes more complex, because the secondary moment is a function of prestressing force and the geometry of the STRUCTURES. In addition, considering that in general the cable profile is parabolic or another type of curves, which also occurs at continuous supports, the load balancing method may not be used. To cope with this problem moment due to prestressing force is assumed to be the prestressing force times a b coefficient. In statically determinate STRUCTURES the b coefficient equals the cable eccentricity to the center of gravity of the section. Therefore, the b coefficient can be considered as a statically indeterminate eccentricity. By assigning that the moment due to prestressing force as a function of prestressing force and by considering the allowable stress requirements at top and bottom fibers, equations can be derived to compute the prestressing force in statically indeterminate STRUCTURES. From the derived equations, the upper and lower bounds of prestressing force can be determined if the section satisfy the requirements. If the optimum prestressing force is needed, the difference of lower and upper bounds should be minimum. Nevertheless, the difference of lower and upper bounds can be considered as a safety level. At the end of the paper examples are presented to show the application of the proposed method.

Puducherry is a coastal region in India where the growth of Ulva fasciata (Delile) is very abundant on all marine STRUCTURES. Though the detrimental effect of this macro algae Ulva fasciata is a secondary one, its effect has to ascertain. To know its effect, the basic mechanism by which Ulva fasciata deteriorates CONCRETE STRUCTURES, M20 grade CONCRETE cubes were casted and kept in the coastal area where there is abundant growth of Ulva fasciata and also laboratory simulation has been carried out. To ascertain the detrimental effect by the macro algae on CONCRETE surface, samples were collected from the CONCRETE cubes kept in the coastal area and also from the laboratory simulated one. The collected samples were analyzed by SEM, EDX and XRD to establish the degree of deterioration done by marine algae on CONCRETE surface. The SEM and EDX results showed that there is a remarkable change in the base materials viz., Ca and Si content and XRD results revealed the absence of Calcium Hydroxide. Both the results confirmed the biodeterioration of CONCRETE by the marine green algae.