Nonlinear static methods are simplified procedures in which the problem of evaluating the maximum expected response of a MDOF system for a specified level of earthquake motion is replaced by response evaluation of its equivalent SDOF system. The common features of these procedures are the use of PUSHOVER ANALYSIS to characterize the structural system. In PUSHOVER ANALYSIS both the force distribution and the target displacement are based on the assumptions that the response is controlled by the fundamental mode and that the mode shape remains unchanged after the structure yields. Therefore, the invariant force distributions does not account for the change of load patterns caused by the plastic hinge formation and changes in the stiffness of different structural elements. That could have some effects in the outcome of the method depending on different structural parameters. This paper introduces an adaptive PUSHOVER ANALYSIS method to improve the accuracy of the currently used PUSHOVER ANALYSIS in predicting the seismic-induced dynamic demands of the structures. Comparison of the common PUSHOVER analyses, adaptive PUSHOVER analyses and time-history analyses performed for a number of multiple-bay, short and high-rise steel structures, demonstrates the efficiency of the proposed method.

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.

Design sensitivity ANALYSIS is a necessary task for optimization of structures. Methods of sensitivity ANALYSIS for linear systems have been developed and well documented in the literature; however there are a few such research works for nonlinear systems. Nonlinear sensitivity ANALYSIS of structures under seismic loading is very complicated. This paper presents an analytical sensitivity technique for Reinforcement Concrete Moment Resisting Frames (RCMRF) that accounts for both material and geometric nonlinearity under PUSHOVER ANALYSIS. The results of proposed method are compared with the results of finite difference method. A three-story, two bays moment frame example is used to illustrate the efficiency of the method. This technique can be very useful and efficient for optimal performance-based design of RC buildings.

The PUSHOVER procedure is extended for seismic damage assessment of asymmetrical buildings. By mean of an example, it is shown that the accuracy of the proposed 3-D PUSHOVER ANALYSIS is similar to those applied to planar structures. The procedure is found to be more successful in estimating the global response parameters such as interstorey drifts than local damage indicators such as beam or column ductility demands.

The main objective of this research is to develop a practical damage criterion based on PUSHOVER ANALYSIS. For this purpose, damage ANALYSIS is performed on several Reinforced Concrete Moment Resisting Frames (RCMRFs). In the static method, performance point of structures is firstly determined using capacity spectrum method and then values of several different damage indices are calculated at these points. By comparing the results of two methods and evaluating correlation between two sets, explicit damage relations are derived based on the static results.

Nonlinear static procedure (NSP) is a common technique to predict seismic demands on various building structures by subjecting a monotonically increasing horizontal loading (PUSHOVER) to the structure. Therefore, the PUSHOVER ANALYSIS is an important part of each NSP. Accordingly, the current paper aims at investigating the efficiency of various algorithms of lateral load patterns applied to the structure in NSPs. In recent years, fundamental advances have been made in the NSPs to enhance the response of NSPs toward nonlinear time history ANALYSIS (NTHA). Among the NSPs, the philosophy of "adaptive procedures" has been focused by many researchers. In the case of utilizing adaptive procedures, the use of incremental force vector considering the effects of higher modes of vibration and stiffness deteriorations is possible and seems that it can lead to a good prediction of seismic response of structures. In this study, a new adaptive procedure called energy-based adaptive PUSHOVER ANALYSIS (EAPA) is implemented based on the work done by modal forces in each level of the structure during the ANALYSIS and is examined for steel moment resisting frames (SMRFs). EAPA is inspired by force-based adaptive PUSHOVER (FAP) and story shear-based adaptive PUSHOVER (SSAP). FAP has applied modal forces directly into load patterns; SSAP, on the other hand, has implemented the energy method in system`s capacity curve for measuring the equivalent movement. EAPA has enforced the concept of energy directly in load pattern; so that by using the modal forces-movements an energy-based adaptive algorithm is obtained. Hence, the effects of higher modes, deterioration in stiffness and strength, and characteristics of a specific site are incorporated and reflected in applied forces on the structure. Results obtained from the method proposed a desirable accordance with the extracted results from NTHA over the height of the structure.

Long-term seismic performance determination of reinforced concrete bridges is one of the effective factors in service life estimation of these structures. Chloride induced corrosion results in deterioration of critical members in the service life of reinforced concrete bridges and therefore leads to degradation of long-term seismic performance of the bridge. Due to seismicity and high rate of corrosion in reinforced concrete structures due to the corrosive environmental condition in Persian Gulf region, evaluation of corrosion-induced degradation on the long-term seismic performance of existing bridges in this region has a high importance. In order to evaluate this problem, at first based on studies done related to Persian Gulf region, corrosion initiation time of columns as critical seismic members of the bridge has been determined. Then effects of corrosion on the reinforced concrete column at specific time intervals (0, 15, 30, 45, 60, 75, 90 years) in bridge service life have been calculated. Effects of corrosion include degradation of cover and core concrete, steel, and bonding between concrete and steel that result in modification of stress-strain relationship of materials. In the next step, at each time interval based on the modified stress-strain relationship of materials, moment-curvature ANALYSIS of bridge column conducted and characteristics of plastic hinge have been determined. Finally, based on plastic hinge characteristic at each time interval, PUSHOVER ANALYSIS of bridge in longitudinal and transverse directions conducted and bridge capacity curves at mentioned time intervals have been compared. Results indicate the time-dependent degradation of bridge capacity under corrosion. According to the obtained results, in order to ensure the long-term seismic performance of reinforced concrete bridges in corrosive environments, value for an increase of design base shear has been proposed.