Journal of Civil Engineering Researchers
Volume:1 Issue: 6, 2017

The existing building can become seismically deficient since seismic code requirements are constantly upgraded and advancement in engineering knowledge. A seismic performance evaluation was conducted for a four-story reinforced concrete (RC) residential building. The structural response is evaluated using pushover analysis. The FEMA 356 and FEMA 440criteria were used to evaluate the seismic performance of the case study building. The calculated values related to the performance of the buildings indicate whether the response of the existing building is sufficient and if rehabilitation is required.

In most regulations, the reduction coefficient for seismic force is onlydependent to the lateral bearing system. However, researches has shown that this coefficient is a function of many factors such as period and modal properties of structure, height, and especially the building plane shape. Regarding the complexities of nonlinear dynamic analysis methods, nowadays, the nonlinear static analysis named Pushover method has been developed in performance-based earthquake engineering as an appropriate practical tool. Considering the simplicity, performance speed, and ease of results interpretation compared to the dynamic analysis methods that are as the most accurate methods of seismic analysis, the nonlinear static analysis (pushover) methods are quickly developed and welcomed. These methods are very applicable in performance-based design as well as retrofitting of structures due to their less computational cost relative to nonlinear time history dynamic analysis methods. Thus, in this study, the way of applying the pushover nonlinear static analysis method in the seismic retrofitting of structures is taken into investigation. The results are presented in the form of capacity diagrams.

The 2800 standard is used as the main reference for theseismic design of structures in Iran. Structural analysis methods consist of two groups of linear and nonlinear analyzes that each hasdifferent parts. In this regard, the nonlinear staticanalysis method(Pushover)is applicable in accordance with the existing code. In this method, the capacity curve, which indicates the changes of the basic shear relative tothe structure of the roof's displacement. In this paper, we have investigated how to determine the capacity curve of a three-storey residential building with a bending frame systemin two main directions, based onthe fourth edition of the 2800 standard.

Many of constructional structures are designed in a way that at leastgo under the pressure of relatively intense loads once in the construct’s lifespan. Along with the progress of earthquake engineering science and emphasis on construct retrofitting against lateral forces, using appropriate systems and safe performance against these forces is needed. Today, all structural engineering science researchers are trying to make a leap forward this scope with studying different kinds of systems. In the science of dynamic of construct, system with one degree of freedom and one crater which includes one flat frame is baseline for starting investigations and calculations. In this article, one metal frame with different ratios of height-to-crater’s length under lateral concentrated force in the ceiling’s balance and also under cyclic loading is placed and performance of this frame in different states in the form of a capacity and Hysteresis curve is investigated. ANSYS software was used for modeling of proposed models and the results were compared with each other.