Change in Education
A plastic hinge, in structural engineering, refers to the deformation of a part of a beam wherever plastic bending happens. Hinge means that having no capability to resist moment. Therefore, a plastic hinge behaves like a standard hinge - permitting free rotation.
The nature of loading governs the kind of analysis to be performed on the structure. The loads are divided into two basic categories
Static Loads are the loads which varies very slowly (the acceleration of load is very very less than the natural frequency of the structure)
Dynamic Loads are the loads which changes with time fairly quickly in comparison to the structure's natural frequency.
Pushover Equivalent Static Analysis
Pushover analysis is a static procedure that uses a simplified nonlinear technique to estimate seismic structural deformations. Structures redesign themselves during earthquakes. As individual components of a structure yield or fail, the dynamic forces on the building are shifted to other components. A pushover analysis simulates this phenomenon by applying loads until the weak link in the structure is found and then revising the model to incorporate the changes in the structure caused by the weak link. A second iteration indicates how the loads are redistributed. The structure is “pushed” again until the second weak link is discovered. This process continues until a yield pattern for the whole structure under seismic loading is identified.
Pushover analysis is commonly used to evaluate the seismic capacity of existing structures and appears in several recent guidelines for retrofit seismic design. It can also be useful for performance-based design of new buildings that rely on ductility or redundancies to resist earthquake forces.
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