ABSTRACT
As described in Chapter 2, pushover analysis is a veri•cation tool for new bridge design. It is also a useful tool to estimate the capacities of existing bridge bents. However, due to material and geometrical nonlinearities of bridge bents, it is imperative to have a computer program to perform the pushover analysis. It is equally important to understand the methodologies used in the pushover analysis. This chapter brie©y describes how INSTRUCT formulates the element bending stiffness matrix using •ve different methods: (1) bilinear interaction axial load-moment (PM), (2) plastic hinge length (PHL), (3) constant moment ratio (CMR), (4) •nite segment-•nite string (FSFS), and (5) •nite segment-moment curvature (FSMC) methods. The PM, PHL, and CMR methods are simpler than FSFS and FSMC, with FSFS method being the most sophisticated.
