This paper presents a numerical analysis of large displacement responses of elastic-plastic plane frames under static and dynamic loads, by applying the vector-form intrinsic finite element method. The VFIFE method defines the structure into a number of mass points, and applies Newton's second law and the internal force equilibrium to describe the motions of each mass point. By tracing the motions of all the mass points, it can analyze the large geometrical and material nonlinear changes during the motion of the structure without using the geometrical stiffness matrix and iterative procedures. Three different numerical examples are presented to demonstrate both the capability and the accuracy of the VFIFE method in a nonlinear dynamic analysis of frame structures with extremely large displacement.CR formulation based on a convected material frame. All of these methods are rather effective for analyzing the transient responses of structures made of inelastic materials and large deformation characteristics [9]. For nonlinear material structures, most of the existing nonlinear material models can be classified into two main categories: lumped and distributed plasticity models. The lumped model is an efficient way to represent inelasticity in frames. A typical finite element method (FEM) considering the geometrical and material nonlinearities requires iterations at each incremental step to achieve the equilibrium [10]. This method encourages flexural yielding and can ensure that plastic hinge rotation will occur at the member ends rather than along the column length. The second-order plastic hinge concept based on the use of stability interpolation functions has been proposed for frame structure analysis [11][12][13][14][15][16][17]. Marante et al. [18] proposed a general criterion of localization and two plastic hinges at the end of the frame member. Some researches improved the lumped plastic hinge method, such as for example the distributed plasticity model (also called plastic-zone model), which allows for the gradual spread of yielding within the member. In the distributed plasticity model, the frame element stiffness can be computed by using either the displacement [19] or the force-based approach [20][21][22]. This allows plastic hinges to form at any location in an element. In addition, the element cross-section can be a fiber section using different stressstrain models for different fibers within the cross-section. Without properly taking into account the internal forces due to pure deformations, most of these studies may not be able to simulate inelastic structural responses of moving structures subjected to extremely large displacements or deformations.Another type of method, the discrete numerical method is suitable to study large deformation, cracking and failure of structures. For example, the rigid-body spring model (RBSM) was proposed by Kawai and Kondou [23]. In this model, each element consists of rigid bodies with two springs, called normal and shear springs which allow the restoring forces to be ...

No abstract

Analysis of a single-span bridge with rubber bearing as the isolation system is performed under earthquakes. The conventional bridge seismic design requires the whole structure to be perfectly connected to avoid interrupting the transfer of earthquake energy from the ground through the bridge. A bridge with this typical design requires a high-cost construction due to the need for a huge section of the bridge to resist the earthquake force demand. Thus, many bridges in Taiwan are designed with a rubber bearing only put in between the column and girder without an anchor system. Thus, the bridge movement by rubber displacement is permissible, but the sliding displacement must be accommodated to limit the movement. The sliding displacement is the method to exploit the friction force provided by the sliding on the top and bottom interface of the rubber with the girder and column to dissipate the earthquake input energy transmitted to the structure. By involving the role of surface friction, the shear force transmitted to the structure can be reduced and the bridge performance optimized. General Functional Bearing Model (GFBM) analysis is a rubber bearing analysis which unmerges the function of friction and restoring force. In contrast with the conventional method, the rubber bearing designed with GFBM analysis may reduce the bridge stiffness and deck acceleration, and it is more convenient because only sliding displacement needs to be controlled. This research proposed GFBM analysis to simulate the rubber bearing that is reflected in the real conditions of bridges in Taiwan.

No abstract