A companion paper presents the formulation of a fibre beam-column element for the non-linear static and dynamic analysis of R/C frames. This paper illustrates the application of the proposed element in the simulation of the hysteretic behaviour of several R/C beam and column specimens. The specimens are subjected to uniaxial and biaxial loading histories with varying axial load. The proposed element shows computationally stable and robust numerical behaviour, while being able to describe very well the hysteretic behaviour of the reinforced concrete members under the imposed complex loading histories.

Fibre beam–column model for non‐linear analysis of r/c frames: part i. formulation

A uniaxial model for concrete confined with fiber-reinforced polymers (FRP), but also with steel jackets or conventional transverse reinforcement, is presented. The model, which is suitable to be i...

FRP-Confined Concrete Model

................................................................................................................................. iii ACKNOWLEDGMENTS ........................................................................................................... iv CONTENTS....................................................................................................................................v LIST OF FIGURES ..................................................................................................................... xi LIST OF TABLES .....................................................................................................................xxv

Global collapse of frame structures under seismic excitations

Object composition offers significant advantages over class inheritance to develop a flexible software architecture for finite-element analysis. Using this approach, separate classes encapsulate fu...

/pdf/nonlinear-finite-element-analysis-software-architecture-2r0yj7uqnf.pdf

Nonlinear Finite-Element Analysis Software Architecture Using Object Composition

A new plastic hinge integration method overcomes the problems with nonobjective response caused by strain-softening behavior in force-based beam-column finite elements. The integration method uses the common concept of a plastic hinge length in a numerically consistent manner. The method, derived from the Gauss-Radau quadrature rule, integrates deformations over specified plastic hinge lengths at the ends of the beam-column element, and it has the desirable property that it reduces to the exact solution for linear problems. Numerical examples show the effect of plastic hinge integration on the response of force-based beam-column elements for both strain-hardening and strain-softening section behavior in the plastic hinge regions. The incorporation of a plastic hinge length in the element integration method ensures objective element and section response, which is important for strain-softening behavior in reinforced concrete structures. Plastic rotations are defined in a consistent manner and clearly related to deformations in the plastic hinges.

/pdf/plastic-hinge-integration-methods-for-force-based-beam-8670ntugn0.pdf

Plastic Hinge Integration Methods for Force-Based Beam¿Column Elements

In recent years nonlinear dynamic analysis of three-dimensional structural models is used more and more in the assessment of existing structures in zones of high seismic risk and in the development...

Evaluation of Nonlinear Frame Finite-Element Models

Mixed formulation of nonlinear beam finite element

The paper presents a model for the inelastic buckling behavior of steel braces. The model consists of a force-based frame element with distributed inelasticity and fiber discretization of the cross section. With this approach, the response of the element can be derived by integration of the uniaxial stress-strain relation of the fibers and can account for kinematic and isotropic hardening as well as the Bauschinger effect of the material. The interaction between axial force and bending moment is thus accounted for. Even though the element only accounts for small deformations in the basic system, large displacement geometry is included in the nonlinear transformation of the force-deformation relation of the basic element following the concept of the corotational formulation. With this approach, two elements for each brace suffice to yield results that match an extensive set of experimental data of braces with different cross sections and slenderness ratios. Even though the model does not account for the effect of local buckling, this phenomenon does not seem to appreciably affect the global response of braces with compact sections.

Model for Cyclic Inelastic Buckling of Steel Braces

This paper presents an inelastic beam element for the analysis of steel-concrete girders with partial composite action under monotonic and cyclic loads. The element is derived from a two-field mixed formulation with independent approximation of internal forces and transverse displacements. The nonlinear response of the steel and concrete component of the girder is based on the section discretization into fibers with uniaxial hysteretic material models for the constituent materials. The partial interaction between concrete deck and steel girder through shear connectors is accounted for by an interface model with distributed force transfer charac- teristics. A direct state determination algorithm for the implementation of the composite element in a general purpose nonlinear analysis program is presented, and the stability characteristics of the algorithm are discussed in conjunction with the selection of appropriate force and displacement interpolation functions. The validity of the model is established by correlation of analytical results with experimental evidence. Numerical studies are used to compare the model with the classical displacement formulation. These studies confirm the superiority of the proposed model in modeling composite girders under monotonic and cyclic loads that induce stiffness deterioration and strength softening.

Filip C. Filippou

Papers

Fibre beam–column model for non‐linear analysis of r/c frames: part i. formulation

Evaluation of Nonlinear Frame Finite-Element Models

Mixed formulation of nonlinear beam finite element

Model for Cyclic Inelastic Buckling of Steel Braces

Mixed formulation of nonlinear steel-concrete composite beam element