Experimental and numerical characterization of a membrane material for orthotropic steel deck bridges: Part 2 - Development and implementation of a nonlinear constitutive model

Preliminary analyses have shown that membrane materials, connecting mastic asphalt surfacings to plates of orthotropic steel deck bridges, play an extremely important role in determining the structural response of these types of bridges. This necessitates search for a realistic representation of the behaviour of membrane materials. For this purpose, an extensive experimental program was carried out, and a nonlinear constitutive model was developed to describe the behaviour of membrane materials. This is the second part of two papers on characterization of the behaviour of a bituminous-based membrane material in an orthotropic steel deck bridge. In this paper, the details of the constitutive model will be discussed. Furthermore, an unconditionally stable, implicit Euler backward algorithm for the integration of the constitutive equations will be presented in details. Comparisons of model predictions and laboratory measurements at different temperatures, deformation rates and con. ning stresses are presented. Some numerical examples, in which various aspects of the finite elements response of a 3D orthotropic steel deck bridge subjected to stationary and moving loads, are presented. The importance of the damage distribution on the membrane material is demonstrated as well as the role of other influencing factors, such as loading speed and temperature. (c) 2008 Elsevier B.V. All rights reserved.