An Integrated Finite Strip Solution for Box Girder Bridges and Slab-on-girder Bridges

In view of the urgent need for an efficient and accurate structural analysis method in bridge design practice, this paper introduces a total integrated analytical solution for multi-span, continuous slab-on-girder and box girder bridges, by modeling the bridge deck and the piers together, using the finite strip method (FSM). FSM has been well accredited for its efficiency in the structural analysis of bridges, reducing the time required for data input and analysis without affecting the degree of accuracy. By using a continuously differentiable smooth series in the longitudinal direction, a complex 3D problem is reduced to a 2D problem using the FSM. However, difficulties are encountered when components of different orientation, such as the piers, are included to the formulation. Thus, the analytical model developed using the conventional FSM is limited to the super-structures, without proper consideration of the interactions between the bridge deck (super-structure) and piers (sub-structure). In this regard, a cantilever type of pier strip element is formulated by the authors, based on the spline finite strip concept, which is compatible with the well developed spline finite strip bridge deck. In addition, by combining the piers and the bridge deck altogether in a single finite strip formulation, with some appropriate connecting boundary conditions, the time required for both static and dynamic analysis can be significantly reduced. In this paper, the development and verification of the vertical cantilever strip is introduced and the overall integrated method of analysis is presented with the aid of numerical examples. In addition, the efficiency of the proposed approach in seismic analysis using the Pseudo Excitation Method (PEM) is also demonstrated as an extension of its application.