Abstract
The limit state design of large-span soil–steel composite bridges (SSCB) entails that understanding their structural behaviour in the ultimate state is as much needed as their performance under service conditions. Apart from box culverts, the largest loading-to-failure test was done on a 6.3-m span culvert. More tests on larger spans are believed essentially valuable for the development of the design methods. This paper presents the numerical simulation efforts of an 18.1-m span SSCB pertaining to its ongoing preparations for a full-scale field test. The effect of the different loading positions on the ultimate capacity is investigated. Comparisons are made between three-dimensional (3D) and two-dimensional (2D) models. The results enabled to realise the important role of the soil load effects on the ultimate capacity. It is found that the failure load is reduced when the structure is loaded in an asymmetrical manner. A local effect is more pronounced for the live load when the tandem load is placed closer to the crown. The study also illustrates the complex correlation between 3D and 2D models, especially if one attempts to simultaneously associate sectional forces and displacements.
Highlights
The design methods for soil–steel composite bridges (SSCB) are generally based on both theoretical and experimental tests
The research work presented by Klöppel and Glock [4] has investigated the load carrying behaviour of flexible embedded pipes.These efforts are considered bases for different design methods such as the Swedish design method (SDM) [5, 6] and the Canadian Highway Bridge Design Code (CHBDC) [7]
The recommended specifications for large-span culverts in the AASHTO were based on the research output from a field testing of a 9.5-m span metal arch together with finite element method models (FEM) [10, 11]
Summary
The design methods for soil–steel composite bridges (SSCB) are generally based on both theoretical and experimental tests. The ring compression theory developed by White and Layer [1] entails that flexible culverts are designed for a prevailing normal force in the wall conduit. Later, this was seen inadequate as SSCBs became bigger and the design demanded for heavier concentrated loads under shallow depths of soil cover. Thereafter, the soil–culvert interaction (SCI) [2, 3] has considered the flexural capacity of SSCB, where design calculations involved bending moments as well as normal forces. The SCI work was mainly based on 2D finite element method models (FEM) where the load. The calculation of load effects should realistically reflect any behaviour differences for the
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