Three finite element models have been developed to analyse the cross-sectional forces in the joints of multi-beam box girder bridges. A major theme of this paper is to indicate the limits of the current design methods based on linear analyses. A model based on shell elements is used in non-linear analyses including two analysis phases. The analysis phases simulate the construction phases. For straight bridges current design methods based on orthotropic plate models give reasonable results compared to the results of the advanced model. For bridges with a skew or curved geometry plan orthotropic plate models give poor predictions for the forces and moments in the joints. Advanced modelling, as presented in this paper, is then to be preferred. C. M. Frissen, M. A. N. Hendriks, TNO Building and Construction Research, Delft, The Netherlands N. Kaptijn, A de Boer, H. Nosewicz Ministry of Public Works and Water Management, The Netherlands
The offshore oil industry is still a comparatively young sector of structural engineering. The first oilfield offshore structures were installed just over 50 years ago in 4m water depth in the Gulf of Mexico. In the last 50 years some 9000 shallow water platforms have been built and the industry is now developing in very deep water. This paper provides an overview of offshore structural engineering through reference to the principle forms of offshore structure and their key design and operational requirements and the floating and sub sea structures that are making it possible to develop oilfields in 2km water depths. Richard Snell, FREng, FICE BP Exploration
This paper reviews the use of reliability techniques for assessing the structural adequacy of bridges and highlights how the output of such an analysis can both inform and guide the user in their investigation of a structure. Three different ways of interpreting the value of reliability indices are identified and the feasibility of using each of these to prioritise repair and strengthening works is examined. An average acceptable value (AAV) of reliability index for different bridge types and failure modes is proposed and it is shown that in some cases priorities can be identified directly by comparing reliability indices, sometimes a measure of the significance of the reliability index is needed, while in other cases priorities are still not obvious and further investigation is required. To achieve this, the principles of risk management are explored and it is shown that where two or more structures have similar reliabilities, consideration of risk does represent a feasible approach. Robert J. Lark, BSc(Eng), PhD, CEng, MICE Cardiff School of Engineering, Cardiff University, UK Dipl.-Ing Katja D. Flaig, PhD Allianz, Munich, Germany