Document Type

Theses, Masters


This item is available under a Creative Commons License for non-commercial use only


Civil engineering

Publication Details

MPhil thesis submitted to Dublin Institute of Technology, September 2012.


With ever-reducing maintenance budgets and ever-deteriorating bridge infrastructure, th assessment of existing bridges is vital. Reliability analysis techniques are becomin increasingly popular in the structural safety assessment of existing bridge structures Commonly, a component based approach is used in reliability analysis techniques Traditional reliability procedures often employ a conservative definition of failure, in that th component is deemed to have failed when the strength capacity has been exceeded at a singl cross section. As a result, the component's degree of redundancy and ductility is ignored giving an often conservative estimate of the load carrying capacity of the bridge component Therefore, this dissertation is focused on the development of a reliability analysis procedur which accounts for material behaviour for indeterminate beams. The structural safety of a representative group of steel composite bridge beams is examined The material response of each beam subjected to a combination of both dead load and liv load is assessed using a one-dimensional nonlinear finite element analysis (NFEA) model The Response Surface Method (RSM) is then used to replace the NFEA model with a approximated explicitly-known polynomial function. This allows a First Order Reliabilit Method (FORM) analysis to be performed. The developed procedure is compared to th traditional approach with regard to three limit states. These limit states are defined as elasti member failure, first formation of a plastic hinge and ultimate failure. Ultimate failure occur when a collapse mechanism has formed. The live load on each structure consists of annua maximum traffic loading events determined from Monte Carlo Simulation (MCS) of Weigh in Motion (WIM) data. The modelling of realistic live loads highlights the practicality of th procedure developed. This procedure may act as a foundation for the development of a evaluation method accounting for material nonlinearity for existing bridge structures.