Risk Analysis of Bridge Falsework Structures

Abstract

Bridge falsework systems are traditionally used to support the formwork during the construction of concrete bridges. These structures have a significant impact on the cost, construction rate and safety of the supported structures. In recent years a high number of accidents involving bridge falsework systems have been reported particularly in the developing world. In order to increase the safety and the efficiency of these systems a risk-informed structural design methodology was developed and applied to selected proprietary system using the results of experimental tests of different types of joints, the results of advanced numerical analyses and newly developed structural robustness and structural fragility indices. Illustrative examples are given detailing the steps and calculations needed, including consideration of model and statistical uncertainties, and the results obtained are discussed. Furthermore, based on the findings obtained through the analysis of different strategies for decreasing risks two scenarios are studied in detail: a reference (baseline) scenario and one selected improved (alternative) scenario. For the cases analysed, it is concluded that if the cost of the permanent structure considerably exceeds the cost of the temporary structure, which is often the case, the extent of improvements in terms of structural and economical risks may justify the extra costs incurred by implementing simple Quality Management procedures.