Modifying the mechanism method of masonry arch bridge analysis

A typical stone masonry arch bridge (Bargower bridge) was assessed by the mechanism method. The collapse load prediction from this method depended on the assumed distribution of lateral earth pressures on the extrados. The arch profile at the onset of failure deviated significantly from its original form. Mechanism analysis is accurate only when all the forces and their positions are known. The authors modified the mechanism method by including a deflection-dependent pressure updating algorithm. Results confirmed that arch deflections had a significant influence on the prediction of the assessed collapse load compared to that observed at Bargower. The problem of predicting exactly what deflection pertains to the collapse state remains a matter for future research. (C) 2003 Elsevier Ltd. All rights reserved.