Case Statistics of Instability Failure of Steel Bridges and Calculation Analysis of Typical Cases

This paper focuses on 44 cases of steel bridges damaged by instability at home and abroad, and analyzes the statistical characteristics of the bridges, from the causes of damage to the phase of failure, bridge type, and the span and the use of bridge. The results show that the large slenderness ratio is the primary cause of instability in steel bridges, accounting for about 79.5% of cases. Meanwhile, the instability of the construction process accounts for about 70.5% of cases, which is much higher than instability recorded in the service phase. In this paper, the typical cases of each type of instability are selected for finite element modeling analysis or discussion on a mechanical level to determine the failure mechanism of various steel bridges. Based on this, several engineering proposals are put forward, which aim to prevent the instability of steel bridges and have reference value for practical engineering.