Abstract
Two types of impacts occur due to a sudden failure in a diagonal tension member of truss bridges. One is the primary impact caused by the longitudinal strain wave propagation from the failure point. The other is the secondary impact resulting from the dynamic transition of the overall equilibrium from the pre-failure state to the post-failure state. It is shown by a precise dynamic analysis that the secondary impact is much larger that the primary impact. Thus, the properties of the secondary impacts are investigated for two types of Warren truss bridges in view of the application to the redundancy analysis as an impact factor. This impact factor takes almost a constant value for the important members where large stress increment occurs by the member failure. For practical application, an approximate method is proposed to predict the secondary impact without carrying out dynamic analysis.
