Abstract:

 Earthquake occurs more frequently in recent years. With a large number of water conveying engineering under construction, aseismic performance of long-distance exposed steel penstock becomes significant. The fact that travelling wave effect has an influence on seismic response of spatial structures with a large plane scale, has been known and accepted widely. The effect of travelling wave on an exposed long steel penstock for inverted siphon is computed by a nonlinear time history method in this study. The results show that travelling wave effect can enlarge seismic deformation and stress responses in the main components of penstock, such as bellow expansion joints, supports, and steel pipe. Its extent much depends on wave speed: the smaller the wave speed, the more significant such an effect. When wave speed exceeds 1000 m/s, the seismic responses are approaching to the ones without this effect. The responses also depend on the structural characteristics of penstock. Thus, in checking aseismic safety of an exposed steel penstock, an accurate model must be adopted and travelling wave effect should be considered for the pipe of low celerity (i.e. below 1000m/s). These results can be useful to aseismic design and analysis of similar structures.