Trag- und Verformungsverhalten von Verteilrohrleitungen

Load-carrying and deformation behaviour of penstock manifolds. Steel penstocks of (pumped) storage power stations have penstock manifolds to distribute the works water from the main pipe to the individual branch pipes for the turbines and pumps in the power house. The paper sums up the results of a research project, lasting for two years, dealing with the load-carrying and deformation behaviour of penstock manifolds, executed by the Institute of steel structures at Graz University of Technology. Based on nonlinear global analyses with 3D FE models with elastic and elastic-plastic material models, the realistic behaviour of penstock manifolds was studied in detail. It was shown that such structures have an unexpected high plastic load-carrying capacity. Based on that, higher settlements at the supports can no longer be assessed as that critical. A realistic assessment of the risk of fatigue with the structural stress concept also allows a focus on a few decisive areas in existing manifolds with regard to targeted inspection and monitoring measures. In addition, also the accuracy of the global analyses in the past was studied, using only a beam-model in combination with 3D FE models for the individual bifurcations of the manifold, compared with a global 3D FE model of the whole manifold.