In the course of a research project, carried out at the Institute for Structural Engineering at Vienna University of Technology, the influence of different testing parameters, like stress range, test frequency, upper load and the number of load cycles, on the fatigue behavior of tendons, was investigated. With the help of the resonance-testing machine, invented by Prof. Kollegger in the year 2006, it was possible to test different parallel strand stay-cable and post-tensioning systems under real loading conditions. A total of 129 fatigue and static tensile tests have been performed with variable sizes of anchorages (1 to 55 strands) and prestressing steels. Based on the experimental test results, an improvement of the anchorages was planned. Also long term fatigue tests with up to 50 million load cycles were carried out to investigate the progress of wire failures at a steady rise of the load cycles. The first part of the experimental investigations showed a very high fatigue resistance of galvanized monostrand systems. The tests demonstrated the functional principle of the wedge anchorages at fatigue and static loading conditions and the achieved endurance limits exceeded the requirements according to [Fib05]. Moreover there was no influence of the testing frequency on the fatigue behavior of the systems detectable between 4 and 14 Hz. In the second part of the experimental program the fatigue and static loading behavior of parallel-strand cables were analyzed. Because the majority of the static tensile tests with galvanized strands showed a brittle failure under load levels much lower than the minimum requirements according to [Fib05], a series of intercomparison tests were conducted. 68 tests with 19 different prestressing steels demonstrated the high sensibility of galvanized strands on the deviation during the static tensile tests. In comparison, non-galvanized strands showed no dependence on the bending angle which occurs through the bundling effect of the cables. The long term fatigue behavior of stay-cable systems with 19 strands showed a very high fatigue resistance of the tested components. The major advantage of parallel strand cable systems is the fact that single wire failures, which can always occur for example due to local material defects, have no impact on the fatigue or the static behavior of the surrounding tendons. The PE-coating of the galvanized strands prevents fretting fatigue problems in the touching tendons. In a worst case scenario, a broken wire could damage the other six wires of the same strand but by no means can progressive damage occur in the surrounding strands. In such a case the current parallel strand systems would also allow a replacement of single broken strands. Based on the results of this thesis, the influence of the deviation of galvanized strands on the static loading behavior should be investigated. Residual stresses induced through the manufacturing process of the strands could lead to critical stresses in the bundled strands during the static tensile tests. Nevertheless, the tests confirmed the high fatigue resistance of the galvanized, waxed and PE-coated strands, although the stress range and the load cycles were much higher than the recommended values according to [Fib05].