Structural behavior of symmetric spindle-shaped Tensairity girders with reinforced chord coupling

Two new designs for spindle-shaped Tensairity girders with a reinforced coupling between the chords are proposed. The first one uses a continuous coated-fabric web and the second one a discrete reinforcement composed of 23 steel wire ropes to facilitate the load transfer between the chords. Both girders are studied experimentally and numerically and compared to the original design. A simple analytical model is proposed for the homogeneous load case. Results show that the behavior of the Tensairity girders is significantly improved by the integration of a reinforcement for all tested load configurations. Under homogeneous distributed load at 25 kPa the coupling increases the stiffness and the ultimate load by about a factor 3 and 2, respectively, while the weight of the girder increases due to the fabric web or the cables by only 12% and 29%, respectively. At 50 kPa a live load to dead load ratio of 95 has been achieved, which is twice as much as for the original design.