Experimental Study of the Anti-Slip Capacity of Saddle-Type Pylon-Anchorage for Extra-Dossed Bridges

Extra-dossed bridges, also known as low-pylon, cable-stayed bridges, have been developed and applied widely in recent years. In cable-stayed bridges, pylon-anchorage is critical for reliable connections between the cable and the pylon. For extra-dossed bridges, the pylon cross-section is small and the anchorage zone is limit. Saddle type pylon-anchorage, a new connection type, overcomes the shortcomings. In this study, based on an actual extra-dossed bridge, Nanpanjiang Bridge, a fullscale segment model is cast to test the anti-slip capability of saddle type pylon-anchorage. First, the structural details and model dimensions are illustrated, and a practical formula is derived for the computation of parameter μ, the friction coefficient between the strand and the sub-wire tube. Then, parameter μ is tested based on the cable force passed from jack loading, which indicates the construction stage. Finally, epoxy mortar is poured into the anchor, which is consistent with the normal operation stage of the bridge, and the effect of epoxy mortar is examined to ensure that the anchorage has sufficient anti-slip capacity. The results of the experiment show that during construction, the friction coefficient is between 0.054 and 0.064, and according to the classification loading test, the friction coefficient increases as the cable force increases. After the external anchorage is sealed, the anti-slip capacity is sufficient for operation, and the simplified method of computation can be referenced for similar engineering.